Method and system for diagnosing a variable displacement engine

Abstract

The present disclosure provides "Methods and systems for diagnosing variable displacement engines". Methods and systems are provided for diagnosing a cylinder deactivation mechanism in an engine system having cam actuated valves. Movement of a latch pin coupled to the deactivation mechanism is inferred from induced current generated by a solenoid coupled to the latch pin, and the inferred movement is used to diagnose operation of the cylinder deactivation mechanism. Camshaft timing and crankshaft timing are also estimated using the inferred movement and a profile of the induced current, enabling improved cylinder fuel delivery in the absence of a camshaft sensor.

Description

Technical Field

[0001] This application relates to methods and systems for monitoring the actuation of cylinder valve deactivation mechanisms in variable displacement engines (VDEs). Background Technology

[0002] An engine may include a cam-based system for controlling intake and exhaust valve timing. The cam is coupled to a camshaft. Because the valves control the flow of air and fuel into the engine cylinders for combustion, the position of the camshaft may be necessary to provide accurate fuel delivery and spark timing for reliable combustion and low emissions. For example, precise and timely knowledge of the camshaft position during engine start-up allows for coordination of spark timing and fuel delivery within the engine, resulting in more repeatable engine starts.

[0003] Typically, engine controllers use position sensors coupled to the camshaft to retrieve camshaft position information. However, such sensors are expensive. Furthermore, sensors can degrade easily and therefore may require periodic diagnostics. An exemplary method for estimating camshaft position without relying on camshaft position sensors is shown in US 20170183982 by Hughes et al. In this method, camshaft position information is inferred from the position information of rocker arms coupled to the valve mechanism. For example, rocker arm position information can be collected over the cam cycle.

[0004] However, the inventors of this paper have recognized the potential problems with such methods. As an example, gathering information on the camshaft cycle can lead to delays before accurate fuel injection and spark delivery can be achieved. Furthermore, in Hughes' method, even with camshaft position information, accurate engine fuel injection may be impossible if the engine crankshaft position is unknown. Specifically, the engine controller may rely on the relationship between the camshaft and crankshaft positions to adjust fuel injection timing. During engine start-up, the controller may spend a variable amount of time determining the crankshaft position based on the output of the crankshaft position sensor. This time may vary based on engine speed, ambient temperature, and the crankshaft's starting position. Alternatively, the crankshaft position sensor may be degraded. For example, the crankshaft position sensor may output a signal corresponding to the presence or absence of teeth on a gear rotating with the crankshaft. If the gear is damaged, the crankshaft position sensor's output may be unreliable. As another example, if the crankshaft position sensor is poorly installed, the signal-to-noise ratio may be reduced. As yet another example, the crankshaft position sensor's output may be degraded due to loose electrical connections. In either case, without crankshaft information, it may be impossible to set the fuel injection timing correctly. Summary of the Invention

[0005] In one example, the problem described above can be addressed by a method for an engine, the method comprising: actuating an electronic latch pin of a cylinder valve deactivation mechanism coupled to a cam-actuated cylinder valve via a solenoid; and estimating camshaft timing based on inferred latch pin movement during said actuation. In this manner, the camshaft position can be accurately determined with reduced reliance on information from camshaft or crankshaft position sensors.

[0006] As an example, an engine system may include a cylinder having valves that can be selectively deactivated via a cylinder deactivation mechanism, the cylinder deactivation mechanism including a latch pin mounted on a rocker arm assembly. Before fuel is added to the engine cylinder, the position of the camshaft connected to the cylinder valve can be determined by an engine controller that applies a voltage pulse to excite a solenoid coupled to the latch pin. The polarity of the voltage during excitation is used to change the state of the latch pin in a specific manner. For example, if the latch pin is engaged with the rocker arm assembly, then the excitation of the solenoid using a first polarity will move the latch pin out of the rocker arm assembly, thereby deactivating the corresponding cylinder valve. Alternatively, if the latch pin is disengaged from the rocker arm assembly, then the excitation of the solenoid using a second polarity will move the latch pin into the rocker arm assembly, thereby restarting the corresponding cylinder valve. The movement of the latch pin between the engaged and disengaged positions during the actuation of the latch pin can be inferred based on measured current characteristics of the solenoid, including the number and (relative) positions of peaks and troughs, as well as the slope of the current. For example, the presence of latch pin movement can be inferred from characteristics including a brief decrease in current (e.g., a decrease to a trough) after voltage application (e.g., a change in the current slope). When the associated intake cam is on its cam lobe and the intake valve rocker arm is loaded, the intake valve latch pin cannot move during the intake stroke. Similarly, when the associated exhaust cam is on its cam lobe and the exhaust valve rocker arm is loaded, the exhaust valve latch pin cannot move during the exhaust stroke. Therefore, the piston stroke of the cylinder can be inferred based on the presence or absence of latch pin movement after the actuation of the solenoid. For example, in response to exhaust latch pin movement after the actuation, it can be inferred that the piston of the cylinder is not in the exhaust stroke. In contrast, if no exhaust latch pin movement occurs after the excitation, it can be inferred that the cylinder piston is in the exhaust stroke. Camshaft timing can then be determined based on the piston stroke and crankshaft information. The crankshaft information may include sensed information retrieved from a crankshaft position sensor. Alternatively, current characteristics and latch pin movement can also be used to infer crankshaft position information.

[0007] In this way, by correlating the current characteristics of the solenoid with the movement of the latch pin, the cylinder piston position can be reliably determined. The cylinder piston position information can then be correlated with crankshaft position information to accurately estimate the camshaft position while reducing the need for a dedicated camshaft position sensor. Alternatively, camshaft position information based on latch pin movement can be used to validate the output of an existing camshaft position sensor. The advantage of actuating the latch pin and monitoring its movement is that the relationship between the latch pin movement and the position of the cam relative to its base circle and cam angle can be fully utilized to estimate the camshaft position information. By accurately estimating the camshaft position, the timing of cylinder fuel delivery can be optimized, thereby improving engine combustion torque generation. Therefore, engine startability is improved.

[0008] It should be understood that the above summary is provided to introduce, in a simplified form, a series of concepts further described in the detailed description. This is not intended to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any of the shortcomings described above or in any part of this disclosure. Attached Figure Description

[0009] Figure 1 A schematic depiction of the vehicle's engine system is shown.

[0010] Figures 2A to 2D An electrically operated latching rocker arm mechanism that can be included in a valve deactivation mechanism is shown.

[0011] Figure 3 It is a table that summarizes the relationship between cam timing, latch pin position, valve status, and latch pin movement capability.

[0012] Figure 4 A high-level flowchart is shown for an exemplary method of controlling cylinder valve operation during operation of a variable displacement engine.

[0013] Figure 5 A flowchart illustrates an exemplary method for deactivating and reactivating cylinder intake and exhaust valves using an electrically latched rocker arm mechanism during transition to and from VDE operating mode.

[0014] Figures 6A to 6B A flowchart is shown of an exemplary method for diagnosing an electrically operated latch rocker arm mechanism when a change in the operating state of a command-corresponding valve is made.

[0015] Figure 7 A flowchart is shown of an exemplary method for diagnosing an electrically latched rocker arm mechanism during low-speed conditions when the operating state of the corresponding valve is not commanded to change.

[0016] Figure 8 An exemplary graph illustrating the engine signals generated when the crankshaft is rotated.

[0017] Figure 9 A flowchart illustrates an exemplary method for determining the camshaft position via an electrically latched rocker arm mechanism when the crankshaft position is known.

[0018] Figure 10 A flowchart is shown for an exemplary method of determining the crankshaft position and camshaft position via an electrically latched rocker arm mechanism.

[0019] Figure 11 A illustrative example depicting the setting of the cylinder intake valves to the desired state during engine start-up without camshaft position information.

[0020] Figure 12 A illustrative example is depicted using an electrically latched rocker arm mechanism to switch the engine to VDE operating mode and to switch from VDE operating mode, and to diagnose the electrically latched rocker arm mechanism during the switch.

[0021] Figure 13 A illustrative example of diagnosing an electric latch rocker arm mechanism under low engine speed conditions is depicted.

[0022] Figure 14 A illustrative example depicting the determination of the camshaft position via an electrically latched rocker arm mechanism when the crankshaft position is known.

[0023] Figure 15 A preliminary example is depicted using the output of an electric latch rocker arm mechanism and a crankshaft position sensor to determine both the crankshaft position and the camshaft position. Detailed Implementation

[0024] The following description relates to the control of an engine (e.g., Figure 1 A system and method for a cylinder valve deactivation mechanism in an engine system. The cylinder valve deactivation mechanism may include an electrically operated latching rocker arm mechanism, for example in... Figures 2A to 2D The electrically operated latching rocker arm mechanism is depicted. For example, by actuating the latch pin of the valve deactivation mechanism between an engaged and disengaged position via an actuated associated solenoid, the corresponding cylinder valve can be switched between an active and deactivated state, as in... Figure 3 As summarized in the table. For example, according to... Figure 4 Methods and about Figure 11 It is explained that the latch pin position can be changed during engine start-up or shutdown, and thus the valve state can be changed, and for example according to Figure 5The method allows for changing the latch pin position and thus the valve state during transitions to and from variable displacement engine (VDE) operating modes. However, the latch pin can only move when the rocker arm is unloaded, for example, when the corresponding cam is engaged with the cam follower while the cam is on its base circle. Furthermore, the movement of the latch pin can be detected based on the sensing characteristics of the associated solenoid during excitation. For example, according to... Figures 6A to 6B as well as Figure 7 The method and as about Figure 12 and Figure 13 To illustrate, deterioration of the cylinder valve deactivation mechanism can be detected based on the movement (or absence) of the latch pin during excitation and the cam position. Furthermore, for example, according to... Figure 9 and Figure 10 The method and as about Figure 14 and Figure 15 To illustrate, the movement (or absence) of the latching pin during solenoid excitation can be correlated with engine signals (e.g., in...). Figure 8 The engine signals described herein are combined to determine the camshaft position and / or crankshaft position. In this way, the electrically latched rocker arm mechanism enables precise control of valve deactivation when desired valve conditions change, using valve deactivation to determine or confirm crankshaft and / or camshaft positions, and to diagnose deterioration.

[0025] Now turn to the diagram. Figure 1 An example of a cylinder 14 of an internal combustion engine 10 that may be included in a vehicle 5 is depicted. Engine 10 may be a variable displacement engine (VDE), as further described below. Engine 10 may be controlled at least in part by a control system including controller 12 and inputs from a vehicle operator 130 via input device 132. In this example, input device 132 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. The cylinder 14 of engine 10 (also referred to herein as a “combustion chamber”) may include a combustion chamber wall 136 and a piston 138 positioned therein. Piston 138 may be coupled to crankshaft 140 such that the reciprocating motion of the piston is converted into rotational motion of the crankshaft. Crankshaft 140 may be coupled to at least one wheel 55 of vehicle 5 via transmission 54, as further described below. Furthermore, a starter motor (not shown) may be coupled to crankshaft 140 via a flywheel to enable starting operation of engine 10.

[0026] In some examples, vehicle 5 may be a hybrid vehicle having multiple torque sources available for one or more vehicle wheels 55. In other examples, vehicle 5 is a conventional vehicle with only an engine. In the example shown, vehicle 5 includes an engine 10 and an electric motor 52. The electric motor 52 may be a motor or a motor / generator. When one or more clutches 56 are engaged, the crankshaft 140 of engine 10 and the electric motor 52 are connected to the wheels 55 via a transmission 54. In the depicted example, a first clutch 56 is provided between the crankshaft 140 and the electric motor 52, and a second clutch 56 is provided between the electric motor 52 and the transmission 54. Controller 12 may send signals to the actuator of each clutch 56 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 140 from the electric motor 52 and components connected to said electric motor, and / or connecting or disconnecting the electric motor 52 from the transmission 54 and components connected to said transmission. The transmission 54 may be a gearbox, a planetary gear system, or another type of transmission.

[0027] The powertrain can be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle. In an electric vehicle implementation, the system battery 58 may be a traction battery that delivers electricity to the motor 52 to provide torque to the vehicle wheels 55. In some implementations, the motor 52 may also operate as a generator, for example, during braking operations, to provide electricity to charge the system battery 58. It will be understood that in other implementations, including non-electric vehicle implementations, the system battery 58 may be a typical starter, lighting, ignition (SLI) battery coupled to the alternator 46.

[0028] Alternator 46 can be configured to charge system battery 58 using engine torque via crankshaft 140 during engine operation. Additionally, alternator 46 can supply power to one or more electrical systems of the engine, such as one or more auxiliary systems including heating, ventilation, and air conditioning (HVAC) systems, lighting, in-vehicle entertainment systems, and other auxiliary systems based on their corresponding electrical needs. In one example, the current drawn from the alternator can vary based on operator cabin cooling needs, battery charging requirements, other auxiliary vehicle system needs, and motor torque. A voltage regulator can be coupled to alternator 46 to adjust the alternator's power output based on system usage requirements, including auxiliary system needs.

[0029] Cylinder 14 of engine 10 can receive intake air via a series of intake ports 142 and 144 and an intake manifold 146. Intake manifold 146 can communicate with other cylinders of engine 10 besides cylinder 14. One or more of the intake ports may include one or more supercharging devices, such as turbochargers or superchargers. For example, Figure 1 An engine 10 is shown equipped with a turbocharger, which includes a compressor 174 disposed between intake manifolds 142 and 144, and an exhaust turbine 176 disposed along an exhaust manifold 135. When the supercharging device is configured as a turbocharger, the compressor 174 may be at least partially powered by the exhaust turbine 176 via a shaft 180. However, in other examples, such as when the engine 10 has a mechanical supercharger, power may be supplied to the compressor 174 via mechanical input from a motor or the engine, and the exhaust turbine 176 may optionally be omitted. In other examples, the engine 10 may have an electromechanical supercharger (e.g., an "eBooster"), and the compressor 174 may be driven by an electric motor. In other examples, the engine 10 may not have a supercharging device, for example, when the engine 10 is a naturally aspirated engine.

[0030] A throttle valve 162, including a throttle plate 164, can be provided in the engine intake manifold to change the flow rate and / or pressure of the intake air supplied to the engine cylinders. For example, the throttle valve 162 can be located downstream of the compressor 174, such as... Figure 1 As shown, or alternatively, the throttle valve may be provided upstream of the compressor 174. The position of the throttle valve 162 may be transmitted to the controller 12 via a signal TP from the throttle valve position sensor.

[0031] Exhaust manifold 148 can receive exhaust gas from cylinders of engine 10 other than cylinder 14. Exhaust sensor 126 is shown coupled upstream of emission control device 178 to exhaust manifold 148. Exhaust sensor 126 can be selected from various suitable sensors for providing an indication of exhaust / fuel ratio (AFR), such as linear oxygen sensor or UEGO (universal or wide-range exhaust oxygen), two-state oxygen sensor or EGO, HEGO (heated EGO), NOx, HC, or CO sensor. Figure 1 In the example, exhaust sensor 126 is a UEGO sensor. Emission control device 178 can be a three-way catalytic converter, a NOx trap, various other emission control devices, or a combination thereof. Figure 1 In the example, emission control device 178 is a three-way catalyst.

[0032] Each cylinder of engine 10 may include one or more intake valves and one or more exhaust valves. For example, cylinder 14 is shown as including at least one intake lift valve and at least one exhaust lift valve located in the upper region of cylinder 14. In some examples, each cylinder of engine 10, including cylinder 14, may include at least two intake lift valves and at least two exhaust lift valves located in the upper region of said cylinder. In this example, intake valve 150 may be controlled by controller 12 via cam actuation via cam actuation system 152, said cam actuation system including one or more cams 151. Similarly, exhaust valve 156 may be controlled by controller 12 via cam actuation system 154 including one or more cams 153. The positions of intake valve 150 and exhaust valve 156 may be determined by valve position sensors (not shown) and / or camshaft position sensors 155 and 157, respectively. In other examples, camshaft position sensors 155 and 157 may be omitted, as per [reference to...]. Figure 9 and Figure 10 Further description.

[0033] During certain conditions, controller 12 can change the signals provided to cam actuation systems 152 and 154 to control the opening and closing of the corresponding intake and exhaust valves. Intake and exhaust valve timing can be controlled simultaneously, or any of the following possibilities can be used: variable intake cam timing, variable exhaust cam timing, dual independent variable cam timing, or fixed cam timing. Each cam actuation system may include one or more cams and may utilize one or more of a variable displacement engine (VDE), cam profile changing (CPS) system, variable cam timing (VCT) system, variable valve timing (VVT) system, and / or variable valve lift (VVL) system, which controller 12 can operate to change valve operation. In alternative embodiments, intake valve 150 and / or exhaust valve 156 may be controlled by electric valve actuation. For example, cylinder 14 may alternatively include an intake valve controlled by electric valve actuation and an exhaust valve controlled by cam actuation including a CPS system and / or a VCT system. In other examples, the intake and exhaust valves can be controlled by a common valve actuator (or actuation system) or a variable valve timing actuator (or actuation system).

[0034] As further described herein, intake valve 150 and exhaust valve 156 can be deactivated via an electrically actuated rocker arm mechanism during VDE mode. (The remaining text appears to be unrelated and likely refers to further details about the VDE mode.) Figures 2A to 2DExamples of such systems are described below. In another example, intake valve 150 and exhaust valve 156 can be deactivated via a CPS mechanism, where a cam lobe without lift is used for the deactivated valve. Alternatively, other valve deactivation mechanisms can still be used, for example, for electrically actuated valves. In one embodiment, the deactivation of intake valve 150 can be controlled by a first VDE actuator (e.g., a first electrically actuated rocker arm mechanism coupled to intake valve 150), while the deactivation of exhaust valve 156 can be controlled by a second VDE actuator (e.g., a second electrically actuated rocker arm mechanism coupled to exhaust valve 156). In an alternative embodiment, a single VDE actuator can control the deactivation of both the intake and exhaust valves of a cylinder. In other embodiments, a single cylinder valve actuator deactivates multiple cylinders (both intake and exhaust valves), such as all cylinders in an engine assembly, or different actuators can control the deactivation of all intake valves of the deactivated cylinders, while another different actuator controls the deactivation of all exhaust valves of the deactivated cylinders. It will be understood that if the cylinder is a non-disabled cylinder of a VDE engine, then the cylinder may not have any valve deactivation actuator.

[0035] Cylinder 14 may have a compression ratio, which is the ratio of the volume of the cylinder at bottom dead center (BDC) to top dead center (TDC) of piston 138. In one example, the compression ratio is in the range of 9:1 to 10:1. However, in some examples where different fuels are used, the compression ratio may be increased. This may occur, for example, when using higher octane fuels or fuels with higher latent enthalpy of vaporization. If direct injection is used, the compression ratio may also be increased due to the effect of direct injection on engine knock.

[0036] Each cylinder of engine 10 may include a spark plug 192 for initiating combustion. Ignition system 190 can provide an ignition spark to combustion chamber 14 via spark plug 192 in response to a spark advance signal SA from controller 12 in a selected operating mode. The timing of signal SA can be adjusted based on engine operating conditions and drive torque requirements. For example, a spark can be provided at maximum braking torque (MBT) timing to maximize engine power and efficiency. Controller 12 can input engine operating conditions, including engine speed, engine load, and exhaust AFR, into a lookup table and output the corresponding MBT timing for the input engine operating conditions. In other examples, the spark can be delayed from the MBT to accelerate catalyst warm-up during engine start-up or reduce the incidence of engine knock.

[0037] In some examples, each cylinder of engine 10 may be configured with one or more fuel injectors for supplying fuel thereto. As a non-limiting example, cylinder 14 is shown as including fuel injector 166. Fuel injector 166 may be configured to deliver fuel received from fuel system 8. Fuel system 8 may include one or more fuel tanks, fuel pumps, and fuel rails. Fuel injector 166 is shown directly coupled to cylinder 14 to directly inject fuel into the cylinder in proportion to the pulse width of the signal FPW received from controller 12 via electronic actuator 168. In this manner, fuel injector 166 provides what is considered a fuel injector that directly injects fuel (hereinafter also referred to as "DI") into cylinder 14. Although Figure 1 A fuel injector 166 is shown positioned on one side of cylinder 14, but the fuel injector 166 can alternatively be positioned on top of the piston, for example, near the location of spark plug 192. When operating the engine with alcohol-based fuels, such a location can increase mixing and combustion due to the lower volatility of some alcohol-based fuels. Alternatively, the injector can be positioned on and near the intake valve head to increase mixing. Fuel can be delivered from the fuel tank of fuel system 8 to the fuel injector 166 via a high-pressure fuel pump and fuel rail. Furthermore, the fuel tank may have a pressure transducer that provides a signal to controller 12.

[0038] In an alternative example, according to one configuration, the fuel injector 166 may be arranged in the intake manifold rather than directly coupled to the cylinder 14, providing a configuration referred to as port fuel injection (hereinafter also referred to as "PFI") into the intake manifold upstream of the cylinder 14. In other examples, the cylinder 14 may include multiple injectors, which may be configured as direct fuel injectors, port fuel injectors, or combinations thereof. Therefore, it should be understood that the fuel system described herein should not be limited to the specific fuel injector configurations exemplified herein.

[0039] Fuel injector 166 can be configured to receive different relative amounts of different fuels as fuel mixtures from fuel system 8, and further configured to inject this fuel mixture directly into the cylinder. Furthermore, fuel can be delivered to cylinder 14 during different strokes of a single cycle of the cylinder. For example, directly injected fuel can be delivered at least partially during the previous exhaust stroke, during the intake stroke, and / or during the compression stroke. Thus, for a single combustion event, one or more fuel injections can be performed in each cycle. These multiple injections can be performed during the compression stroke, intake stroke, or any suitable combination thereof, in a process known as split fuel injection.

[0040] The fuel tank in fuel system 8 can hold fuels of different types, such as fuels with different fuel masses and different fuel compositions. These differences can include different alcohol contents, different water content, different octane ratings, different heats of vaporization, different blends, and / or combinations thereof. An example of fuels with different heats of vaporization includes gasoline as a first fuel type with a lower heat of vaporization and ethanol as a second fuel type with a higher heat of vaporization. In another example, the engine can use gasoline as the first fuel type and a blend containing alcohol (e.g., E85 (approximately 85% ethanol and 15% gasoline) or M85 (approximately 85% methanol and 15% gasoline)) as the second fuel type. Other feasible substances include water, methanol, mixtures of alcohol and water, mixtures of water and methanol, and mixtures of alcohols. In another example, both fuels can be alcohol mixtures with different alcohol compositions. The first fuel type can be a gasoline-ethanol mixture with a lower alcohol concentration, such as E10 (which contains approximately 10% ethanol), while the second fuel type can be a gasoline-ethanol mixture with a higher alcohol concentration, such as E85 (which contains approximately 85% ethanol). Furthermore, the first and second fuels can also differ in other fuel qualities, such as temperature, viscosity, octane number, etc. Additionally, the fuel characteristics of one or both fuel tanks may vary frequently due to daily changes in fuel tank refilling.

[0041] Controller 12 in Figure 1The image shows a microcomputer, which includes a microprocessor unit 106, an input / output port 108, an electronic storage medium for executable programs (e.g., executable instructions) and calibration values, shown in this particular example as a non-transitory read-only memory chip 110, a random access memory 112, a non-fail-out memory 114, and a data bus. The controller 12 can receive various signals from sensors connected to the engine 10, including the signals previously discussed, and additionally including the measurement result of the intake mass airflow (MAF) from the mass airflow sensor 122; the engine coolant temperature (ECT) from the temperature sensor 116 connected to the cooling sleeve 118; the exhaust temperature from the temperature sensor 158 connected to the exhaust manifold 135; the surface ignition sensing signal (PIP) from the Hall effect sensor 120 (or other type) connected to the crankshaft 140; the throttle position (TP) from the throttle position sensor; the UEGO signal from the exhaust sensor 126, which the controller 12 can use to determine the exhaust airflow rate (AFR); and the absolute manifold pressure signal (MAP) from the MAP sensor 124. The controller 12 can generate an engine speed signal (RPM) from the PIP signal. The manifold pressure signal (MAP) from the MAP sensor 124 can be used to provide an indication of vacuum or pressure in the intake manifold. The controller 12 can infer the engine temperature based on the engine coolant temperature and infer the temperature of the emission control device 178 based on the signal received from the temperature sensor 158.

[0042] The Hall effect sensor 120 can be configured as a crankshaft position sensor. For example, the Hall effect sensor 120 can be configured to monitor a gear rotating with the crankshaft 140, the gear having teeth positioned in equal angular increments (e.g., 6 degrees). Whenever a tooth passes, the voltage output of the Hall effect sensor 120 can switch from a near-zero voltage (off) to the maximum voltage in a square wave (on), as per [reference to...]. Figure 8 The output of Hall effect sensor 120 enables controller 12 to determine the relative angle of crankshaft 140 as it rotates. Typically, one or more missing teeth are present at defined positions on the gears. These missing teeth may be aligned with a specific crankshaft position, such as top dead center (TDC) of cylinder 1. The absolute position of crankshaft 140 can be known after the missing teeth have passed through Hall effect sensor 120 during the initial time of an engine start-up event. Before that time, controller 12 can detect changes in position and crankshaft speed based on the output of Hall effect sensor 120, but cannot determine the absolute position of the crankshaft. The orientation of the crankshaft may change before engine start-up, and therefore the angular rotation of the crankshaft before the missing teeth are observed.

[0043] Controller 12 from Figure 1 Various sensors receive signals and employ Figure 1 The various actuators adjust engine operation based on received signals and instructions stored in the controller's memory. For example, the controller can deactivate selected cylinders by actuating the valve actuators to switch the engine to VDE mode operation, as per the description of... Figure 5 Further description.

[0044] As described above, Figure 1 Only one cylinder of a multi-cylinder engine is shown. Therefore, each cylinder can similarly include its own set of intake / exhaust valves, fuel injectors, spark plugs, etc. It will be understood that engine 10 can include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders. Furthermore, each of these cylinders can include components manufactured by… Figure 1 Some or all of the various components described and depicted with reference to cylinder 14.

[0045] During selected conditions, such as when the full torque capability of engine 10 is not requested, controller 12 can selectively deactivate either the first or second cylinder bank (also referred to herein as VDE operating mode). During the VDE mode, cylinders in the selected cylinder bank can be deactivated by closing the corresponding fuel injector 166 and deactivating the corresponding intake and exhaust valves 150 and 156. While the fuel injectors of the deactivated cylinders are closed, the remaining active cylinders continue to burn with their corresponding fuel injectors and intake and exhaust valves active and operating. To meet the total engine torque requirement, the engine produces a greater amount of torque in each of the remaining active cylinders than in all the cylinders burning. This requires higher manifold pressure, resulting in reduced pumping losses and increased engine efficiency. Additionally, the lower effective surface area exposed to combustion (from the active cylinders only) reduces engine heat loss, thereby increasing engine thermal efficiency.

[0046] Turn now Figures 2A to 2D This shows a cross-sectional side view of the valve mechanism 200. The valve mechanism 200 can control the engine (e.g., Figure 1 The intake and exhaust valves in engine 10) are operated. Therefore, Figure 1 and Figures 2A to 2D The same parts are numbered the same and need not be described again. Specifically, in Figures 2A to 2DThe view shown depicts an electrically latched (also referred to herein as "e-latch") rocker arm mechanism 202 included in the valve mechanism 200 for operating and deactivating the intake valve 150 of one cylinder of the engine. While the valve mechanism 200 will be described with respect to operating the intake valve 150, the description is not limited to operating the intake valve 150. For example, similar operations can be performed... Figure 1 The exhaust valve 156 and any other engine intake and / or exhaust valves.

[0047] The e-latch rocker arm mechanism 202 transmits information about the radius of the cam 151's lobes as linear movement of the intake valve 150. For example, based on the lift profile of the cam 151, the e-latch rocker arm mechanism 202 lifts the intake valve 150 from the valve seat 230 to selectively open and close the intake passage 236 of the combustion chamber 14 defined in the cylinder head 240. The e-latch rocker arm mechanism 202 includes an inner arm 204 and an outer arm 206. A cam follower 208 can be mounted to the inner arm 204 via bearings and a rocker arm shaft 210. The cam follower 208 is configured to engage the cam 151 as the cam follower rotates via the camshaft 201. The cam follower 208 is shown as a roller follower (e.g., a switching roller finger follower, SRFF), but may alternatively be any other type of cam follower, such as a slider. Cam 151 includes a base circle 151a (shaded area) and a cam angle 151b (unshaded area), wherein the radius between the periphery of cam 151 and the center of camshaft 201 is variable and larger than the radius of base circle 151a. When cam follower 208 engages cam 151 on base circle 151a, intake valve 150 is closed (e.g., not lifted). When cam follower 208 engages cam 151 on cam angle 151b, intake valve 150 is lifted from valve seat 230, as further described below. The position on cam angle 151b is referred to herein as lift.

[0048] A latching pin 214 mounted in the outer arm 206 can engage the lip 218 of the inner arm 204, thereafter restricting the inner arm 204 and outer arm 206 to uniform movement. A valve clearance adjuster 220 can engage the outer arm 206 and provide a fulcrum, about which the inner arm 204 and outer arm 206 pivot together as a unit when the latching pin 214 is engaged. The latching pin 214 can be positioned as follows: Figure 2A and Figure 2C The engagement position shown (also referred to as the active position or latching position) is similar to... Figure 2B and Figure 2DThe latch pin 214 is translated between the disengaged position (also referred to as the deactivated position or unlocked position) shown. In the disengaged position, the latch pin 214 no longer engages (e.g., contacts) the lip 218 of the inner arm 204, thereby disengaging the inner arm 204 from the outer arm 206. When the latch pin 214 is in the engaged position, the intake valve 150 can be considered to be in an operational (e.g., active) state. When the latch pin 214 is in the disengaged position, the intake valve 150 can be considered to be deactivated, as further described below. The latch pin 214 can be switched between the engaged (latched) position and the disengaged (unlocked) position via actuation of the solenoid 216. The solenoid 216 can be an electromagnetic solenoid actuator with a coil that can generate a magnetic force when excited by an electric current. Furthermore, the latch pin 214 can include a magnetic material that can be moved by a change in the magnetic field. For example, the latch pin can at least partially comprise iron. Therefore, the latch pin 214 and the solenoid 216 can be considered as part of the cylinder valve deactivation mechanism 252.

[0049] exist Figures 2A to 2D In the example, the latching mechanism is bistable, so that no holding current is required to maintain the latch pin 214 in the engaged or disengaged position. For example, the controller 12 can provide a short voltage pulse of first polarity to energize the solenoid 216 to disengage the latch pin 214 from the engaged position (in the first position). Figure 2A (as shown in the image) Move to the disengaged position (in the image) Figure 2B (As shown in the diagram). This action can also be referred to as unlocking the latch pin. The latch pin 214 can be held in the disengaged position by an integrated permanent magnet. Similarly, a short voltage pulse of a second polarity opposite to the first polarity can be applied to excite the solenoid 216 to unlock the latch pin 214 from the disengaged position (as shown in the diagram). Figure 2B (as shown in the image) Move to the engagement position (in Figure 2A (As shown in the figure), the latch pin 214 can be held by different integrated permanent magnets. This action can also be referred to as latching the latch pin. In some examples, one or more travel stops may be included to prevent the latch pin 214 from moving past the disengaged position and / or the engaged position.

[0050] For example, when solenoid 216 is energized, as the solenoid current begins to rise, the inductance of the solenoid circuit generates a magnetic force that causes the latch pin 214 to move. The generated magnetic force is related to... Proportional, of which I It is the current flowing into the coil and gThis is the air gap between latch pin 214 and the magnet. As the speed of latch pin 214 increases, a back (e.g., reverse) electromotive force (EMF) is generated in the solenoid circuit. The reverse EMF produces a voltage opposite to the applied voltage and is proportional to the speed of latch pin 214. Therefore, the current in the solenoid circuit decreases as latch pin 214 moves. Once latch pin 214 reaches the end of its journey, the movement stops, and the reverse EMF also stops, resulting in a "valley" (e.g., a local minimum) in the solenoid current signal. In some examples, a permanent magnet can be added to generate flux to hold the latch pin in place after latch pin 214 has moved to the magnet. Because the reverse EMF from the movement of the latch pin causes a decrease in the solenoid current (referred to as the inductive characteristic), the movement of latch pin 214 can be inferred based on the inductive characteristic (also referred to herein as the current characteristic) of solenoid 216 during actuation.

[0051] In an alternative example, the latching mechanism can be monostable, wherein the latch pin 214 is held in the engaged position by one or more springs and in the disengaged position by an integrated permanent magnet. For example, by supplying a higher current to the solenoid 216, the latch pin 214 can be moved to the disengaged position, after which the current can be reduced to a holding current. The latch pin 214 can then be returned to the engaged position via one or more springs by de-energizing the solenoid 216. As further described herein, the movement of the latch pin 214 between the engaged and disengaged positions may be limited when the cam 151 is on the base circle (e.g., ...). Figure 2A and Figure 2B (as shown in the image).

[0052] like Figure 2C As shown, when the latch pin 214 engages with the lip 218 and the cam 151 rises from the base circle 151a to the cam angle 151b, the outer arm 206 pivots against the valve clearance adjuster 220, while the inner arm 204 presses down on the valve stem 234 via the elephant foot 224, thereby compressing the valve spring 226 against the cylinder head 240. Therefore, the intake valve 150 is lifted away from the valve seat 230. The valve lift profile is determined by the shape of the cam 151 (e.g., the shape of the cam angle 151b) and varies with the angular position of the camshaft 201. When the cam 151 returns to the base circle 151a, the valve spring 226 pushes the valve stem 234 against the elephant foot 224, causing the inner arm 204 to rise, the outer arm 206 to rise, and the intake valve 150 to close, as... Figure 2A As shown in the image.

[0053] In contrast, when the latch pin 214 disengages from the lip 218 and the cam 151 rises from the base circle 151a to the convex angle 151b, the cam 151 drives the inner arm 204 downwards via the cam follower 208, as... Figure 2DAs shown in the diagram. For example, cam 151 can be in or near its maximum lift position. When the outer arm 206 remains stationary, the inner arm 204 does not compress the valve spring 226, but instead pivots about the shaft 222, thereby decoupling the inner arm 204 from the cam follower 208. The intake valve 150 remains against the valve seat 230, and the intake passage 236 of the cylinder 14 remains closed. When cam 151 returns to the base circle 151a, the inner arm 204 can be pivoted back to its starting position (e.g., in) via a freewheeling spring (not shown). Figure 2B (as shown in the diagram). The idler spring can be a coil spring, a torsion spring, or any suitable means for ensuring that the inner arm returns to a position where the lip 218 is above the edge of the latch pin 214 so that the latch pin can move unimpeded to the latched position. The intake valve 150 is deactivated even when the cam 151 is on the convex angle 151b and has lift, by actuating the latch pin 214 to the disengaged position.

[0054] Figures 2A to 2D Exemplary configurations with relative positioning of various components are shown. In at least one example, if shown as being in direct contact or direct coupling with each other, such components may be referred to as being in direct contact or direct coupling, respectively. Similarly, in at least one example, components shown as being adjacent to or next to each other may be referred to as being adjacent to or next to each other, respectively. For example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. As another example, in at least one example, components positioned apart from each other with only space between them and no other components may be classified as such. As another example, components shown as being above / below each other, on opposite sides of each other, or to the left / right of each other may therefore be referred to relative to each other. Furthermore, as shown in the figures, in at least one example, the topmost element or point of the component may be referred to as the “top” of the component, and the bottommost element or point of the component may be referred to as the “bottom” of the component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the figure and used to describe the positioning of the components of the figure relative to each other. Thus, in one example, an element shown as being above other components is positioned vertically above other components. As another example, the shape of an element depicted in a figure can be described as having those shapes (e.g., circular, straight, flat, curved, rounded, chamfered, angled, etc.). Furthermore, in at least one example, elements shown as intersecting each other can be described as intersecting elements or intersecting each other. Additionally, in one example, an element shown as being inside another element or shown as being outside another element can be referred to as such.

[0055] Turning Figure 3Table 300 illustrates the relationship between cam timing, latch pin position, valve state, and latch pin movement capability. The engine controller can fully utilize the relationships depicted in Table 300 to accurately and reliably diagnose the cylinder valve deactivation mechanism.

[0056] As indicated at 302-304, when the cam position is at the base circle (e.g., as... Figures 2A to 2B When the base circle 151a shown is rotated, that is, when the cam is rotated so that the corresponding cam follower (e.g., Figures 2A to 2D When the cam follower 208 engages with the base circle of the cam, the latch pin can move. That is, if the latch pin is actuated by energizing the corresponding solenoid, it can be latched into the engaged position (line 302) or unlocked into the disengaged position (line 304). When the latch pin is engaged, the corresponding cylinder valve is active, and the valve will draw air through the cylinder when lifted. Therefore, the corresponding cylinder is active, and if all engine cylinders are active, the engine is in non-VDE mode. In contrast, when the latch pin is disengaged, the corresponding cylinder valve is deactivated, and the valve will remain closed and will not draw air through the cylinder. Therefore, the corresponding cylinder is deactivated, and the engine is in VDE mode. See reference... Figures 4 to 7 as well as Figures 9 to 10 As described, the engine controller can monitor latch pin movement when the latch pin is latched or unlocked (e.g., actuated between an engaged and disengaged position). Latch pin movement can be inferred based on the associated solenoid current characteristics. If no latch pin movement is detected when the latch pin is actuated with the cam in the base circle position, it can be inferred that the cylinder valve deactivation mechanism has deteriorated. Specifically, it can be inferred that the latch pin cannot move due to a temporary or permanent fault, such as a hydraulic clearance adjuster pumped to the top, preventing the unlocked pin from re-engaging the inner arm, or a permanent fault, such as a latch pin that has become stuck due to contamination between the outer arm (e.g., the outer arm pin bore) and the latch pin.

[0057] As indicated at 306-308, when the cam position is in the convex position (e.g., as... Figures 2C to 2DWhen the convex angle 151b is shown, that is, when the cam follower engages with the cam away from the base circle, the latch pin cannot move. In other words, if the latch pin is actuated by energizing the corresponding solenoid when it is in the engaged position, the latch pin cannot be unlocked to the disengaged position because the load from the inner arm on the latch pin creates friction that the force of the solenoid cannot overcome (line 306). Similarly, if the latch pin is actuated by energizing the corresponding solenoid when it is in the disengaged position, the latch pin cannot be latched to the engaged position because the pin will stop due to the lip of the inner arm striking the top of the latch pin (line 308). When the latch pin is engaged, the corresponding cylinder valve is active, and the valve draws air through the cylinder. Therefore, the corresponding cylinder is active, and if all engine cylinders are active, the engine is in non-VDE mode. In contrast, when the latch pin is disengaged, the corresponding cylinder valve is deactivated, and the valve does not draw air through the cylinder. Therefore, the corresponding cylinder is deactivated, and the engine enters VDE mode. (See reference...) Figures 4 to 7 as well as Figures 9 to 10 As described, the engine controller can monitor latch pin movement when the latch pin is engaged or disengaged. Latch pin movement can be inferred based on the current characteristics of the associated solenoid. If latch pin movement is detected when the corresponding solenoid is energized while the cam is in the camshaft position, then it can be inferred that the cylinder valve deactivation mechanism has deteriorated. Specifically, it can be inferred that the latch pin has moved due to a broken camshaft (e.g., low oil pressure) or a worn camshaft. In one example, it can be inferred that the latch pin moved because the cam was still in the base circle position even when it was expected to be in the camshaft position, due to wear on the camshaft.

[0058] Next, Figure 4 This illustrates the control of the VDE engine (e.g., in...). Figure 1 An exemplary method 400 for operating the engine 10) shown in the figure, the VDE engine including Figures 2A to 2D The valve deactivation mechanism shown herein (e.g., valve deactivation mechanism 252) allows the cylinder intake and exhaust valves to be placed in a desired state (e.g., active or deactivated) even when the camshaft position is unknown and / or the current valve state is unknown. Different valve activation and deactivation modes can, for example, induce the engine to start and deactivate by minimizing the cylinder air springs, respectively. Instructions for implementing method 400 and the remainder of the methods included herein can be provided by a controller (e.g., Figure 1 The controller 12) executes based on instructions stored in the controller's memory and in conjunction with signals received from sensors in the engine system, such as those referenced above. Figure 1The sensor described. The controller can employ an engine actuator of the engine system, such as an e-latch rocker arm solenoid (e.g., according to the method described below). Figures 2A to 2D The solenoid 216 is used to adjust engine operation.

[0059] Method 400 begins at 402 and includes estimating and / or measuring engine operating conditions. These engine operating conditions may include, for example, engine speed, engine load, torque demand, engine temperature, exhaust temperature, air-fuel ratio, MAP, MAF, ambient conditions (e.g., ambient temperature, pressure, and humidity), engine state, and vehicle ignition state. Engine state may refer to whether the engine is on (e.g., operating at a non-zero speed, where combustion occurs in the engine cylinders), off (e.g., at rest, where no combustion occurs in the engine cylinders), or electrically powered (e.g., via torque from an electric motor, where no combustion occurs in the engine cylinders). Vehicle ignition state may refer to the position of the ignition switch. For example, the ignition switch may be in the "off" position, indicating that the vehicle is off (e.g., power is cut off, where the vehicle speed is zero), or the ignition switch may be in the "on" position, indicating that the vehicle is on (e.g., power is supplied to the vehicle systems). The engine state and the vehicle state may differ. For example, the vehicle can be started and operated in pure electric mode, where the electric motor supplies torque to propel the vehicle and the engine is off and does not supply torque to propel the vehicle. As another example, the vehicle can be started, where the engine is off during an idle-stop period. In one example, the vehicle can be stationary during an idle-stop. In another example, the vehicle can be in motion (e.g., coasting) during an idle-stop.

[0060] At point 404, it is determined whether to request engine start. For example, engine start can be requested by the vehicle operator switching the ignition switch to the "on" position, such as by turning the ignition key, pressing the ignition button, or by requesting engine start from a remote device (e.g., remote key, smartphone, tablet, etc.). In another example, the controller can request engine start to switch the vehicle from pure electric mode to engine mode, where combustion occurs in the engine and the vehicle is propelled at least partially by the torque obtained from the engine. For example, when the system battery (e.g., Figure 1When the state of charge (SOC) of the system battery (58) drops below a threshold SOC, the vehicle can be switched to engine mode. The threshold SOC can be a positive, non-zero battery SOC level below which the system battery may not be able to support or perform additional vehicle functions while propelling the vehicle via torque derived from the motor (e.g., 3010). As another example, if the torque demand rises above a threshold torque, the vehicle can be switched to engine mode. The threshold torque can be, for example, a positive, non-zero amount of torque that the motor alone cannot meet or maintain. In another example, the vehicle controller may request engine start to exit idle-stop mode.

[0061] If engine start is not requested, then method 400 proceeds to 406 to determine whether the engine is on (e.g., operating at a non-zero speed in the case of combustion in one or more engine cylinders). If the engine is on, then method 400 proceeds to 420, which will be described below. If the engine is not on (e.g., the engine is off), then method 400 proceeds to 408 and includes maintaining the engine off. After 408, method 400 ends.

[0062] If engine start is requested at 404, then method 400 proceeds to 410 and includes determining the desired intake valve start state (e.g., Figure 1 The intake valve 150) and the desired exhaust valve starting state (e.g., Figure 1 The desired starting conditions for the intake and exhaust valves can vary based on engine operating conditions, such as engine temperature (e.g., whether the requested engine start is a hot or cold start), and can differ for the intake and exhaust valves. For example, when the engine is hot (e.g., above a threshold temperature corresponding to a steady-state operating temperature), it may be necessary to avoid pumping air to the (hot) downstream catalyst (e.g., ...). Figure 1In the emission control device 178), if it is necessary to run the engine without pumping air, for example when the engine is hot, then the desired starting state of the intake and exhaust valves can be deactivated. In another example, the desired starting state of the intake valves can be deactivated when the desired starting state of the exhaust valves may be active. Both examples will result in zero net airflow through the engine, but with different torque characteristics. That is, deactivating the intake valves while the exhaust valves are active will result in more net pumping losses and one air spring event per cylinder per engine cycle. Deactivating both the intake and exhaust valves will result in two air spring events per engine cycle, but with lower net pumping losses. In contrast, when the engine is cold, in one example, the desired starting state of the intake and exhaust valves may be active. In other examples, the desired starting state of the intake valves and the desired starting state of the exhaust valves may differ on a cylinder-by-cylinder basis. For example, when starting the engine under reduced torque conditions, the desired starting state of a subset of the intake and exhaust valves of the cylinders can be deactivated (or only the desired starting state of the intake valves can be deactivated), while the desired starting state of the intake and exhaust valves of the remaining cylinders can be active. Furthermore, the desired valve state during engine shutdown can differ from the desired state during engine startup, as further described below; therefore, when engine startup is requested, the valves can be in a state different from the desired starting state.

[0063] At 412, method 400 includes using a voltage of appropriate polarity to excite the e-latch solenoid of each valve to place each valve in a desired state (as determined at 410). For example, if the desired starting state is deactivated, the controller can use a voltage pulse with a first polarity to excite the e-latch solenoid included in the e-latch rocker arm mechanism of the corresponding valve. (See also: Regarding...) Figures 2A to 2D As described, using a voltage pulse of the first polarity to excite the solenoid will cause the latch pin that connects the outer arm of the e-latch rocker arm mechanism to the inner arm of the e-latch rocker arm mechanism (e.g., Figures 2A to 2DThe latch pin 214, outer arm 206, and inner arm 204 move from the engaged position to the disengaged position. Specifically, moving the latch pin from the engaged position (where the inner and outer arms pivot in unison to lift the corresponding valve as the associated cam rises from the base circle onto the cam face) to the disengaged position (where the outer arm is no longer engaged with the inner arm and the corresponding cylinder valve cannot be lifted) deactivates the corresponding valve. If the latch pin is already in the disengaged position, actuating the associated solenoid with a voltage pulse of the first polarity will not cause further latch pin movement. As another example, if the desired starting state is active, the controller can use a voltage pulse with a second polarity opposite to the first polarity to actuate the e-latch solenoid of the e-latch rocker arm mechanism of the corresponding valve. (See also: Regarding...) Figures 2A to 2D As described, energizing the solenoid with a voltage pulse of the second polarity causes the latch pin to move from the disengaged position to the engaged position. If the latch pin is already in the engaged position, energizing the associated solenoid with a voltage pulse of the second polarity will not cause further latch pin movement. Therefore, the controller can command the desired valve state even if the current valve state is unknown.

[0064] Such as about Figures 2A to 2D The description and Figure 3 As summarized in the table, latch pin movement only occurs during excitation when the associated cam is on the base circle. During engine starting operation, the position of each cam during said excitation may be unknown. Therefore, the latch pin of any valve will not move if any valve cam leaves the base circle.

[0065] At 414, method 400 includes transmission via an electric motor (e.g., a starter motor) or an electric motor (e.g., Figure 1 The motor 52) starts the engine by turning it. For example, electricity can be supplied to the electric motor, where the amount of electricity supplied corresponds to the amount of electric torque required to start the engine at the desired speed.

[0066] At 416, method 400 includes re-energizing the e-latch solenoid of each valve after a threshold rotation has been reached. The threshold rotation corresponds to the maximum valve duration, for example, a value between 200 and 280 degrees of crankshaft rotation. After the maximum valve duration, any cam that previously left the base circle (e.g., at the cam lobes), resulting in no latch pin movement during the energization (e.g., the first energization) at 412, will return to the base circle. Therefore, any latch pin not in a position corresponding to the desired valve actuation state will move during re-energization. Re-energizing the e-latch solenoid of each valve includes sending a second voltage pulse of the same polarity as during the first energization. Latch pins that previously moved during the first energization will remain in place, as will any latch pins that were already in a position corresponding to the desired actuation state before the first energization. In this way, each valve can be reliably placed in its desired actuation state in less than one engine rotation and without any prior knowledge of cam position or valve state. Furthermore, the current valve state is known after each valve has been placed in the desired starting state.

[0067] At 418, method 400 includes determining the crankshaft position and camshaft position, such as regarding... Figure 9 and Figure 10 The following description is provided. In short, after each valve state is known, the movement or non-movement of the latch pin during subsequent actuation provides information for inferring the stroke of the corresponding cylinder. For example, when the associated intake cam is on its convex side and the intake valve rocker arm is loaded, the intake valve latch pin will not move during the intake stroke, and when the associated exhaust cam is on its convex side and the exhaust valve rocker arm is loaded, the exhaust valve latch pin will not move during the exhaust stroke. The movement or non-movement of the latch pin during actuation can be determined based on the inductive characteristics of the corresponding e-latch solenoid. Inductive characteristics refer to the e-latch solenoid current generated during actuation. If the cam is on its base circle and the associated latch pin moves, this movement causes a momentary decrease in current (e.g., a change in the current slope), which manifests as a trough in the trajectory of the solenoid current during actuation, as shown in the description of... Figures 2A to 2D The description and about Figures 14 to 15To illustrate, when the camshaft is in the camshaft position and the associated latch pin is not moving, the solenoid current will increase steadily without a trough before reaching its maximum. In this way, the controller can determine which latch pins are moving and which are not moving based on the presence or absence of a decrease in current in the induction characteristics of the associated solenoid, thus providing information about the camshaft position. With the crankshaft and camshaft positions determined, fuel and spark can be provided to initiate combustion within the engine cylinders, wherein fuel injection and spark are provided at timings associated with the determined crankshaft and camshaft positions.

[0068] At 420, method 400 includes switching between non-VDE mode operation and VDE mode operation based on operating conditions, such as regarding... Figure 5 The following description is provided. For example, the controller can determine whether to operate in non-VDE mode or VDE mode based at least on torque demand. In non-VDE mode, combustion occurs in all cylinders of the engine, while in VDE mode, a subset of cylinders are deactivated, and combustion occurs in the remaining cylinders. For example, non-VDE mode can be selected when torque demand is high, and VDE mode can be selected when torque demand is low. The engine can switch between non-VDE and VDE modes multiple times during a driving cycle. The switching can include, for example, selectively deactivating (when switching from non-VDE mode to VDE mode) or restarting (when switching from VDE mode to non-VDE mode) the intake and exhaust valves of a cylinder by activating the e-latch solenoid of the corresponding valve deactivation mechanism to move the associated latch pin between an engaged position and a disengaged position. The switching can also include selectively deactivating some cylinders and / or restarting others when switching from one VDE mode to another.

[0069] At 422, it is determined whether an engine shutdown request is requested. As an example, a shutdown request from a vehicle operator can be confirmed in response to the ignition switch being moved to the "off" position or by the vehicle operator pressing a button. As another example, the controller can initiate engine shutdown, for example, in response to the fulfillment of an idle-stop condition and without receiving an operator request to stop the engine. Idle-stop conditions may include, for example, battery SOC exceeding a threshold SOC (e.g., as defined at 404), vehicle speed within a desired range (e.g., not exceeding 30 mph), no request for air conditioning operation, torque requested by the driver less than a predetermined threshold torque, brake sensor status indicating the brake pedal has been pressed, engine speed below a threshold engine speed, input shaft rotation number less than a predetermined threshold rotation number, etc. In one example, the vehicle may be stationary when the idle-stop condition is met. In another example, the vehicle may be in motion (e.g., coasting) when the idle-stop condition is met. Any or all idle-stop conditions can be met to confirm the idle-stop condition. As another example, the controller can, for instance, initiate engine shutdown to switch the vehicle to pure electric mode when the battery SOC is greater than a threshold and the torque demand is less than a threshold torque.

[0070] If engine shutdown is not requested, method 400 proceeds to 424 and includes maintaining engine on. Combustion thus continues to occur in one or more engine cylinders, with the engine operating at a non-zero speed. The method can then exit. If engine shutdown is requested, method 400 proceeds to 426 and includes determining the desired intake valve closing state and the desired exhaust valve closing state. The desired closing states can be the same or different for the intake and exhaust valves. Furthermore, the desired intake valve closing states and the desired exhaust valve closing states can differ for different cylinders. As a first example, the desired closing states of the intake and exhaust valves for all cylinders can be active (e.g., conventional engine shutdown). In a second example, the desired closing states of both the intake and exhaust valves for all cylinders can be deactivated to achieve zero net airflow through the engine and fewer air spring events. Deactivating the intake and exhaust valves of each cylinder during shutdown reduces net engine pumping work and friction, allowing the engine to run for a longer period, thus preparing the engine for subsequent restarts. As a third example, for all cylinders, the desired intake valve closure state can be deactivated when the desired exhaust valve closure state is active, resulting in zero net airflow through the engine. As a fourth example, the desired intake and exhaust valve closure states of a subset of cylinders can be deactivated (or only the desired intake valve closure state can be deactivated), while the desired intake and exhaust valve closure states of the remaining cylinders can be active. The controller can determine the desired intake valve closure state and the desired exhaust valve closure state based on operating conditions (e.g., catalyst temperature) and whether a subsequent engine restart is expected. Therefore, the desired closure state can vary based on the origin of the closure request (e.g., vehicle operator or controller). For example, the controller can input operating conditions into one or more lookup tables, mappings, or algorithms and output the corresponding desired intake and exhaust valve closure states for each cylinder. As another example, the controller can make a logical determination of the desired closure state for each intake and each exhaust valve based on operating condition-dependent logic rules. For example, the controller can select either the second or third example to avoid sending oxygen to the catalyst during shutdown when the catalyst temperature is high. As another example, the controller can select the second example when a subsequent engine restart is anticipated, such as when the engine is shut down to achieve an idle-stop.

[0071] At 428, method 400 includes energizing the e-latch solenoid of each valve with a voltage of appropriate polarity when the corresponding cam is on the base circle, to place each valve in its desired closed state. As another example, only the e-latch solenoid corresponding to the valve that is not yet in its desired closed state may be energized. For example, if the desired closed state of the exhaust valve is deactivated, the exhaust valve may be deactivated by moving the latch pin of the active exhaust valve to the disengaged position by energizing the corresponding e-latch solenoid with a voltage pulse of the first polarity when the associated cam is on the base circle. If the cam position is unknown for any reason, the valve may be energized after a threshold rotation has been reached, as described above at 416.

[0072] At 430, method 400 includes shutting off the engine. For example, shutting off the engine may include disabling fuel delivery and spark plugs, causing combustion to cease within the engine cylinders and allowing the engine to run until it stops. After 430, method 400 ends.

[0073] In this way, the intake and exhaust valve actuation states can be accurately and efficiently controlled via an actuated e-latch rocker arm mechanism. The e-latch rocker arm mechanism allows valves to be quickly placed in a desired actuation state (e.g., active or deactivated) during engine start-up without interaction with the camshaft positioning system or knowledge of the current valve state. Valves can also be placed in a desired closed state during engine shutdown, which may differ from the desired actuation state. The desired actuation and closed states can respectively induce engine rotation and deceleration. Furthermore, the e-latch rocker arm mechanism enables rapid determination of crankshaft and camshaft positions and facilitates engine transitions between VDE and non-VDE operating modes, thereby increasing fuel economy. In some examples, such as when the current valve state is known, the controller can monitor latch pin movement during each solenoid actuation via the sensing characteristics of the solenoid, as further described herein. However, setting the valve to the desired state does not require monitoring latch pin movement, especially when the current valve state is unknown (e.g., when requesting engine start) and therefore it is unknown whether latch pin movement is expected.

[0074] Turn now Figure 5An exemplary method 500 for selectively disabling a cylinder valve actuator and diagnosing a cylinder valve actuator in response to engine operating conditions is illustrated. The cylinder valve can be selectively deactivated by actuating an electrically operated latch (e-latch) rocker arm mechanism via an actuation of an associated electric solenoid (also referred to herein as an e-latch solenoid). The e-latch rocker arm mechanism can then be diagnosed based on the movement of the latch pin during said actuation. This can be achieved via… Figure 1 as well as Figures 2A to 2D The system to generate Figure 5 The operation sequence.

[0075] At 502, the method includes estimating and / or measuring engine operating conditions, such as engine speed, engine load, driver torque demand, boost pressure, MAP, MAF, vehicle speed, engine temperature, and environmental conditions (e.g., ambient temperature, pressure, and humidity). At 504, it can be determined whether the estimated engine conditions enable the engine to enter VDE mode, in which the engine can be operated with one or more cylinders selectively deactivated. In one example, if the torque demand or vehicle speed is below a threshold, then the VDE mode entry condition can be met.

[0076] If the VDE mode entry conditions are not met, then at 506, the method includes maintaining activity in all engine cylinders and burning fuel in all cylinders. At 508, when operating in non-VDE mode, the method includes performing low-speed e-latch mechanism diagnostics as appropriate, such as... Figure 7 The following is a detailed explanation. In short, the e-latch solenoid can be actuated to actively and invasively move the latch pin of the rocker arm mechanism between an engaged and disengaged position. The e-latch rocker arm mechanism is then diagnosed based on the characteristics of the inductive current generated during the actuation. Method 500 ends after step 508.

[0077] If the VDE entry condition is met, then at 510, the method includes selecting the cylinders to be deactivated. This includes selecting the total number of cylinders to be deactivated and the identity of the cylinders to be deactivated. In one example, the number of cylinders to be deactivated can increase as the driver's torque demand decreases. For example, in the case of an engine with two rows of cylinders, half of the total number of engine cylinders can be deactivated by deactivating all cylinders in one row while maintaining activity in all cylinders in the other row. Alternatively, an equal number of cylinders in both rows can be deactivated. As another example, if the torque demand is low, more than half of the cylinders, including cylinders in both rows, can be deactivated.

[0078] In other examples, the controller may determine the desired intake ratio based at least on the operator's torque requirements. The engine cylinder intake ratio is the actual total number of cylinder ignition events divided by the actual total number of cylinder intake strokes. In one example, the actual total number of cylinder intake strokes is a predetermined number. As used herein, a cylinder start event refers to cylinder ignition during the cylinder cycle with the intake and exhaust valves open and closed, while a cylinder deactivation event refers to cylinder inactivity during the cylinder cycle with the intake and exhaust valves closed. Engine events can be the stroke of a cylinder event (e.g., intake, compression, power, exhaust), the opening or closing time of the intake or exhaust valves, the ignition timing of the air-fuel mixture in the cylinder, the position of the piston in the cylinder relative to the crankshaft, or other engine-related events. Engine event numbers correspond to specific cylinders. For example, engine event number one may correspond to the compression stroke of cylinder number one. Engine event number two may correspond to the compression stroke of cylinder number two. A cycle number refers to an engine cycle that includes one event (start or stop) in each cylinder. For example, the first cycle is completed when each cylinder of the engine has completed all four stroke events (intake, compression, expansion, and exhaust) in the firing order. The second cycle begins when each cylinder of the engine begins another repetition of all four stroke events. The target or desired intake ratio can be determined based on the engine torque requested by the operator. Specifically, permissible engine cylinder intake ratio values ​​can be stored in a table or function indexed by the desired engine torque and engine speed. The engine cylinder intake ratio values ​​that can provide the requested engine torque can be a portion of a set of available engine cylinder intake ratio values. Subsequently, the engine cylinder intake ratios that provide the minimum number of active engine cylinders during the cycle can be selected from said set of available engine cylinder intake ratio values ​​to provide the desired engine cylinder intake ratio. In this way, a single desired engine cylinder intake ratio can be selected from a large set of engine cylinder intake ratios. It will be understood that the selected engine cylinder intake ratio can then be provided via one of several possible cylinder deactivation modes.

[0079] As an example, a target intake ratio of 1 / 2 (or 0.5) implies that for every 2 cylinder events, one cylinder is active or ignited and one cylinder is deactivated or skipped. As another example, a target intake ratio of 1 / 3 (or 0.33) implies that for every 3 cylinder events, one cylinder is active and the remaining two cylinders are deactivated.

[0080] The controller can also select cylinder deactivation modes, which provide a desired intake ratio. For example, an intake mode with a 1 / 2 intake ratio could include selectively deactivating every other cylinder to produce an average of half the power. Furthermore, the same mode can be applied for each consecutive engine cycle, such that the same cylinders are skipped in each consecutive engine cycle, while the remaining cylinders are fired in each of the remaining engine cycles. As another example, an intake mode with a 1 / 3 intake ratio could include selectively deactivating two out of every three cylinders to produce an average of one-third the power. Additionally, the intake ratio can be provided by skipping different cylinders in each engine cycle.

[0081] Once a cylinder mode corresponding to the desired intake ratio is selected, the controller can deactivate fuel and spark and deactivate the cylinder valve mechanism to provide the target intake ratio. Selective cylinder deactivation includes keeping the cylinder valve closed for the selected cylinder to be deactivated, wherein no fuel is injected into the cylinder during the entire engine cycle of 720 degrees of crank angle (i.e., during all four strokes of the cylinder).

[0082] It will be understood that decisions to start or deactivate a cylinder and to open or close its intake and exhaust valves can be made at a predetermined number of cylinder events (e.g., one cylinder event, or alternatively, one cylinder cycle) prior to starting or deactivating the cylinder, thus allowing time to begin the process of opening and closing the cylinder's intake and exhaust valves. For example, for an eight-cylinder engine with a firing order of 1-3-7-2-6-5-4-8, the decision to start or deactivate cylinder number seven can be made during the intake or compression stroke of cylinder number seven at a time one engine cycle prior to starting or deactivating it. Alternatively, the decision to start or not start a cylinder can be made at a predetermined number of engine events or cylinder events prior to starting or deactivating a selected cylinder. In other examples, the number of cylinder events can be adjusted based on hardware capabilities and current engine operating conditions.

[0083] At 512, the method includes actuating the e-latch rocker arm mechanism of selected cylinders to maintain the intake and exhaust valves of those cylinders closed. This includes, at 514, the controller sending a signal to activate the e-latch solenoids of the e-latch rocker arm mechanism coupled to the intake and exhaust valves of the selected cylinders. The timing of the signals to the intake and exhaust solenoids is selected to coincide with the associated cams being on the base circle. Activation of the solenoids causes the outer arm of the e-latch rocker arm mechanism to engage the inner arm of the e-latch rocker arm mechanism (e.g., ...). Figures 2A to 2D The latching pins of the outer arm 206 and the inner arm 204 (e.g., Figures 2A to 2DThe position of the latch pin 214 is changed. Specifically, a voltage pulse of the first polarity is used to excite the e-latch solenoid to move the latch pin to a disengaged position, in which the outer arm is no longer connected to the inner arm and the corresponding cylinder valve cannot be raised. (See also: Regarding...) Figure 2D As described, when the outer arm disengages from the inner arm, the outer arm remains stationary as the associated cam rises away from the base circle, while the inner arm pivots against the shaft instead of lifting the valve. At 516, the method also includes timely diagnosis of the e-latch rocker arm mechanism based on latch pin movement during solenoid actuation when transitioning to VDE mode. Figure 6A The description states that the movement of the latch pin during the excitation of the associated solenoid is inferred by the inductive characteristics of the current generated during the excitation of the solenoid. By diagnosing the movement of the latch pin when it has already been commanded into VDE mode, the VDE mechanism achieves non-invasive diagnosis and does not rely on expensive sensors. At 518, the method includes disabling fuel and spark supply to the selected cylinder. This can be achieved by disabling the cylinder fuel injector (e.g., Figure 1 The fuel injector 166) and deactivate the spark plug to the given cylinder (e.g., Figure 1 The spark plug (192) commands a spark signal to stop the fuel flow and spark to the deactivated cylinder. Alternatively, the method can be performed without a spark signal, since even in the presence of a spark, the cylinder will not be able to ignite without fuel and air. Therefore, the deactivated cylinder does not burn air and fuel and thus does not produce any torque. At 520, the method includes adjusting engine operating parameters to maintain torque demand via the remaining cylinder. The remaining active cylinder operates in VDE mode at a higher average cylinder load (relative to non-VDE mode) to meet the driver's torque demand, thereby increasing engine pumping efficiency and fuel economy. For example, one or more of the airflow, spark timing, and cylinder valve timing can be adjusted in the remaining active cylinder to maintain engine torque demand and minimize torque disturbances during transition to VDE mode operation.

[0084] At point 522, it can be determined whether the engine operating condition has changed to allow the engine to exit VDE mode and enter a non-VDE mode, in which the engine can be operated with all cylinders active. In one example, if the torque demand or vehicle speed exceeds a threshold, then the non-VDE mode entry condition (or VDE mode exit condition) can be met.

[0085] If the non-VDE mode entry condition is not met, then at 524, the method includes maintaining engine operation while deactivating one or more cylinders and burning fuel in the remaining active cylinders. Otherwise, if the non-VDE mode entry condition is met, then at 526, the method includes actuating the e-latch rocker arm mechanism of the selected cylinder to allow the intake and exhaust valves of the previously deactivated cylinder to lift. This includes at 528 the controller sending a signal to activate the e-latch solenoid of the e-latch rocker arm mechanism coupled to the valve of the deactivated cylinder. The timing of the signals to the intake and exhaust solenoids is selected to coincide with the associated camshafts on the base circle. Activation of the solenoid causes a change in the position of the latch pin. Specifically, the e-latch solenoid is activated using a voltage pulse of a second polarity opposite to the first polarity to move the latch pin to an engaged position, in which the outer arm engages the inner arm and valve lifting is possible. (See regarding...) Figure 2C As described, with the latch pin in the engaged position, the outer and inner arms move in unison, thereby pivoting against the valve clearance adjuster and lifting the valve based on the profile of the associated cam. At 530, the method further includes timely diagnosis of the e-latch rocker arm mechanism based on the latch pin movement during solenoid actuation. Figure 6B The text explains that by monitoring the movement of the latch pin via sensing characteristics during the excitation of the associated solenoid, VDE mechanisms can be reliably diagnosed non-invasively. Specifically, deterioration of the e-latch rocker arm mechanism in which the latch pin is stuck in the deactivated position can be identified, allowing the controller to adjust engine operation accordingly to account for the deactivation of the corresponding cylinder. Furthermore, pumped-to-top (e.g., overextended) lifters or worn cam lobe angles can be identified.

[0086] At 532, the method includes restoring fuel and spark in the previously deactivated cylinder. The restarted cylinder then begins to burn air and fuel therein and thus begins to generate torque. At 534, the method includes adjusting engine operating parameters to maintain torque demand. At this point, because all cylinders are active, each active cylinder can operate at a lower average cylinder load relative to VDE mode to meet the driver's torque demand. In some examples, one or more of the airflow, spark timing, and cylinder valve timing can be adjusted to minimize torque disturbances during transition to non-VDE mode operation. Additionally, as referenced... Figures 6A to 6B As described, one or more engine operating parameters can be adjusted based on the results of a diagnosis, such as whether any of the cylinder valves has deteriorated (e.g., whether they are stuck open or stuck closed). Method 500 ends after 534.

[0087] Turn now Figure 6A and Figure 6B An exemplary method 600 is described for diagnosing a cylinder valve deactivation mechanism during entry and exit from a cylinder deactivation mode in a driving cycle. The method is non-invasive and does not require execution of VDE mode. Alternatively, the method is performed via an e-latch rocker arm mechanism (e.g., Figures 2A to 2D The e-latch rocker arm mechanism 202) fully utilizes the inherent transition of the engine into and out of VDE mode during the driving cycle. Figure 6A The method can be used as Figure 5 This is part of the method to be executed, for example, at position 516 when entering VDE mode. Therefore, it is executed after the cylinder valves have already been commanded to deactivate. Figure 6A All the steps. Similarly, Figure 6B The method can be used as Figure 5 This is part of the method to be executed, for example, at 530 when entering non-VDE mode. Therefore, it is executed after the cylinder valve has been commanded to restart. Figure 6B All steps.

[0088] At point 604, after the cylinder valve of the selected cylinder has been commanded to deactivate, it is determined whether the cam of the selected cylinder is on the base circle. In this document, the cam may be the intake cam or exhaust cam of the selected cylinder, the intake cam being coupled to the intake valve deactivation mechanism, and the exhaust cam being coupled to the exhaust valve deactivation mechanism of the given cylinder. In one example, the cam position on the base circle can be inferred based on the output of a camshaft position sensor. In another example, it can be based on the crankshaft position (e.g., by a crankshaft position sensor (e.g., ...). Figure 1 The Hall effect sensor 120 outputs the cam position on the base circle and the cylinder firing sequence to infer the cam position on the base circle, as shown in the following... Figure 9 Further description. For example, the controller can infer that the intake cam is on the base circle during the compression, exhaust, and power strokes, and that the exhaust cam is on the base circle during the same strokes. The crankshaft position when the intake and exhaust cams move away from the base circle can be further based on the cam phasing and lift profiles of the corresponding cams. If the cams are not on the base circle, then at 618, method 600 includes not actuating the e-latch rocker arm mechanism. That is, the controller can wait until the cams have returned to the base circle to actuate the e-latch rocker arm mechanism because the valve state may not change when the cams leave the base circle (e.g., during cam lift).

[0089] If the cam is on the base circle when VDE mode is already commanded, then at 606, the method includes inferring latch pin movement parameters based on the inductive characteristics generated when the e-latch solenoid is actuated to move the latch pin to the disengaged position. For example, the latch pin movement can be inferred based on a decrease in the current characteristics of the solenoid and the time corresponding to said decrease (e.g., a valley). For example, when the solenoid is actuated (using a voltage pulse with a first polarity), the current increases, resulting in an increase in the magnetic force on the latch pin until the magnetic force is strong enough to pull the latch pin into the disengaged position. The movement of the latch pin causes a brief decrease in the current through the solenoid due to the anti-EMF, after which the current continues to increase to its maximum level. For example, regarding Figure 12 This describes such sensing characteristics. When latch pin movement occurs, the controller can record the crank angle. For example, the controller can record the angle at which the latch pin transitions from an engaged position to a disengaged position. The inferred movement parameters can include, for example, the rate of change of current inferred from the slope of the current (e.g., the derivative of the current signal). As another example, the inferred parameters include the time taken for the latch pin to move from the initial engaged position to the final disengaged position. As another example, the inferred parameters can include the velocity of the latch pin when it strikes the end stop, inferred based on the magnitude of the current reduction (e.g., the reverse EMF is proportional to the latch pin velocity). As another example, the inferred parameters include determining the strength of the latch pin's impact on the end stop when it reaches the disengaged position (i.e., the relative force of the latch pin impacting the end stop), inferred based on the magnitude of the current reduction. Other parameters can be inferred.

[0090] At 608, based on the inductive characteristics generated during solenoid excitation, and further based on the inferred latch pin movement parameters, it can be determined whether latch pin movement was detected. (See reference...) Figure 3As illustrated in the table, specifically at 302 and 304, when the cam is at the base circle, the latch pin is movable during the transition from the engaged position to the disengaged position to deactivate the cylinder valve. That is, latch pin movement is expected in response to solenoid excitation. If the sensing characteristics indicate that latch pin movement was detected as expected, then at 610, it can be inferred that the e-latch rocker arm mechanism is functioning. At 612, the method includes adjusting the current applied to the e-latch mechanism of the given cylinder during a subsequent transition to VDE mode (e.g., when the valve of the given cylinder is subsequently commanded to deactivate). For example, the engine controller can adjust the amount of current applied to excite the solenoid during subsequent valve deactivation operations based on the inferred latch pin movement time to the disengaged position and the strength of the latch pin impacting the end stop. For example, a controller can reduce the current applied to the solenoid to reduce the force of the latch pin striking the end stop when entering the disengaged position, thereby reducing pin wear and extending component life. As another example, the controller can use the time it takes for the latch pin to transition from the engaged to the disengaged position to measure inter-component variability, such as the variability of solenoid mechanics in the actual flux path in the magnetic circuit. As yet another example, the controller can use the final maximum current through the solenoid coil to determine the inter-component variability of the solenoid resistance. Furthermore, the controller can increase or decrease the engine speed range that enables switching. For example, a degraded connection to the solenoid (e.g., high resistance) will slow down actuator response. If the controller detects that one or more latch pins are moving slower than expected, the controller can reduce the maximum speed at which VDE can be utilized, because a slowly moving latch pin may not be able to complete its stroke during a shorter base circle event at higher engine speeds. As yet another example, the controller can use inferred parameters to confirm camshaft dynamics, such as... Figure 9 and Figure 10 Location description. Method 600 ends after 612.

[0091] Returning to 608, if the sensing characteristics indicate no movement of the latch pin, then at 614, the e-latch rocker arm mechanism can be indicated as deteriorated. Specifically, if no brief decrease in solenoid current is observed, it can be inferred that the latch pin has not moved. Indicating deterioration of the e-latch rocker arm mechanism may include setting diagnostic codes, illuminating lights, and / or notifying the vehicle occupant via a data center. At 616, in response to the deterioration indication, the method includes deactivating the given cylinder until the e-latch rocker arm is confirmed to be repaired or replaced. After 616, method 600 ends.

[0092] Turn now Figure 6BAt 630, after the cylinder valve of the selected cylinder has been commanded to restart, it is determined whether the cam of the selected cylinder is on the base circle. In this document, the cam may be the intake cam or exhaust cam of the selected cylinder, the intake cam being coupled to the intake valve deactivation mechanism, and the exhaust cam being coupled to the exhaust valve deactivation mechanism of the given cylinder. As previously explained, the cam position on the base circle can be inferred based on the output of a cam position sensor or based on the measured or sensed cam timing. If the cam is not on the base circle, then at 644, method 600 includes not actuating the e-latch rocker arm mechanism. That is, the controller may wait until the cam has returned to the base circle to actuate the e-latch rocker arm mechanism because the valve state may not change when the cam leaves the base circle (e.g., during cam lift).

[0093] If the cam is on the base circle when VDE mode is already commanded, then at 632, the method includes inferring latch pin movement parameters based on inductive characteristics generated when the e-latch solenoid is energized to move the latch pin to the engaged position. As described above... Figure 6A As described at 606, movement of the latch pin causes a brief decrease in the current through the solenoid, after which the current continues to increase to its maximum level. Therefore, the movement of the latch pin from the disengaged position to the engaged position can be inferred from the brief decrease in the solenoid current. When latch pin movement occurs, the controller can record the crank angle. For example, the controller can record the angle at which the pin transitions from the disengaged position to the engaged position. The inferred movement parameters can include, for example, the rate of change of current inferred from the slope of a curve in the sensing characteristics. As another example, the inferred parameters include the time taken for the latch pin to move from the initial position to the engaged position, inferred from the time taken to move from the disengaged position to the engaged position. As another example, the inferred parameters can include the velocity of the latch pin when it strikes the end stop, inferred from the magnitude of the current decrease (e.g., the reverse EMF is proportional to the velocity of the latch pin). As another example, the inferred parameters include determining the strength of the latch pin impact on the inner arm when it reaches the engaged position (i.e., the force with which the latch pin impacts the hard stop in the inner arm), which is inferred based on the magnitude of the current drop. Other parameters can be inferred.

[0094] At position 634, based on the inductive characteristics generated during solenoid excitation, and further based on the inferred latch pin movement parameters, it can be determined whether latch pin movement was detected. (See reference...) Figure 3As illustrated in the table, specifically at 302 and 304, when the cam is at the base circle, the latch pin can move from the disengaged position to the engaged position to restart the cylinder valve. That is, the solenoid is energized, and latch pin movement is expected. If the sensing characteristics indicate that latch pin movement was detected as expected, then at 636, it can be inferred that the e-latch rocker arm mechanism is functioning. At 638, the method includes adjusting the current applied to the latch mechanism of the given cylinder during a subsequent transition to a non-VDE mode (e.g., when a valve restart of the given cylinder is subsequently commanded) based on the inferred latch pin movement parameters. For example, the engine controller can adjust the amount of current applied during subsequent valve restart operations to energize the solenoid based on the inferred time taken for the latch pin to move to the engaged position and the intensity of the latch pin impact. For example, the controller can reduce the current applied to the e-latch solenoid to reduce the force (or velocity) at which the latch pin strikes the hard stop of the inner arm of the e-latch rocker arm mechanism when entering the engaged position, thereby reducing pin wear and extending component life. As another example, the controller can use the time taken for the latch pin to transition from the disengaged to the engaged position to measure inter-part variability, such as the variability in the actual flux path of the solenoid mechanism in the magnetic circuit. As yet another example, the controller can use the final maximum current through the solenoid coil to determine the inter-part variability of the solenoid resistance. Furthermore, the controller can increase or decrease the engine speed range that enables switching. For example, if the controller detects that one or more latch pins are moving slower than expected, the controller can reduce the maximum speed at which the VDE can be utilized, because a slowly moving latch pin may not be able to complete its stroke during a shorter base circle event at higher engine speeds. As yet another example, the controller can use inferred parameters to confirm camshaft dynamics. Method 600 ends after 638.

[0095] Returning to 634, if the sensing feature indicates no latch pin movement, then at 640, the e-latch rocker arm mechanism can be indicated as deteriorated. Specifically, it can be inferred that the latch pin is stuck in the disengaged position. Indicating deterioration of the e-latch rocker arm may include setting a diagnostic code, illuminating a light, and / or notifying the vehicle occupant via a data center. At 642, in response to the deterioration indication, the method includes maintaining the corresponding cylinder deactivated until the e-latch rocker arm is confirmed to be repaired or replaced. For example, if it is determined that the exhaust valve deactivation mechanism is deteriorated and the latch pin is stuck in the disengaged position, then the controller can maintain the intake valve deactivated while the exhaust valve is stuck in the deactivated position, even if the intake valve is not deteriorated, and adjust the engine operation accordingly. For example, the average load of all remaining active cylinders can be increased to compensate for the given cylinder being maintained deactivated. After 642, method 600 ends.

[0096] In this way, by disabling the cylinder valves in relation to the movement of the latch pin, the cam timing of the movement can be determined while performing VDE diagnostics.

[0097] Turn now Figure 7 An exemplary method 700 is described for timely diagnosis of an e-latch rocker arm mechanism, which functions as a cylinder valve deactivation mechanism, during low-speed conditions when cylinder deactivation is not required. At low engine speeds, there is time for the latch pin of the e-latch rocker arm mechanism (e.g., ...) to engage. Figures 2A to 2D The latch pin 214 moves from the first position to the second position and returns to the first position to confirm the operation of the e-latch rocker arm mechanism, regardless of the desired valve operating state (e.g., start-up or deactivation). Figures 6A to 6B Unlike other methods, method 700 does not require conversion to VDE operating mode. However, most steps of method 700 can be performed similarly to... Figures 6A to 6B The method is repeated.

[0098] At 702, the method includes estimating and / or measuring engine operating conditions. These may include, for example, engine speed, engine load, torque demand, engine temperature, exhaust temperature, MAP, MAF, air-fuel ratio, etc. At 704, the method includes confirming whether conditions for performing low-speed e-latch rocker arm mechanism (e.g., VDE mechanism) diagnostics have been met. In one example, if the engine is idle, then the low-speed diagnostic conditions can be considered met. In another example, if the engine is at or below a threshold speed, then the low-speed diagnostic conditions can be considered met. The threshold speed can be a positive non-zero speed value that can be at or near typical idle speed. As a non-limiting example, the threshold speed can be 1000 RPM. In another example, the low-speed diagnostic conditions are met when the engine is a green engine being started for the first time since assembly (e.g., while still in the assembly plant). Therefore, cylinder valve deactivation is not required at low engine speeds. Therefore, by selectively enabling VDE mechanism diagnostics during low-speed conditions, the cylinder deactivation mechanism can be diagnosed under higher engine speed load conditions in the same driving cycle before the diagnostics are required. Specifically, the e-latch rocker arm system can be verified before valve lift control is performed using the latching mechanism. Additionally, the likelihood of completing VDE mechanism diagnostics on a given driving cycle is increased by utilizing more time to enable or disable the VDE mechanism. If the low-speed e-latch rocker arm mechanism diagnostic conditions are not met, then at 706, the method includes not actuating the e-latch rocker arm mechanism. For example, the associated solenoid (e.g., ...) will not be energized. Figures 2A to 2DThe solenoid 216 is used because moving the latch pin when the low-speed diagnostic conditions are not met may unintentionally change the operating state of the corresponding valve. The method exits and VDE diagnostics are not performed at this time.

[0099] If the diagnostic conditions for the low-speed e-latch rocker arm mechanism are met, then at point 708, the cam is determined to be positioned at the beginning of the base circle of the selected cylinder and valve. In this document, the cam may be the intake cam or exhaust cam of the selected cylinder, the intake cam being coupled to the deactivation mechanism of the intake valve, and the exhaust cam being coupled to the deactivation mechanism of the exhaust valve of the given cylinder. In one example, the cam position at the beginning of the base circle can be inferred based on the output of a camshaft position sensor. In another example, it can be based on the crankshaft position (e.g., by a crankshaft position sensor (e.g., ...). Figure 1 The camshaft position at the beginning of the base circle is inferred using the Hall effect sensor 120 output and the cylinder firing order. For example, the controller can infer that the intake camshaft is at the beginning of the base circle during the compression stroke and the exhaust camshaft is at the beginning of the base circle during the intake stroke. The crankshaft position when the intake and exhaust camshafts reach the beginning of the base circle can be further determined based on the cam phasing and lift profiles of the corresponding cams. If the camshaft is not at the beginning of the base circle, then at 736, it can be determined whether the camshaft is at the beginning of the lift profile. In one example, the camshaft position sensor output or cam timing can be used to infer that the camshaft is at the beginning of the lift profile. If the camshaft is neither at the beginning of the base circle nor at the beginning of the lift profile, then the method returns to 704 to continue checking the camshaft position, so that the method can continue to execute as long as the conditions for performing low-speed diagnostics continue to be met.

[0100] If the cam is at the beginning of the base circle, then at 710, the method includes energizing the e-latch solenoid to move the latch pin to the disengaged position. Specifically, the e-latch solenoid can be energized using a voltage pulse of first polarity. Subsequently, at 712, the method includes inferring latch pin movement parameters based on the inductive characteristics generated when the e-latch solenoid is energized to move the latch pin to the disengaged position. When latch pin movement occurs, the controller can record the crank angle. For example, the controller can record the angle or time when the latch pin transitions from the engaged position to the disengaged position based on a brief decrease in the current through the solenoid, as described above regarding... Figure 6AThe deduced movement parameters may include, for example: the rate of change of current (or the derivative of current) inferred from the slope of the current; the time taken for the latch pin to move from the engaged position to the disengaged position, inferred based on the time taken for the current to exhibit a brief decrease relative to the start of the voltage pulse supplied to the solenoid; and the determination of the strength of the latch pin impact when it reaches the disengaged position (i.e., the force with which the latch pin strikes the end stop), inferred based on the timing and magnitude of the current decrease. Other parameters may be deduced, such as the velocity of the latch pin when it strikes the end stop. For example, the diagnostic may include applying a voltage or duty cycle below normal levels to deactivate the rocker arm in order to test whether the latch pin can move even in the presence of lower actuation force. Successful switching at lower actuation voltages suggests a higher probability of successful switching at normal actuation voltages, even in the presence of other noise factors, such as increased coil resistance due to heating and increased pin friction due to different oil conditions.

[0101] At point 714, based on the inductive characteristics generated during solenoid excitation, and further based on the inferred latch pin movement parameters, it can be determined whether latch pin movement was detected. (See reference...) Figure 3 As illustrated in the table, when the cam is at the base circle, the latch pin is movable as it transitions from the engaged position to the disengaged position to deactivate the cylinder valve. That is, the latch pin is expected to move in response to solenoid excitation. If the sensing characteristics do not detect latch pin movement, then at 716, it can be indicated that the e-latch rocker arm mechanism has deteriorated. Specifically, it can be inferred that the latch pin has not moved from the engaged position to the disengaged position and is stuck in the engaged position. Indicating deterioration of the e-latch rocker arm may include setting diagnostic codes, illuminating lights, and / or notifying the vehicle occupant via a data center.

[0102] Alternatively, before indicating degradation, the controller can first confirm that the latch pin was not in the disengaged position when the unlock command was given, which would result in no latch pin movement. To confirm that the latch pin was not in the disengaged position, the controller can re-energize the solenoid using a voltage pulse of a second polarity opposite to the first polarity and monitor latch pin movement. (See also: Regarding...) Figures 2A to 2D As described, the voltage pulse of the second polarity actuates the latch pin from the disengaged position to the engaged position. Therefore, if latch pin movement is detected in response to the voltage pulse of the second polarity, it can be inferred that the latch pin is now in the engaged position, and deterioration is not indicated; the diagnostic routine can be repeated to verify full latch pin functionality. Conversely, if no latch pin movement is detected in response to the voltage pulse of the second polarity, deterioration of the e-latch rocker arm mechanism can be confirmed.

[0103] At 718, in response to a degradation indication, the method includes deactivating the given cylinder until the e-latch rocker arm is confirmed to be repaired or replaced. That is, the degraded cylinder activity is maintained because the latch pin is held in the engaged position. The method then terminates.

[0104] If the sensing characteristics indicate that latch pin movement was detected as expected at 714, then at 720, it can be inferred that the e-latch rocker arm mechanism is functioning. Next, the method moves to 722 and includes energizing the e-latch solenoid to move the latch pin to the engaged position. For example, because no change in valve operating state is required (e.g., no operation in VDE mode is needed), the latch pin can quickly return to the engaged position before the cam moves away from the base circle. Subsequently, at 724, the method includes inferring latch pin movement parameters based on the sensing characteristics generated when the e-latch solenoid is energized to move the latch pin to the engaged position.

[0105] At position 726, as at position 714, based on the inductive characteristics generated during solenoid excitation, and further based on the inferred latch pin movement parameters, it can be determined whether latch pin movement was detected. (See reference...) Figure 3 As illustrated in the table, when the cam is at the base circle, the latch pin is movable as it transitions from the disengaged position to the engaged position to restart the cylinder valve. That is, the latch pin is expected to move in response to solenoid excitation. If the sensing characteristics indicate that no latch pin movement is detected, then at 728, the e-latch rocker arm mechanism can be indicated as deteriorated. Specifically, it can be inferred that the latch pin has not moved from the disengaged position to the engaged position and is stuck in the disengaged position. Indicating deterioration of the e-latch rocker arm may include setting a diagnostic code, illuminating a light, and / or notifying the vehicle occupant via a data center. At 730, in response to the deterioration indication, the method includes maintaining the corresponding cylinder deactivated until the e-latch rocker arm mechanism is repaired, replaced, or otherwise indicated to be active. For example, if it is determined that the exhaust valve deactivation mechanism is deteriorated and stuck in the disengaged position, maintaining the exhaust valve deactivated can deactivate the intake valve, even if the intake valve deactivation mechanism is active, thereby maintaining the cylinder deactivated. The method then ends.

[0106] In some examples, the controller may additionally attempt to latch the rocker arm mechanism periodically by energizing the corresponding solenoid with a voltage pulse of the second polarity and monitoring latch pin movement. For example, latching may be attempted once per driving cycle, or once per duration of engine operation (e.g., as a non-limiting example, once every 3 hours of engine operation). If latch pin movement is detected due to the latch pin moving to the engaged position, the cylinder may be kept active until the e-latch rocker arm mechanism is repaired.

[0107] If the sensing characteristics indicate that latch pin movement has been detected as expected, then at 732, it can be inferred that the e-latch rocker arm mechanism is functioning. Next, at 734, the method includes adjusting the current applied to the e-latch mechanism of the given cylinder during a subsequent transition to VDE mode (e.g., when the valve of the given cylinder is subsequently commanded to deactivate), based on the inferred latch pin movement parameters. For example, the engine controller can adjust the amount of current applied to the solenoid during subsequent valve deactivation operations based on the inferred time taken for the latch pin to move to the disengaged position and the intensity of the latch pin impact. For example, the controller can reduce the applied current to the solenoid to reduce the force of the latch pin impacting the end stop when entering the disengaged or engaged position, thereby reducing pin wear and extending component life. After 734, method 700 ends.

[0108] In this way, the controller can deactivate and then reactivate the rocker arm mechanism when the cam is on the base circle, resulting in no change in valve lift. Therefore, the controller can measure the start-up time and thus understand the solenoid response time, and confirm the e-latch rocker arm mechanism is functioning without interrupting engine operation.

[0109] Returning to 736, if at 738 the cam is at the beginning of the lift profile, then the method includes monitoring latch pin movement based on inductive characteristics generated during the actuation of the e-latch solenoid. At 740, based on the inductive characteristics generated during solenoid actuation, it can be determined whether latch pin movement was detected. (See reference...) Figure 3 As illustrated in the table, when the cam is on the lift profile, the latch pin is immovable during the transition from the engaged position to the disengaged position to deactivate the cylinder valve. That is, latch pin movement is not expected in response to solenoid excitation. If the sensing characteristics indicate no latch pin movement (e.g., no decrease occurs during the current rise during solenoid excitation), then at 742, it can be inferred that the e-latch rocker arm mechanism is functioning. In this paper, the controller can confirm that the latch pin remains unchanged when the cam is in the maximum lift position. The method then terminates.

[0110] If the sensing characteristics indicate that latch pin movement has been detected, then at 744, the e-latch rocker arm mechanism can be indicated as deteriorated. Specifically, it can be inferred that the camshaft lob is worn or a faulty lifter is present. Indicating deterioration may include setting a diagnostic code, illuminating a light, and / or notifying the vehicle occupant via a data center. Furthermore, at 744, the method includes: in response to the deterioration indication, activating the e-latch solenoid to move the latch pin back to the engaged position. At 746, also in response to the deterioration indication, the method includes preferentially deactivating the corresponding cylinder during subsequent VDE operations. For example, the corresponding cylinder may exhibit a higher-than-average misfire rate due to a faulty lifter or a worn camshaft lob. By preferentially deactivating the corresponding cylinder, the overall misfire rate during subsequent VDE operations can be reduced. As another example, the controller may select to operate the engine smoothly, but deactivate a given cylinder during rough engine operation (e.g., with more NVH) with all cylinders active. In other examples, the controller may compare the fuel economy and / or NVH of the engine when operating with all cylinders active with the fuel economy and / or NVH when operating with a given cylinder deactivated, and select the state that provides the highest fuel economy and / or lowest NVH. The method then terminates.

[0111] In this way, the controller can proactively and timely induce latch pin movement when transitioning to and from VDE state without a command, and subsequently correlate the functionality of the VDE mechanism with the latch pin movement. Specifically, the controller can detect latch pin movement when the cam is on the base circle and when the rocker arm state is inconsequential. The controller can actuate the solenoid to move the latch pin to the disengaged position (to move the valve to the deactivated state), and then actuate the solenoid again to move the latch pin back to the engaged position (to move the valve to the active state), and use the detected opening and closing times to diagnose the e-latch mechanism and understand the solenoid response time. Similarly, the controller can detect latch pin movement (or its absence) when the cam is on lift, wherein the solenoid is actuated to attempt to move the latch pin to the disengaged position. The controller can correlate the detection of no movement to confirm that the latch pin remains latched due to the operation of the e-latch mechanism. If latch pin movement occurs, indicating a deterioration of the e-latch rocker arm mechanism, the solenoid can then be re-energized to move the latch pin back to the engaged position (to move the valve to the active state).

[0112] Next, Figure 8Exemplary graph 800 shows the crankshaft position sensor output and camshaft position sensor output relative to the piston position and stroke of each cylinder in a four-cylinder engine. Graph 802 shows the piston position of cylinder 1, graph 808 shows the piston position of cylinder 2, graph 814 shows the piston position of cylinder 3, graph 820 shows the piston position of cylinder 4, graph 826 shows the crankshaft position sensor output, and graph 828 shows the camshaft position sensor output. For all the above graphs, the horizontal axis represents the crank angle (e.g., in degrees of the crankshaft), where the crank angle increases from left to right along the horizontal axis. In the example of graph 800, 0 degrees of crank angle is defined as the TDC of the intake stroke of cylinder 1, and the engine has a firing order of 1-3-4-2. The vertical axis represents each labeled parameter, where the value of the labeled parameter increases from bottom to top along the vertical axis. Furthermore, shaded area 804 shows the timing zone in which the latch pin of the intake valve e-latch rocker arm mechanism of cylinder 1 cannot move; shaded area 806 shows the timing zone in which the latch pin of the exhaust valve e-latch rocker arm mechanism of cylinder 1 cannot move; shaded area 810 shows the timing zone in which the latch pin of the intake valve e-latch rocker arm mechanism of cylinder 2 cannot move; and shaded area 812 shows the timing zone in which the latch pin of the exhaust valve e-latch rocker arm mechanism of cylinder 2 cannot move. The shaded area 816 shows the timing zone where the latch pin of the intake valve e-latch rocker arm mechanism of cylinder 3 cannot move; the shaded area 818 shows the timing zone where the latch pin of the exhaust valve e-latch rocker arm mechanism of cylinder 3 cannot move; the shaded area 822 shows the timing zone where the latch pin of the intake valve e-latch rocker arm mechanism of cylinder 4 cannot move; and the shaded area 824 shows the timing zone where the latch pin of the exhaust valve e-latch rocker arm mechanism of cylinder 4 cannot move. The crankshaft reference edge is indicated by a long dashed line 830, and the camshaft reference edge is indicated by a short dashed line 832.

[0113] Each of the four cylinders completes one cycle every 720 degrees of crankshaft rotation, or one cycle of all four strokes (e.g., intake, compression, power, and exhaust) every two full revolutions of the crankshaft. A crankshaft position sensor (e.g., Figure 1The Hall effect sensor 120 is configured to sense the presence or absence of equally spaced teeth on a sprocket or gear (e.g., a pulse wheel) coupled to the crankshaft. As the crankshaft rotates, each time a tooth passes the crankshaft position sensor, the sensor's voltage output switches from a near-zero voltage (off) in a square wave to a maximum voltage (on), as shown in graph 826. The gap in the teeth positioned at a known crankshaft position (resulting in a gap in the square wave) serves as a position reference for the crankshaft position sensor. For example, between 0 degrees and 180 degrees of crank angle, the crankshaft position sensor output (graph 826) shows a square wave. Between 180 degrees and 270 degrees of crank angle (e.g., around 230 degrees of crank angle), a gap in the square wave appears due to the missing teeth of the crankshaft pulse wheel. The return of the square wave after this gap (e.g., around 250 degrees of crank angle) produces a crankshaft reference edge 830. For example, for instance, in… Figure 8 The document states that the gap can have a 20-degree crank angle window. As another example, the gap can have a 12-degree crank angle window. The controller can use a combination of the presence, absence, and return of a square wave to identify the crankshaft reference edge 830. For example, the absence of a square wave, or the absence followed by the presence of a square wave, may not alone reliably represent the crankshaft reference edge 830. Therefore, depending on the initial crankshaft position, the controller may need to spend a variable duration (or crankshaft rotation) to detect the presence, absence, and return of the crankshaft position sensor square wave.

[0114] The crankshaft reference edge appears once every 360 degrees of crank rotation. For example, such as Figure 8 As shown, the second crankshaft reference edge 830 appears approximately at a crankshaft angle of 610 degrees. Therefore, the crankshaft reference edge 830 alone does not reveal the stroke of each cylinder. For example, when the crankshaft reference edge 830 is identified, cylinder 1 may be in either the compression stroke or the exhaust stroke.

[0115] The intake and exhaust camshafts each rotate once every 720 crank angles (e.g., once per cycle in a four-stroke engine). Each of the intake and exhaust camshafts may have a gear or sprocket (e.g., a pulse wheel) coupled to it, which can be detected by a corresponding camshaft position sensor (e.g., in...). Figure 1The camshaft position sensors 155 and 157 shown in the diagram sense the rotation of the gear or sprocket. Specifically, the camshaft pulse wheel may include unequally spaced, variable-sized teeth, such that some teeth are positioned closer to each other, while others are positioned further apart. The unequal pulse durations and spacing between pulses in the resulting pulse train, shown in graph 828, generate a camshaft reference edge 832, which appears once every 720 degrees of crankshaft rotation. The camshaft reference edge 832 may correspond to a specific crankshaft orientation and piston stroke, such as the TDC of the compression stroke of cylinder 1. Similar to determining the crankshaft position, the controller can use signal data from before and after the camshaft reference edge to decisively identify the camshaft reference edge and determine the camshaft position from it. Furthermore, the falling edges of each camshaft pulse wheel tooth may be equally spaced over the entire 720-degree crankshaft rotation, while the rising edges may be spaced according to a defined pattern that the controller can recognize and synchronize with the crankshaft position signal. In alternative examples, rising edges can be equally spaced, while falling edges are spaced according to a defined pattern.

[0116] exist Figure 8 (Graph 828) shows the output of only one camshaft position sensor (which can be either an exhaust camshaft position sensor or an intake camshaft position sensor) because, in this example, the pulse train output by the exhaust camshaft position sensor has the same timing as the pulse train output by the intake camshaft position sensor. However, in other examples, such as when using variable camshaft timing, the output of the exhaust camshaft position sensor can be shifted relative to the output of the intake camshaft position sensor.

[0117] Unlike the crankshaft reference edge 830, which occurs once every 360 degrees of crankshaft rotation at the defined position, and the camshaft reference edge 832, which occurs once every 720 degrees of crankshaft rotation at the defined position, the sensing characteristics of the e-latch solenoid for each intake valve and the e-latch solenoid for each exhaust valve provide piston stroke information throughout the entire 360-degree crankshaft rotation and 720-degree camshaft rotation. For example, at any given crankshaft and camshaft position, a cylinder is in the intake stroke, during which the intake valve latch pin is immovable, and a cylinder is in the exhaust stroke, during which the exhaust valve latch pin is immovable. (See also: Regarding...) Figure 3As summarized in Table 300, when the corresponding cam is positioned on its cam angle, the latch pin is immovable regardless of the valve actuation state. Therefore, if the intake valve e-latch solenoid is activated and the corresponding latch pin is determined to be immovable by the solenoid's sensing characteristics, it can be inferred that the corresponding cylinder is in its intake stroke. Similarly, if the exhaust valve e-latch solenoid is activated and the corresponding latch pin is immovable, it can be inferred that the corresponding cylinder is in its exhaust stroke. For example, if the intake valve e-latch solenoid of each cylinder is activated at a 90-degree crank angle, the latch pin of the intake valve of cylinder 1 will not move (shaded area 804), while the latch pins of the intake valves of cylinders 2, 3, and 4 will move. As another example, if the exhaust valve e-latch solenoid of each cylinder is actuated at a 400-degree crank angle, then the latch pin corresponding to the exhaust valve of cylinder 2 will not move (shaded area 812), while the latch pins of the exhaust valves of cylinders 1, 3, and 4 will move. It should be noted that in Figure 8 The shaded time zone shown is exemplary in nature, and in other examples, the time and duration may vary.

[0118] Turn now Figure 9 This illustrates the use of an e-latch rocker arm mechanism (e.g., Figures 2A to 2D An exemplary method 900 for detecting the camshaft position in a fixed-cam engine is described, using an e-latch rocker arm mechanism 202. Camshaft position detection via the e-latch mechanism can be used to diagnose existing camshaft position sensors, replace camshaft position sensors, or estimate camshaft timing during situations where the output of the camshaft position sensor is unavailable or unreliable. Knowing the camshaft timing can increase fuel delivery accuracy. Figure 9 This method enables the determination of the camshaft position when, for example, crankshaft position data is available from a crankshaft position sensor. In contrast, Figure 10 This method allows the camshaft position to be determined even when crankshaft position data is not yet available.

[0119] At 902, the method includes estimating and / or measuring engine operating conditions. These may include, for example, engine speed, engine load, torque demand, engine temperature, exhaust temperature, air-fuel ratio, MAP, MAF, and environmental conditions (e.g., ambient temperature, pressure, and humidity). At 904, it can be determined whether the crankshaft position is known. In one example, this is based on a functional crankshaft position sensor (e.g., Figure 1The controller uses the output of a Hall effect sensor 120 to determine the crankshaft position. During engine start-up, the controller may spend a variable amount of time determining the crankshaft position from the output of the crankshaft position sensor, said time being based on, for example, engine speed, ambient temperature, and the initial position of the crankshaft. As an example, if the crankshaft position sensor receives a pulse indicating that the crankshaft is rotating but has not yet encountered a clearance or reference edge, then the controller will not know the crankshaft position. As another example, the crankshaft position sensor may not provide a reliable signal due to sensor degradation (e.g., due to a loose electrical connection to the sensor). If the crankshaft position is not already known, or if the crankshaft position sensor has degraded, then at 906, the method includes using a cylinder valve deactivation mechanism to determine the crankshaft position. Figure 10 As explained, this includes inferring crankshaft position in part based on the sensing characteristics of each intake valve e-latch solenoid, which are generated after the intake valve solenoid of each engine cylinder is energized.

[0120] If the crankshaft position is known, then at 908, the method includes energizing the e-latch solenoid of the exhaust valve corresponding to the cylinder when the piston of the cylinder is just after the BDC (Blowdown Directional Movement) and near the beginning of the upstroke. The BDC point can be inferred based on the sensed crankshaft position. In a fixed camshaft engine, the camshaft rotates at half the engine speed (e.g., the camshaft rotates once every 720 degrees of crankshaft rotation). Using a four-cylinder engine as an example, at the first engine position (e.g., 180 degrees of crank angle), such as Figure 8 As shown, the pistons of the first two cylinders will begin their upstroke, while the pistons of the second two cylinders will begin their downstroke. Similarly, in a second engine position at a subsequent 180-degree crankshaft angle (e.g., at a 360-degree crankshaft angle), the pistons of the first two cylinders will begin their downstroke, while the pistons of the second two cylinders will begin their upstroke. Of the two cylinders in the upstroke position at the given crankshaft position, one cylinder is in the exhaust stroke, and the other is in the compression stroke, but the crankshaft position alone cannot distinguish between the two cylinders.

[0121] A voltage pulse can be used to excite the e-latch solenoid corresponding to the exhaust valve of the cylinder when the piston is in its upstroke phase, in order to attempt to move the latch pin of the e-latch rocker arm mechanism. (See also: Regarding...) Figures 2A to 2D The description and Figure 3As summarized in the table, when the corresponding cam is on the base circle but not on the cam cam angle, the latch pin can move between the engaged and disengaged positions. During the compression stroke, the exhaust valve cam is on the base circle and therefore movable, but during the exhaust stroke, the exhaust valve cam is on the cam cam angle and therefore immovable. Therefore, assuming the current position of the latch pin is known, the controller can use a voltage of appropriate polarity to actuate the exhaust valve e-latch solenoid to induce movement. For example, if the latch pin is in the engaged position, then a voltage of the first polarity can be used to actuate the e-latch solenoid to attempt to move the latch pin to the disengaged position. In another example, if the latch pin is in the disengaged position, then a voltage of the second polarity opposite to the first polarity can be used to actuate the e-latch solenoid to attempt to move the latch pin to the engaged position. If the current position of the latch pin is unknown, then, for example, according to Figure 4 The method allows the latch pin position to be reset before executing method 900.

[0122] At 910, the method includes monitoring latch pin movement via an inductive characteristic of the e-latch solenoid during excitation. The inductive characteristic refers to the measured current passing through the e-latch solenoid during excitation. If the cam is on the base circle and the associated latch pin moves, this movement causes a momentary decrease in current (e.g., a change in the current slope), which manifests as a trough in the solenoid current during excitation, as per [reference to...]. Figure 14 To illustrate, when the cam is on the convex angle and the associated latch pin does not move, the solenoid current will increase steadily without any troughs before reaching the maximum current.

[0123] At 912, it can be determined whether latch pin movement was detected based on the generated sensing characteristics. In one example, if the sensing characteristics include a valley in the measured solenoid current and / or a change in the slope of the solenoid current, then latch pin movement can be confirmed, and if the sensing characteristics include a steady increase (e.g., no decrease) before reaching the maximum current, then no latch pin movement can be confirmed.

[0124] If latch pin movement is confirmed, then at 914, the method includes indicating that the piston of the given cylinder is in the compression stroke. At 916, after indicating that the piston is in the compression stroke, the method includes actuating the exhaust valve e-latch solenoid to return the latch pin of the given cylinder to its previous position. For example, if the exhaust valve latch pin begins in the engaged position, then the exhaust valve latch pin can be returned to the engaged position by actuating the associated solenoid using a voltage pulse of second polarity. In another example, if the exhaust valve latch pin begins in the disengaged position, then the exhaust valve latch pin can be returned to the disengaged position by actuating the associated solenoid using a voltage pulse of first polarity. In this way, unintentional changes in valve state (e.g., from active to inactive or from inactive to active) can be avoided.

[0125] Returning to 912, if latch pin movement is not confirmed, then at 918, the method includes indicating that the piston of a given cylinder is in the exhaust stroke. The method moves from each of 916 and 918 to 920 and includes inferring the camshaft position based on the crankshaft position (sensed from a crankshaft position sensor) and the indicated piston stroke. As an example, refer to... Figure 8 If the crankshaft is sensed to be at reference edge 830, then the crankshaft can be at 250 degrees or 610 degrees. If the solenoid of the exhaust valve on cylinder 1 is actuated and the latch pin is detected to have moved, then it can be determined that cylinder 1 is on the compression stroke and therefore the crankshaft is at angle 250 degrees instead of angle 610 degrees. As another example, if the latch pin of the exhaust valve on cylinder 1 does not move in response to actuation, then it can be determined that cylinder 1 is on the exhaust stroke and therefore the crankshaft is at angle 610 degrees instead of angle 250 degrees.

[0126] While the controller can determine the piston stroke by activating the exhaust valve e-latch solenoid corresponding to one cylinder (and subsequently the camshaft position via crankshaft position and piston stroke), in other examples, the exhaust valve e-latch solenoids of more than one cylinder can be activated, for example, activating two cylinders whose pistons are in their upstroke or activating each cylinder. In this example, the lack of movement of the exhaust valve latch pin determines the piston stroke (e.g., the exhaust stroke).

[0127] In alternative examples, the intake valve e-latch solenoid can be actuated in a similar manner when the piston is in the downstroke. For example, when the piston begins its downstroke, a given cylinder is in the intake stroke, during which the corresponding intake cam is on its convex angle and the latch pin is immovable; or a given cylinder is in the power stroke, during which the corresponding intake cam is on its base circle or the latch pin is movable. Based on whether the sensing characteristics of the intake valve e-latch solenoid indicate latch pin movement, the controller can distinguish between the power stroke (e.g., confirming latch pin movement) and the intake stroke (e.g., confirming the lack of latch pin movement). In some examples, the controller can determine camshaft timing based on the desired valve state, operating conditions, etc., during startup, prioritizing the use of the exhaust valve deactivation mechanism over the intake valve deactivation mechanism (and vice versa).

[0128] In this way, camshaft timing can be accurately detected without relying on a camshaft sensor, although such a sensor can be used separately. Furthermore, by determining camshaft timing without relying on misfire detection or crankshaft acceleration data, exhaust emissions can be improved.

[0129] Turn now Figure 10 This illustrates an exemplary method 1000 for detecting camshaft and crankshaft positions using an e-latch mechanism. Knowing the camshaft timing can improve fuel delivery accuracy. Figure 10 This method enables the determination of the camshaft position when crankshaft position data is unavailable (e.g., when the engine has been restarted from a standstill). Method 1000 can be used as... Figure 9 A portion of method 900 (e.g., at 906) is used to perform this.

[0130] At 1002, the method includes estimating and / or measuring engine operating conditions. These may include, for example, engine speed, engine load, torque demand, engine temperature, exhaust temperature, air-fuel ratio, and environmental conditions (e.g., ambient temperature, pressure, and humidity). Engine operating conditions may also include the operating states of the intake and exhaust valves. The latch pin position of each valve e-latch rocker arm mechanism (e.g., engaged or disengaged, respectively, when the valve is active or deactivated) can be inferred from the operating states of the intake and exhaust valves. If the current operating states of the intake and exhaust valves are unknown, the controller may, for example, determine based on... Figure 4 The corresponding latch pin is reset using this method.

[0131] At point 1004, it can be determined whether engine starting conditions exist. For example, it can be determined whether an engagement event has occurred, whether the starter motor has been engaged to start the engine without fuel, and / or whether the engine speed is at or below the engine starting speed. If engine starting is not confirmed, the method moves to point 1006 to maintain operating parameters. At this point, the crankshaft position is not obtained and cannot be determined, and therefore the camshaft position cannot be determined either.

[0132] If engine start is confirmed, then at 1008, the method includes energizing the intake valve e-latch solenoid of each engine cylinder and monitoring the corresponding sensing characteristics generated after energization to detect latch pin movement. For example, if the intake valve latch pin is in the engaged position, a voltage pulse of first polarity can be used to energize the corresponding solenoid to attempt to move the latch pin to the disengaged position. In another example, if the intake valve latch pin is in the disengaged position, a voltage pulse of second polarity opposite to the first polarity can be used to energize the corresponding solenoid to attempt to move the latch pin to the engaged position. As described above... Figure 9 As described at 910, a decrease in the sensing characteristic indicates latch pin movement. If the intake valve latch pin moves, the corresponding cylinder may be in its exhaust stroke, compression stroke, or power stroke, during which the corresponding intake cam is on the base circle and latch pin movement is possible. If the intake valve latch pin does not move, it is inferred that the corresponding cylinder is in its intake stroke, during which the corresponding intake cam is on the cam angle and no latch pin movement occurs. Using a four-cylinder engine as an example, at any (unknown) crankshaft position, one cylinder is in its intake stroke. Once the intake stroke cylinder is identified, the strokes of the remaining cylinders can be inferred based on the engine's known firing order. At 1009, method 1000 optionally includes re-energizing the intake valve e-latch solenoid corresponding to the previously moved latch pin to actuate the corresponding latch pin to the previous position. If a change in the intake valve state is not required, returning the latch pin to its previous (e.g., starting) position prevents unintentional deactivation (when the starting position is the engaged position) or activation (when the starting position is the disengaged position) of the corresponding intake valve. If the latch pin is actuated in the engaged position, a voltage pulse of the second polarity can be used to energize the corresponding solenoid to move the latch pin from the disengaged position back to the engaged position. If the latch pin is actuated in the disengaged position, a voltage pulse of the first polarity can be used to energize the corresponding solenoid to move the latch pin from the engaged position back to the disengaged position. In another example, 1009 can be omitted when a change in the intake valve state is required.

[0133] At 1010, the method includes determining the crankshaft position based on at least two of the crankshaft position sensor output, the intake camshaft position sensor output, and sensing characteristics of each intake valve e-latch solenoid. The controller can select the first two signals from the crankshaft position sensor output, the intake camshaft position sensor output, and the sensing characteristics of each intake valve e-latch solenoid, which provide available information for determining the crankshaft position. For example, the controller may spend a variable duration identifying a characteristic crankshaft reference edge signal (e.g., a "synchro pulse") from the crankshaft position sensor output and a characteristic camshaft reference edge signal from the camshaft position sensor output, based on the engine's starting position, engine speed, and ambient temperature. In contrast, the sensing characteristics of each e-latch solenoid reveal which cylinder is in the intake stroke at any (unknown) engine position.

[0134] Return to temporarily Figure 8 As an example, if the engine starting position is 450 degrees, the sensing characteristics of each intake valve e-latch solenoid will identify that cylinder 4 is in the intake stroke (shaded area 822). This piston stroke identification can be combined with a subsequent change in the signal from the camshaft position sensor to determine the crankshaft angle. For example, moving forward from the (unknown) crankshaft angle 450, the next change in the camshaft signal occurs at angle 530, where the signal changes from high to low. Combining the information that cylinder 4 is in the intake stroke with the detected change in the camshaft signal from high to low allows it to be determined that the engine is at angle 530 at that time. Determining the crankshaft signal to this level of accuracy requires that the intake camshaft be a fixed camshaft (e.g., not changeable or phase-shifted relative to the crankshaft), or that the camshaft is known to be in a specific phase position (e.g., default locked position) when performing method 1000. Pulses from the crankshaft signal can be used to update the crankshaft and camshaft angles forward from that point. As another example, if the engine starting position is 200 degrees, then the sensing characteristics of each intake valve e-latch solenoid will identify cylinder 3 as being in the intake stroke (shaded area 816). This piston stroke identification can be combined with a signal from the crankshaft as it rotates to identify the next crankshaft reference edge as angle 250 degrees. As another example, the crankshaft position sensor output can be combined with the camshaft position sensor output when the crankshaft reference edge and camshaft signal states are available before interpreting the sensing characteristics from the excitation latch pin solenoid.

[0135] Return to Figure 10At 1012, the method includes determining the intake camshaft position of each cylinder based on the sensing characteristics of each intake valve e-latch solenoid and further based on one of the inferred crankshaft position and the intake camshaft position sensor output. For example, particularly when a camshaft position sensor is not included or when the camshaft position sensor output has not yet identified the camshaft position, the inferred crankshaft position and the inferred cylinder stroke (e.g., determined by the sensing characteristics of each intake valve e-latch solenoid) can be used to determine the rotational orientation of the intake camshaft relative to the crankshaft. If the intake camshaft is a fixed camshaft whose angular position relative to the crankshaft cannot be changed, then the intake camshaft position can be calculated directly after the crankshaft position is known. In an alternative example, if a camshaft phasing mechanism can be used to change the intake camshaft and a camshaft position sensor is included, then the known crankshaft position information can be combined with the signal from the camshaft position sensor to determine the camshaft position, and the intake camshaft position can be determined without using sensing characteristics.

[0136] At 1014, the method includes determining the exhaust camshaft position for each cylinder based on the inferred intake camshaft position. For example, the exhaust camshaft position may be at a known offset (e.g., a few degrees of rotation) relative to the intake camshaft position. The exhaust camshaft position can then be determined using the inferred intake camshaft position and the known offset. In another example, both intake and exhaust camshafts may be included on a single camshaft. The method then terminates.

[0137] In an alternative example, the exhaust valve e-latch solenoid of each cylinder can be excited in a similar manner during crankshaft position determination. If the exhaust valve latch pin moves, the corresponding cylinder may be in its intake, compression, or power stroke, during which the corresponding exhaust cam is on the base circle and latch pin movement is possible. If the exhaust valve latch pin does not move, the corresponding cylinder is inferred to be in its exhaust stroke, during which the corresponding exhaust cam is on the camshaft and no latch pin movement occurs. Using a four-cylinder engine as an example, in any (unknown) crankshaft position, one cylinder is in its exhaust stroke. Once the exhaust stroke cylinder is identified, the strokes of the remaining cylinders can be inferred based on the engine's known firing order. In some examples, the controller can determine the crankshaft position based on the desired valve states, operating conditions, etc., during startup, prioritizing the use of the exhaust valve deactivation mechanism over the intake valve deactivation mechanism (and vice versa).

[0138] In this way, crankshaft timing and camshaft timing can be accurately detected with or without a camshaft sensor. The e-latch rocker arm mechanism provides additional signals that can be used to determine the crankshaft and / or camshaft positions, enabling rapid and reliable determination of these positions. This allows for accurate control of fuel injection timing and ignition timing, and reduces engine start-up time. Furthermore, by determining the camshaft position without relying on misfire detection or crankshaft acceleration data, exhaust emissions can be improved.

[0139] Next, Figure 11 An exemplary graph 1100 illustrates setting the intake valves of a four-cylinder engine to a desired operating state during engine start-up. For example, according to... Figure 4 An exemplary method may be used to set the intake valve to a desired operating state in response to an engine start request and before the intake valve camshaft timing is known. While the example of Figure 1100 illustrates setting the intake valve to a desired operating state, it should be understood that the exhaust valve may also be set to a desired operating state during engine start-up, and the desired operating state may differ from the desired intake valve operating state in some examples. Furthermore, in some examples, the desired intake valve operating state and / or exhaust valve operating state may differ for each cylinder. Graph 1102 shows the intake cam lift of cylinder 1, graph 1104 shows the intake valve solenoid voltage of cylinder 1, graph 1106 shows the intake cam lift of cylinder 2, graph 1108 shows the intake valve solenoid voltage of cylinder 2, graph 1110 shows the intake cam lift of cylinder 3, graph 1112 shows the intake valve solenoid voltage of cylinder 3, graph 1114 shows the intake cam lift of cylinder 4, graph 1116 shows the intake valve solenoid voltage of cylinder 4, graph 1118 shows the desired intake valve state (e.g., for all four cylinders), and graph 1120 shows the engine state. For all the above graphs, the horizontal axis represents time, where time increases from left to right along the horizontal axis. In addition to curves 1118 and 1120, the vertical axis represents each labeled parameter, where the value of the labeled parameter increases from bottom to top along the vertical axis. In curve 1118, the vertical axis indicates whether the desired valve state is active or deactivated. As labeled, in curve 1120, the vertical axis indicates whether the engine is on (e.g., operating at non-zero speeds, where combustion occurs in the engine cylinders) or off (e.g., at rest, where no combustion occurs in the cylinders). In curves 1102, 1106, 1110, and 1114, intake cam lift refers to the cam (e.g., in...) Figures 2A to 2DThe radius of the base circle of the cam with convex angle 151b (on the convex angle of the cam), the radius of which changes as the cam rotates against the cam follower during engine operation.

[0140] Before time t1, the engine is shut off, as shown in curve 1120. During the previous engine shutdown, the intake valves are kept active (curve 1118) so that each intake valve can open in response to the intake cam lift. For example, the latch pin of each intake valve e-latch rocker arm mechanism is in the engaged position, as per [reference to...]. Figures 2A to 2D Explain and Figure 3 As summarized in the table. When the engine is off, the intake cam of each cylinder does not rotate. The intake cams of cylinder 1 (Figure 1102), cylinder 3 (Figure 1110), and cylinder 4 (Figure 1114) lie on their base circles, as illustrated by zero intake cam lift. Therefore, the corresponding intake valve e-latch rocker arm mechanism of each of cylinders 1, 3, and 4 is unloaded, and the latch pin of each of the e-latch rocker arm mechanisms is movable. The intake cam of cylinder 2 (Figure 1106) lies on its convex angle, as illustrated by non-zero intake cam lift. Therefore, the corresponding intake valve e-latch rocker arm mechanism is loaded, and the latch pin of the intake valve e-latch rocker arm mechanism of cylinder 2 is immovable.

[0141] At time t1, the requested engine starts, and the engine state changes to "on" (Graph 1120). In response to the engine start request, the intake valves need to be deactivated (Graph 1118) to reduce the air springs in each cylinder during engine start. However, the engine controller (e.g., Figure 1 The controller 12) may no longer be aware of the cam position of each intake valve, such as the raised position of the intake cam of cylinder 2 (Figure 1106), and may no longer be aware of the latch pin position of each intake valve e-latch rocker arm mechanism. Between time t1 and time t2, a voltage pulse with a first polarity (e.g., positive voltage) is used to excite the solenoid of each intake valve e-latch rocker arm mechanism in an attempt to move any latched latch pin to the disengaged position (Figures 1104, 1108, 1112, and 1116). Since the intake cams of cylinders 1, 3, and 4 are on the base circle (Figures 1102, 1110, and 1114, respectively), the latch pins of the corresponding intake valve e-latch rocker arm mechanisms move from the engaged position to the disengaged position of the deactivated valve. If the inductive characteristics of each solenoid are monitored, the latch pin movement appears as a momentary decrease in the solenoid current, as shown in Figure 1104. Figure 12As shown in the diagram, because the intake cam of cylinder 2 is raised during the excitation period (e.g., between time t1 and time t2), the intake valve latch pin of cylinder 2 does not move. Therefore, at time t2, the intake valves of cylinders 1, 3, and 4 are deactivated, while the intake valve of cylinder 2 remains active, wherein the latch pin of the intake valve is in the engaged position.

[0142] At time t3, the threshold rotation indicated by line 1122 is reached. (See also: Regarding...) Figure 4 As described, the threshold rotation corresponds to the maximum valve duration, after which any raised cam will return to the base circle. Therefore, between time t3 and time 4, a voltage pulse of the first polarity is used to re-energize the intake valve e-latch solenoid of each cylinder (curves 1104, 1108, 1112, and 1116). At time t3, the intake cam of cylinder 2 is no longer raised (curve 1106), and thus the intake valve latch pin of cylinder 2 moves from the engaged position to the disengaged position. Because the intake valves of cylinders 1, 3, and 4 have been deactivated, with their corresponding intake valve latch pins in the disengaged position, re-energizing their intake valve e-latch solenoids using a voltage pulse of the first polarity will not further move the corresponding latch pins or change the valve operating state. Therefore, at time t4, all intake valves are deactivated. In this way, engine starting is facilitated by disabling the cylinder intake valves even without knowing the cam position or starting valve status of each cylinder.

[0143] Figure 12 An exemplary graph 1200 is shown illustrating the diagnostic process of the cylinder valve deactivation mechanism during engine transition to and from VDE operating mode. For example, according to... Figure 5 This method allows the engine to switch between VDE and non-VDE operating modes, and can be based on... Figures 6A to 6BThe method described above is used to diagnose the cylinder valve deactivation mechanism. Engine speed is shown in graph 1202, commanded valve state in graph 1204, camshaft lift in graph 1206, solenoid voltage in graph 1208, solenoid current in graph 1210, latch pin position in graph 1212, and an indication of valve deactivation mechanism deterioration in graph 1214. For all the above graphs, the horizontal axis represents time, which increases from left to right along the horizontal axis. In addition to graphs 1204, 1212, and 1214, the vertical axis represents each labeled parameter, with the value of each labeled parameter increasing from bottom to top along the vertical axis. In graph 1204, the vertical axis shows the commanded valve state (e.g., as labeled “active” or “disengaged”), in graph 1212, the vertical axis shows the latch pin position (e.g., as labeled “engaged” or “disengaged”), and in graph 1214, the vertical axis shows whether degradation is indicated (e.g., “yes” or “no”). In the example of graph 1200, the commanded valve state (graph 1204), camshaft lift (graph 1206), solenoid voltage (graph 1208), solenoid current (graph 1210), and latch pin position (graph 1212) of a single valve are shown, as well as an indication of valve deactivation mechanism deterioration (graph 1214). The valve can be a cylinder exhaust valve or a cylinder intake valve. It should be understood that multiple valves can be controlled simultaneously and operated similarly.

[0144] Before time t1, the engine is started and operates at a non-zero speed greater than the threshold speed (graph 1202) to perform low-speed VDE mechanism diagnostics (indicated by dashed line 1216). Therefore, the valve deactivation mechanism can be diagnosed when the valve state is commanded to change and not when the valve state is not commanded to change (e.g., Figures 2A to 2D Valve deactivation mechanism 252). Furthermore, before time t1, the valve is in the commanded active valve state (graph 1204). Valve deactivation mechanism (e.g., Figures 2A to 2D The latch pin 214 is in the engaged position (curve 1212), allowing the valve to open due to the cam lob lift (curve 1206), as per [reference to...]. Figure 2C As described.

[0145] At time t1, the valves are commanded to deactivate (Graph 1204) to allow the engine to operate in VDE mode. In response to the commanded change in valve state, a voltage pulse with a first (e.g., positive) polarity is used to excite the solenoid of the valve deactivation mechanism (e.g., ...). Figures 2A to 2DThe solenoid 216 (Graph 1208). When the solenoid is excited, the solenoid current increases (Graph 1210), thus generating an inductive characteristic. As the solenoid current increases, the magnetic field of the solenoid expands and acts on the latch pin. Because the cam lob lift is zero, it indicates that the cam is at its base circle (e.g., in...). Figures 2A to 2D On the base circle 151a shown in the figure, the corresponding latch pin is expected to move due to the magnetic force.

[0146] During the excitation period, at time t2, the solenoid current (Figure 1210) begins to decrease (e.g., the slope of the current changes), thus indicating the movement of the latch pin. At time t3, the solenoid current (Figure 1210) reaches a local minimum, indicating that the latch pin has completed its movement from the engaged position to the disengaged position (Figure 1212). Therefore, the characteristics of the solenoid current (Figure 1210) show the inductive characteristics indicating the expected movement of the latch pin and do not indicate deterioration of the valve deactivation mechanism (Figure 1214).

[0147] After time t3, the solenoid current (curve 1210) increases until it reaches its maximum, and then decays after the voltage pulse ends (curve 1208). With the latch pin in the disengaged position, the corresponding valve is deactivated and will not open in response to camshaft lift, as per [reference to...]. Figure 2D As described. The duration between time t1 and time t3 corresponds to the solenoid response time (e.g., the amount of time taken from energizing the solenoid to the latch pin completing its movement). The controller can learn the solenoid response time to achieve inter-part adaptation and operate within an increased RPM range, as described regarding Figure 6A As described.

[0148] However, if the valve deactivation mechanism has deteriorated, the inductive characteristics of the solenoid current can indicate that the latch pin has not moved in response to solenoid excitation, as shown, for example, in short dashed segment 1210a. In short dashed segment 1210a, the solenoid current continues to increase until it reaches a maximum value, without decreasing at time t2 and without reaching a local minimum at time t3. Therefore, the inductive characteristics of the solenoid indicate that no latch pin has moved, although the latch pin could move (e.g., the camshaft lift is zero). The latch pin is stuck in the engaged position (short dashed segment 1212a) and indicates deterioration of the valve deactivation mechanism (short dashed segment 1214a).

[0149] At time t4, the command valve is activated (Figure 1204). For example, this can switch the engine to a non-VDE operating mode. At the time of command valve activation, the camshaft lift (Figure 1206) is close to its maximum lift. When the camshaft lift is close to its maximum lift, the corresponding rocker arm is under load, and the latch pin movement in response to solenoid excitation is not expected. Therefore, the controller can wait until the camshaft approaches the base circle to begin excitation.

[0150] At time t5, as the cam lobe lift decreases (Figure 1206) and approaches its return to the base circle, a voltage pulse with a second (e.g., negative) polarity is used to excite the solenoid (Figure 1208), allowing the latch pin to be pulled into the engaged position as soon as the cam returns to the base circle and the associated rocker arm becomes unloaded. At time t7, as the cam lobe reaches the base circle and the latch pin begins to move, the solenoid current begins to decrease (Figure 1210). The controller can record the cam angle at time t7 to confirm the cam position. At time t8, the local minimum of the solenoid current (Figure 1210) indicates that the latch pin has completed its return to the engaged position (Figure 1212). Because the latch pin moves as expected when the cam returns to the base circle (e.g., the cam lobe lift is zero), it does not indicate deterioration of the valve deactivation mechanism (Figure 1214).

[0151] If the solenoid current decreases earlier than expected at time t6, as shown in dashed segment 1210c, then a worn cam lobe may be detected. A worn cam lobe results in a smaller cam lobe lift and a faster return to the base circle, as shown in dashed segment 1206c, and the latch pin transitions from the disengaged position to the engaged position earlier (dashed segment 1212c). In response to the detection of a worn cam lobe, the controller can preferentially deactivate the corresponding cylinder, as per [reference to...]. Figure 6A As described. In this way, the deterioration of the valve deactivation mechanism and the camshaft itself can be identified.

[0152] Next, Figure 13 For example, according to Figure 7The method diagnoses the cylinder valve deactivation mechanism during low-speed engine operation and without commanded changes to valve operating states, as illustrated in exemplary graph 1300. Graph 1302 shows engine speed, graph 1304 shows the commanded valve state, graph 1306 shows camshaft lift, graph 1308 shows solenoid voltage, graph 1310 shows solenoid current, graph 1312 shows latch pin position, and graph 1314 shows an indication of valve deactivation mechanism deterioration. For all the above graphs, the horizontal axis represents time, where time increases from left to right along the horizontal axis. In addition to graphs 1304, 1312, and 1314, the vertical axis represents each marked parameter, with the value of each marked parameter increasing from bottom to top along the vertical axis. In graph 1304, the vertical axis shows the commanded valve state (e.g., as marked "active" or "disengaged"). In graph 1312, the vertical axis shows the latch pin position (e.g., as marked "engaged" or "disengaged"). In graph 1314, the vertical axis shows whether degradation is indicated (e.g., "yes" or "no"). In the example of graph 1300, the commanded valve state (graph 1304), camshaft lift (graph 1306), solenoid voltage (graph 1308), solenoid current (graph 1310), latch pin position (graph 1312), and indication of valve deactivation mechanism deterioration (graph 1314) for a single valve are shown. The valve can be a cylinder exhaust valve or a cylinder intake valve. It should be understood that multiple valves can be operated simultaneously and similarly.

[0153] Before time t1, the engine is started and operates at a non-zero speed below the threshold speed (graph 1302) to perform low-speed VDE mechanism diagnostics (indicated by dashed line 1316). Therefore, valve deactivation mechanisms can be diagnosed without commanding a change in valve state (e.g., Figures 2A to 2D Valve deactivation mechanism 252). Furthermore, before time t1, the valve is in the commanded active valve state (graph 1304). Valve deactivation mechanism (e.g., Figures 2A to 2D The latch pin 214 is in the engaged position (curve 1312), allowing the valve to open due to the cam lob lift (curve 1306), as per the relevant... Figure 2C As described.

[0154] At time t1, the cam lob lift is zero (Graph 1306), thus indicating that the cam is at its base circle (e.g., at time t1). Figures 2A to 2D On the base circle 151a shown in the diagram. Due to the low engine speed, there is sufficient time for the cam to rotate away from the base circle and rotate to its lobed angle (e.g., at the base circle). Figures 2A to 2DThe latch pin is actuated from the engaged position to the disengaged position and returned to the engaged position before being moved to the convex angle 151b shown in the diagram. To check for deterioration of the valve deactivation mechanism, a voltage pulse of the first (e.g., positive) polarity is used to excite the solenoid of the valve deactivation mechanism (e.g., ...). Figures 2A to 2D The solenoid 216 (Figure 1308). When the solenoid is excited, the solenoid current increases (Figure 1310), thus generating an inductive characteristic. As the solenoid current increases, the magnetic field of the solenoid expands and acts on the latch pin. Because the cam cam lift is zero and the corresponding e-latch rocker arm mechanism is unloaded, the latch pin is expected to move due to the force of the magnetic field.

[0155] During the excitation period, at time t2, the solenoid current (Figure 1310) begins to decrease (e.g., the slope of the current changes), thus indicating the movement of the latch pin. At time t3, the solenoid current (Figure 1310) reaches a local minimum, indicating that the latch pin has completed its movement from the engaged position to the disengaged position (Figure 1312). Therefore, the characteristics of the solenoid current (Figure 1310) show the inductive characteristics indicating the expected movement of the latch pin and do not indicate deterioration of the valve deactivation mechanism (Figure 1314).

[0156] After time t3, the solenoid current (graph 1310) increases until it reaches its maximum current, and then decays after the voltage pulse ends (graph 1308). The duration between time t1 and time t3 corresponds to the solenoid response time (e.g., the amount of time taken from energizing the solenoid to the latch pin completing its movement). The controller can learn about this solenoid response time to achieve inter-part adaptation and operate within an increased RPM range, as per [reference to...]. Figure 6A As described. With the latch pin in the disengaged position, the corresponding valve is deactivated and will not open in response to camshaft lift, as per the description. Figure 2D As described. However, valve deactivation is not required, as indicated by the commanded valve state of the remaining activity (Figure 1304). Therefore, at time t4, a voltage pulse of second (e.g., negative) polarity is used to re-excite the solenoid to move the latch pin back to the engaged position. The movement of the latch pin from the disengaged position to the engaged position is confirmed by the characteristic current decrease at time t5 and the local minimum of the solenoid current at time t6 as the latch pin completes its movement to the engaged position (Figure 1312) (Figure 1310). The successful return of the latch pin to the engaged position does not indicate deterioration of the valve deactivation mechanism (Figure 1314).

[0157] However, if the valve deactivation mechanism has deteriorated, the inductive characteristics of the solenoid current can indicate that the latch pin has not moved in response to solenoid excitation, as shown, for example, by the short dashed segment 1310a (e.g., during a voltage pulse of the first polarity) and the dotted segment 1310b (e.g., during a voltage pulse of the second polarity). In the short dashed segment 1310a, the solenoid current increases until it reaches a maximum value without decreasing at time t2 and without reaching a local minimum at time t3. Therefore, the inductive characteristics of the solenoid indicate that no latch pin has moved, although the latch pin could move (e.g., the camshaft lift is zero, as shown in graph 1306). The latch pin is stuck in the engaged position (short dashed segment 1312a) and indicates deterioration of the valve deactivation mechanism (short dashed segment 1314a). Similarly, in the dotted segment 1310b, the solenoid current increases until it reaches a maximum value without decreasing at time t5 and without reaching a local maximum at time t6. Therefore, the solenoid's sensing characteristics indicate no latch pin movement, even though the latch pin could move. The latch pin is either stuck in the engaged position or already in the engaged position. If trajectory 1310 has been followed between time t1 and time t4, indicating successful disengagement of the latch pin, then it can be concluded that the trajectory of dashed segment 1310b indicates the latch pin is stuck in the disengaged position and indicates deterioration of the valve deactivation mechanism (dotted segment 1314b). However, if the trajectory of short dashed segment 1310a has been followed between time t1 and time t4, then the latch pin does not move to the disengaged position during that time period. The trajectory of dashed segment 1310b will then indicate that the latch pin is still stuck in the engaged position.

[0158] The cam lobe lift (curve 1306) is at lift at time t7. In the case of cam lobe lift, the corresponding rocker arm is loaded, and latch pin movement in response to solenoid excitation is not expected. At time t7, a voltage pulse of the first polarity is used to excite the solenoid to check for deterioration of the valve deactivation mechanism, specifically to see if the latch pin remains in the engaged position when the rocker arm is loaded. During excitation, the solenoid current (curve 1310) increases until it reaches a maximum and does not decrease. Therefore, the sensing characteristics indicate that the latch pin has not moved and remains in the engaged position as expected (curve 1312), and do not indicate deterioration of the valve deactivation mechanism (curve 1314). However, if the sensing characteristics show a decrease in the characteristic indicating latch pin movement and a local minimum (as shown in dashed segment 1310c), then it can be inferred that the latch pin has unexpectedly moved to the disengaged position (dashed segment 1312c). In response to the movement of the latch pin indicated by the sensing feature when the cam is raised, the valve deactivation mechanism is deteriorated (dashed segment 1314c).

[0159] Next, Figure 14 For example, according to Figure 9The method for determining the camshaft position based on the sensing characteristics of the e-latch rocker arm mechanism solenoid when the crankshaft position is known is illustrated in exemplary graph 1400. Graph 1402 shows the piston position, graph 1404 shows the exhaust cam lobe lift of a first example, graph 1406 shows the exhaust valve solenoid voltage of a first example, graph 1408 shows the exhaust valve solenoid current of a first example, and graph 1410 shows the latch pin position of a first example. For comparison purposes, the exhaust cam lobe lift of a second example is shown in dashed graph 1405, the exhaust valve solenoid voltage of a second example is shown in dashed graph 1407, the exhaust valve solenoid current of a second example is shown in dashed graph 1409, and the latch pin position of a second example is shown in graph 1411. For all the above graphs, the horizontal axis represents time, where time increases from left to right along the horizontal axis. In addition to graphs 1410 and 1411, the vertical axis represents each labeled parameter, with the value of each labeled parameter increasing from bottom to top along the vertical axis. In graphs 1410 and 1411, the vertical axis shows the latch pin position (e.g., as labeled "engaged" or "disengaged"). The piston position relative to bottom dead center (BDC) and top dead center (TDC) is shown (graph 1402).

[0160] At time t1, the controller (e.g., Figure 1 The controller 12) determines the BDC position of the cylinder based on the output of the crankshaft position sensor (not shown). However, the camshaft position is unknown, and therefore the controller does not know whether the piston is at the BDC of the intake stroke or the power stroke. That is, the controller does not know whether the exhaust cam of the cylinder has the lift profile shown in the curve diagram 1404 or the dashed curve diagram 1405.

[0161] The latch pin of the exhaust valve e-latch rocker arm mechanism (e.g., Figures 2A to 2DThe latch pin 214 is known to be in the engaged position (Figure 1410). As the piston rises during the upstroke, at time t2, a voltage pulse with a first (e.g., positive) polarity is used to excite the exhaust valve e-latch solenoid (Figure 1406) to attempt to move the latch pin from the engaged position to the disengaged position. The resulting solenoid current is monitored for the torque on the associated latch pin. In the first example, the cylinder is in the exhaust stroke, and the exhaust cam lob is raised (Figure 1404). With the exhaust cam lob raised, the corresponding exhaust valve e-latch rocker arm mechanism is loaded, thereby preventing the latch pin from moving. The solenoid current (Figure 1408) continues to increase until it reaches a maximum current, thus producing a sensing characteristic indicating that no latch pin movement has occurred. Because no latch pin movement is detected during solenoid excitation, it is inferred that the exhaust valve latch pin remains in the engaged position (Figure 1410) and the cylinder is in the exhaust stroke. Identifying the exhaust stroke allows the controller to determine the orientation of the camshaft relative to a known crankshaft position.

[0162] In the second example, when the exhaust valve solenoid is actuated at time t2, the cylinder is in the compression stroke. With the cylinder in the compression stroke, the exhaust camshaft is on its base circle, where the cam lift is zero at time t2 (dashed curve, Figure 1405). The exhaust valve rocker arm mechanism is unloaded, allowing the latch pin to move in response to the solenoid actuation. The solenoid current increases and then momentarily decreases until it reaches a local minimum at time t3 (dashed curve, Figure 1409), indicating that the latch pin has moved from the engaged position to the disengaged position (dashed curve, Figure 1411). Because latch pin movement is detected during solenoid actuation, it is inferred that the cylinder is in the compression stroke. Identification of the compression stroke allows the controller to determine the orientation of the camshaft relative to the known crankshaft position.

[0163] Because valve deactivation is not required, in the second example, a second voltage pulse of opposite polarity (dashed curve 1407) is supplied to the exhaust valve solenoid before the exhaust camshaft moves away from the base circle. Consequently, the exhaust valve latch pin moves back to the engaged position (dashed curve 1411), as indicated by the exhaust valve solenoid current reaching a local minimum at time t5 (dashed curve 1409). In this way, the cylinder stroke is determined by using the sensing characteristics of the exhaust valve e-latch solenoid, thus determining the camshaft position without the output of a camshaft position sensor.

[0164] Figure 15 For example, according to Figure 10The method is based on the sensing characteristics of the e-latch rocker arm mechanism solenoid and the output of the crankshaft position sensor to determine the crankshaft and camshaft positions in a fixed-cam four-cylinder engine, as illustrated in exemplary curve 1500. While the example of curve 1500 shows the use of an intake valve deactivation mechanism to determine the crankshaft and camshaft positions, it should be understood that an exhaust valve deactivation mechanism can be used alternatively. The intake valve solenoid voltage of cylinder 1 is shown in curve 1502; the intake valve solenoid current of cylinder 1 is shown in curve 1504; the intake valve solenoid voltage of cylinder 2 is shown in curve 1506; the intake valve solenoid current of cylinder 2 is shown in curve 1508; the intake valve solenoid voltage of cylinder 3 is shown in curve 1510; the intake valve solenoid current of cylinder 3 is shown in curve 1512; the intake valve solenoid voltage of cylinder 4 is shown in curve 1514; the intake valve solenoid current of cylinder 4 is shown in curve 1516; and the crankshaft position sensor (e.g., [missing information]) is shown in curve 1518. Figure 1 The output of the Hall effect sensor 120. For all the above graphs, the horizontal axis represents time, where time increases from left to right along the horizontal axis. The vertical axis represents each labeled parameter, where the value of the labeled parameter increases from bottom to top along the vertical axis. In the example of graph 1500, the engine does not include a camshaft position sensor.

[0165] Before time t1, the engine is started from rest, and the crankshaft and camshaft positions are unknown. Therefore, the engine controller (e.g., Figure 1 The controller 12) is unable to accurately time the fuel and spark delivery. Additionally, it is known that each intake valve latch pin is in the engaged position (e.g., each intake valve e-latch rocker arm mechanism is latched).

[0166] At time t2, a voltage pulse of first (e.g., positive) polarity is used to excite the intake valve e-latch solenoid of each cylinder (curves 1502, 1506, 1510, and 1514). During this excitation, the current of each solenoid is monitored to detect inductive characteristics indicating the movement of the corresponding latch pin. At time t3, local minimums of the solenoid current in cylinder 1 (curve 1504), cylinder 3 (curve 1512), and cylinder 4 (curve 1516) indicate that the corresponding latch pin has moved (e.g., from the engaged position to the disengaged position). A steady increase in current and the absence of a local minimum in the solenoid of cylinder 2 indicate that the intake valve latch pin of cylinder 2 has not yet moved. Therefore, the controller infers that the intake cam of cylinder 2 is on its convex angle, thus placing cylinder 2 in the intake stroke.

[0167] Between time t3 and time t4, a gap exists in the crankshaft position sensor output, representing a missing tooth on the pulse wheel connected to the crankshaft. Due to this gap in the output, at time t4, when the square wave signal returns, a crankshaft reference edge (e.g., regarding...) is identified. Figure 8 (As described). Due to the known relationship between the crankshaft position and intake stroke of cylinder 2, the controller can infer that the identified crankshaft reference edge is correct and not due to a missing signal. The crankshaft reference edge corresponds to the known rotational orientation of the crankshaft, thus enabling the determination of the crankshaft position. Furthermore, due to the known relationship between the crankshaft position, cylinder stroke, and camshaft position, the camshaft position is determined relative to the crankshaft position.

[0168] exist Figure 15 In the example, the intake valves need to be deactivated during engine start-up, and the intake valve latch pins of cylinders 1, 3, and 4 have been actuated to the disengaged position, thus deactivating the corresponding intake valves at time t3. However, the intake valve of cylinder 2 remains in the engaged position. Therefore, when the intake cam of cylinder 2 is on the base circle (not shown) at time t5, the intake valve solenoid of cylinder 2 is re-energized using a voltage pulse of the first polarity (Figure 1506) to move the intake valve latch pin of cylinder 2 to the disengaged position. The latch pin movement is confirmed based on the instantaneous decrease in the intake valve solenoid current of cylinder 2 during the energization period (Figure 1508). However, in other examples, when a change in valve operating state is not required, the latch pins of cylinders 1, 3, and 4 can be returned to their energized positions.

[0169] In this way, by inferring the presence or absence of movement of the latch pin of the cylinder valve deactivation mechanism based on the current characteristics of the associated solenoid, the movement of the latch pin can be correlated with VDE operation. A technical aspect of verifying whether the latch pin moves when the associated solenoid is energized is that the cylinder valve deactivation mechanism can be reliably diagnosed with reduced reliance on dedicated sensors. By timely diagnosing and mitigating problems associated with VDE mechanism deterioration, engine misfire rates can be reduced, while also extending the fuel economy benefits of VDE operation. The diagnosis can be performed before operating the VDE mechanism on a driving cycle by performing the diagnosis during the idle period after activation. Alternatively, by performing the diagnosis at appropriate times on a driving cycle when operating the VDE mechanism according to changing engine speed-load, the diagnosis can be performed without intrusively commanding undesirable VDE states. The technical advantage of correlating the expected movement of the latch pin with the position of the camshaft corresponding to the actuated cylinder valve is that the camshaft position can be known with reduced reliance on camshaft position sensors. Furthermore, the aforementioned correlation can be used to identify the piston stroke of a cylinder and infer the state of the corresponding cylinder valve or associated rocker arm. By understanding camshaft and crankshaft timing based on latch pin movement, fuel can be delivered to the engine more accurately, especially during engine restart events. Similarly, cylinder fuel delivery timing can be optimized by placing valves in a target state during engine start-up, for example, by placing the intake and exhaust valves of at least the first cylinder to be ignited during engine restart in the desired start-up or deactivation state. Engine startability is improved by enhancing combustion torque generation. Costs can be reduced by understanding camshaft position, crankshaft position, and valve or rocker arm state while minimizing the need for dedicated sensors. Additionally, the outputs of existing sensors can be validated. Overall, the performance of engines equipped with selective cylinder deactivation can be improved.

[0170] For example, a method for an engine includes: actuating an electronic latch pin of a cylinder valve deactivation mechanism coupled to a cam-actuated cylinder valve via a solenoid; and estimating camshaft timing based on an inferred latch pin movement during said actuation. In the foregoing example, the method further or optionally includes inferring latch pin movement based on induced current characteristics of the solenoid, said characteristics including the positions of current peaks and troughs and the slope of said current. In any or all of the foregoing examples, the method further or optionally includes adjusting cylinder fuel injection timing based on said estimated camshaft timing. In any or all of the foregoing examples, the method further or optionally includes estimating crankshaft position based on said inferred latch pin movement during said actuation, and wherein said cylinder fuel injection timing is further adjusted based on said estimated crankshaft position. In any or all of the foregoing examples, further or optionally, said actuation includes energizing the solenoid to move the latch pin from an engaged position to a disengaged position or from said disengaged position to said engaged position. In any or all of the foregoing examples, additionally or optionally, the cylinder valve is the exhaust valve of the cylinder, and the solenoid is actuated when the piston of the cylinder is in the upstroke. In any or all of the foregoing examples, additionally or optionally, the estimation includes: indicating that the piston of the cylinder is in the exhaust stroke in response to the absence of latch pin movement; and indicating that the piston of the cylinder is in the compression stroke in response to the presence of latch pin movement. In any or all of the foregoing examples, additionally or optionally, the cylinder valve is the intake valve of the cylinder, and the solenoid is actuated when the piston of the cylinder is in the downstroke. In any or all of the foregoing examples, additionally or optionally, the estimation includes: indicating that the piston of the cylinder is in the intake stroke in response to the absence of latch pin movement; and indicating that the piston of the cylinder is in the power stroke in response to the presence of latch pin movement. In any or all of the foregoing examples, additionally or optionally, the estimation of the camshaft timing is further based on the crankshaft position sensed via a crankshaft position sensor.

[0171] As another example, a method for an engine includes: energizing a solenoid of a cylinder valve deactivation mechanism coupled to a valve actuated by a cam; inferring the stroke of the cylinder based on a current in the solenoid during the energization; and estimating a camshaft position based on the inferred cylinder stroke. In the foregoing example, additionally or optionally, the cylinder valve deactivation mechanism includes a latching pin, and energizing the solenoid causes the latching pin to move between an engaged position and a disengaged position when the cam is on its base circle and not when the cam is raised. In any or all of the foregoing examples, additionally or optionally, the presence of latching pin movement is inferred based on the presence of a local current minimum when the current increases to its maximum value, and the absence of latching pin movement is inferred based on the absence of the local current minimum when the current increases to the maximum value. In any or all of the foregoing examples, additionally or optionally, the valve is an exhaust valve, and inferring the cylinder stroke based on the current in the solenoid during the excitation period includes inferring the exhaust stroke in response to the absence of latch pin movement. In any or all of the foregoing examples, additionally or optionally, the valve is an intake valve, and inferring the cylinder stroke based on the current in the solenoid during the excitation period includes inferring the intake stroke in response to the absence of latch pin movement. In any or all of the foregoing examples, the method additionally or optionally further includes adjusting the cylinder fuel injection timing based on the estimated camshaft position. In any or all of the foregoing examples, additionally or optionally, the estimation of the camshaft position is further based on the engine crankshaft position retrieved from a crankshaft position sensor during a first condition, and wherein the inferred cylinder stroke is further used to determine the engine crankshaft position during a second condition.

[0172] As another example, an engine system includes: an engine cylinder including an intake valve and a fuel injector; an intake cam mounted on an intake camshaft for opening and closing the intake valve; and a valve deactivation mechanism coupled to the intake valve, the mechanism including a rocker arm assembly and a latching pin, the inner arm of the rocker arm assembly being coupled to the cam via a cam follower and to a rod of the intake valve, the outer arm of the rocker arm assembly being coupled to the latching pin, and the inner arm being engageable via the latching pin to the intake valve. An outer arm; an electric solenoid coupled to the latch pin; and a controller having computer-readable instructions that, upon execution, cause the controller to: actuate the solenoid to actuate the latch pin; measure an induced current generated by the solenoid after actuation; infer a movement of the latch pin after actuation based on the measured induced current; estimate an intake camshaft position based on the inferred movement; and adjust the pulse width of a command to the fuel injector based on the estimated intake camshaft position. In the foregoing example, the system may additionally or optionally include a crankshaft, an exhaust valve, and an exhaust camshaft, and wherein the controller includes additional instructions that, upon execution, cause the controller to: estimate a crankshaft position based on the inferred movement, an output from a crankshaft position sensor coupled to the crankshaft, and an output from a camshaft position sensor coupled to the intake camshaft; update the intake camshaft position based on the estimated crankshaft position; and estimate the exhaust camshaft position based on the estimated intake camshaft position. In any or all of the foregoing examples, additionally or optionally, the controller estimates the intake camshaft position based on the inferred movement by: indicating that the piston of the cylinder is in the intake stroke in response to the absence of the inferred latch pin movement; and indicating that the piston of the cylinder is in the compression stroke, power stroke, or exhaust stroke in response to the presence of the inferred latch pin movement.

[0173] In another representation, a method for an engine includes: actuating a latch pin of a valve deactivation mechanism of a cam-actuated valve coupled to a cylinder; inferring movement of the latch pin during said actuation; estimating a camshaft position based on said inferred movement; and adjusting the fuel injection timing and ignition timing of the cylinder based on said estimated camshaft position. In the foregoing examples, additionally or optionally, actuating the latch pin includes energizing a solenoid coupled to the latch pin using a voltage pulse. In any or all of the foregoing examples, additionally or optionally, inferring movement of the latch pin during said actuation includes: measuring a current in the solenoid during said energization; indicating the presence of movement in response to a brief decrease in the current when said current increases to a maximum value; and indicating the absence of movement in response to the current increasing to said maximum value without a brief decrease. In any or all of the foregoing examples, additionally or optionally, the cam-actuated valve is an exhaust valve, and said actuation is performed when the piston in the cylinder is in its upstroke. In any or all of the foregoing examples, additionally or optionally, estimating the camshaft position based on the inferred movement includes indicating that the cylinder is in the exhaust stroke in response to the absence of movement; and indicating that the cylinder is in the compression stroke in response to the presence of movement. In any or all of the foregoing examples, additionally or optionally, the cam-actuated valve is an intake valve, and the actuation is performed when the piston in the cylinder is in the downstroke. In any or all of the foregoing examples, additionally or optionally, estimating the camshaft position based on the inferred movement includes indicating that the cylinder is in the intake stroke in response to the absence of movement; and indicating that the cylinder is in the power stroke in response to the presence of movement. In any or all of the foregoing examples, additionally or optionally, the estimation of the camshaft position is further based on the crankshaft position measured by a crankshaft position sensor.

[0174] It should be noted that the exemplary control and estimation routines included herein can be used in various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system comprising a combination of controllers and various sensors, actuators, and other engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, etc. Therefore, the various actions, operations, and / or functions described can be executed in the illustrated sequence, in parallel, or in some cases omitted. Similarly, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for the sake of simplicity of illustration and description. One or more of the illustrated actions, operations, and / or functions can be repeatedly executed according to the specific strategy used. Furthermore, the described actions, operations, and / or functions can clearly represent code to be programmed into a non-transitory memory of a computer-readable storage medium in the engine control system, wherein the described actions are implemented by executing instructions in a system comprising a combination of various engine hardware components and electronic controllers.

[0175] It will be understood that the configurations and routines disclosed herein are exemplary in nature and should not be viewed in a limiting sense, as numerous variations are possible. For example, the above techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations disclosed herein with other features, functions, and / or properties.

[0176] The appended claims specifically point to particular combinations and sub-combinations considered novel and non-obvious. These claims may refer to an element or a first element or its equivalent. Such claims should be understood to include one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amending these claims or by presenting new claims in this or related applications. Such claims, whether broader, narrower, equivalent, or different in scope from the original claims, are also considered to be included within the subject matter of this disclosure.

[0177] According to the present invention, a method for an engine includes: actuating an electronic latch pin of a cylinder valve deactivation mechanism coupled to a cam-actuated cylinder valve via a solenoid; and estimating camshaft timing based on a deduced latch pin movement during said actuation.

[0178] According to the implementation scheme, the invention is further characterized in that the movement of the latch pin is inferred based on the induced current characteristics of the solenoid, the characteristics including one or more of the positions of the current peaks and valleys and the slope of the current.

[0179] According to the implementation scheme, the invention is further characterized in that the timing of cylinder fuel injection is adjusted based on the estimated camshaft timing.

[0180] According to an embodiment, the invention is further characterized in that the crankshaft position is estimated based on the inferred latch pin movement during the actuation, and wherein the timing of cylinder fuel injection is further adjusted based on the estimated crankshaft position.

[0181] According to the implementation scheme, the actuation includes energizing the solenoid to move the latch pin from the engaged position to the disengaged position or from the disengaged position to the engaged position.

[0182] According to the implementation scheme, the cylinder valve is the exhaust valve of the cylinder, and the solenoid is actuated when the piston of the cylinder is in the upstroke.

[0183] According to the implementation scheme, the estimation includes: indicating that the piston of the cylinder is in the exhaust stroke in response to the absence of latch pin movement; and indicating that the piston of the cylinder is in the compression stroke in response to the presence of latch pin movement.

[0184] According to the implementation scheme, the cylinder valve is the intake valve of the cylinder, and the solenoid is actuated when the piston of the cylinder is in the downstroke.

[0185] According to the implementation scheme, the estimation includes: indicating that the piston of the cylinder is in the intake stroke in response to the absence of latch pin movement; and indicating that the piston of the cylinder is in the power stroke in response to the presence of latch pin movement.

[0186] According to the implementation scheme, the estimation of the camshaft timing is further based on the crankshaft position sensed via a crankshaft position sensor.

[0187] According to the present invention, a method for an engine includes: energizing a solenoid of a cylinder valve deactivation mechanism coupled to a valve of a cylinder, the valve being actuated by a cam; inferring the stroke of the cylinder based on a current in the solenoid during the energization; and estimating a camshaft position based on the inferred cylinder stroke.

[0188] According to the implementation scheme, the cylinder valve deactivation mechanism includes a latching pin, and when the cam is on the base circle and not when the cam is lifted, energizing the solenoid causes the latching pin to move between an engaged position and a disengaged position.

[0189] According to the implementation scheme, the existence of latch pin movement is inferred based on the existence of a local current minimum when the current increases to the maximum value, and the non-existence of latch pin movement is inferred based on the non-existence of the local current minimum when the current increases to the maximum value.

[0190] According to the implementation scheme, the valve is an exhaust valve, and inferring the stroke of the cylinder based on the current of the solenoid during the excitation includes inferring the exhaust stroke in response to the absence of latch pin movement.

[0191] According to the implementation scheme, the valve is an intake valve, and inferring the stroke of the cylinder based on the current of the solenoid during the excitation includes inferring the intake stroke in response to the absence of latch pin movement.

[0192] According to the implementation scheme, the invention is further characterized in that the timing of cylinder fuel injection is adjusted based on the estimated camshaft position.

[0193] According to the implementation scheme, the estimation of the camshaft position is further based on the engine crankshaft position retrieved from the crankshaft position sensor during a first condition, and the inferred cylinder stroke is further used to determine the engine crankshaft position during a second condition.

[0194] According to the present invention, an engine system is provided, the engine system comprising: an engine cylinder including an intake valve and a fuel injector; an intake cam mounted on an intake camshaft for opening and closing the intake valve; and a valve deactivation mechanism coupled to the intake valve, the mechanism including a rocker arm assembly and a latching pin, the inner arm of the rocker arm assembly being coupled to the cam via a cam follower and to a rod of the intake valve, the outer arm of the rocker arm assembly being coupled to the latching pin, and the inner arm being connectable via the latching pin to... The system comprises: an outer arm; an electric solenoid connected to the latch pin; and a controller having computer-readable instructions that, when executed, cause the controller to: actuate the solenoid to actuate the latch pin; measure the induced current generated by the solenoid after actuation; infer the movement of the latch pin after actuation based on the measured induced current; estimate the intake camshaft position based on the inferred movement; and adjust the pulse width of the command to the fuel injector based on the estimated intake camshaft position.

[0195] According to an embodiment, the invention is further characterized by a crankshaft, an exhaust valve, and an exhaust camshaft, wherein the controller includes additional instructions that, when executed, cause the controller to perform the following operations: estimating a crankshaft position based on the inferred movement, an output from a crankshaft position sensor coupled to the crankshaft, and an output from a camshaft position sensor coupled to the intake camshaft; updating the intake camshaft position based on the estimated crankshaft position; and estimating the exhaust camshaft position based on the estimated intake camshaft position.

[0196] According to the implementation scheme, the controller estimates the intake camshaft position based on the inferred movement by: indicating that the piston of the cylinder is in the intake stroke in response to the absence of the inferred latch pin movement; and indicating that the piston of the cylinder is in the compression stroke, power stroke, or exhaust stroke in response to the presence of the inferred latch pin movement.

Claims

1. A method for an engine, the method for an engine comprising: An electronic latch pin of a cylinder valve deactivation mechanism is actuated via a solenoid and connected to a cam-actuated cylinder valve. The cylinder valve deactivation mechanism includes a rocker arm assembly. The inner arm of the rocker arm assembly is connected to a cam via a cam follower and to the rod of the cam-actuated cylinder valve. The outer arm of the rocker arm assembly is connected to the electronic latch pin, and the inner arm can engage with the outer arm via the electronic latch pin. Camshaft timing is estimated based on the inferred latch pin movement during the actuation period; as well as The crankshaft position is estimated based on the inferred latch pin movement during the actuation, and the timing of cylinder fuel injection is further adjusted based on the estimated crankshaft position.

2. The method of claim 1, further comprising inferring latch pin movement based on induced current characteristics of the solenoid, the induced current characteristics including one or more of the positions of current peaks and valleys and the slope of the current.

3. The method of claim 1, further comprising adjusting the timing of cylinder fuel injection based on the estimated camshaft timing.

4. The method of claim 1, wherein the actuation comprises energizing the solenoid to move the electronic latch pin from an engaged position to a disengaged position or from the disengaged position to the engaged position.

5. The method of claim 4, wherein the cam-actuated cylinder valve is the cylinder's exhaust valve, and wherein the solenoid is actuated when the piston of the cylinder is in the upstroke.

6. The method of claim 5, wherein estimating camshaft timing comprises: The piston of the cylinder is indicated to be in the exhaust stroke in response to the absence of latch pin movement; as well as The piston of the cylinder is indicated to be in the compression stroke in response to the presence of movement of the latch pin.

7. The method of claim 4, wherein the cam-actuated cylinder valve is the intake valve of the cylinder, and wherein the solenoid is actuated when the piston of the cylinder is in the downstroke.

8. The method of claim 7, wherein estimating camshaft timing comprises: The piston of the cylinder is indicated to be in the intake stroke in response to the absence of latch pin movement; as well as The piston of the cylinder is indicated to be in the power stroke in response to the presence of movement of the latch pin.

9. The method of claim 1, wherein the estimation of the camshaft timing is further based on the crankshaft position sensed via a crankshaft position sensor.

10. An engine system, the engine system comprising: An engine cylinder, the engine cylinder including an intake valve and a fuel injector; An intake cam, which is mounted on an intake camshaft for opening and closing the intake valve; A valve deactivation mechanism is connected to the intake valve. The valve deactivation mechanism includes a rocker arm assembly and a latching pin. The inner arm of the rocker arm assembly is connected to the intake cam via a cam follower and to the intake valve stem. The outer arm of the rocker arm assembly is connected to the latching pin. The inner arm can engage with the outer arm via the latching pin. An electric solenoid, the electric solenoid being connected to the latch pin; as well as The controller has computer-readable instructions that, when executed, cause the controller to: The solenoid is actuated to actuate the latch pin; The induced current generated by the solenoid after excitation is measured; The movement of the latch pin after excitation is inferred based on the measured induced current; The intake camshaft position is estimated based on the inferred latch pin movement; The pulse width of the command to the fuel injector is adjusted based on the estimated intake camshaft position. as well as The crankshaft position is estimated based on the inferred latch pin movement during the actuation, and the timing of cylinder fuel injection is further adjusted based on the estimated crankshaft position.

11. The system of claim 10, further comprising a crankshaft, exhaust valves, and an exhaust camshaft, and wherein the controller includes additional instructions that, when executed, cause the controller to perform the following operations: The crankshaft position is estimated based on two or more of the inferred latch pin movement, the output from the crankshaft position sensor coupled to the crankshaft, and the output from the camshaft position sensor coupled to the intake camshaft.

12. The system of claim 11, wherein the controller includes additional instructions that, when executed, cause the controller to perform the following operations: The intake camshaft position is updated based on the estimated crankshaft position; and The exhaust camshaft position is estimated based on the estimated intake camshaft position.

13. The system of claim 11, wherein the controller estimates the intake camshaft position based on the inferred latch pin movement, comprising: The piston of the cylinder is indicated to be in the intake stroke in response to the inferred absence of latch pin movement; as well as The piston of the cylinder is indicated to be in a compression stroke, power stroke, or exhaust stroke in response to the presence of a deduced latch pin movement.

14. The system of claim 10, wherein the induced current includes a brief decrease in current in response to movement of the latch pin.

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