System and method for wastegate diagnosis

Abstract

The present disclosure provides "Systems and methods for wastegate diagnosis". Methods and systems are provided for diagnosing a wastegate valve during a vehicle off condition. In one example, the engine can be reverse rotated without fueling, and air flow via an intake manifold can be estimated and compared to a baseline air flow. A stuck open wastegate valve can be indicated based on the comparison between the intake air flow and the baseline air flow.

Description

Technical Field

[0001] This specification generally relates to methods and systems for diagnosing exhaust valves connected to exhaust gas passages of exhaust turbines. Background Technology

[0002] Some internal combustion engines utilize compression devices such as turbochargers to increase engine torque / power output density. In one example, a turbocharger may include a compressor and a turbine connected via a drive shaft, with the turbine coupled to the exhaust manifold side and the compressor coupled to the engine's intake manifold side. In this way, the exhaust-driven turbine supplies energy to the compressor to increase the pressure in the intake manifold (e.g., boost or boost pressure) and increase the airflow into the engine. Boost pressure can be controlled by adjusting the amount of gas reaching the turbine (e.g., through the wastegate). The spring-loaded wastegate valve can be controlled based on operating conditions to achieve the desired boost pressure. The wastegate valve spring may deteriorate over time, causing the wastegate valve to become stuck in at least a partially open position. A partially stuck wastegate valve can reduce boost pressure and adversely affect engine emissions.

[0003] Propernick discloses an exemplary method for diagnosing exhaust gas valve operation in U.S. Patent Application No. 20020148224. Diagnostics of a turbocharger component, including the exhaust gas valve, can be performed during engine shutdown. Pressurized air from a source can be delivered to the turbocharger, and the air pressure within the turbocharger can be estimated via a pressure gauge. Any leaks in the turbocharger system, including the exhaust gas valve, can be detected under applied pressure.

[0004] However, the inventors in this paper have recognized the potential problems with such systems. As an example, additional components such as an air supply source, ducts for the air supply, and one or more pressure gauges may be required to perform exhaust valve diagnostics, thereby increasing cost and packaging issues. Summary of the Invention

[0005] In one example, the above problem can be addressed by an engine method comprising: testing the degradation of an exhaust valve by directing airflow from the engine's exhaust system through a wastegate valve to the engine's intake port and comparing the airflow in the intake port with a baseline airflow entering the engine intake port through the wastegate valve, the wastegate valve being located in a wastegate passage connected in parallel with a turbine located in the exhaust system. In this way, the degradation of the wastegate valve can be detected by directing ambient air through the wastegate valve during the vehicle's ignition switch-off state.

[0006] In one example, when the engine is not in operation, diagnostic procedures for the wastegate valve can be performed as appropriate during the vehicle's ignition switch-off state. The engine may be a turbocharged engine comprising a turbine-driven intake compressor and an electrically driven intake compressor (also referred to herein as a battery-powered electric supercharger), which selectively operates to provide additional boost during periods of increased torque demand. During the vehicle's off state, the wastegate valve may be in a default closed position. The engine may be reverse-rotated without fuel, and the electric supercharger may also be reverse-rotated to draw ambient air from the tailpipe and direct that air to the intake manifold via the exhaust turbine. The intake airflow can be estimated via a manifold airflow sensor and compared to a baseline airflow. When the wastegate valve is installed, the baseline airflow can be obtained by reverse-rotating the engine, reverse-rotating the electric supercharger, and estimating the airflow through the intake manifold via the MAF sensor. In response to the intake airflow being higher than the baseline airflow, the wastegate valve can be diagnosed as stuck in at least a partially open position. The opening degree of the exhaust valve can be estimated based on the difference between the intake airflow and the baseline airflow, the opening degree increasing as the difference between the intake airflow and the baseline airflow increases. Upon detection of exhaust valve deterioration, the electric supercharger operation can be adjusted during subsequent engine operation to account for the loss of boost pressure due to undesired exhaust flow via the deteriorated exhaust valve.

[0007] In this way, by utilizing existing engine components (such as electric superchargers and manifold airflow sensors) in a timely manner, the need for additional sensors and / or equipment for diagnosing the exhaust valves can be reduced or eliminated. By reversing the engine rotation, the drop in exhaust pressure can be used to draw in ambient air and perform exhaust valve diagnostics. The advantage of allowing air to flow through the turbocharger during engine non-combustion conditions is that the opening degree of the deteriorated exhaust valve can be determined based on a comparison between the intake airflow and the baseline airflow. By identifying the deterioration of the exhaust valves, appropriate mitigation steps can be taken during subsequent engine cycles to improve engine performance. In summary, by regularly monitoring the health of the exhaust valves, fuel efficiency and emissions quality can be improved.

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

[0009] Figure 1 An exemplary vehicle system including a turbocharger is schematically shown.

[0010] Figure 2 An example of an electrically operated exhaust valve according to an embodiment of the present disclosure is shown.

[0011] Figure 3 An example of a pneumatic exhaust valve according to an embodiment of the present disclosure is shown.

[0012] Figure 4 A block diagram of an exemplary autonomous driving system is shown schematically.

[0013] Figure 5A and Figure 5B An exemplary H-bridge circuit is schematically shown, which can be used to rotate a vehicle engine in the forward or reverse direction.

[0014] Figure 6 A flowchart illustrating the diagnostic procedure for diagnosing a deteriorated exhaust valve is shown.

[0015] Figure 7 An exemplary diagnostic of the exhaust valve during engine shutdown is shown in accordance with this disclosure. Detailed Implementation

[0016] The following description relates to diagnostic connections included in Figure 1 The system and method for the exhaust valve of the exhaust turbine in the exemplary engine shown are illustrated. The exhaust valve can be as follows: Figure 2 The electric exhaust valve shown is or as Figure 3 The pneumatic exhaust valve is shown. In some examples, exhaust valve diagnostics can be performed in autonomous vehicles, where... Figure 4 An exemplary autonomous vehicle control system is described. During diagnostics, in order to rotate the engine without fuel in both the forward and reverse directions, an H-bridge circuit, such as in... Figures 5A to 5B The H-bridge circuit depicted herein. During the vehicle's ignition switch-off state, the vehicle's engine controller can be configured to execute an exemplary procedure to indicate deterioration of the exhaust valve. In the example, the procedure can be executed... Figure 6 The diagnostic procedure shown. Figure 7 An exemplary engine operation is shown that performs exhaust valve diagnostics while the vehicle's ignition switch is off.

[0017] Figure 1A schematic diagram 101 of a vehicle system 102 having an exemplary engine system 100 including an engine 10 is shown. In one example, engine system 100 may be a diesel engine system. In another example, engine system 100 may be a gasoline engine system. In the depicted embodiment, engine 10 is a turbocharged engine coupled to a turbocharger 15, which includes a compressor 114 driven by a turbine 116. Specifically, fresh air is introduced into engine 10 via an air purifier 112 along an intake duct 42 and flows to compressor 114. The compressor may be any suitable intake compressor, such as a motor-driven or drive shaft-driven supercharger compressor. In engine system 10, the compressor is a turbocharger compressor mechanically coupled via a shaft 19 to a turbine 116 driven by the expansion of engine exhaust.

[0018] like Figure 1 As shown, compressor 114 is connected to throttle body 20 via supercharged air cooler (CAC) 118. Throttle body 20 is connected to engine intake manifold 122. Compressed air charges from the compressor, flows through supercharged air cooler 118 and throttle body 20 to intake manifold 122. Figure 1 In the illustrated embodiment, the manifold airflow (MAF) sensor 124 senses the airflow through the intake manifold 122. The temperature of the ambient air entering the intake duct 42 can be estimated via the intake air temperature (IAT) sensor 51.

[0019] One or more sensors may be connected to the inlet of compressor 114. For example, temperature sensor 55 may be connected to the inlet to estimate compressor inlet temperature, while pressure sensor 56 may be connected to the inlet to estimate compressor inlet pressure. As another example, ambient humidity sensor 57 may be connected to the inlet to estimate the humidity of the air entering the intake manifold. Other sensors may include, for example, an air-fuel ratio sensor. In other examples, one or more compressor inlet conditions (such as humidity, temperature, pressure, etc.) may be inferred based on engine operating conditions. Additionally, sensors may estimate the temperature, pressure, humidity, and air-fuel ratio of the air-fuel mixture comprising fresh air, recirculated compressed air, and exhaust residue received at the compressor inlet.

[0020] To assist the turbocharger 15, an additional intake compressor (also referred to herein as an electric supercharger 155) can be integrated into the vehicle propulsion system. The electric supercharger 155 can be powered via an on-board energy storage device 250, which may include a battery, capacitor, supercapacitor, etc. The electric supercharger may include a compressor driven by an electric motor. The operating speed of the electric supercharger may include adjusting the operating speed of the electric motor, which is operated via the on-board energy storage device 250.

[0021] In one example, the electric supercharger 155 can be actuated in response to a demand for increased wheel torque to rapidly deliver the desired boost air to the engine while the turbocharger spools up. As a result, the increased torque can be met without causing turbo lag, which could otherwise occur if assistance from the electric supercharger is unavailable. In such an example, the electric supercharger 155 can be actuated to shut down or deactivate in response to the turbocharger reaching a threshold speed (e.g., 70,000 rpm). More specifically, the operation of the electric supercharger 155 can be controlled based on command signals (e.g., duty cycle or pulse width signals) received from a vehicle controller (e.g., controller 12). For example, the controller can send a signal to the electric supercharger actuator 155b that actuates to turn the electric supercharger on. In another example, the controller can send a signal to the electric supercharger actuator 155b that actuates to turn the electric supercharger off. In one example, the electric supercharger actuator may include an electric motor that drives air compression.

[0022] An electric supercharger 155 may be located between a first electric supercharger conduit 159a and a second electric supercharger conduit 159b. The first electric supercharger conduit 159a may fluidly connect the intake manifold 42 to the electric supercharger 155 upstream of the electric supercharger bypass valve 161. The second electric supercharger conduit 159b may fluidly connect the electric supercharger 155 to the intake manifold 42 downstream of the electric supercharger bypass valve 161. As an example, air may be drawn into the electric supercharger 155 upstream of the electric supercharger bypass valve 161 via the first electric supercharger conduit 159a, and compressed air may exit the electric supercharger 155 and be guided downstream of the electric supercharger bypass valve 161 to the intake manifold 42. In this way, compressed air can be directed to the engine intake port 122.

[0023] When the electric supercharger 155 is activated to provide boost faster than when relying solely on the turbocharger 15, it is understood that the electric supercharger bypass valve 161 can be commanded to close when the electric supercharger 155 is activated. In this way, intake air can flow through the turbocharger 15 and then through the electric supercharger 155. Once the turbocharger reaches its threshold speed, the electric supercharger 155 can be shut off, and the electric supercharger bypass valve 161 can be commanded to open.

[0024] Waste gas valve 92 can be connected to exhaust passage 104 to regulate the volume of exhaust gas flowing through the turbine. A waste gas passage 90 connects to exhaust passage 104 from upstream to downstream of turbine 116, and a waste gas valve connected to waste gas passage 90 can regulate exhaust flow via exhaust turbine 116. Waste gas valve (actuator) 91 can be actuated to open to discharge at least some exhaust pressure from upstream to downstream of turbine via waste gas passage 90. Waste gas valve 91 can be maintained in the default closed position to guide exhaust gas via turbine 116. Based on boost demand, the controller can estimate the pressure setpoint for opening waste gas valve 91. If the exhaust pressure upstream of turbine increases above the setpoint pressure, waste gas valve 91 can open to guide at least a portion of the exhaust gas from upstream to downstream of turbine 116 via waste gas passage 90 until the exhaust pressure decreases below the setpoint. By reducing the exhaust pressure upstream of turbine, turbine speed can be reduced, which in turn helps reduce compressor surge. Figure 2 and Figure 3 An exemplary embodiment of the exhaust valve 92 is shown.

[0025] As exhaust gas is directed through the wastegate passage 90, soot and other carbonaceous materials can accumulate in the wastegate system over time. As an example, wastegate valve 91 may become heavily carbonized, which in some cases can lead to deterioration of wastegate valve 91 (e.g., stuck in at least a partially open position). Diagnostic procedures for wastegate valve 91 can be performed periodically or as needed during vehicle ignition-off conditions. The engine can be reverse-rotated without fuel via the motor, and the electric supercharger 155 can also be reverse-rotated to direct ambient air from the exhaust system through wastegate valve 91 and turbine 116 into engine intake manifold 122. Airflow in intake manifold 122 can be estimated via manifold airflow (MAF) sensor 124 and compared to a baseline airflow. During vehicle ignition-off conditions, when wastegate valve 91 is installed, a baseline airflow can be established via MAF sensor 124 by directing ambient air through wastegate valve 91 while simultaneously reversing the engine and electric supercharger 155. When the vehicle ignition switch is off, the exhaust valve 91 can remain in the default closed position, and the entire volume of ambient air can flow from the exhaust manifold 104 to the intake manifold 122 via the turbine 116. If the exhaust valve 91 deteriorates and becomes stuck in the open position, the airflow may increase because a smaller, more restrictive flow path (compared to the turbine 116) is available for airflow. Deterioration of the exhaust valve can be indicated in response to airflow in the intake manifold 122 being higher than the baseline airflow. No deterioration of the exhaust valve 91 can be indicated in response to airflow in the intake manifold 122 being substantially equal to the baseline airflow (e.g., within 5% of the baseline airflow). In response to indications of exhaust valve deterioration, a diagnostic code can be set, and the operation of the electric supercharger 155 can be adjusted during subsequent engine operation to compensate for the exhaust valve deterioration.

[0026] Intake manifold 122 is connected to a series of combustion chambers 30 via a series of intake valves (not shown). The combustion chambers are also connected to exhaust manifold 36 via a series of exhaust valves (not shown). In the depicted embodiment, a single exhaust manifold 36 is shown. However, in other embodiments, the exhaust manifold may include multiple exhaust manifold sections. A configuration with multiple exhaust manifold sections allows effluent from different combustion chambers to be directed to different locations within the engine system.

[0027] In one embodiment, each of the exhaust valve and the intake valve may be electronically actuated or controlled. In another embodiment, each of the exhaust valve and the intake valve may be cam-actuated or controlled. Whether electronically or cam-actuated, the opening and closing timing of the exhaust valve and the intake valve can be adjusted as needed to achieve desired combustion and emission control performance.

[0028] Combustion chamber 30 can be supplied with one or more fuels, such as gasoline, alcohol-fuel mixtures, diesel, biodiesel, compressed natural gas, etc., via injector 66. Fuel can be supplied to the combustion chamber via direct injection, port injection, throttle body injection, or any combination thereof. Combustion can be initiated in the combustion chamber via spark ignition and / or compression ignition.

[0029] like Figure 1 As shown, exhaust gas from one or more exhaust manifold sections can be directed to turbine 116 to drive the turbine. The combined flow from the turbine and exhaust valve then flows through emission control device 170. In one example, emission control device 170 may be an ignition catalyst. Typically, exhaust aftertreatment device 170 is configured to catalytically treat the exhaust stream, thereby reducing the amount of one or more substances in the exhaust stream. For example, exhaust aftertreatment device 170 may be configured to capture NO from the exhaust stream when the exhaust stream is lean. x Furthermore, when the exhaust flow is rich, the amount of NO captured is reduced. x In other examples, the exhaust aftertreatment device 170 can be configured to cause NO to... x Disproportionate or selective reduction of NO using reducing agents x In other examples, exhaust aftertreatment device 170 may be configured to oxidize residual hydrocarbons and / or carbon monoxide in the exhaust stream. Different exhaust aftertreatment catalysts having any of this function may be disposed individually or together in the base coating or elsewhere in the exhaust aftertreatment stage. In some embodiments, the exhaust aftertreatment stage may include a regenerable soot filter configured to capture and oxidize soot particles in the exhaust stream.

[0030] An exhaust gas recirculation (EGR) delivery passage 180 may be coupled upstream of the turbine 116 to the exhaust passage 104 to provide high-pressure EGR (HP-EGR) downstream of the compressor 114 to the engine intake manifold. An EGR valve 152 may be coupled to the EGR passage 180 at its junction with the intake passage 42. The EGR valve 152 may be opened to allow a controlled amount of exhaust gas to reach the compressor outlet to achieve desired combustion and emission control performance. The EGR valve 152 may be configured as a continuously variable valve or an on / off valve. In other embodiments, the engine system may include a low-pressure EGR (LP-EGR) flow path, wherein exhaust gas is drawn downstream of the turbine 116 and recirculated to the engine intake manifold upstream of the compressor 114.

[0031] Multiple other sensors can also be coupled to EGR channel 180 to provide details about the composition and condition of the EGR. For example, a temperature sensor can be provided to determine the temperature of the EGR, a humidity sensor can be provided to determine the humidity or water content of the EGR, and an air-fuel ratio sensor can be provided to estimate the air-fuel ratio of the EGR. Optionally, the EGR condition can be inferred from one or more temperature, pressure, humidity, and air-fuel ratio sensors coupled to the compressor inlet.

[0032] Multiple sensors, including an exhaust temperature sensor 128, an exhaust oxygen sensor, an exhaust flow sensor, and an exhaust pressure sensor 129, can be connected to the main exhaust manifold 104. The oxygen sensor can be a linear oxygen sensor or a UEGO (universal or wide-range exhaust oxygen sensor), a dual-state oxygen sensor or an EGO, HEGO (heated EGO), NOx, HC, or CO sensor.

[0033] Engine system 100 may also include control system 14. Control system 14 is shown receiving information from a plurality of sensors 16 (various examples of which are described herein) and sending control signals to a plurality of actuators 18 (various examples of which are described herein). As an example, sensors 16 may include an exhaust sensor 126, an MAF sensor 124, an exhaust temperature sensor 128, an exhaust pressure sensor 129, a compressor inlet temperature sensor 55, a compressor inlet pressure sensor 56, an ambient humidity sensor 57, an IAT sensor 51, an engine coolant temperature sensor, and an EGR sensor located upstream of turbine 116. Other sensors (such as additional pressure, temperature, air-fuel ratio, and composition sensors) may be coupled to various locations within engine system 100. Additionally, sensors coupled to the outside of the vehicle system (such as a rain sensor (windshield sensor) 130) may be used to estimate ambient humidity.

[0034] Actuator 18 may include, for example, an electric supercharger bypass valve 161, a throttle valve 20, an electric supercharger actuator 155b, an EGR valve 152, an exhaust gas valve 91, and a fuel injector 66. Control system 14 may include controller 12. Controller 12 may receive input data from various sensors, process the input data, and trigger various actuators in response to the processed input data based on instructions corresponding to one or more programs or codes programmed in the instructions. In one example, during the vehicle's ignition switch-off state, controller 12 may send signals to the electric motor and electric supercharger actuator 155b to reverse the rotation of each of the engine and electric supercharger 155, respectively, to allow ambient air to flow through turbine 116. Intake airflow is estimated via MAF sensor 124, and the presence or absence of deterioration of exhaust gas valve 91 may be indicated based on a comparison between the intake airflow and a baseline airflow.

[0035] In some examples, the controller can be placed in a reduced-power mode or a sleep mode, where the controller maintains only basic functions and operates with lower battery consumption than the corresponding wake-up mode. For example, the controller can be placed in sleep mode after a vehicle shutdown event to perform diagnostic procedures for a period of time after the vehicle shutdown event. The controller can have a wake-up input that allows the controller to return to wake-up mode based on input received from one or more sensors. For example, opening a door can trigger a return to wake-up mode. For example, the wake-up function can enable circuitry to wake up the controller to perform timely diagnostics on the exhaust valve 91.

[0036] In some examples, vehicle 102 may be a hybrid vehicle having multiple torque sources available for one or more wheels 157. In other examples, vehicle 102 may be a conventional vehicle with only an engine or an electric vehicle with only an electric motor. In the example shown, vehicle 102 includes an engine 10 and an electric motor 52. The electric motor 52 may be a motor or an electric motor / generator. When one or more clutches 156 are engaged, the crankshaft of engine 10 and electric motor 52 are connected to wheels 157 via transmission 54. In the depicted example, a first clutch 156 is disposed between the crankshaft and electric motor 52, while a second clutch 156 is disposed between electric motor 52 and transmission 54. Controller 12 may send signals to the actuators of each clutch 156 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft from electric motor 52 and its connected components, and / or connecting or disconnecting electric motor 52 from transmission 54 and its connected components. Transmission 54 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain may be configured in various ways, including parallel, series, or series-parallel hybrid vehicles.

[0037] The motor 52 receives power from the traction battery 58 to provide torque to the wheel 157. For example, during braking operations, the motor 52 can also be used as a generator to provide power to charge the traction battery 58.

[0038] Turn now Figure 2 An example of an exhaust valve 200 is shown, which can be Figure 1 Exhaust valve 92. Exhaust valve 200 along... Figure 1A portion of the exhaust duct 104 shown is included. In the illustrated embodiment, the wastegate 200 is an electrically operated wastegate and is driven by an actuator 150, which in this example is a solenoid, but various suitable devices can also be used to drive the wastegate. The actuator 150 transmits driving force to the wastegate valve 206 via a linkage 204 (e.g., a cylindrical rod), which can switch between a fully closed position and a fully open position and can be stabilized at any position in between. The position of the wastegate valve 206 can therefore be continuously variable and can be monitored via a position sensor 203, which is configured to send signals to the engine controller (such as...). Figure 1 The controller 12) sends a signal. However, it should be understood that the state of the exhaust valve 206 can be tracked in other ways (e.g., by other types of sensors or soft models).

[0039] When the exhaust valve 206 is opened from the fully closed position, an opening is formed through which gas flowing through the exhaust passage 104 can flow into the chamber 207. Gas can then flow from the chamber 207 to the vent 208, which receives and discharges gas from the exhaust passage 104 when the exhaust valve 206 is not in the fully closed position. Therefore, the position of the exhaust valve 206 and its access to the intake manifold and the turbocharger turbine (e.g., ...) can be changed by actuating the exhaust valve 206 via the actuator 150. Figure 1 The amount of gas supplied to the engine is controlled by the amount of gas in the turbine 116. In one example, valve 206 may be formed via a needle shaft whose surface area faces the flow through manifold 202. The pressure difference across the needle shaft can generate a force for moving the needle shaft. Although not shown, exhaust valve 200 may include a motor and a gearbox, with connecting rod 204 extending from the output shaft of the gearbox to exhaust valve 206. In some embodiments, position sensor 203 may measure the orientation of such components, such as the translational position of connecting rod 204, the rotational orientation of the output shaft, or another component within the motor. In this example, such measurements may be used to indirectly determine the position of exhaust valve 206. Furthermore, in other embodiments, the position of exhaust valve may be based on the use of the above reference. Figure 1 The soft model is used to determine one or more of the signals (e.g., BOOST) described and sent to controller 12.

[0040] The wastegate 200 may optionally include a biasing device 210. The biasing device 210 is attached to the wastegate 200 at one end and to the wastegate valve 206 at the other end. In some embodiments, the biasing device 210 is selected to supply a closing force that holds the wastegate valve 206 in a fully closed position until a threshold pressure is reached. As a non-limiting example, the biasing device 210 may be selected to allow the wastegate valve 206 to open so that the average pressure difference across the turbocharger turbine is between 0.75 bar and 1 bar. In the event of wastegate degradation, for example due to power loss from the actuator 150, the wastegate valve 206 can be held in a fully closed position until the threshold pressure via spring preload, thereby ensuring sufficient boost accumulation is delivered to the engine. This configuration may be particularly advantageous in downsized engines, as the degree of size reduction need not be limited to taking into account the possibility of wastegate actuator degradation. Conversely, at pressures equal to or above the threshold pressure, the biasing device 210 allows the exhaust valve 206 to move to the fully open position, thereby limiting maximum boost pressure, especially under high loads. Furthermore, the size and power consumption of the exhaust valve actuator (e.g., actuator 150) can be reduced because the biasing device 210 supplies additional closing force to the exhaust valve 200. Therefore, during non-degraded operation, the actuator can hold the valve in the fully closed position with a current level lower than the current level when the spring preload is zero. The current supplied to the actuator 150 can be selected to account for the closing force of the biasing device (such as a spring). In the illustrated embodiment, the biasing device 210 is shown as a pre-compressed spring, but various suitable configurations can be used to supply additional closing force to the exhaust valve 200. With a spring, the spring constant can be selected to supply closing force up to a specific threshold pressure and provide sufficient boost pressure to the engine.

[0041] In the fully closed position, the exhaust valve 206 contacts the valve seat 212, abutting the valve seat and fluidly sealing the exhaust valve 200 to isolate it from the exhaust passage 104, preventing gas flowing through the exhaust passage from entering the exhaust valve. In this position, according to, for example Figure 1 The position of the throttle valve 20 and other conditions provide maximum boost to the engine 10. Figure 2A low-lift region 214 is also depicted, which specifies the area where the gap between the wastegate valve 206 and the valve seat 212 is considered relatively small relative to various positions (e.g., lift) of the wastegate valve within this low-lift region. As used herein, "lift" can also refer to the gap between the wastegate valve and the corresponding valve seat. The low-lift region 214 can extend from the upper surface 216 of the valve seat 212 to any suitably defined point within the chamber 207, and can be measured from that upper surface to the upper surface of the wastegate valve 206. For example, the low-lift region 214 can extend from the upper surface 216 of the valve seat 212 to approximately 20% of the total height of the chamber 207. However, it should be understood that a suitable low-lift region can be predetermined based on the physical characteristics of the wastegate or dynamically determined based on various operating parameters.

[0042] Turn now Figure 3 This shows another example of an exhaust valve 300, which can be Figure 1 The exhaust valve 92. And... Figure 2 As shown in the diagram, the electric exhaust valve 200, the exhaust valve 300 along... Figure 1 A portion of the exhaust duct 104 shown is included, and includes an exhaust valve 302 connected to a connecting rod 304 (e.g., a cylindrical rod). However, the exhaust valve 300 is a pneumatic exhaust valve controlled by pressurized fluid. Therefore, the connecting rod 304 is connected to a diaphragm 306, which is in turn connected to a biasing device 308, which may be... Figure 2 The biasing device 210 or any other suitable biasing device. The biasing device 308 can bias the exhaust valve 302 and diaphragm 306 to any suitable position, such as fully closed, fully open, or any position in between. The position sensor 303 tracks the position of the exhaust valve 302, thereby relaying the tracked position to the engine controller (such as...). Figure 1 (Controller 12). Optionally or additionally, the exhaust valve 300 may include a pressure sensor 305 to facilitate tracking of the exhaust valve's state.

[0043] To facilitate the pneumatic positioning of the exhaust valve 302, a pressurized fluid source 310 supplies varying levels of pressurized fluid (e.g., pressurized air) to the first chamber 312 of the exhaust valve 300 via a first conduit 313. The pressurized fluid entering the first chamber 312 acts on the diaphragm 306, thereby adjusting the position of the diaphragm 306 and thus the exhaust valve 302 with sufficient pressure. When the exhaust valve 302 is in the fully closed position (e.g., completely abutting the valve seat 314 and fluidly sealing the gas flowing through the exhaust passage 104 to isolate it from the first chamber 312), the pressurized fluid supplied from the pressurized fluid source 310 to the first chamber provides the mechanism by which the exhaust valve 302 can begin to open. However, in other partially open positions, the pressurized fluid supplied from the pressurized fluid source 310 can combine with exhaust gas entering the first chamber 312 from the exhaust passage 104 to position the exhaust valve 302. The pressurized fluid source 310 can be, for example, an air compressor or from... Figure 1 The exhaust valve 300 is the intake source of the engine 10. Although not shown, the pressurized fluid source 310 may include a vacuum regulator and / or one or more valves to control the supply of pressurized fluid to the first chamber 312. Similarly, the exhaust valve 300 may optionally include a second pressurized fluid source 316 configured to supply pressurized fluid (e.g., pressurized air) to a second chamber 318 in the exhaust valve 300 via a second conduit 320. The pressurized fluid supplied from this source to the second chamber 318 may act on the diaphragm 306 in the opposite direction to the direction of the fluid supplied to the first chamber 312. Because a vacuum regulator and / or one or more valves are included in the second pressurized fluid source 316 and / or the second conduit 320, precise positioning of the exhaust valve 302 can be achieved by balancing the supply of pressurized fluid to both the first chamber 312 and the second chamber 318. It should be understood that the exhaust valve 300 may be suitably modified without departing from the scope of this disclosure. For example, vents (not shown) may be provided to further assist in pressure regulation in the exhaust valve.

[0044] Figure 3 A low-lift region 322 is also shown, in which the interval between the exhaust valve 302 and the valve seat 314 is considered relatively small for the various positions (e.g., lift) of the exhaust valve in this low-lift region. Figure 2Similar to the low-lift region 214 shown, the low-lift region 322 can extend from the upper surface 324 of the valve seat 314 to any suitable defined point within the first chamber 312, and can be measured from that upper surface to the upper surface of the exhaust valve 302. As a non-limiting example, the low-lift region 322 can extend from the upper surface 324 of the valve seat 314 to approximately 15% of the total height of the first chamber 312 and the second chamber 318. The low-lift region 322 can be defined as any suitable portion of the total height of the first chamber 312 and the second chamber 318, and can be predetermined based on the physical characteristics of the exhaust valve 300 or dynamically determined based on various desired operating parameters.

[0045] The diagnostic procedure for the exhaust valve 91 can be performed in a vehicle configured as an autonomous vehicle, and an exemplary autonomous driving system is referenced below. Figure 4 Let's have a discussion. Figure 4 It is possible to operate the above. Figure 1 The block diagram shows an exemplary autonomous driving system 400 for vehicle 102 described herein. As shown, the autonomous driving system 400 includes a user interface device 410, a navigation system 415, at least one autonomous driving sensor 420, and an autonomous mode controller 425.

[0046] The user interface device 410 can be configured to present information to vehicle occupants in situations where vehicle occupants may be present. However, it is understood that in certain situations, the vehicle can operate autonomously in the absence of vehicle occupants.

[0047] The presented information may include audible or visual information. Furthermore, the user interface device 410 may be configured to receive user input. Therefore, the user interface device 410 may be located in the passenger compartment (not shown) of the vehicle. In some possible approaches, the user interface device 410 may include a touch-sensitive display screen.

[0048] The navigation system 415 can be configured to use, for example, a Global Positioning System (GPS) receiver to determine the vehicle's current location, which is configured to triangulate the vehicle's position relative to a satellite or ground transmission tower. The navigation system 415 can also be configured to develop a route from the current location to a selected destination, and to display a map and present driving directions to the selected destination via, for example, a user interface device 410.

[0049] The autonomous driving sensor 420 may include any number of devices configured to generate signals that aid in navigating the vehicle. Examples of the autonomous driving sensor 420 may include radar sensors, lidar sensors, vision sensors (e.g., cameras), vehicle-to-vehicle infrastructure networks, etc. The autonomous driving sensor 420 enables the vehicle to “see” the road and its surroundings, and / or to traverse various obstacles when the vehicle 102 is operating in autonomous mode. The autonomous driving sensor 420 may be configured to output sensor signals to, for example, an autonomous mode controller 425.

[0050] The autonomous mode controller 425 can be configured to control one or more subsystems 430 when the vehicle is operating in autonomous mode. Examples of subsystems 430 that can be controlled by the autonomous mode controller 425 may include a braking subsystem, a suspension subsystem, a steering subsystem, and a powertrain subsystem. The autonomous mode controller 425 can control any or more of these subsystems 430 by outputting signals to control units associated with the subsystems 430. In one example, the braking subsystem may include an anti-lock braking system (ABS) configured to apply braking force to one or more wheels. This document discusses applying braking force to one or more wheels as potentially activating the brakes. To autonomously control the vehicle, the autonomous mode controller 425 may output appropriate commands to the subsystems 430. These commands may cause the subsystems to operate according to driving characteristics associated with a selected driving mode. For example, driving characteristics may include the aggressiveness of vehicle acceleration and deceleration, the amount of space left behind the vehicle in front, the frequency of autonomous lane changes, etc.

[0051] Figure 5A and Figure 5B An exemplary circuit 500 is shown that can be used to reverse the rotational orientation of an electric motor. Circuit 500 schematically depicts an H-bridge circuit that can be used to alternately operate the motor 510 in a first (forward) direction and a second (reverse) direction. The H-bridge circuit can be used as needed to rotate an engine (such as...) without fuel in either the forward or reverse direction via an electric motor. Figure 1 The circuit 500 includes a first (LO) side 520 and a second (HI) side 530. Side 520 includes transistors 521 and 522, while side 530 includes transistors 531 and 532. The circuit 500 also includes a power supply 540.

[0052] exist Figure 5AIn this configuration, transistors 521 and 532 are activated (excited), while transistors 522 and 531 are deactivated. In this configuration, the left lead 551 of motor 510 is connected to power supply 540, while the right lead 552 of motor 510 is connected to ground. In this way, motor 500 can operate in the forward (or default) direction. When the engine is operated in the forward direction via the motor, the engine can be in a rotation start mode for initial combustion initiation. Additionally and / or alternatively, when the engine is operated in the forward direction via the motor, the engine (and the motor or another motor) can be in a drive mode to drive the vehicle. It is understood that in some examples, the engine can rotate in the forward (e.g., default) direction while the vehicle is stationary, and it is desirable for the engine to rotate or spin in the forward direction without combustion.

[0053] exist Figure 5B In this configuration, transistors 522 and 531 are activated (energized), while transistors 521 and 532 are deactivated. In this configuration, the right lead 552 of motor 510 is connected to power supply 540, while the left lead 551 of motor 510 is connected to ground. In this way, motor 510 can operate in the reverse direction.

[0054] In this way, Figures 1 to 5B The components implement a system comprising: a vehicle, including autonomous vehicles and / or hybrid vehicles; an electric motor; an engine including an intake manifold and an exhaust manifold; an intake throttle valve coupled to the intake manifold; a turbocharger including an intake compressor coupled to the intake manifold and an exhaust turbine coupled to the exhaust manifold; a wastegate passage coupled to the exhaust manifold across the exhaust turbine, and a wastegate valve coupled to the wastegate passage; a manifold airflow (MAF) sensor coupled to the intake manifold; and a duct coupled downstream of the intake compressor and upstream of the boost air cooler to the... An intake duct, the duct including a motor-driven electric supercharger; and a controller having computer-readable instructions stored in a non-transitory memory to perform the following: obtaining a baseline airflow via the MAF sensor by reversing the engine with the motor when the exhaust valve is first installed, and obtaining a first intake airflow via the MAF sensor after the exhaust valve has been used for a threshold duration since its installation and while reversing the engine with the motor, and indicating deterioration of the exhaust valve in response to the first intake airflow being higher than the baseline airflow.

[0055] Figure 6 An exemplary method 600 is shown that can be implemented to perform exhaust valve diagnostics during engine non-combustion conditions. This can be performed by a controller based on instructions stored in the controller's memory and in conjunction with data from sensors in the engine system (such as those referenced above). Figure 1The sensor described receives signals to execute instructions for performing method 600 and the remaining methods included herein. According to the methods described below, the controller can employ the engine actuator of the engine system to adjust engine operation.

[0056] At 602, the method includes determining whether the conditions for triggering an exhaust valve (such as...) are met. Figure 1 The status of the exhaust valve (91) diagnostic is as follows. In one example, the status for initiating exhaust valve diagnostics may include the vehicle's closed state when the vehicle is not occupied (no passengers are in the vehicle). Seat load sensors, onboard cameras, and / or door sensing technologies can be used to ensure the vehicle is not occupied. In another example, exhaust valve diagnostics can be performed during autonomous vehicle mode when the vehicle is operating without a driver and when the vehicle is not being propelled by engine torque. Vehicle operation can be controlled from a remote location or pre-programmed in the controller memory. During vehicle operation in autonomous mode, diagnostics can be performed as appropriate when the vehicle stops at a traffic signal or immediately after completing a driving cycle. In yet another example, exhaust valve diagnostics can be performed in response to the controller waking up after a predetermined duration following an ignition switch off event. Status for initiating exhaust valve diagnostics includes confirming that engine sensors such as the MAF sensor and oxygen sensor are not deteriorated and that there are generally no diagnostic codes (flags) indicating any engine component deterioration. In addition, before initiating exhaust valve diagnostics, the controller can verify whether a predetermined duration has elapsed since the execution of an existing exhaust valve diagnostic procedure. In some examples, such a predetermined duration may include one day, more than one day but less than two days, more than two days, etc. In other examples, the predetermined duration may include miles driven, vehicle operating hours, or other parameters.

[0057] If the conditions for initiating exhaust valve diagnostics are not met, at point 503, the exhaust valve diagnostic procedure can be postponed until the conditions are met. In some examples, if the exhaust valve diagnostic conditions are not met, the current operating parameters can continue until the exhaust valve diagnostic conditions are met. Such operating parameters may include fuel delivered to one or more engine cylinders via fuel injectors through the fuel system and fuel that performs the combustion of air and fuel in the cylinders when the vehicle is operating. The engine torque generated by combustion in the engine cylinders can be used to propel the vehicle. Based on the boost pressure and engine operating conditions, the controller can estimate a pressure setpoint above which the exhaust valve can open via the exhaust valve passage (such as...). Figure 1 A portion of the exhaust gas flows through the exhaust valve passage 90, thus bypassing the exhaust turbine (such as...). Figure 1(Exhaust turbine 116 in the example). In one example, the controller can use a lookup table to determine the setpoint pressure of the exhaust valve. Torque demand and exhaust pressure can be used as inputs to the lookup table, and the setpoint pressure can be the output of the lookup table. If the exhaust pressure upstream of the turbine is lower than the setpoint pressure, the exhaust valve can remain in the default closed position, and the entire volume of exhaust can be directed through the turbine to provide the desired boost pressure.

[0058] Electric superchargers (such as) Figure 2 The electric supercharger 155 can be connected to a duct parallel to the intake manifold, and can be operated by a turbocharger (such as...) Figure 2 During periods when the boost pressure provided by the intake compressor 114 and exhaust turbine 116 is lower than the desired boost pressure, energy from the on-board energy storage device can be used to operate the electric supercharger to provide the desired boost.

[0059] If the conditions for initiating exhaust valve diagnostics are determined to be met, at 604, the procedure includes rotating or turning the engine in the reverse direction at a predetermined speed (e.g., predetermined RPM) without fuel. Rotating the engine in the reverse direction can include rotating the engine in the opposite direction to when the engine operates to burn air and fuel. Rotating the engine in the reverse direction without fuel can create lower pressure in the exhaust manifold and allow ambient air to flow sequentially through the exhaust system, engine, and intake manifold. Rotating the engine in the reverse direction without fuel can include via a motor (such as...) Figure 1 The motor 52 in the motor rotates the engine, wherein the motor can be connected to the vehicle battery (such as...) Figure 1 The battery 58 in the middle is powered. In non-hybrid vehicles, the engine can be rotated in reverse via the vehicle's starter motor and the battery. To rotate the engine in reverse, an H-bridge circuit (such as...) can be used. Figures 5A to 5B The circuit shown can be used to control the engine speed to a predetermined speed via a motor. The predetermined engine speed can be controlled via a MAF sensor (such as...) when the engine is rotating in the reverse direction. Figure 1 The speed at which the MAF sensor 124 in the middle obtains robust airflow measurements. In one example, the predetermined speed can be below 500 rpm.

[0060] At 606, the electric supercharger (such as...) Figure 1 The electric supercharger 155 can rotate in the reverse direction. During periods when the boost pressure provided by operating the turbocharger is lower than the desired boost pressure, the electric supercharger can operate in the forward default direction to provide the desired boost. The reverse rotation of the electric supercharger creates a lower pressure at the intake manifold relative to the pressure at the exhaust manifold, thereby promoting airflow from the exhaust system to the intake manifold. The controller can direct the electric supercharger actuator (such as...) Figure 1 The actuator 155b in the middle sends a signal to use the energy storage device (such as the one connected to the electric supercharger) to power the electric supercharger. Figure 1 The energy stored in the energy storage device 250 in the supercharger is used to actuate the electric supercharger. During the diagnostic procedure, the electric supercharger's speed can be lower than the speed at which it operates to compensate for the lag of the mechanical turbocharger. In one example, the electric supercharger's speed during the diagnostic procedure could be 2500 RPM. By operating the electric supercharger at a lower speed, power consumption and noise generation during operation can be reduced. By simultaneously reversing the rotation of the engine and the electric supercharger, the engine speed can be lower than the engine idle speed during the exhaust valve diagnostic. By rotating the engine at a speed lower than the idle speed, the electric motor's power consumption can be reduced.

[0061] In one example, step 606 of method 600 can be optional, and the exhaust valve diagnostics can be performed without rotating the electric supercharger. During the exhaust valve diagnostic procedure, the electric supercharger can remain in a deactivated state while the engine rotates in reverse. In another example, the electric supercharger can rotate in reverse during the exhaust valve diagnostics without rotating the engine in reverse. The engine can remain in a deactivated state while the electric supercharger can rotate in reverse to allow ambient air from the exhaust manifold to flow into the intake manifold. In yet another example, each of the engine and the electric supercharger can rotate in reverse until a threshold non-zero airflow is reached, after which the electric supercharger can be deactivated to reduce energy consumption.

[0062] At 607, the controller can direct the throttle valve (such as...) connected to the engine intake port. Figure 1 The throttle valve 20 sends a signal to actuate it to the fully open position. As the engine and electric supercharger rotate in their respective opposite directions, a lower pressure is created at the engine exhaust manifold, and ambient air can enter the engine system via the exhaust passage. When the throttle valve is fully open, the higher portion of the ambient air can enter the engine via the exhaust passage and flow through the turbine and wastegate passages to the engine intake. The ambient air can then be released into the atmosphere via the intake throttle valve.

[0063] At point 608, the baseline intake airflow can be retrieved from a database in the controller memory. In one example, during the installation of the wastegate valve, the baseline airflow can be estimated via the MAF sensor during the vehicle's ignition switch-off state by turning the starter in the reverse direction without fuel and rotating the electric supercharger in the reverse direction. In one example, wastegate valve installation may include installing the wastegate valve in the engine at a manufacturing facility. In another example, wastegate valve installation may include replacing an older wastegate valve with a new one at a service location. The baseline airflow can be estimated for a first threshold duration since wastegate valve installation, while wastegate valve diagnostics can be performed if the wastegate valve has been used for a second threshold duration longer than the first threshold duration. In one example, the first threshold duration may be one day since wastegate valve installation. In another example, the second threshold duration may be 30 days since wastegate valve installation. Optionally, baseline airflow can be estimated over a first threshold driving distance (of the vehicle) since the exhaust valve was installed, while exhaust valve diagnostics can be performed if the exhaust valve has been used for more than a second threshold driving distance, which is longer than the first threshold distance. In one example, the first threshold distance could be 30 miles since the air filter was installed. In another example, the second threshold distance could be 300 miles since the air filter was installed.

[0064] A baseline airflow can be obtained by operating the engine and electric supercharger under a set of predetermined conditions, including engine speed, engine start-up duration, open intake throttle position, and electric supercharger speed. As an example, the set of predetermined conditions for estimating the baseline airflow is the same as the set of predetermined conditions when the engine is running in step 604 and the electric supercharger is rotating in step 606.

[0065] When estimating baseline airflow while the vehicle's ignition switch is off, the newly installed exhaust valve can be in a default closed position, allowing ambient air to flow from the exhaust manifold through the exhaust turbine. The turbine can provide a restrictive path for the airflow, resulting in a smaller amount of air flowing through the engine components (from the exhaust manifold to the intake manifold) compared to the amount of air flowing through the engine components when the exhaust valve is open.

[0066] At 610, the method continues with the diagnostic procedure for the exhaust valve and estimates the airflow through the intake manifold (intake airflow) via the MAF sensor. Since the exhaust valve remains in the default closed position during engine non-combustion conditions, ambient air can flow from the exhaust manifold to the intake manifold via the exhaust turbine.

[0067] At 612, the procedure includes determining whether the intake airflow is higher than the baseline airflow. In one example, it can be determined whether the intake airflow is more than 5% higher than the baseline airflow. If it is determined that the intake airflow is not higher than the baseline airflow, then at 614, it can be inferred that the intake airflow is substantially equal to the baseline airflow (e.g., within 5% of the baseline airflow), and that air flows from the exhaust manifold to the intake manifold through a restricted path including the exhaust turbine (not through the wastegate passage). At 614, it can be indicated that the wastegate valve is not deteriorated.

[0068] If the intake airflow is determined to be higher than the baseline airflow, it can be inferred that at least a portion of the ambient air entering the exhaust manifold can flow from the exhaust manifold to the intake manifold via the wastegate passage. Compared to the exhaust turbine, the wastegate passage provides a flow path with lower resistance, resulting in a greater amount of air flowing from the exhaust manifold to the intake manifold. Therefore, the estimated intake airflow increases. Because the wastegate is expected to remain in the default closed position during the diagnostic procedure, it can be inferred that the wastegate is stuck in at least a partially open position based on the airflow through the wastegate passage. In one example, carbon particles from the exhaust stream may accumulate in the wastegate, causing it to be stuck in the partially open position. At 618, a diagnostic code (flag) indicating blockage or deterioration of the wastegate can be set. In one example, the wastegate opening can be estimated based on the difference between the intake airflow and the baseline airflow. Therefore, the difference between the intake airflow and the baseline airflow can increase as the wastegate opening increases. The controller can use a lookup table to determine the wastegate opening based on the difference between the intake airflow and the baseline airflow. The difference between the intake airflow and the baseline airflow can be used as the input to a lookup table, while the opening degree of the exhaust valve can be the output of that lookup table.

[0069] Because of exhaust valve deterioration, an excess of exhaust gas can flow through the exhaust valve passage during subsequent engine operation, bypassing the exhaust turbine. Since the amount of exhaust gas flowing through the turbine is lower, the turbine speed may not increase to the desired level. Therefore, at 620, during subsequent engine operation, the operating speed of the electric supercharger can be adjusted to compensate for the exhaust valve deterioration. In one example, the electric supercharger speed can be increased in response to exhaust valve deterioration. The controller can estimate the electric supercharger speed based on torque demand and exhaust valve opening. In one example, the electric supercharger speed can increase with each of the torque demand and exhaust valve opening. The controller can use a lookup table to determine the electric supercharger operating speed. Each of the torque demand and exhaust valve opening can be used as input to the lookup table, and the electric supercharger speed can be used as the output of the lookup table.

[0070] At point 616, the diagnostic procedure is completed and neither the engine nor the electric supercharger needs to be rotated. The controller can send a signal to the motor that powers the engine to stop it from rotating. The controller can also send a signal to the actuator connected to the electric supercharger to pause its operation, and the vehicle can return to the ignition switch off state.

[0071] In this way, during a first engine condition, the engine can be rotated in the reverse direction to direct ambient air through one or more of the exhaust turbine located in the engine's exhaust port and the wastegate valve located in the wastegate passage, thereby bypassing the exhaust turbine, and a baseline intake airflow can be recorded; during a second engine condition, the engine can be rotated in the reverse direction to direct ambient air through one or more of the exhaust turbine and the wastegate valve, and an updated intake airflow can be recorded; and the wastegate valve can be instructed to be stuck in the open position in response to the updated intake airflow being higher than the baseline intake airflow. As an example, the first engine condition may include an engine condition when less than a first threshold duration has elapsed since the wastegate valve was installed, while the second engine condition may include an used engine condition when the wastegate valve has been used for more than a second threshold duration, which is longer than the first threshold duration.

[0072] Figure 7 An exemplary timeline 700 is shown, which illustrates an exhaust valve (such as...) Figure 1 Diagnosis of the exhaust valve 91, which is connected to the exhaust valve passage (such as the exhaust turbine) that bypasses the exhaust turbine. Figure 1 The exhaust valve passage 90 is shown in the diagram. The horizontal line (x-axis) represents time, while the vertical markers t0 to t5 indicate critical times in the procedure used to diagnose the intake air filter.

[0073] The first graph (line 702) shows the vehicle speed over time. The second graph (line 704) shows the direction of engine rotation. For example, during engine operation, the engine can rotate in the default forward direction, with air and fuel burning in the engine cylinders, fuel supplied to the engine cylinders via fuel injectors. Alternatively, the engine can rotate in the opposite direction without fuel, such as via an electric motor connected to a hybrid electric vehicle (HEV) or via a starter motor. The third graph (line 706) shows the electric supercharger (such as...) Figure 1The electric supercharger 155 in the diagram is connected downstream of the intake compressor and upstream of the supercharged air cooler (CAC) to a duct parallel to the intake manifold. The electric supercharger can rotate in either the forward or reverse direction by reversing the circuitry of the actuator connected to it. The electric supercharger is powered via an onboard energy storage device. The forward rotation direction of the electric supercharger is opposite to its reverse rotation direction. The fourth graph (line 707) shows the operation of the motor connected to the hybrid electric vehicle (HEV). The machine can be operated to provide motor torque to propel the HEV. The fifth graph (line 708) shows the opening of the exhaust valve. During engine non-combustion conditions, the exhaust valve remains in the default closed position. The sixth graph (line 710) shows the MAF sensor (such as...) connected to the intake manifold. Figure 1 The readings of the MAF sensor (124) are used. During exhaust valve diagnosis, the MAF sensor readings correspond to the intake airflow. The seventh graph (dashed line 716) shows the indicators representing the diagnostic codes set to indicate a deteriorating exhaust control valve.

[0074] Before time t0, a new (unused) wastegate valve is installed in the vehicle's wastegate passage at the manufacturing facility. During wastegate valve installation, between time t0 and t1, when the vehicle is not propelled by engine torque or motor torque, a baseline airflow is estimated. At time t0, the controller sends a signal to the HEV machine to rotate the engine in the opposite direction at a first engine speed without fuel. Simultaneously, the controller sends a signal to the actuator connected to the electric supercharger to rotate the electric supercharger in the opposite direction at a first electric supercharger speed. As the engine and electric supercharger rotate in their respective opposite directions, a lower pressure is created at the engine exhaust manifold, and ambient air enters the engine system via the exhaust manifold. During the engine's non-combustion period, the wastegate valve remains in the default closed position. Ambient air then flows through the exhaust turbine, the intake manifold, and is then directed into the atmosphere via the intake manifold. Between time t0 and t1, as shown by dashed line 709, the intake airflow estimated by the MAF sensor is stored as a baseline airflow corresponding to the unused (undegraded) wastegate valve in the onboard database. This reference airflow 709 was subsequently used during the diagnostics of the exhaust valve. Because the exhaust valve was not indicated to be deteriorated, the indicator remained in the closed position.

[0075] At time t1, once the baseline airflow is stored in the controller memory, the controller sends signals to each of the HEV machine and electric supercharger actuators to suspend operation and stop the rotation of the engine and electric supercharger, respectively (for diagnostic purposes). The duration between time t1 and t2 corresponds to a threshold duration after which diagnostic procedures for the intake air filter are expected to be executed in a timely manner. The duration between time t1 and t2 includes multiple driving cycles and periods of vehicle inactivity (not propelled by engine torque or machine torque).

[0076] At time t2, the vehicle starts from a standstill and is operated via engine torque. The engine is driven by combustion and rotates in the forward direction. Based on torque demand, the controller determines the setpoint pressure for opening the wastegate valve. Based on exhaust pressure above the setpoint, the wastegate valve opens to guide a portion of the exhaust gas from upstream of the turbine through the wastegate passage to downstream of the turbine. Because the turbochargers (exhaust turbine and intake compressor) meet the desired boost pressure, the electric supercharger is not operated. The HEV machine is not operated for engine rotation or vehicle propulsion. Between times t2 and t3, the MAF reading represents the amount of air entering the engine via the intake manifold for combustion. The amount of air entering the intake manifold is proportional to the throttle opening.

[0077] At time t3, the vehicle speed decreases to zero, and between times t3 and t4, engine torque and / or machine torque are no longer used to operate the vehicle (the vehicle ignition switch is off from this point). Therefore, at time t3, the engine is shut down by suspending fuel injection and spark delivery to the engine cylinders. After the engine shuts down, the wastegate valve returns to its default closed position when the exhaust pressure drops below the setpoint pressure. Between times t3 and t4, the engine remains off.

[0078] At time t4, after a threshold duration since the vehicle ignition switch was turned off at time t3, diagnostics of the exhaust valve is initiated by waking up the controller. The controller sends a signal to the HEV machine to cause the engine to run in the opposite direction at a first engine speed without fuel. Simultaneously, the controller sends a signal to the actuator connected to the electric supercharger to cause the electric supercharger to rotate in the opposite direction at a first electric supercharger speed. As the engine and electric supercharger rotate in their respective opposite directions, a lower pressure is created at the engine exhaust manifold, and ambient air can enter the engine system via the exhaust passage. The intake throttle opens to the fully open position to facilitate ambient airflow through engine components. Between times t4 and t5, ambient air flows sequentially through the exhaust passage, exhaust turbine, engine cylinders, and intake manifold. The baseline airflow 709 estimated between times t0 and t1 is retrieved from the onboard database and compared with the intake airflow estimated based on MAF readings.

[0079] Between times t4 and t5, the intake airflow was observed to be essentially equal to the baseline airflow 709. Therefore, it was inferred that the exhaust gas valve was in the closed position during the engine's non-combustion period. At time t5, at the end of the diagnostic procedure, the controller sent signals to each of the HEV machine and electric supercharger actuators to suspend operation and stop the rotation of the engine and electric supercharger, respectively. After time t5, the vehicle was not propelled using engine torque and / or machine torque, and the engine remained in the off position until the subsequent vehicle ignition switch was turned on. The indicator for exhaust gas valve deterioration remained in the closed position.

[0080] However, between times t4 and t5, if the intake airflow is not substantially equal to the baseline airflow 709, it can be inferred that the exhaust valve is deteriorating and an indicator of deterioration has been set. In one example, if the intake airflow is higher than the first threshold airflow 713 but lower than the second threshold airflow 714, it can be inferred that the exhaust valve is partially open, allowing ambient air to flow from the exhaust duct through the exhaust valve passage into the intake manifold. As an example, the first threshold airflow 713 is 20% higher than the baseline airflow, while the second threshold airflow 714 is 50% higher than the baseline airflow. In another example, if the intake airflow is higher than the second threshold airflow 714, it can be inferred that the exhaust valve is fully open, allowing a larger amount of ambient air to flow from the exhaust duct through the exhaust valve passage into the intake manifold.

[0081] In this way, existing engine components such as MAF sensors can be reused as intake airflow meters for EVO valve diagnostics. The advantage of determining the EVO valve opening is that appropriate mitigation actions can be taken during subsequent engine cycles to provide the desired boost pressure. In short, by monitoring the health of the EVO valve in a timely manner, valve deterioration can be detected promptly, and stuck EVO valves can be repaired quickly.

[0082] An exemplary engine method includes testing the degradation of an exhaust valve by directing airflow from the engine's exhaust system through a wastegate valve to the engine's intake port and comparing the airflow in the intake port with a baseline airflow entering the engine intake port through the wastegate valve, the wastegate valve being located in a wastegate passage connected in parallel with a turbine located in the exhaust system. In any of the foregoing examples, additionally or alternatively, the airflow from the exhaust system is directed through the wastegate valve by forcing ambient air into the exhaust system through reverse rotation of the engine. In any or all of the foregoing examples, additionally or alternatively, the engine is coupled to a vehicle and, when the vehicle is not moving, the reverse rotation of the engine is performed via a battery-powered motor under a set of predetermined conditions. In any or all of the foregoing examples, additionally or alternatively, the wastegate passage is connected from upstream to downstream of the turbine to an engine exhaust passage, and the wastegate valve regulates the exhaust flow via the exhaust turbine. In any or all of the foregoing examples, additionally or optionally, the wastegate valve is in a default closed position during the test. In any or all of the foregoing examples, the method further includes, additionally or optionally, operating an intake electric supercharger coupled to the engine intake in the reverse direction during the test to direct airflow from the exhaust system to the intake via the wastegate valve. In any or all of the foregoing examples, the method also additionally or optionally includes an intake throttle valve coupled to the engine intake, and wherein the predetermined set of conditions includes engine speed, engine start-up duration, intake throttle position, and the speed of the intake electric supercharger. In any or all of the foregoing examples, additionally or optionally, estimating the airflow in the intake via a manifold airflow (MAF) sensor coupled to the engine intake, the method further includes indicating wastegate valve deterioration in response to the airflow in the intake being higher than the baseline airflow. In any or all of the foregoing examples, the method further includes, optionally, indicating that the exhaust valve is not deteriorated in response to the airflow in the intake being substantially equal to the baseline airflow. In any or all of the foregoing examples, further optional, the baseline airflow is established via the MAF sensor when the exhaust valve is installed by guiding ambient air through the exhaust valve while simultaneously reversing the engine under the set of predetermined conditions. In any or all of the foregoing examples, the method further includes, optionally, setting a diagnostic code in response to an indication of exhaust valve deterioration, and adjusting the operation of the electric supercharger to compensate for the exhaust valve deterioration during subsequent engine operation.

[0083] Another exemplary engine method includes: during a first engine condition, reversing the engine to direct ambient air through one or more of an exhaust turbine located in the engine's exhaust port and an exhaust valve located in the wastegate passage, bypassing the exhaust turbine, and recording a baseline intake airflow; during a second engine condition, reversing the engine to direct ambient air through one or more of the exhaust turbine and the exhaust valve, and recording an updated intake airflow; and in response to the updated intake airflow being higher than the baseline intake airflow, instructing the exhaust valve to be engaged in an open position. In any of the foregoing examples, the method further includes, additionally or optionally, during each of the first and second engine conditions, the exhaust valve being actuated to a closed position, while a throttle valve coupled to the engine intake port is actuated to a fully open position. In any or all of the foregoing examples, additionally or optionally, the first engine condition includes the engine condition when less than a first threshold duration has elapsed since the installation of the exhaust valve, and the second engine condition includes the used engine condition when the exhaust valve has been used for more than a second threshold duration, the second threshold duration being longer than the first threshold duration. In any or all of the foregoing examples, additionally or optionally, the engine propulsion includes autonomous vehicles and / or hybrid vehicles, and wherein for both the first and second operating conditions, the engine rotates in reverse without fuel via an electric motor during the vehicle's ignition switch-off state. In any or all of the foregoing examples, additionally or optionally, each of the baseline intake airflow and the updated intake airflow is estimated via a manifold airflow (MAF) sensor coupled to the engine intake port. In any or all of the foregoing examples, the method further additionally or optionally includes estimating the opening of the exhaust valve based on the difference between the updated intake airflow and the baseline airflow, the opening increasing as the difference between the updated intake airflow and the baseline airflow increases.

[0084] In yet another example, a system includes: a vehicle, including autonomous vehicles and / or hybrid vehicles; an electric motor; an engine including an intake manifold and an exhaust manifold; an intake throttle valve coupled to the intake manifold; a turbocharger including an intake compressor coupled to the intake manifold and an exhaust turbine coupled to the exhaust manifold; a wastegate passage coupled to the exhaust manifold across the exhaust turbine, and a wastegate valve coupled to the wastegate passage; a manifold airflow (MAF) sensor coupled to the intake manifold; and a duct coupled downstream of the intake compressor and upstream of the boost air cooler to the intake manifold. The system includes an air duct, the duct comprising a motor-driven electric supercharger; and a controller having computer-readable instructions stored in a non-transitory memory to: obtain a baseline airflow via the MAF sensor by reversing the engine with the motor upon initial installation of the wastegate valve; obtain a first intake airflow via the MAF sensor after the wastegate valve has been used for a threshold duration since installation and while reversing the engine with the motor; and indicate deterioration of the wastegate valve in response to the first intake airflow being higher than the baseline airflow. In any of the foregoing examples, additionally or optionally, the engine is reversed during the vehicle's ignition switch-off state. In any or all of the foregoing examples, additionally or optionally, the controller further includes instructions to: increase the rotational speed of the electric supercharger in response to deterioration of the wastegate valve during subsequent engine cycles.

[0085] Note that the exemplary control and estimation programs included herein can be used in conjunction with various engine and / or vehicle system configurations. The control methods and programs disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific programs described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threaded processing strategies, etc. Therefore, the various actions, operations, and / or functions shown may be executed sequentially, in parallel, or in some cases omitted. Similarly, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown may be repeatedly executed depending on the specific strategy used. Furthermore, the actions, operations, and / or functions can be graphically represented as code programmed into a non-transitory memory of a computer-readable storage medium in an engine control system, wherein the actions are performed by executing instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0086] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments should not be considered limiting, as many variations are possible. For example, the above-described techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations disclosed herein, as well as other features, functions, and / or properties.

[0087] The following claims specifically point to certain combinations and sub-combinations considered novel and non-obvious. These claims may relate to an “a” element or a “first” element or its equivalent. These claims should be understood to include the incorporation of one or more such elements, thus neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amendments to the claims of this invention or by setting forth new claims in this application or related applications. Such claims, whether broader or narrower in scope, equivalent or different in scope from the original claims, are considered to be included within the subject matter of this disclosure.

[0088] According to the present invention, a method includes testing the degradation of an exhaust valve by guiding airflow from an engine's exhaust system through an exhaust valve to an intake port of the engine and comparing the airflow in the intake port with a baseline airflow entering the engine intake port through the exhaust valve, the exhaust valve being located in an exhaust valve passage connected in parallel with a turbine located in the exhaust system.

[0089] According to an embodiment, the invention is further characterized in that the airflow from the exhaust system is guided through the exhaust valve by forcing ambient air into the exhaust system through the reverse rotation of the engine.

[0090] According to an embodiment, the engine is connected to a vehicle, and when the vehicle is not moving, the reverse rotation of the engine is performed via a battery-powered motor under a set of predetermined conditions.

[0091] According to an embodiment, the wastegate passage connects to the engine exhaust manifold from upstream to downstream of the turbine, and the wastegate valve regulates the exhaust flow via the exhaust turbine.

[0092] According to an embodiment, the exhaust valve is in the default closed position during the test.

[0093] According to an embodiment, during the test, the invention is further characterized in that an intake electric supercharger connected to the engine intake is operated in the opposite direction to guide the airflow from the exhaust system to the intake via the exhaust valve.

[0094] According to an embodiment, the invention is further characterized by an intake throttle valve connected to the engine intake port, wherein the set of predetermined conditions includes engine speed, engine start-up duration, intake throttle valve position, and intake electric supercharger speed.

[0095] According to an embodiment, the invention is further characterized in that the airflow in the intake is estimated via a manifold airflow (MAF) sensor connected to the engine intake, and the method further includes indicating exhaust valve deterioration in response to the airflow in the intake being higher than the baseline airflow.

[0096] According to an embodiment, the invention is further characterized in that the exhaust valve is indicated as not deteriorating in response to the airflow in the intake being substantially equal to the baseline airflow.

[0097] According to an embodiment, when the exhaust valve is installed, the baseline airflow is established via the MAF sensor by guiding ambient air through the exhaust valve while simultaneously rotating the engine in the opposite direction under the set of predetermined conditions.

[0098] According to an embodiment, the invention is further characterized in that a diagnostic code is set in response to an indication of exhaust valve deterioration, and the operation of the electric supercharger is adjusted during subsequent engine operation to compensate for the exhaust valve deterioration.

[0099] According to the present invention, an engine method includes, during a first engine condition, reversing the engine to direct ambient air through one or more of an exhaust turbine located in the exhaust port of the engine and an exhaust valve located in an exhaust valve passage, bypassing the exhaust turbine, and recording a baseline intake airflow; during a second engine condition, reversing the engine to direct ambient air through one or more of the exhaust turbine and the exhaust valve, and recording an updated intake airflow; and, in response to the updated intake airflow being higher than the baseline intake airflow, instructing the exhaust valve to be engaged in an open position.

[0100] According to an embodiment, the invention is further characterized in that, during each of the first engine condition and the second engine condition, the exhaust valve is actuated to the closed position, while the throttle valve connected to the engine intake is actuated to the fully open position.

[0101] According to an embodiment, the first engine condition includes the engine condition when less than a first threshold duration has elapsed since the exhaust valve was installed, and the second engine condition includes the used engine condition when the exhaust valve has been used for more than a second threshold duration, the second threshold duration being longer than the first threshold duration.

[0102] According to an embodiment, the engine propels a vehicle including an autonomous vehicle and / or a hybrid vehicle, and wherein, for both the first and second operating conditions, the engine rotates in the reverse direction without fuel via the electric motor during the vehicle's ignition switch-off state.

[0103] According to an embodiment, each of the baseline intake airflow and the updated intake airflow is estimated via a manifold airflow (MAF) sensor coupled to the engine intake port.

[0104] According to an embodiment, the invention is further characterized in that the opening degree of the exhaust valve is estimated based on the difference between the updated intake airflow and the baseline airflow, the opening degree increasing as the difference between the updated intake airflow and the baseline airflow increases.

[0105] According to the present invention, a system is provided comprising: a vehicle, including an autonomous vehicle and / or a hybrid vehicle; an electric motor; an engine including an intake manifold and an exhaust manifold; an intake throttle valve coupled to the intake manifold; a turbocharger including an intake compressor coupled to the intake manifold and an exhaust turbine coupled to the exhaust manifold; a wastegate passage coupled to the exhaust manifold across the exhaust turbine, and a wastegate valve coupled to the wastegate passage; a manifold airflow (MAF) sensor coupled to the intake manifold; and a duct coupled downstream of the intake compressor and upstream of a boost air cooler to... The intake duct, the duct including a motor-driven electric supercharger; and a controller having computer-readable instructions stored in a non-transitory memory to perform the following: obtaining a baseline airflow via the MAF sensor by reversing the engine with the motor when the exhaust valve is first installed, and obtaining a first intake airflow via the MAF sensor after the exhaust valve has been used for a threshold duration since its installation and while reversing the engine with the motor, and indicating deterioration of the exhaust valve in response to the first intake airflow being higher than the baseline airflow.

[0106] According to an embodiment, the invention is further characterized in that the engine rotates in the reverse direction when the vehicle ignition switch is off.

[0107] According to an embodiment, the controller further includes instructions for performing the following: increasing the rotational speed of the electric supercharger in response to deterioration of the exhaust valve during a subsequent engine cycle.

Claims

1. A method for an engine, comprising: The degradation of the exhaust valve is tested by guiding airflow from the engine's exhaust system through the exhaust valve to the engine's intake port and comparing the airflow in the intake port with a baseline airflow entering the engine's intake port through the exhaust valve. The exhaust valve is located in an exhaust valve passage connected in parallel with an exhaust turbine in the exhaust system. When the exhaust valve is installed, the baseline airflow is established via a manifold airflow sensor (MAF sensor) at the engine's intake port by guiding ambient air through the exhaust valve while simultaneously rotating the engine in the opposite direction under a set of predetermined conditions.

2. The method of claim 1, wherein ambient air is forced into the exhaust system by the reverse rotation of the engine to guide the airflow from the exhaust system through the exhaust valve.

3. The method of claim 2, wherein the engine is coupled to a vehicle, and the reverse rotation of the engine is performed via a battery-powered motor under the set of predetermined conditions when the vehicle is not in motion.

4. The method of claim 1, wherein the wastegate passage is connected to the engine exhaust passage from upstream to downstream of the exhaust turbine, and the wastegate valve regulates the exhaust flow via the exhaust turbine.

5. The method of claim 1, wherein the exhaust valve is in the default closed position during the test.

6. The method of claim 1, further comprising, during the test, operating an intake electric supercharger coupled to the engine intake in the opposite direction to direct airflow from the exhaust system to the intake via the exhaust valve.

7. The method of claim 6, further comprising an intake throttle valve coupled to the engine intake port, wherein the set of predetermined conditions includes engine speed, duration of engine start-up, intake throttle valve position, and speed of the intake electric supercharger.

8. The method of claim 1, wherein the airflow in the intake is estimated via the MAF sensor coupled to the intake of the engine, the method further comprising indicating that the exhaust valve is deteriorated in response to the airflow in the intake being higher than the baseline airflow, or indicating that the exhaust valve is not deteriorated in response to the airflow in the intake being equal to the baseline airflow.

9. The method of claim 8, further comprising setting a diagnostic code in response to indicating exhaust valve deterioration, and adjusting the operation of the electric supercharger to compensate for the exhaust valve deterioration during subsequent engine operation.

10. A system for an engine, comprising: Vehicles, including autonomous vehicles and / or hybrid vehicles; Electric motor; An engine, which includes an intake manifold and an exhaust manifold; An intake throttle valve, which is connected to the intake manifold; A turbocharger, comprising an intake compressor coupled to the intake manifold and an exhaust turbine coupled to the exhaust manifold; An exhaust valve passage, which is connected to the exhaust passage across the exhaust turbine, and an exhaust valve is connected to the exhaust valve passage; The manifold airflow sensor, also known as the MAF sensor, is connected to the air intake. A duct, connected downstream of the intake compressor and upstream of the boost air cooler, to the intake duct, the duct including a motor-driven electric booster; and A controller having computer-readable instructions stored in non-transitory memory to perform the following: During the first engine condition, the engine is rotated in the reverse direction to direct ambient air through one or more of the exhaust turbine and the exhaust valves that bypass the exhaust turbine, and baseline airflow is recorded via the MAF sensor. During the second engine condition, the engine is rotated in reverse to direct ambient air through one or more of the exhaust turbine and the wastegate valve, and the updated intake airflow is recorded via the MAF sensor; and The exhaust valve is instructed to remain in the open position in response to the updated intake airflow being higher than the baseline airflow.

11. The system of claim 10, wherein the controller further includes instructions for performing the following: during each of the first engine condition and the second engine condition, the exhaust valve is actuated to a closed position, and the intake throttle is actuated to a fully open position.

12. The system of claim 10, wherein the first engine condition includes an engine condition when less than a first threshold duration has elapsed since the exhaust valve was installed, and the second engine condition includes an used engine condition when the exhaust valve has been used for more than a second threshold duration, the second threshold duration being longer than the first threshold duration.

13. The system of claim 10, wherein, for both the first engine condition and the second engine condition, the engine rotates in the reverse direction without fuel via the motor during the vehicle ignition switch-off state.

14. The system of claim 10, wherein the controller further includes instructions for performing the following: estimating the opening of the exhaust valve based on the difference between the updated intake airflow and the baseline airflow, the opening increasing as the difference between the updated intake airflow and the baseline airflow increases.

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