METHOD AND SYSTEM FOR AN ENGINE WITH CYLINDER DECAPACITY

Abstract

Method comprising: operating a cylinder deactivation engine with an intake ratio based on operator torque demand; and in response to the throttle position being within a threshold distance to wide-open throttle, irrespective of the operator torque demand, increasing the intake ratio, wherein the intake ratio is a commanded intake ratio; and estimating an actual intake ratio based on a modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle, comparing the commanded intake ratio with the estimated actual intake ratio, and indicating wear of a cylinder deactivation engine mechanism based on the comparison.

Description

Area

[0001] The present description generally concerns methods and systems for torque monitoring for an engine with cylinder deactivation. General state of the art / Summary

[0002] Engines can be designed to operate with a variable number of active or deactivated cylinders to improve fuel efficiency, while optionally maintaining the overall exhaust-air-fuel ratio at approximately stoichiometry. Such engines are known as variable displacement engines (VDE). In this design, a portion of the engine cylinders can be deactivated under selected conditions defined by parameters such as an engine speed / load window, as well as under various other operating conditions, including operator torque requirements.Conventional VDE ignition systems can shut off a selected group of cylinders, such as a specific cylinder bank, by controlling a variety of cylinder valve shut-off devices that affect the operation of the intake and exhaust valves of that cylinder, or by controlling a variety of selectively shut-off fuel injectors that affect the fuel supply to the cylinders. Newer skip-ignition or roll-VDE systems can be designed to continuously switch individual cylinders on and off to provide a specific ignition schedule based on a named control algorithm.

[0003] VDE systems can employ various torque monitoring methods to ensure proper torque delivery and diagnose potential wear of the VDE system. Exemplary attempts to address torque monitoring involve comparing two independent sources of torque estimates with the torque requested by an operator. One exemplary approach is presented by Light et al. in U.S. Patent No. 6,705,286. In this approach, a torque monitoring algorithm compares the operator's torque demand with two independent torque estimates, one estimated based on the throttle position and the other based on the mass airflow (MAF) to the intake manifold. If either of the two actual torque estimates exceeds the torque requested by the operator, the monitoring algorithm logic intervenes in the engine torque generation and sets a diagnostic code.Other approaches to torque monitoring include fuel injection-based methods, where valve wear can be assessed based on the duration of an ignition event.

[0004] The inventors of the present invention have, however, recognized potential problems with such systems. For example, fuel injection-based torque monitoring may not be suitable for use with rolling VDE systems, as the number of active cylinders can often be overestimated, and space constraints may limit the feasibility of the included fuel injection device sensing for each cylinder individually. As another example, MAP-based approaches for torque estimation rely on comparing the airflow measurement, as determined by a MAF sensor output, with the dynamic effect of intake cylinders, as determined by a change in MAP. However, the reliance on MAF sensors for airflow measurement and MAP sensors for manifold pressure increases the cost and complexity of the vehicle system. Furthermore, the sensors themselves can be susceptible to wear.Other approaches to airflow measurement can simulate the airflow across a throttle body under selected engine operating conditions. However, such models can be inaccurate at or near wide-open throttle (WOT) conditions. As a result of this inaccuracy, the actual torque provided by the VDE system may exceed the torque requested by the driver, leading to a loss of fuel efficiency and unpleasant driving characteristics. For example, the vehicle may feel jerky. Inaccuracies in airflow estimation can also result in an inaccurate estimation of the actual intake ratio and a falsely reported VDE mechanism as worn.If the VDE mechanism is deactivated in response to the specification, the engine running time in VDE mode is unnecessarily reduced, resulting in a loss of fuel efficiency.

[0005] The inventors of the present invention have recognized that during conditions where the engine operates at or near wide-open throttle (WOT), torque inaccuracies can be reduced by restricting the intake ratio. For example, the VDE system can be restricted to operation at an intake ratio of 1 to reduce problems with excessive torque. The resulting temporary decrease in fuel efficiency may be acceptable to a vehicle driver in view of the improved drivability.Thus, the aforementioned problems can be addressed, at least partially, in an example by a procedure comprising operating a cylinder deactivation engine with an intake ratio based on operator torque demand; and, in response to the fact that the throttle position is within a threshold range of being too far open, increasing the intake ratio regardless of the operator torque demand. In this way, a more accurate torque estimate can be used to more precisely infer the actual intake ratio of a VDE system.

[0006] In one example, an engine with cylinder deactivation can operate with one or more selectively deactivated engine cylinders in response to operator torque demand. For instance, at higher engine speeds and loads, the engine can operate with fewer deactivated cylinders at a higher intake ratio, while at lower engine speeds and loads, the engine can operate with more deactivated cylinders at a lower intake ratio. If the desired intake ratio is within a threshold of 1.0, the applied intake ratio can be restricted to 1.0, overriding the desired intake ratio. Additionally, during engine operating conditions where the desired intake ratio is outside the threshold of 1.0, but the intake throttle is at or within a threshold distance of wide open throttle (WOT), the applied intake ratio can be increased toward 1.0 (e.g.,(Increased incrementally towards 1.0 by moving to the next highest possible intake ratio) while overriding the desired intake ratio. By limiting the applied intake ratio during conditions where airflow measurement may be inaccurate, torque inaccuracies can be reduced. During other conditions, an actual intake ratio can be inferred from a throttle body model used to infer airflow and a rate of change of manifold pressure across the throttle. If the actual intake ratio differs significantly from the commanded intake ratio, wear of the VDE system can be inferred, and corrective action can be taken.

[0007] In this way, using a throttle body model to measure airflow reduces reliance on a MAF sensor without compromising the accuracy of torque estimation or the identification of potential VDE wear. The technical benefit of selectively restricting the intake ratio during operating conditions where airflow and torque estimation may be inaccurate is that it reduces the likelihood of excessive torque delivery. By increasing the reliability of the actual intake ratio estimation, the probability of misdiagnosing VDE wear and prematurely shutting down VDE operation is reduced. Enabling VDE operation for a longer period of engine operation extends the fuel efficiency and power benefits of VDE operation.

[0008] It is understood that the foregoing summary is provided to present, in simplified form, a selection of concepts that are described in more detail in the detailed description. It is not intended to identify important or essential features of the claimed subject matter, the scope of protection of which is defined solely by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that overcome the disadvantages mentioned above or in any part of this disclosure. List of characters Fig. Figure 1 shows an exemplary embodiment of a motor system arrangement. Fig. Figure 2 shows a partial view of the engine. Fig. Figure 3 shows an exemplary routine that can be implemented to operate an engine, including controlling the intake ratio in response to a throttle position. Fig. Figure 4 shows an exemplary routine that can be implemented to diagnose VDE wear based on the measured inlet ratio. Fig. Figure 5 shows a prospective operation of an engine, including the control of the intake ratio in response to a throttle position, according to the present disclosure. Fig. Figure 6 shows an exemplary block diagram of a torque monitoring method according to the present disclosure. Detailed description

[0009] The following description concerns systems and methods for torque monitoring for an engine designed for the deactivation of selected, individual cylinders (also referred to here as Roll-VDE), such as for the engine system from Fig. 1-2. By using a throttle body model to estimate the actual airflow in addition to data from an existing MAP sensor, independent torque estimates can be determined and compared, as shown in Fig. 6 shown. An engine control unit can be designed to execute a control routine, such as the exemplary routine from Fig. 3. To coordinate throttle and intake ratio settings, to maintain the throttle position at a distance from an excessively open throttle. The control unit may also be configured to perform a diagnostic routine, such as the exemplary routine from Fig. 4. To identify wear of the VDE mechanism, the controller may use the airflow control to identify situations where an estimated actual intake ratio, estimated based on independent torque estimates, differs significantly from a desired intake ratio, estimated based on operator torque requirements. Additionally, the controller may limit the applied intake ratio during conditions where airflow estimation may be prone to inaccuracies, such as when the throttle position of the wide-open throttle ( WOT ) approaches. An example of engine operation with VDE diagnostics is in Fig. 5 shown.

[0010] With reference to Fig. 1 will be an exemplary engine system 100 shown. The engine system 100 includes a motor 10 , which is a cylinder bank 13 and a second cylinder bank 14 exhibits. In the illustrated example, the engine 10a V8 engine with two cylinder banks, each with four cylinders 15 exhibit. In alternative examples, however, the engine may have an alternative configuration, such as an alternative number of cylinders (e.g., V-4, V-6, etc.) or an inline arrangement of cylinders (e.g., I-3, I-4, etc.). The engine 10 features an intake manifold 17 , with an intake throttle 20 , and an exhaust manifold 18 , which is connected to an exhaust gas purification system 30 is coupled. To the exhaust gas purification system 30 This includes one or more catalysts and air-fuel ratio sensors, as described in reference to Fig. 2 described. The engine 10 can work with a variety of substances that are transmitted via a fuel system 8 can be supplied. To give a non-restrictive example, the engine can 10as part of a drive system for a passenger car.

[0011] The engine 10 Can an engine system with cylinder deactivation ( VDE ) that has one or more cylinders 15 with optionally switchable inlet valves 50 and optionally switchable exhaust valves 56 It features a function that allows selected cylinders to be deactivated by deactivating the respective cylinder valves, as described below. In one example, the intake valves are... 50 and exhaust valves 56 designed for electric valve actuation (EVA) via individual electric cylinder valve actuators. While the example shown demonstrates that each cylinder has a single inlet valve and a single exhaust valve, alternative examples, such as in Fig. 2. Each cylinder shall have a plurality of selectively switchable inlet valves and / or a plurality of selectively switchable exhaust valves.

[0012] In some examples, the engine 10 additionally, selectively switchable (direct) fuel injection devices 66 exhibit, and the selected cylinders can be shut down by switching off the corresponding fuel injections, while the operation of the intake and exhaust valves is maintained in such a way that air continues to be pumped through the cylinders.

[0013] Under selected conditions, such as when the engine's full torque capacity is not required, one or more of the engine's cylinders can be deactivated. 10 Selective shutdown (also referred to here as individual cylinder shutdown) can be selected. This can involve the selective shutdown of one or more cylinders on the first cylinder bank. 13and / or the selective deactivation of one or more cylinders on the second cylinder bank 14 This includes the number and identifier of deactivated cylinders in the cylinder bank, which can be symmetrical or asymmetrical. An engine control unit 12 It can continuously analyze individual cylinders and, based on a driver's pedal position input and torque demand, determine whether each cylinder should be switched on or off, thus providing what is known as skip-ignition or roll-VDE operating mode. In other examples, entire banks or subsets of cylinders can be deactivated.

[0014] During shutdown, selected cylinders can be deactivated by closing individual cylinder valve mechanisms (e.g., VDE mechanisms), such as intake valve mechanisms, exhaust valve mechanisms, or a combination of both. Cylinder valves can be selectively deactivated via hydraulically actuated lifting devices (e.g., lifting devices coupled to valve pushrods), via a cam profile switching mechanism where a cam hump without lift is used for deactivated valves, or via the electrically actuated cylinder valve mechanism coupled to each cylinder. Additionally, the fuel supply to the deactivated cylinders can be interrupted, for example, by shutting off the fuel injection devices of those cylinders. 66In some examples, the ignition spark to the deactivated cylinders can also be interrupted, for example by selectively controlling the vehicle's ignition system so that it only sends ignition sparks to active cylinders.

[0015] While the selected cylinders are deactivated, the remaining switched-on or active cylinders operate with active and functioning fuel injection devices. 66 and cylinder valve mechanisms continue with the combustion. To meet the torque requirements, the engine generates the same amount of torque in the active cylinders. This requires higher manifold pressures, which leads to reduced pumping losses and increased engine efficiency. Furthermore, due to the smaller usable area (only of the active cylinders) exposed to combustion, heat losses in the engine are reduced, thus improving the engine's thermal efficiency.

[0016] Cylinders can be deactivated to provide a specific ignition scheme (e.g., skip-ignition or roll-VDE scheme) based on a defined control algorithm. Specifically, selected "skipped" cylinders are not fired, while other "active" cylinders are fired. Optionally, an ignition timing associated with a selected ignition of a selected combustion chamber can also be set based on a firing order or ignition sequence of the selected combustion chamber. The ignition scheme or deactivation scheme, as used here, can include a total number of deactivated cylinders relative to the remaining active cylinders, as well as an identity of the deactivated and active cylinders. The ignition scheme can further specify a total number of combustion events for which each deactivated cylinder is kept deactivated and / or a number of engine cylinders through which the scheme is operated. The engine control 12The controller can be designed, with suitable logic as described below, to determine a cylinder deactivation scheme (or skip-fire scheme) based on engine operating conditions. For example, the controller can select a desired intake ratio to apply based on engine operating parameters, including operator torque demand, and then select a cylinder deactivation scheme that enables the provision of the desired intake ratio. As used here, the intake ratio is defined as the number of actual cylinder intake events (e.g., firing cylinders) that occur, divided by the number of possible cylinder intake event possibilities (e.g., total engine cylinders).

[0017] The engine control 12It can include a drive pulse generator and a sequence control system to determine a cylinder configuration that provides the desired intake ratio, based on the desired engine power output under current engine operating conditions. For example, the drive pulse generator can use adaptive predictive control to dynamically calculate a drive pulse signal indicating which cylinders need to fire and at what intervals to achieve the desired power output (i.e., the cylinder firing / non-firing scheme). The cylinder firing scheme can be adjusted to provide the desired power output without generating excessive or undesirable vibration inside the engine. Thus, the cylinder configuration can be selected based on the engine's design, such as whether it is a V-engine or an inline engine, the number of cylinders, and so on.Based on the selected cylinder configuration, the individual cylinder valve mechanisms of the selected cylinders can be closed while the fuel supply and spark delivery to the cylinders are interrupted, thus providing the desired intake ratio.

[0018] Since the optimal efficiency for each cylinder is close to its full power output, a lower firing rate can be chosen to reduce power. For example, skipping every other cylinder would, on average, produce half the power. Additionally, the interval between firing events can be adjusted to minimize NVH (noise, vibration, and harshness). Whether all cylinders are included in the skip firing scheme can depend on the desired fraction of the full engine output, with the full engine torque output itself depending on various factors such as cam timing, cylinder temperature, and so on.

[0019] In this way, by adjusting the cylinder scheme of individual cylinder valve mechanisms and individual cylinder fuel injection devices, a desired engine output can be provided by operating fewer cylinders more efficiently, thus improving fuel efficiency.

[0020] The engine 10 can be at least partially controlled by a control system that manages the steering 12 It includes being controlled. The control 12 It can receive various signals from the sensors 16 received, which are connected to the engine 10 are coupled (and with reference to Fig. 2 are described) and control signals to various actuators 81 sends which are coupled to the engine and / or the vehicle (as referred to in Fig. 2 described). The various sensors can include, for example, different temperature, pressure, and air-fuel ratio sensors. Furthermore, the control system can12 A throttle position reading was received from a throttle position sensor. With reference to Fig. 2 is now an exemplary embodiment 200 a combustion chamber or cylinder of the internal combustion engine 10 (such as the engine) 10 out of Fig. 1) shown. Components previously shown in Fig. The first ones presented may be similarly numbered. The engine 10 can be coupled to a drive system, such as the vehicle 5 , which is designed for road use. The engine 10 control parameters from a control system that controls 12 (such as the control system) 12 out of Fig. 1) includes, and input from a driver 130 via an input device 132 received. In this example, the input device includes 132 an accelerator pedal and a pedal position sensor 134to generate a proportional pedal position signal PP . Cylinder (here also called "combustion chamber") 15 of the engine 10 can combustion chamber walls 136 contained in which a piston 138 is arranged. The piston 138 can be attached to the crankshaft 140 They are coupled so that the piston's reciprocating motion is translated into a rotational motion of the crankshaft. The crankshaft 140 can be coupled to at least one drive wheel of the passenger car via a transmission system (not shown).

[0021] The cylinder 15 can be accessed via a series of intake air ducts 142 , 144 and 146 Take in intake air. The intake air duct 146 can be added to the cylinder 15 with other cylinders of the engine 10communicate. In some embodiments, one or more of the intake ports may include a charging device, such as a turbocharger or a compressor. For example, shows Fig. 2 the engine 10 , which is equipped with a turbocharger, including a compressor 174 , which is between the intake ports 142 and 144 is arranged, and an exhaust turbine 176 is designed to run along the exhaust duct 148 is arranged. The compressor 174 can at least partially via a wave 180 through the exhaust turbine 176 They are supplied with electricity if the charging device is designed as a turbocharger. In other examples, such as when the engine 10 equipped with a compressor, the exhaust turbine can 176 However, they can be omitted optionally, whereby the compressor 174It can be driven by mechanical inputs from an electric motor or the engine itself. A throttle 20 , which has a throttle valve 164 A throttle valve can be located along an intake port of the engine to vary the flow rate and / or pressure of the intake air supplied to the engine's cylinders. For example, the throttle valve can... 20 downstream of the compressor 174 It can be arranged or alternatively downstream of the compressor. 174 be provided.

[0022] The exhaust duct 148 exhaust gases in addition to the cylinder 15 from other cylinders of the engine 10 record the exhaust gas sensor 128 is connected to an exhaust duct 148 shown coupled, upstream of an emission control device 178 is part of the exhaust gas purification system 30 is as in Fig. 1 shown. The exhaust gas sensor 128The exhaust gas air / fuel ratio sensor can be selected from various suitable sensors, such as a linear lambda sensor or UEGO sensor (universal exhaust gas oxygen sensor; wide-range lambda sensor), a binary lambda sensor or EGO sensor (as shown), a HEGO sensor (heated EGO sensor), or a NOx, HC, or CO sensor. This is part of the emissions control device. 178 It could be a three-way catalytic converter (TWC), a NOx trap, various other emission control devices, or combinations thereof.

[0023] Each cylinder of the engine 10 It can include one or more intake valves and one or more exhaust valves. For example, the cylinder has 15 The illustration shows at least one inlet valve. 150 with valve cone and at least one exhaust valve 156 with valve cone, located in an upper area of ​​the cylinder15 are arranged. In some embodiments, each cylinder of the engine can be assigned to one. 10 , which the cylinder 15 includes at least two inlet control valves and at least two exhaust control valves, which are located in an upper area of ​​the cylinder.

[0024] The inlet valve 150 can be controlled 12 by cam actuation via the cam actuation system 151 can be controlled. Similarly, the exhaust valve can be controlled. 156 through the control 12 via the cam actuation system 153 They are controlled. The cam actuation systems 151 and 153They can each contain one or more cams and utilize one or more of the following systems: Cam Profile Switching (CPS), Variable Cam Timing (VCT), Variable Valve Timing (WT), and / or Variable Valve Lift (VVL), controlled by the 12 They can be operated to vary the valve operation. The operation of the inlet valve 150 and exhaust valve 156 can be caused by (not shown) valve position sensors and / or camshaft position sensors 155 or 157 can be determined. In alternative embodiments, the inlet and / or exhaust valve can be controlled by an electric valve actuator. For example, to the cylinder 15Alternatively, an inlet valve controlled by an electric valve actuator and an exhaust valve controlled by a cam actuator, including CPS and / or VCT systems, may be included. In further embodiments, the inlet and exhaust valves may be controlled by a common valve actuator or actuator system, or by a variable valve actuation actuator or actuator system.

[0025] As with reference to Fig. 1 executed, the engine 10 a cylinder deactivation engine wherein the intake and exhaust valves can be selectively deactivated in response to operator torque requirements in order to operate the engine at a desired intake ratio with a desired cylinder deactivation (or ignition) scheme.

[0026] In some designs, each cylinder of the engine can 10 A spark plug is used to initiate combustion. 192exhibit the ignition system 190 can the cylinder 15 about spark plugs 192 a spark in response to the pre-ignition signal SA from the control unit 12 provide this in selected operating modes. In other embodiments, such as when cylinder combustion is initiated using compression ignition, the cylinder may not contain a spark plug.

[0027] In some designs, each cylinder of the engine can 10 be designed with one or more injection devices for delivering fuel to the cylinder. As a non-restrictive example, the cylinder 15 According to the illustration, two fuel injection devices 166 and 170 up. The fuel injection devices 166 and 170 can be designed to be from a fuel system 8The fuel is delivered via a high-pressure fuel pump and fuel distributor. Alternatively, the fuel can be delivered at a lower pressure by a single-stage fuel pump, although in this case the timing of the direct fuel injection during the compression stroke may be more limited than with a high-pressure fuel system. Furthermore, the fuel tank can have a pressure converter which is part of the control system. 12 provides a signal.

[0028] According to the illustration, the fuel injection device 166 directly to the cylinder 15 coupled to supply fuel proportionally to the pulse width of the FPW signal 1 , which is controlled 12 via an electronic driver 168 The fuel is received and injected directly into it. This is how the fuel injection device works. 166a so-called direct injection (hereinafter referred to as "DI") of fuel into the combustion cylinder 15 ready. Although Fig. 1 the injection device 166 on one side of the cylinder 15 Positioned as shown, it can alternatively be located above the piston, such as near the spark plug position. 192 Such a position can improve mixing and combustion when the engine runs on an alcohol-based fuel, as some alcohol-based fuels have lower volatility. Alternatively, the injector can be located above and near the intake valve to improve mixing.

[0029] As with reference to Fig. 1 executed, the engine 10 be an engine with cylinder deactivation, wherein the fuel injection device 166can be selectively deactivated in response to operator torque requirements in order to operate the engine at a desired intake ratio with a desired cylinder deactivation (or ignition) scheme.

[0030] The fuel injection device 170 is in a design that uses the so-called port fuel injection (hereinafter referred to as "PFI") into the intake port upstream of the cylinder 15 provides, in the intake duct 146 instead in the cylinder 15 The fuel injection device is shown arranged as follows. 170 can from the fuel system 8 Fuel consumed is proportional to the pulse width of the FPW-2 signal, which is generated by the control unit. 12 via the electronic driver 171 The received signal is injected. It should be noted that a single electronic driver is used. 168 or 171can be used for both fuel injection systems or, as shown, multiple drivers, for example the electronic driver 168 for the fuel injection device 166 and the electronic driver 171 for the fuel injection device 170 , can be used.

[0031] Fuel can be supplied to the cylinder by either injection device during a single cylinder cycle. For example, each injection device can provide a portion of the total fuel injection, which is delivered to the cylinder. 15is burned. Thus, even in the case of a single combustion event, injected fuel can be injected at different times by the intake port injection system and the direct injection system. Furthermore, multiple injections of the delivered fuel can be carried out per cycle during a single combustion event. These multiple injections can occur during the compression stroke, intake stroke, or any suitable combination thereof.

[0032] As previously described, Fig. 2. Only one cylinder of a multi-cylinder engine. Therefore, each cylinder can have its own set of intake / exhaust valves, fuel injection device(s), spark plug, etc. It is understood that the engine 10 any suitable number of cylinders, including 2 , 3 , 4 , 5 , 6 , 8 , 10 ,12 or more cylinders. Furthermore, each of these cylinders can include some or all of the various components that are in Fig. 2 with reference to cylinder 15 are described and illustrated.

[0033] The engine can further include one or more exhaust gas recirculation (EGR) channels for recirculating a portion of the exhaust gas from the engine outlet to the engine intake. This recirculation of a portion of the exhaust gas can dilute the mixture within the engine, which can improve engine performance by reducing engine knock, peak combustion temperatures and pressures in the cylinders, throttling losses, and NOx emissions. In the illustrated embodiment, exhaust gas can be routed via an EGR channel. 141 from the outlet channel 148 to the intake manifold 144 be returned. The one at the inlet channel 144 The scope of EGR provided can be controlled 12 via the EGR valve 143can be varied. Furthermore, an EGR sensor can be used. 145 be located within the EGR channel and provide a reading of one or more parameters of the pressure, temperature and concentration of the exhaust gas.

[0034] In some examples, the vehicle 5 a hybrid vehicle with multiple torque sources that supply one or more vehicle wheels 55 are available. In other examples, the vehicle 5 A conventional vehicle with only one engine or an electric vehicle with only one electric motor. In the example shown, the vehicle includes 5 an engine 10 and an electric machine 52 . In the case of the electric machine 52 It could be an engine or an engine / generator. The crankshaft 140 of the engine 10 and the electric machine 52 are via a gearbox 54 with the vehicle wheels 55connected when one or more couplings 56 are engaged. In the example shown, a first coupling is 56 between the crankshaft 140 and the electric machine 52 provided and is a second coupling 56 between the electric machine 52 and the gearbox 54 provided. The control 12 Can a signal be sent to an actuator of any coupling? 56 send to engage or disengage the clutch, thus moving the crankshaft 140 with or from the electric machine 52 and to connect or disconnect the associated components and / or to operate the electric machine 52 with or from the gearbox 54 and to connect or disconnect the associated components. The gearbox 54It can be a manual transmission, a planetary gear system, or another type of transmission. The powertrain can be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle.

[0035] The electric machine 52 draws electrical power from a traction battery 58 up, to the vehicle wheels 55 To provide torque. The electric machine 52 It can also be operated as a generator, for example to provide electrical power for charging the battery during braking. 58 to provide.

[0036] The control 12 is represented as a microcomputer, which includes a microprocessor unit 106 , Input / output connections 108 , an electronic storage medium for executable programs and calibration values, in this specific example as read-only storage 110 shown, direct access memory112 Keep-Alive memory 114 and a data bus are included. The control system 12 In addition to the signals explained above, various other signals can be sent to the motor. 10 coupled sensors received, including measurement of the engine coolant temperature ( ECT ) from a temperature sensor 116 , which is equipped with a cooling sleeve 118 is coupled; a profile ignition reception signal ( PIP ) from a Hall effect sensor 120 (or other type) that is connected to a crankshaft 140 is coupled; a throttle position ( TPS ) from a throttle position sensor; and an intake manifold absolute pressure (MAP) signal from a sensor 124 A motor speed signal, rpm, can be generated by the controller. 12 generated from the PIP signal. The manifold pressure signal MAP A manifold pressure sensor can be used to provide an indication of vacuum or pressure in the intake manifold. Other sensors can include fuel level sensors and fuel composition sensors connected to the fuel tank(s) of the fuel system.

[0037] On a read-only memory chip 110 Computer-readable data can be programmed to represent instructions to be executed by a microprocessor unit. 106 to carry out the procedures described below, as well as other variants that are required but not listed in detail.

[0038] The control 12 receives signals from the various sensors Fig. 1-2 and uses the various actuating elements from Fig. 1-2, to adjust engine operation based on received signals and instructions stored in the controller's memory. For example, in response to an operator torque command, as inferred from the pedal position sensor, the controller can send a signal to a throttle actuator to set a throttle opening, increasing the opening as the torque demand increases. As another example, in response to a desired intake ratio determined based on operator torque demand, the controller can send signals to selected cylinder fuel injectors and valves to selectively shut off those cylinders according to a cylinder deactivation scheme that provides the desired intake ratio.

[0039] During engine operation in VDE mode with one or more selectively deactivated cylinders, torque can be monitored via one or more monitors to ensure that the actual intake ratio matches the commanded intake ratio. For example, as referenced in Fig. As described in section 4, by comparing the airflow through the throttle, as estimated via a throttle body-based model, with changes in manifold pressure across the throttle (e.g., from a MAP sensor), the dynamic effect of cylinders actually taking intake air can be learned. This can be used to infer not only the actual intake ratio but also the actual torque delivered. By limiting the intake ratio applied during engine operating conditions where airflow measurement is inaccurate, such as at or near wide-open throttle (WOT), the likelihood of delivering more engine torque than requested by the operator, for example, due to operation at an actual intake ratio larger than the desired ratio, can be avoided.

[0040] For example, the control 12 , as with reference to Fig. 3-4 and Fig. 6. Implemented, employ airflow-based torque monitoring methods to compare the desired amount of torque with the amount of torque produced by the motor. 10The actual intake ratio is generated while the engine is operating with one or more selectively deactivated cylinders. For example, the control unit can apply a selected cylinder deactivation scheme that provides a desired intake ratio based on operator torque demand and then estimate an actual intake ratio to characterize the torque produced by the engine. If the difference between the desired intake ratio and the estimated actual intake ratio exceeds a threshold, wear of the VDE mechanisms can be inferred, and corrective actions can be taken, such as limiting the range of intake ratios that can be provided during subsequent engine operation.

[0041] In this way, the components exhibit Fig. 1 and Fig. 2 a motor system comprising a cylinder deactivation engine; a plurality of cylinders, each having selectively deactivatable valve mechanisms and a selectively deactivatable fuel injection device; a manifold pressure sensor; a throttle position sensor; an intake throttle; and a control system.The control system can be configured with computer-readable instructions stored in non-volatile memory to: selectively shut down a number of the plurality of cylinders to provide a commanded intake ratio based on operator torque demand; increase the throttle opening in response to increasing operator torque demand while maintaining the commanded intake ratio until the throttle position is at a threshold of excessively open throttle; and when the throttle position is at the threshold of excessively open throttle, increase the commanded intake ratio by selectively restarting one of the shut-off cylinders while reducing the throttle opening to move the throttle position to a higher than the threshold of excessively open throttle.The control may further include instructions to keep the entire plurality of cylinders active in response to increasing operator torque requirements while the throttle position is at the threshold distance to wide-open throttle and the commanded intake ratio is increased to 1.0; and to increase the throttle opening to move the throttle position to wide-open throttle.The control system further includes instructions to estimate, in response to each throttle position being outside the threshold distance of a wide-open throttle, an actual engine intake ratio based on modeled mass airflow through the throttle relative to detected manifold pressure change across the throttle; to estimate a torque error based on the actual intake ratio relative to the commanded intake ratio; and to update the commanded intake ratio based on the torque error, with the modeled mass airflow not based on the output of an air mass flow sensor.The control system further includes instructions to indicate wear of the selectively shut-off valve mechanisms or the selectively shut-off fuel injection device in response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold; and in response to the indication to reactivate the selectively shut-off one or more of the multiple cylinders.

[0042] With reference to Fig. 3 is an example routine 300 This demonstrates how to maintain an intake throttle at a distance from wide open throttle (WOT), even when operator torque requirements increase, by coordinating throttle settings with intake ratio settings. Instructions for performing the routine are provided. 300and the other methods included herein can be executed by a controller based on instructions stored in a memory of the controller and in conjunction with signals received from sensors of the motor system, such as those referred to above. Fig. 1-2 described sensors. The controller can use engine actuators of the engine system to adjust engine operation according to the procedures described below. In one example, the controller can control an engine intake ratio based on sensor inputs indicating an operator torque demand. Specifically, based on inputs from an accelerator pedal position sensor or other torque requester indicating a drop in operator torque demand, the controller can send a signal to a selected number of individual cylinder valve mechanisms and fuel injectors to selectively shut off fuel and valve operation to the selected cylinders, while the remaining engine cylinders continue to operate with active fuel and valve operation, thus providing the desired intake ratio and torque.

[0043] At 302The routine includes estimating and / or measuring engine operating conditions, including engine speed, operator torque requirement, throttle position, barometric pressure ( BP ), boost pressure, accelerator pedal position ( PP ), manifold absolute pressure ( MAP ), air mass flow ( MAF ), engine dilution (e.g. EGR level), manifold air temperature ( MAT ), engine coolant temperature ( ECT ) and ambient humidity.

[0044] At 304The routine includes determining a desired intake ratio, at least based on operator torque requirements. The engine cylinder intake ratio is the actual total number of cylinder ignition events divided by the actual total number of cylinder compression strokes over a given total number of cylinder compression strokes. In one example, the actual total number of cylinder compression strokes is a predetermined number. In the context used here, a cylinder activation event refers to a cylinder that fires with its intake and exhaust valves opening and closing during a cylinder cycle, whereas a cylinder deactivation event refers to a cylinder that does not fire with its intake and exhaust valves remaining closed during a cylinder cycle. An engine event can be: a completed stroke of a cylinder (e.g.,Intake stroke, compression stroke, power stroke, exhaust stroke), the opening or closing time of an intake or exhaust valve, the ignition time of an air-fuel mixture in the cylinder, the position of a piston in the cylinder relative to the crankshaft position, or any other engine-related event. The engine event number corresponds to a specific cylinder. For example, engine event number one might correspond to a compression stroke of cylinder number one. Engine event number two might correspond to a compression stroke of cylinder number three. A cycle number denotes an engine cycle that includes one event (on or off) in each cylinder. For example, a first cycle is complete when each cylinder of an engine has completed all four stroke events (intake, exhaust, compression, and power events) in firing order.The second cycle begins when each cylinder of the engine initiates a different 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 cylinder firing ratio values ​​can be stored in a table or function that can be indexed based on the desired engine torque and engine speed. The cylinder firing ratio values ​​that can provide the requested engine torque can be included in a group of available cylinder firing ratio values. Subsequently, based on other vehicle operating conditions, some cylinder firing ratios can be deleted from the group of available cylinder firing ratio values. For example, some cylinder firing ratios can be removed from the group if they cause higher levels of engine vibration.Then, the cylinder firing rate that provides the fewest active cylinders during a cycle can be selected from the group of available cylinder firing rate values ​​to provide the desired cylinder firing rate. In this way, a single desired cylinder firing rate can be selected from a group containing a large number of cylinder firing rates. It is understood that the selected cylinder firing rate can then be provided via one of a variety of possible cylinder deactivation schemes, as described below.

[0045] For example, a target intake ratio of 1 / 2 (or 0.5) means that every two cylinder events, one cylinder fires and one is skipped. Another example: a target intake ratio of 1 / 3 (or 0.33) means that every three cylinder events, one cylinder fires and the other two are skipped.

[0046] At 306 The routine involves selecting a cylinder deactivation scheme that provides the desired intake ratio. For example, an intake scheme for a 1 / 2 intake ratio might involve selectively de-fueling every other cylinder to produce half the power on average. Furthermore, the same scheme can be applied to each successive engine cycle, so that in successive cycles the same cylinders are skipped, while the remaining cylinders fire in each cycle, creating a steady-state scheme. In an example where the cylinders 1 - 8 as two benches, each with 4 are arranged in cylinders (where bank one has the cylinders) 1 - 4 features and bank two the cylinders 5 - 8 exhibits) and the firing order 1 - 5 - 4 - 2 -6 - 3 - 7 - 8 The intake ratio of 1 / 2 can be achieved by ignition according to the intake scheme. S-5 - S-2 - S-3 - S-8 be provided, whereby S represents a skipped cylinder event.

[0047] As another example, an intake scheme for a 1 / 3 intake ratio might involve selectively de-fueling two out of three cylinders to produce, on average, one-third of the power. Furthermore, the intake ratio can be achieved by skipping different cylinders in each engine cycle, creating a non-steady-state pattern. In an example where the cylinders 1 - 8 as two benches, each with 4 are arranged in cylinders (where bank one has the cylinders) 1 - 4 features and bank two the cylinders 5 - 8 exhibits) and the firing order1 - 5 - 4 - 2 - 6 - 3 - 7 - 8 The formula states that an intake ratio of 1 / 3 can be achieved by ignition according to the scheme. 1 - S - S - 2 - S - S - 7 - S - S - 5 - S - S - 6 - S - S - 8 - S - S - 4 - S - S - 3 - S - S be provided, whereby S represents a skipped cylinder event.

[0048] In each of the preceding examples, distributing the ignition events at even intervals minimizes NVH caused by varying torque output. In this way, by adjusting the cylinder configuration of individual cylinder valve mechanisms and individual cylinder fuel injectors, a desired engine output can be achieved by operating fewer cylinders more efficiently, thus improving fuel efficiency.

[0049] Once the cylinder configuration is selected according to the desired intake ratio, the control unit can deactivate cylinders according to the selected configuration to provide the target intake ratio. Selective cylinder deactivation involves keeping the cylinder valves closed for the selected cylinders, with no fuel injected into them, for a full 720-degree engine cycle (i.e., for all cylinders). 4(Cylinder strokes).

[0050] In one example, cylinder deactivation can involve closing selected individual cylinder valve mechanisms (e.g., VDE mechanisms), such as intake valve mechanisms, exhaust valve mechanisms, or a combination of both, by sending a valve closing command from the control unit to valve actuators. Cylinder valves can be selectively deactivated via hydraulically actuated lifting devices (e.g., lifting devices coupled to valve pushrods), via a cam profile switching mechanism where a cam hump without lift is used for deactivated valves, or via the electrically actuated cylinder valve mechanism coupled to each cylinder. Additionally, the fuel supply and spark delivery to the deactivated cylinders can be interrupted, for example, by switching off fuel injection devices for cylinders and disabling a spark signal to a spark plug in a given cylinder.

[0051] It will be understood that the decision to activate or deactivate a cylinder and open or close the cylinder's intake and exhaust valves is made a predetermined number of cylinder events (e.g., one cylinder event, or alternatively, one cylinder cycle, or eight cylinder events) before the cylinder is to be activated or deactivated, in order to allow time for the process of opening and closing the cylinder's intake and exhaust valves to begin. For example, for an eight-cylinder engine with a firing order of 1 - 3 - 7 - 2 - 6 - 5 - 4 - 8The decision to activate or deactivate cylinder number seven during an intake or compression stroke of cylinder number seven in an engine cycle can be made before cylinder number seven is deactivated. Alternatively, the decision to activate or deactivate a cylinder can be made after a predetermined number of engine events or cylinder events before the selected cylinder is activated or deactivated. In yet other examples, the number of cylinder events can be set based on hardware capabilities and current engine operating conditions.

[0052] In addition to setting the intake ratio, the control unit can also set a throttle opening based on operating conditions, including torque demand, to provide a manifold airflow based on the selected intake ratio. For example, when operating at a lower intake ratio, with some cylinders deactivated, the engine can run with a larger throttle opening to provide a greater airflow to each of the smaller number of active cylinders, each operating at a higher displacement. Conversely, the engine can run with a smaller throttle opening to provide a smaller airflow to each of the larger number of active cylinders, each operating at a lower displacement.

[0053] At 308It can be determined whether there is an increase in operator torque requirement. For example, the torque requirement might increase if the operator presses the accelerator pedal during a pedal actuation event. Another example is that the torque requirement might increase while the vehicle is moving on an incline. If an increase in torque requirement is not confirmed, the procedure involves... 310 Maintaining the current throttle position and intake ratio means that a certain degree of throttle opening can be maintained and the engine can continue to operate with one or more selectively deactivated cylinders.

[0054] If an increase in torque requirement is confirmed, the procedure includes the following: 312Increasing the throttle opening as torque demand increases until the intake throttle position is within a certain range of wide-open throttle (WOT). This means that if torque demand increases while maintaining the intake ratio and keeping the selected one or more cylinders selectively deactivated, the control unit can meet the torque demand by increasing airflow to the cylinders through a more open intake throttle position. The throttle opening can be increased based on increasing operator torque demand (e.g., via a lookup table, model, or algorithm) until the throttle position is within a threshold range of WOT, where the threshold range defines a specific distance from WOT.If the intake throttle is opened beyond this distance (and moved to or towards the WOT position), the airflow measurement modeled at the throttle position may be prone to inaccuracies, leading to potential torque errors. Furthermore, the actual intake ratio may not be accurately determined. The threshold distance may be a predefined value. Additionally, the threshold distance may vary with engine speed.

[0055] Next, at 314It must be determined whether a further increase in throttle opening is required. For example, during prolonged driving on an incline, or when the incline angle is very steep, the increase in torque demand may not be adequately met by increasing the throttle opening to the threshold distance from WOT. Instead, additional airflow may be required, which can be provided by moving the throttle to WOT. In one example, the controller can reference a lookup table, with the operator torque demand as the input and the desired throttle position as the output. If it is determined that the desired throttle position is WOT, the routine can proceed to 318 proceed. If no further increase in the throttle opening is required, the procedure involves... 316Maintaining the selected IR and continuing to adjust the throttle opening based on torque requirements while keeping the throttle position at a threshold distance to WOT.

[0056] If a further increase in the throttle opening is confirmed, then the procedure includes 318In response to the intake throttle already being at the threshold distance to WOT (wide-open throttle), the intake ratio is increased while the throttle opening is reduced to move the throttle to a less open position where the distance to WOT is greater than the threshold. As a result, the distance to WOT increases. For example, the intake ratio can be incrementally increased to the nearest possible intake ratio achievable by re-energizing one cylinder at a time. For instance, if the engine is a 4-cylinder engine that has been operating at an intake ratio of 0.5 with 2 cylinders deactivated and 2 active, one of the deactivated cylinders can be reactivated, resulting in an intake ratio of 0.67 with 1 cylinder deactivated and 3 active.As another example, if the 4-cylinder engine has been operating with an intake ratio of 0.67 with 1 deactivated cylinder and 3 active cylinders, the deactivated cylinder can be reactivated and the engine can operate with an intake ratio of (. IR ) from 1.0 with all cylinders active.

[0057] Since the average cylinder airflow requirement decreases as the number of active cylinders increases, the throttle opening can be reduced accordingly by increasing the intake ratio, thereby increasing the distance between the throttle position and WOT (wide open throttle). As a result, the engine continues to operate at a distance from WOT with the airflow measurement remaining reliable. The change in throttle position (and increase in distance) can correspond to the increase (change) in the intake ratio. Referring back to the previous example, the throttle position may change by a smaller amount when the intake ratio is increased from 0.5 to 0.67 (smaller effective change in IR) and by a larger amount when the intake ratio is increased from 0.67 to 1.0 (larger effective change in IR).

[0058] In this way, as the operator torque demand changes, the control unit can further adjust the intake ratio and throttle opening in coordination to maintain a distance between the intake throttle position and wide open throttle (WOT). For example, as the operator torque demand increases, the control unit can increase the throttle position toward the threshold distance while maintaining an initial intake ratio until the throttle position reaches the threshold distance. Afterward, the control unit can decrease the throttle position away from the threshold distance while incrementally increasing the intake ratio from the initial ratio to a second, higher intake ratio. If the operator torque demand increases during the second intake ratio, the control unit can increase the throttle position toward the threshold distance while maintaining the second intake ratio until the throttle position again reaches the threshold distance.The control unit can then reduce the throttle position away from the threshold distance, while the intake ratio is incrementally increased from the second intake ratio to a third, higher intake ratio (towards 1.0), and so on. At... 320 The procedure involves diagnosing the VDE mechanism based on actual IR relative to commanded IR, where the actual IR is measured (or modeled) while the intake throttle is at more than the threshold distance to WOT. As in Fig. 4. When executed, the control system can more reliably model the inlet airflow based on the throttle position in that position and use the airflow estimate to calculate a torque that corresponds to the actual IR.

[0059] At 322It can be determined whether the intake ratio is at 1.0 and a further increase in the throttle opening (beyond the threshold distance) is required. If not, the control system can be adjusted. 324 The control unit further coordinates the intake ratio and throttle opening settings. For example, it can maintain the applied intake ratio and hold the throttle at a certain distance from WOT. As previously described, each time the operator torque demand increases and the throttle opening reaches the threshold distance to WOT, the control unit can increment the intake ratio and move the throttle position further away from WOT. Once the intake ratio has been incremented to 1.0, where all cylinders are active, and the throttle opening reaches the threshold distance, a further increase in torque demand cannot be met by further increasing the intake ratio. After that, the control unit can... 326If the intake ratio is at 1.0 and a further increase in throttle opening beyond the threshold distance is required, the increased torque demand can be met by maintaining the intake ratio at 1.0 while increasing the throttle opening to WOT (wide open throttle). In this way, the throttle can only be moved to a WOT position if the intake ratio has already been incremented to 1.0 (all cylinders are active) and any further increase in torque demand can only be met by throttle adjustments.

[0060] Restricting engine operation with the throttle at wide open throttle (WOT) improves torque delivery. Specifically, airflow measurement using a throttle-based model can be unreliable when the throttle is at WOT. As a result, an engine control unit (ECU) may be unable to reliably determine whether the applied actual intake ratio is the commanded intake ratio. If the actual intake ratio is higher than the commanded intake ratio, it is possible that more torque than desired will be delivered, causing drivability issues that can be unpleasant for the rider. For example, the commanded intake ratio might be calibrated to deliver torque at an intake pressure that is 95% of ambient pressure. However, this will raise the throttle position threshold.In such a case, the intake ratio would be increased to the next highest available intake ratio to avoid operating in the region where the throttle model is inaccurate. By maintaining the throttle at a threshold distance from WOT through intake ratio adjustments, even as torque demand changes, the actual intake ratio can be measured and accounted for more reliably. Furthermore, excessive torque can be avoided. Moreover, as with... Fig. By performing step 4, VDE wear can be detected earlier and addressed in a timely manner.

[0061] With reference to Fig. 4 enables the procedure 400Now, the diagnosis of a VDE engine based on reliable and accurate airflow measurements taken with the throttle closed (WOT) is possible. By limiting an engine intake ratio based on a throttle position to reduce inaccuracies in airflow measurement and airflow-based torque measurements, VDE diagnosis can be performed with higher confidence. An example of this procedure is presented below. Fig. 4 as part of the procedure Fig. 3 carried out, as in the case of 320 .

[0062] At 402It can be confirmed that the throttle is in a position at or above a threshold distance from WOT. For example, it can be confirmed that a required distance to WOT is being maintained. If the distance is provided, airflow measurement via a throttle body model can be more reliable and can therefore be used for VDE diagnostics. If the throttle is not at the threshold distance, such as if the throttle is already at or around WOT, the procedure moves to 403 , where the actual intake ratio is not estimated based on the throttle body model and MAP sensor output. For example, torque and intake ratio adjustments are not made using closed-loop control based on the throttle body model. Furthermore, no VDE diagnostics are initiated. The procedure then terminates.

[0063] At 404The routine includes estimating an actual intake ratio according to an airflow estimate based on a throttle body model and MAP sensor output, as referenced in Fig. 6. The throttle body model can be based on an opening flow equation for compressible flow (see Equation 1 shown below) and includes parameters such as throttle angle to determine the cross-sectional area of ​​the opening hole, ambient conditions to characterize the airflow, engine speed to determine the flow rates, and an output from the manifold absolute pressure sensor to characterize upstream and downstream pressure across the throttle. q m = C A 2 2 ρ 1 p 1 ( k k − 1 ) [ ( p 2 / p 1 ) 2 / k − ( p 2 / p 1 ) ( k + 1 ) / k ] where: qm = mass flow rate (for any cross-section), kg / s C = Opening flow coefficient, dimensionless A2 = Cross-sectional area of ​​the opening hole, m 2 p1 = Fluid upward pressure, Pa with dimensions of kg / (m·s) 2 ) p2 = Fluid downward pressure, Pa with dimensions of kg / (m·s) 2 ) k = specific heat ratio, dimensionless qv,1 = volumetric flow rate under upstream conditions, m 3 / s ρ1 = Actual gas density under upstream conditions, kg / m³ 3

[0064] It will be understood that averaging MAP data and airflow estimates (such as those based on the output of existing MAP and / or MAF sensors on the engine) over one or more cylinder events can be used to improve the robustness of the throttle body model to pressure pulsations. By using a throttle body model to estimate the airflow through the system under conditions where airflow measurement is not susceptible to inaccuracies, the estimation of torque and intake ratio can be performed accurately with reduced reliance on a MAF sensor, thereby reducing costs.

[0065] At 406The routine involves comparing the desired intake ratio with the estimated actual intake ratio and determining whether the absolute difference between the desired and estimated actual intake ratios exceeds a threshold. In some examples, the threshold may be determined based on an acceptable error in the estimated actual intake ratio. The acceptable error in the intake ratio may correspond to an acceptable torque error that is imperceptible or undesirable to a driver. For example, if the acceptable torque error is 10% of the maximum torque, then the acceptable intake ratio error may be 0.1. Alternatively, the threshold may be based on expected wear scenarios of the VDE mechanisms, such as acceptable levels of VDE wear.

[0066] It will be understood that while the routine represents determining whether the absolute difference between the desired intake ratio and the estimated actual intake ratio is greater than a threshold, in alternative examples it can determine whether the estimated actual intake ratio is greater than the desired intake ratio in order to reduce conditions of excessive torque, where more engine torque is delivered than desired.

[0067] If the absolute difference between the desired intake ratio and the estimated actual intake ratio is greater than a threshold, the routine proceeds to 412 about, where the routine includes indicating wear of the VDE mechanism. At 414The routine includes limiting cylinder deactivation during subsequent engine operation if engine operation with cylinder deactivation is possible in response to indicated wear. In one example, limiting cylinder deactivation might involve operating at a higher intake ratio than desired for the given engine operating conditions by keeping certain cylinders active instead of deactivating them.

[0068] If the absolute difference between the desired intake ratio and the estimated actual intake ratio is not greater than a threshold, the routine is executed with 408 continued where no wear of the VDE mechanism is indicated. At 410 The control system continues to operate the engine in VDE mode with one or more cylinders deactivated, and the process ends.

[0069] Furthermore, the control system can resume the reassessment if there is a change in operating conditions that causes the throttle to be within a WOT threshold (as in the case of...). Fig. (discussed in section 3) or when the pressure ratio across the throttle (throttle pressure ratio or TR) is within a threshold pressure ratio. The throttle pressure ratio is defined as the pressure before the throttle divided by the pressure after the throttle, as measured by any existing pressure sensors. In some examples, this may involve controlling the desired intake ratio based on manifold absolute pressure (MAP), such as with a MAP sensor. 124 out of Fig. 1. In one example, the desired intake ratio can be controlled such that the MAP remains less than or equal to the barometric pressure (BP)*(1 - throttle pressure ratio). In other words, the desired intake ratio should remain greater than the estimated actual intake ratio in order to deliver torque at an intake pressure equal to the barometric pressure (BP)*(1 - throttle pressure ratio).

[0070] If the throttle position is within a wide-open threshold or the pressure ratio is within a threshold of 1, the control system continues to incrementally increase the intake ratio (such as by one step or one degree) and / or re-engages one or more cylinders according to the increment of the intake ratio, as shown in Fig. 3. In one example, restarting a cylinder might involve the selective reopening of cylinder valves via hydraulically actuated lifters using a cam profile switching mechanism. In other examples, restarting a cylinder might involve the selective reintroduction of spark and / or fuel into the cylinder selected for restarting. The restarted cylinder could be the next cylinder in the firing order.

[0071] It goes without saying that the procedure consists of Fig. 3-4 can be performed continuously during engine operation, while the operator torque requirement and engine intake ratio change. Alternatively, the procedure can be performed from Fig. 3-4 are triggered in response to a change in operator torque requirement that necessitates a change in throttle position or a change in intake ratio.

[0072] In this way, an engine with cylinder deactivation can be operated with an intake ratio based on operator torque demand; and in response to the throttle position being within a threshold range of fully open throttle, regardless of the operator torque demand, the intake ratio can be increased. Operating with an intake ratio based on operator torque demand involves operating with a higher intake ratio when the operator torque demand is higher and operating with a lower intake ratio when the operator torque demand is lower, with the higher intake ratio being provided by selectively deactivating fewer engine cylinders, and the lower intake ratio being provided by selectively deactivating more engine cylinders.In one example, increasing the intake ratio might involve incrementally increasing the number of active cylinders by incrementally reactivating selectively deactivated cylinders. In another example, increasing the intake ratio might involve restricting the intake ratio to 1.0. The intake ratio could be a commanded intake ratio, with the method further comprising estimating an actual intake ratio based on a modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle, comparing the commanded intake ratio with the estimated actual intake ratio, and indicating wear of a cylinder deactivation engine mechanism based on the comparison.The notification can include a response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold difference. Furthermore, selective cylinder deactivation can be disabled in response to this notification, regardless of operator torque requirements. The modeled air mass flow can be based on a throttle position if the throttle position is outside the threshold range for a fully open throttle. Specifically, the modeled air mass flow is not based on the output of an air mass flow sensor.Estimating the actual intake ratio can involve estimating an actual engine torque output based on the modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle; estimating a torque error based on the actual engine torque relative to a desired torque based on the commanded intake ratio; and estimating the actual intake ratio based on the commanded intake ratio and the torque error. Furthermore, the intake ratio can be increased in response to the commanded intake ratio being within a threshold of 1.0, regardless of operator torque demand or throttle position.

[0073] With reference to Fig. 6 is now an exemplary torque estimation method. 600This method demonstrates that it enables the torque to be accurately determined with reduced dependence on a MAF sensor. The procedure allows for a comparison of actual torque with a desired torque, enabling a comparison of the actual intake ratio with a commanded or desired intake ratio and allowing engine operation to be adjusted to prevent excessive torque delivery.

[0074] The procedure 600 includes estimating an airflow measurement or mass airflow (MAF) at 602To reduce reliance on costly MAF sensors, the MAF is determined using a throttle body model as a function of throttle position, manifold pressure, and barometric pressure (BP). The throttle body model can be based on an opening flow equation for compressible flow (see Equation 1 above) and includes parameters such as throttle angle to determine the cross-sectional area of ​​the opening hole (here, across the throttle), and ambient conditions to characterize the airflow (here, BP). The method compares the mass airflow to a measured change in manifold pressure across the throttle based on outputs from a MAP sensor. The MAP sensor output characterizes a pressure downstream of the throttle, while a BP sensor, compressor outlet pressure sensor, or throttle inlet pressure sensor characterizes a pressure upstream of the throttle. The rate of change of MAP 404This reflects the dynamic effect of the engine's actual intake cylinders. By calculating averages over one or more cylinder events, the robustness of torque estimates against pressure pulsations is improved while still providing sufficient attenuation. Using this approach, the control unit can detect a discrepancy between the desired intake ratio and the actual intake ratio. If the discrepancy exists, the control unit can indicate wear in the VDE system. The comparison of airflow and change in MAP is then used, along with an estimate of the engine speed. 406 used to determine an actual inlet ratio 408 to determine the engine load 410 and the actual admission ratio 408These values ​​are then used as inputs in a specified torque lookup table 412. By comparing the desired intake ratio with the output of the specified torque lookup table, a torque error can be determined. 414 to be learned, which is then used to calculate an estimated specified torque. 416 to output. This torque estimate is then used to adjust the motor operation and diagnose VDE wear.

[0075] With reference to Fig. Figure 5 shows an exemplary timeline of the operation of an engine with cylinder deactivation. The engine may have the capability to perform a diagnostic routine for the VDE system based on the throttle body model, such as the one shown in Fig. 4. Diagnostic routine shown for the VDE system. The throttle position and intake ratio of the engine can be adjusted in response to changes in torque demand via a control unit that executes a control routine, such as the routine from Fig. 3, coordinated. Within this, the probability of excessive torque delivery can be reduced by selectively restricting the desired intake ratio in response to a throttle position. By using a throttle body model to represent the airflow across the throttle, the need for a MAF sensor can be reduced, providing advantages in terms of component cost and complexity. The map 500 out of Fig. 5 represents an accelerator pedal position (PP) during the course 502 , a throttle position (or degree of opening) relative to WOT during the course 504 , a MAP sensor output during history 506, a mandated admission ratio in the course of 508 , and a marking indicating VDE wear, as the process progresses 512 All curves are plotted against time on the x-axis. Additionally, the magnitude of any given parameter increases along the y-axis from bottom to top, as shown. The time markers t1-t8 represent times at which significant errors occur.

[0076] Before time t1, the accelerator pedal (progression) 502 ) is actuated by a large quantity, which represents an increased operator torque requirement. At this point, the torque requirement is met by running the engine with all cylinders actively engaged, as indicated by the intake ratio of 1.0. Additionally, the engine is run with the throttle in a more open position, while the throttle opening remains below the level 503is maintained. As a result, more than a minimum distance is maintained. 505 Provided at WOT. MAP reflects the degree of throttle opening and is therefore increased at this time.

[0077] At t1, there is a drop in operator torque demand, as indicated by the pedal being released a certain amount. For example, the drop in operator torque demand could be due to the operator releasing the pedal. The change in torque demand is met by lowering the intake ratio (IR). Specifically, a number of cylinders are selectively deactivated. In the example shown, the change in torque demand is met by lowering the intake ratio to the lowest possible intake ratio for the given engine configuration. Additionally, the throttle opening is reduced, but the change in throttle position is not as large as the change in IR. As a result, the change in MAP is also not significant.

[0078] At t2, there is a further drop in operator torque demand, as indicated by the pedal being released a further amount, for example, due to the vehicle coasting. Since no further drop in intake ratio (IR) is possible, the change in torque demand is met by reducing the throttle opening while maintaining the intake ratio (IR) at its lowest setting. At this point, the throttle opening is reduced by a larger amount. The mapped mean air-fuel ratio (MAP) changes proportionally to the change in throttle opening.

[0079] At t3, there is an increase in operator torque demand, such as when the pedal is released a certain amount. For example, the increase in operator torque demand can result from a pedal actuation event by the operator, such as when the vehicle is traveling uphill on a segment with a steep incline. The change in torque demand is met by increasing the throttle opening as the torque demand increases, while maintaining the (lowest) intake ratio (IR). As a result of the change in throttle position, the MAP (mapped manifold absolute pressure) increases.

[0080] At t4, the throttle opening reaches level 503 , where the minimum distance 505 is provided. However, the pedal is still depressed and the operator torque requirement continues to increase. Would the throttle exceed the level 503Moving outwards towards WOT, the torque estimation can be affected. Therefore, the intake ratio is adjusted to at least maintain the minimum clearance. 505 To maintain the intake ratio, it is incremented to the next higher acceptable intake ratio in response to the increased torque demand, while simultaneously reducing the throttle opening. For example, the next higher acceptable intake ratio can be achieved by re-enabling one of the previously deactivated cylinders. Alternatively, the next higher acceptable intake ratio can be achieved by operating with a higher number (e.g., one more) of re-enabling cylinders. This is because, with a rolling VDE mechanism, the identity of the deactivated and re-enabling cylinders can be continuously adjusted.

[0081] Between t4 and t5In response to the further increase in torque demand, the throttle opening is increased, while the most recent (incremented by one step) intake ratio is maintained. t5 The throttle is once again at the same level 503 Thus, at t5 as in t4 In response to the pedal remaining depressed, the intake ratio is incremented by a further step by reactivating one or more cylinders while simultaneously reducing the throttle opening. The same occurs between t5 and t6 instead, until all cylinders are re-energized and the intake ratio is at 1.0. Each time the throttle opening is reduced, the reduction is by an amount based on the corresponding increase in the intake ratio. Furthermore, as the throttle opening increases and decreases, the MAP (mapped manifold absolute pressure) increases and decreases accordingly. In this way, betweent4 and t6 Despite the increased torque requirement, the throttle should be at least at a minimum distance 505 held to WOT.

[0082] At t6 The intake ratio is 1.0 and the throttle opening is at level 503 The accelerator pedal is pressed further. At this point, the throttle is moved to wide open throttle (WOT), while all cylinders remain active to meet the increased torque demand.

[0083] Between t0 and t6 The actual intake ratio, modeled based on the throttle body model, matches the commanded intake ratio, and no wear indicator is set. Between t6 and t7 , if the choke is at WOT, the choke body model is not used and the VDE wear is not determined based on the choke body model.

[0084] At t7There is a reduction in operator torque requirement, which is achieved by lowering the intake ratio and reducing the throttle opening to increase the distance to WOT. As with t1 The intake ratio is reduced to the lowest intake ratio, and the throttle opening is reduced by a smaller amount (than the change in the intake ratio). Between t7 and t8 The actual intake ratio is determined based on the throttle body model. The actual intake ratio determined based on the throttle body model 510 This differs significantly from the mandated admission ratio. Specifically, the actual admission ratio is... 510 by more than a threshold quantity higher than the ordered intake ratio (progression) 508 In response to the difference, wear of the VDE mechanism is determined and a mark is placed on it. t8The marking can indicate that fewer cylinders than desired are deactivated, resulting in a higher than desired torque output. In one example, this could be due to wear in the VDE mechanisms, preventing the cylinders from deactivating as expected. In another example, there could be wear in the control system, preventing the VDE mechanisms from being actuated to deactivate cylinders. Due to the wear in the VDE mechanism, the actual intake during operation is... 510 The measured MAP is higher than the commanded intake ratio, lower than desired or expected. When all cylinders are subsequently activated, the actual MAP returns to the same value as the desired or expected MAP.

[0085] Additionally, cylinder deactivation may be restricted in response to wear indications during subsequent engine operation. Specifically, even during conditions suitable for operating the engine in VDE mode (e.g., with one or more cylinders deactivated), cylinder deactivation may be restricted based on the degree of wear. For example, the commanded intake ratio may be 0.5, while the actual intake ratio may be determined to be 0.75. As a result of the wear indication, the commanded intake ratio during subsequent operation cannot be reduced below 0.75, thus limiting the intake ratio to 0.75 or greater.

[0086] In this way, an engine control unit can selectively shut down one or more engine cylinders to operate an engine at a commanded intake ratio based on operator torque demand; estimate an actual intake ratio based on modeled mass airflow through an intake throttle relative to a detected manifold pressure change across the throttle; and indicate wear on a selectively shut-off cylinder mechanism based on the commanded intake ratio relative to the estimated actual intake ratio. The control unit can also restrict the commanded intake ratio to 1.0 in response to the throttle position being within a threshold range of wide-open throttle, regardless of operator torque demand. Restricting the commanded intake ratio to 1.0 can involve operating the engine with all cylinders actively engaged.Here, the modeled air mass flow can be based on a throttle position when the throttle position is outside the threshold range for a fully open throttle, and the detected manifold pressure change is based on outputs from a manifold pressure sensor. The control unit can further restrict the commanded intake ratio to 1.0 in response to the commanded intake ratio being within a threshold of 1.0, regardless of the operator torque demand or throttle position. Wear indication can include indicating wear in response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold. Furthermore, the control unit can reactivate the selectively deactivated one or more engine cylinders in response to wear indications.Furthermore, in response to the throttle opening being within a threshold distance to wide-open throttle, the control can, regardless of the operator torque requirement, increase the commanded intake ratio to a first intake ratio while reducing the throttle opening to more than the threshold distance to wide-open throttle, where the first intake ratio is the next available intake from the commanded intake ratio, and where the first intake ratio is higher than the commanded intake ratio.Furthermore, after increasing the ordered intake ratio to the first intake ratio, adjusting the throttle opening based on the operator torque requirement and in response to the fact that the throttle opening after adjustment is within the threshold distance of wide open throttle, increasing the first intake ratio to a second intake ratio, wherein the second intake is the next available intake ratio from the first intake ratio, and the second intake ratio is higher than the first intake ratio.

[0087] In this way, by using a throttle body model to characterize airflow entering the engine over a wide range of engine operating conditions, the need for a MAF sensor for airflow measurement during torque estimation is reduced. This provides component reduction benefits in terms of cost and complexity. By using the throttle body model-based airflow estimation in conjunction with a specification of the pressure change across the throttle (e.g., using an existing MAP sensor), independent data can be provided for torque monitoring. This allows for an accurate and reliable estimation of the actual intake ratio using fewer sensors.The technical benefit of coordinating throttle settings with intake ratio settings as torque demand changes is that the throttle position can be maintained at a minimum distance from wide open throttle (WOT) for a larger proportion of a driving cycle, thus enabling greater accuracy in airflow measurement via the throttle body model over that longer period. Specifically, by reducing the throttle opening while simultaneously incrementally increasing the intake ratio, engine torque output can be increased without moving the throttle to a WOT position. By comparing the estimated actual intake ratio with the desired intake ratio (based on torque demand), wear of the VDE mechanism can be learned.The technical effect of restricting the commanded intake ratio during conditions where airflow measurement may be inaccurate, such as when the throttle is within a wide-open threshold, is that deficiencies in the use of the throttle body model can be overcome and the likelihood of excessive torque delivery can be reduced. As a result, the drivability of a vehicle equipped with a cylinder deactivation engine is improved.

[0088] An exemplary procedure comprises: operating a cylinder-deactivating engine with an intake ratio based on operator torque demand; and, in response to the throttle position being within a threshold range of wide-open throttle, regardless of the operator torque demand, increasing the intake ratio. In the preceding example, additionally or optionally, operating with an intake ratio based on an operator torque demand includes operating with a higher intake ratio when the operator torque demand is higher and operating with a lower intake ratio when the operator torque demand is lower, the higher intake ratio being provided by selectively deactivating fewer engine cylinders, and the lower intake ratio being provided by selectively deactivating more engine cylinders.In any or all of the preceding examples, increasing the intake ratio additionally or optionally includes incrementally increasing the number of active cylinders that fire over each engine cycle. In any or all of the preceding examples, increasing the intake ratio additionally or optionally includes limiting the intake ratio to or towards 1.0.In any or all of the preceding examples, the intake ratio is additionally or optionally a commanded intake ratio, the method further comprising estimating an actual intake ratio based on a modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle, comparing the commanded intake ratio with the estimated actual intake ratio, and indicating wear of a cylinder deactivation engine mechanism based on the comparison.In any or all of the preceding examples, the procedure additionally or optionally includes, in response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold difference, disabling the shutdown of selected cylinders in response to the indication, irrespective of the operator torque requirement. In any or all of the preceding examples, the modeled mass airflow is additionally or optionally based on a throttle position when the throttle position is outside the threshold distance to a wide-open throttle. In any or all of the preceding examples, the modeled mass airflow is additionally or optionally not based on the output of a mass airflow sensor.In any or all of the preceding examples, estimating the actual intake ratio additionally or optionally includes estimating an actual engine torque based on the modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle; and estimating the actual intake ratio based on the actual engine torque. In any or all of the preceding examples, the method further additionally or optionally includes increasing the intake ratio in response to the commanded intake ratio being within a threshold of 1.0, regardless of the operator torque requirement and throttle position. In another embodiment, increasing the intake ratio includes incrementally increasing the number of active cylinders by incrementally reactivating selectively deactivated cylinders.

[0089] Another exemplary procedure includes: selectively shutting down one or more engine cylinders to operate an engine at a commanded intake ratio based on operator torque demand; estimating an actual intake ratio based on modeled mass airflow through an intake throttle relative to a detected manifold pressure change across the throttle; and indicating wear of a selectively shut-off cylinder mechanism based on the commanded intake ratio relative to the estimated actual intake ratio.In the preceding example, the method additionally or optionally further comprises, in response to the fact that the throttle opening is within a threshold distance to wide-open throttle, regardless of the operator torque requirement, increasing the commanded intake ratio to a first intake ratio while reducing the throttle opening to more than the threshold distance to wide-open throttle, wherein the first intake ratio is the next available intake from the commanded intake ratio, and the first intake ratio is higher than the commanded intake ratio.In any or all of the preceding examples, the method additionally or optionally further comprises, after increasing the ordered intake ratio to the first intake ratio, adjusting the throttle opening based on the operator torque requirement, and in response to the fact that the throttle opening after adjustment is within the threshold distance of wide open throttle, increasing the first intake ratio to a second intake ratio, wherein the second intake is the next available intake ratio from the first intake ratio, and wherein the second intake ratio is higher than the first intake ratio.In any or all of the preceding examples, the modeled air mass flow is additionally or optionally modeled based on a throttle position when the throttle position is outside the threshold distance to a wide-open throttle, and the detected manifold pressure change is based on outputs from a manifold pressure sensor. In any or all of the preceding examples, the method further additionally or optionally includes increasing the intake ratio to 1.0 in response to the commanded intake ratio being within a threshold of 1.0, regardless of the operator torque requirement and the throttle position.In any or all of the preceding examples, the specification additionally or optionally includes the specification of wear in response to the fact that a difference between the ordered intake ratio and the estimated actual intake ratio is greater than a threshold, the procedure further comprising, in response to the specification, the reactivation of the selectively deactivated one or more engine cylinders.

[0090] Another exemplary engine system comprises: a cylinder deactivation engine; a plurality of cylinders, each having selectively deactivatable valve mechanisms and a selectively deactivatable fuel injection device; a manifold pressure sensor; a throttle position sensor; an intake throttle; and a controller with computer-readable instructions stored in non-volatile memory to: selectively deactivate a number of the plurality of cylinders to provide a commanded intake ratio based on operator torque demand; increase the throttle opening in response to increasing operator torque demand while maintaining the commanded intake ratio until the throttle position is within a threshold range of fully open throttle;and when the throttle position is at the threshold of excessively open throttle, increasing the commanded intake ratio by selectively reactivating one of the deactivated cylinders while reducing the throttle opening to move the throttle position to a higher value than the threshold of excessively open throttle. In any or all of the preceding examples, the control additionally or optionally includes further instructions to keep the entire plurality of cylinders active in response to increasing operator torque demand while the throttle position is at the threshold of excessively open throttle and the commanded intake ratio is increased to 1.0;and to increase the throttle opening to move the throttle position to a wide-open throttle. In any or all of the preceding examples, the control additionally or optionally includes further instructions to, in response to any throttle position being outside the wide-open throttle threshold, estimate an actual engine intake ratio based on modeled mass airflow through the throttle relative to detected manifold pressure change across the throttle; estimate a torque error based on the actual intake ratio relative to the commanded intake ratio;and updating the commanded intake ratio based on the torque error, where the modeled mass airflow is not based on the output of a mass airflow sensor. In any or all of the preceding examples, the control additionally or optionally includes instructions to indicate wear of the selectively shut-off valve mechanisms or the selectively shut-off fuel injection device in response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold; and in response to the indication to re-enable the selectively shut-off one or more of the plurality of cylinders. In another representation, the engine system is coupled in a hybrid vehicle system.

[0091] In yet another embodiment, a method for an engine with selectively deactivatable cylinders involves maintaining engine operation with a first intake ratio in response to an increase in operator torque demand, while increasing the throttle opening as required by the torque demand up to a threshold distance from a fully open throttle. In the preceding example, the first intake ratio additionally or optionally includes an initial number of deactivated cylinders, and the first intake ratio is based on the operator torque demand.In any or all of the preceding examples, additionally or optionally, after the throttle opening is increased to the threshold distance to wide-open throttle, in response to a further increase in operator torque demand, the engine is operated with a second intake ratio higher than the first intake ratio, while the throttle opening is reduced away from the threshold distance to wide-open throttle. In any or all of the preceding examples, additionally or optionally, the second intake ratio has a second number of deactivated cylinders, the second number having one fewer deactivated cylinder than the first number. In any or all of the preceding examples, additionally or optionally, the reduction of the throttle opening is based on a difference between the first and second intake ratios, with the throttle opening being further reduced as the difference increases.

[0092] It should be noted that the exemplary control and estimation sequences contained herein can be used with various engine and / or vehicle system configurations. The control procedures and sequences disclosed herein can be stored as executable instructions in non-volatile memory and can be executed by the control system, which includes the control unit in combination with the 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, and the like. Accordingly, various illustrated actions, operations, and / or functions can be performed in the illustrated sequence or in parallel, or in some cases, omitted.Similarly, the processing sequence is not strictly necessary to achieve the features and advantages of the exemplary embodiments described here, but is provided to facilitate illustration and description. One or more of the illustrated actions, processes, and / or functions can be performed repeatedly, depending on the specific strategy employed. Furthermore, the described actions, processes, and / or functions can graphically represent code to be programmed into non-volatile memory of the computer-readable storage medium in the engine control system, with the described actions being executed by carrying out the instructions in a system that includes the various engine hardware components in combination with the electronic control unit.

[0093] It is understood that the interpretations and routines disclosed herein are exemplary in nature and that these specific embodiments are not to be interpreted in a restrictive sense, as numerous variations are possible. For example, the foregoing technology can be applied to V-6, I-4, I-6, V-12, 4-cylinder boxer, 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 and other features, functions, and / or properties disclosed herein.

[0094] The following claims describe, in particular, certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element, "a first" element, or the equivalent thereof. Such claims should be understood as including one or more such elements and neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application.Such patent claims shall also be considered as included in the subject matter of the present disclosure, irrespective of whether they have a broader, narrower, the same or a different scope compared to the original patent claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 6705286

[0003]

Claims

[1] Procedure, encompassing: Operating an engine with cylinder deactivation and an intake ratio based on operator torque requirement; and In response to the fact that the throttle position is within a threshold distance of a wide-open throttle, regardless of the operator torque requirement, the intake ratio is increased. [2] Method according to claim 1, wherein operating with an intake ratio based on an operator torque requirement includes operating with a higher intake ratio when the operator torque requirement is higher and operating with a lower intake ratio when the operator torque requirement is lower, wherein the higher intake ratio is provided by selectively shutting down fewer engine cylinders, and wherein the lower intake ratio is provided by selectively shutting down more engine cylinders. [3] Method according to claim 1, wherein increasing the intake ratio includes incrementally increasing the number of active cylinders that fire over each engine cycle. [4] Method according to claim 1, wherein increasing the inlet ratio includes restricting the inlet ratio to or in the direction of 1.

0. [5] Method according to claim 1, wherein the intake ratio is a commanded intake ratio, the method further comprising estimating an actual intake ratio based on a modeled mass airflow through the throttle relative to a detected manifold pressure change rate across the throttle, comparing the commanded intake ratio with the estimated actual intake ratio and indicating wear of a cylinder deactivation engine mechanism based on the comparison. [6] Method according to claim 5, wherein the indication is made in response to the fact that a difference between the ordered intake ratio and the estimated actual intake ratio is greater than a threshold difference, wherein the method further comprises, in response to the indication, disabling the shutdown of selected cylinders irrespective of the operator torque requirement. [7] Method according to claim 5, wherein the modeled air mass flow is modeled on the basis of a throttle position when the throttle position is outside the threshold distance to a throttle that is wide open. [8] Method according to claim 7, wherein the modeled air mass flow is not based on the output of an air mass flow sensor. [9] Method according to claim 5, wherein estimating the actual inlet ratio includes: Estimating actual engine torque based on the modeled air mass flow through the throttle relative to a measured manifold pressure change rate across the throttle; and Estimating the actual intake ratio based on the actual engine torque. [10] Method according to claim 5, further comprising, in response to the fact that the ordered inlet ratio is within a threshold of 1.0, increasing the inlet ratio irrespective of the operator torque requirement and the position of the throttle. [11] Method according to claim 5, further comprising, in response to the indication, the reactivation of one or more selectively deactivated engine cylinders. [12] Engine system, comprising: an engine with cylinder deactivation; a plurality of cylinders, each having selectively switchable valve mechanisms and a selectively switchable fuel injection device; a manifold pressure sensor; a throttle position sensor; an intake throttle; and a controller with computer-readable instructions stored in non-volatile memory for the following: Selective shutdown of a number of cylinders from the multitude to provide a commanded intake ratio based on operator torque requirements; Increasing the throttle opening in response to increasing operator torque requirements, while maintaining the commanded intake ratio, until the throttle position is at a threshold distance from a fully open throttle; and If the throttle position is at the threshold distance of excessively open throttle, increase the commanded intake ratio by selectively reactivating one of the deactivated cylinders while reducing the throttle opening to move the throttle position higher than the threshold distance of excessively open throttle. [13] System according to claim 12, wherein the control further includes instructions for the following: in response to an increase in operator torque requirement, while the throttle position is at the threshold distance to a wide-open throttle and the commanded intake ratio is increased to 1.0, Keeping the entire multitude of cylinders active; and Increasing the throttle opening to move the throttle position to a fully open throttle. [14] System according to claim 13, wherein the control further includes instructions for the following: as a reaction to the fact that each throttle position is outside the threshold distance to a throttle that is too wide open, Estimating the actual intake ratio of the engine based on modeled air mass flow through the throttle relative to a measured manifold pressure change rate across the throttle; Estimating a torque error based on the actual intake ratio relative to the commanded intake ratio; and Updating the commanded intake ratio based on the torque error, where the modeled air mass flow is not based on the output of an air mass flow sensor. [15] System according to claim 13, wherein the control further includes instructions for the following: Indicating wear of the selectively switchable valve mechanisms or the selectively switchable fuel injection device in response to a difference between the commanded intake ratio and the estimated actual intake ratio exceeding a threshold; and as a reaction to the indication, reactivation of the selectively deactivated one or more cylinders from the multitude.

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