Method and system for exhaust gas regulating valve diagnostics

Abstract

The present disclosure provides "Methods and systems for exhaust regulation valve diagnosis". Methods and systems are provided for diagnosing an exhaust regulation valve during a vehicle off state. In one example, the engine can be run in reverse without fueling, while changing a position of an exhaust regulation valve and estimating an intake air flow at each position of the exhaust regulation valve. The exhaust regulation valve can be diagnosed based on a change in air flow as a function of a change in position of the exhaust regulation valve.

Description

TECHNICAL FIELD

[0001] The present specification generally relates to methods and systems for diagnosing an exhaust regulation valve during a vehicle off state. BACKGROUND

[0002] In certain vehicles, an operator can customize an audible exhaust noise level via a user interface. Based on input from the operator, a position of an exhaust regulation valve is adjusted to regulate the level of audible exhaust noise. However, the operator can not frequently change the desired level of exhaust noise and can select a constant level of noise. The exhaust regulation valve can exhibit degradation over time. The presence of degradation in the regulation valve can reduce the ability to adjust the audible noise level as needed, thereby adversely affecting the driving experience.

[0003] Various methods for performing a diagnosis of an exhaust system valve are provided. In one exemplary method, as shown in U.S. Patent No. 8543288 to Bligard et al., a diagnostic method is shown for performing on an exhaust pressure regulator (butterfly flap valve) in an exhaust system connected to a turbocharged internal combustion engine during engine braking. The method includes: requiring engine braking; measuring a back pressure in the exhaust by a back pressure sensor while requiring engine braking; measuring a boost pressure by a boost pressure sensor while requiring engine braking; and then comparing the measured back pressure to the boost pressure to determine if the pressure regulator or the back pressure sensor is faulty. SUMMARY

[0004] However, the inventors herein have recognized potential shortcomings of the above-described methods. As one example, the above-described diagnostic procedure is performed during an engine combustion state. However, this method can not be suitable for performing a diagnosis of an exhaust regulation valve because the driving experience can be adversely affected due to undesirable changes in the exhaust noise perceived by the operator. For example, if the operator selects a constant exhaust noise level, such as with the exhaust regulation valve in a closed position, the position of the exhaust regulation valve can not change, and a diagnosis of the exhaust regulation valve can not be performed corresponding to each position of the valve during a drive cycle. Thus, if the valve is stuck in a certain position, such as a fully closed position, degradation of the valve can not be detected. Further, adjusting the position of the exhaust regulation valve can not result in a change in exhaust back pressure high enough to detect degradation during all driving conditions.

[0005] The inventors herein have recognized that the above problems can be solved by an engine method comprising: changing a position of an exhaust regulation valve during a reverse rotation of the engine while the engine is not fuelled for a start; and diagnosing the exhaust regulation valve based on an intake air flow at one or more positions of the exhaust regulation valve. In this way, by timely reverse rotating the engine during a vehicle off state and changing the position of the exhaust regulation valve, the exhaust regulation valve can be diagnosed based on the intake air flow corresponding to each position of the exhaust regulation valve.

[0006] As one example, an exhaust regulation valve, such as a butterfly valve, can be positioned in an exhaust bypass passage two ends of a muffler to control back pressure in the system and / or exhaust flow through the muffler. Based on a desired exhaust noise level by an operator, as indicated via an in-vehicle human machine interface (HMI), the position of the regulation valve can be adjusted to regulate exhaust flow via the regulation valve and the muffler. The engine can include a battery operated electric supercharger for providing additional boost during increased torque demand. A diagnostic procedure of the exhaust regulation valve can be performed timely during a vehicle off state when the engine is not operating and the vehicle is unoccupied. The diagnostic procedure includes rotating the engine in a reverse direction via an electric motor and also turning the electric supercharger in a reverse direction to draw in ambient air from an exhaust tailpipe and direct the air to an intake manifold. The opening of the exhaust regulation valve is continuously varied from a fully open position to a fully closed position as the engine is rotated. At each position of the exhaust regulation valve, the air flow via the intake manifold can be estimated based on input from a manifold air flow (MAF) sensor. If the MAF reading changes proportionally with the increase in exhaust regulation valve opening from the fully open position to the fully closed position, then the exhaust regulation valve can be confirmed to be not deteriorated. If the MAF reading is not proportional to the opening of the exhaust regulation valve, then the valve can be confirmed to be deteriorated and a flag can be set.

[0007] In this way, the diagnosis of the exhaust regulation valve can be performed timely at each position of the valve even if the desired exhaust noise level has not changed over a period of time. By using existing engine components, such as the electric supercharger and the MAF sensor, to detect deterioration of the exhaust regulation valve, no additional components are needed, thereby providing cost and component benefits. A technical effect of performing the diagnosis during an engine non-combustion state is that even if the position of the exhaust regulation valve is changed, no undesirable noise is generated during the diagnostic procedure because the vehicle is not combusting. In summary, by periodically monitoring the health of the exhaust regulation valve, the operator's adjustment of audible exhaust noise can be maintained and the driving experience can be improved.

[0008] It should be appreciated that the above Summary of the Invention is provided merely for purposes of summarizing some implementation of the concepts described in the detailed description which are further described below. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any section of this disclosure or any part of any section of this disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 An example hybrid vehicle propulsion system is schematically illustrated.

[0010] Figure 2 An example vehicle system with an electric supercharger is schematically illustrated.

[0011] Figure 3 A block diagram of an example autonomous driving system is schematically illustrated.

[0012] Figure 4A And Figure 4B An example H-bridge circuit that can be used to rotate a vehicle engine in a forward direction or a reverse direction is schematically illustrated.

[0013] Figure 5 A flowchart illustrating an example method that can be implemented to diagnose deterioration of an exhaust gas regulation valve is shown.

[0014] Figure 6 Example operation of an engine and electric supercharger for exhaust gas regulation valve diagnosis according to the present disclosure is shown.

[0015] Figure 7A And Figure 7B A flowchart illustrating an example method for diagnosing deterioration of an intake air filter is shown.

[0016] Figure 8 Example operation of an engine and electric supercharger for intake air filter diagnosis according to the present disclosure is shown. DETAILED DESCRIPTION

[0017] The following description relates to systems and methods for diagnosing exhaust gas regulation valves and intake air filters during a vehicle off state. Such methods can include turning or rotating an engine without fuel injection, where the un-fueled turning of the engine is performed via an electric motor of a hybrid vehicle, such as the hybrid vehicle depicted in Figure 1 The exhaust gas regulation valve for regulating exhaust noise and the intake air filter for cleaning ambient air entering the engine intake manifold are in Figure 2In some examples, a set of predetermined conditions for conducting diagnostics of one or more of the exhaust regulation valve and the intake air filter can include an indication that the vehicle is unoccupied. Accordingly, in some examples, such measurements can be performed in an autonomous vehicle that is unoccupied, where Figure 3 An example autonomous vehicle control system is depicted. To turn the engine without fuel in the forward direction and the reverse direction, an H-bridge circuit can be utilized, such as the H-bridge circuit depicted in Figures 4A-4B An engine controller can be configured to execute a control program, such as the example program of Figure 5 The engine controller can execute an example program of Figures 7A-7B to detect a clogged intake air filter. Example electric supercharger operations and engine operations for implementing exhaust regulation valve diagnostics and intake air filter diagnostics are shown in Figure 6 and Figure 8 respectively.

[0018] Figure 1 An example vehicle propulsion system 100 is shown. The vehicle propulsion system 100 includes a fuel-burning engine 110 and a motor 120. As non-limiting examples, the engine 110 includes an internal combustion engine, while the motor 120 includes an electric motor. The motor 120 can be configured to utilize or consume a different energy source than the engine 110. For example, the engine 110 can consume a liquid fuel (e.g., gasoline) to produce an engine output, while the motor 120 can consume electrical energy to produce a motor output. Accordingly, a vehicle having the propulsion system 100 can be referred to as a hybrid electric vehicle (HEV).

[0019] The vehicle propulsion system 100 can utilize various different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes can enable the engine 110 to remain in an off state in which fuel combustion is stopped (i.e., set to an inactive state). For example, under selected operating conditions, when the engine 110 is inactive, the motor 120 can propel the vehicle via drive wheels 130 as indicated by arrow 122.

[0020] During other operating conditions, the engine 110 can be set to an inactive state (as described above), while the motor 120 can operate to charge the energy storage device 150. For example, as indicated by arrow 122, the motor 120 can receive wheel torque from the drive wheels 130, where the motor can convert the kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150 as indicated by arrow 124. This operation can be referred to as regenerative braking of the vehicle. Thus, in some examples, the motor 120 can provide a generator function. However, in other examples, a generator 160 can instead receive wheel torque from the drive wheels 130, where the generator can convert the kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150 as indicated by arrow 162.

[0021] During other operating conditions, the engine 110 can be operated by combusting fuel received from the fuel system 140 as indicated by arrow 142. For example, when the motor 120 is inactive, the engine 110 can be operated to propel the vehicle via the drive wheels 130 as indicated by arrow 112. During other operating conditions, both the engine 110 and the motor 120 can each be operated to propel the vehicle via the drive wheels 130 as indicated by arrows 112 and 122, respectively. The configuration in which both the engine and the motor can selectively propel the vehicle can be referred to as a parallel type vehicle propulsion system. Note that in some examples, the motor 120 can propel the vehicle via a first set of drive wheels, while the engine 110 can propel the vehicle via a second set of drive wheels.

[0022] In other examples, the vehicle propulsion system 100 can be configured as a series type vehicle propulsion system, whereby the engine does not directly propel the drive wheels. Rather, the engine 110 can be operated to power the motor 120, which in turn can propel the vehicle via the drive wheels 130 as indicated by arrow 122. For example, during selected operating conditions, the engine 110 can drive the generator 160 as indicated by arrow 116, which in turn can do one or more of the following: supply electrical energy to the motor 120 as indicated by arrow 113 or to the energy storage device 150 as indicated by arrow 162. As another example, the engine 110 can be operated to drive the motor 120, which in turn can provide a generator function to convert the engine output into electrical energy, where the electrical energy can be stored at the energy storage device 150 for subsequent use by the motor.

[0023] In other examples, which will be discussed in detail below, the motor 120 can be used in some examples to turn or rotate the motor in a fuel-free configuration. More specifically, the motor 120 can use power from an on-board energy storage device 150, which can include, for example, a battery, to rotate the engine fuel-free. Where the motor 120 is used to rotate the engine fuel-free, fuel injection to the engine cylinders can be prevented, and a spark can not be provided to each engine cylinder.

[0024] The fuel system 140 can include one or more fuel storage tanks 144 for storing fuel on the vehicle. For example, the fuel tank 144 can store one or more liquid fuels including, but not limited to, gasoline, diesel, and alcohol fuels. In some examples, fuel can be stored on the vehicle as a blend of two or more different fuels. For example, the fuel tank 144 can be configured to store a blend of gasoline and ethanol (e.g., E10, E85, etc.) or a blend of gasoline and methanol (e.g., M10, M85, etc.), whereby these fuels or fuel blends can be delivered to the engine 110 as indicated by the arrow 142. Other suitable fuels or fuel blends can also be supplied to the engine 110, where they can be combusted at the engine to produce an engine output. The engine output can be used to propel the vehicle as indicated by the arrow 112 or to recharge the energy storage device 150 via the motor 120 or the generator 160.

[0025] In some examples, the energy storage device 150 can be configured to store electrical energy that can be supplied to other electrical loads (in addition to the motor) that reside on the vehicle, including cabin heating and air conditioning, engine starting, headlamps, cabin audio-video systems, etc. As a non-limiting example, the energy storage device 150 can include one or more batteries and / or capacitors.

[0026] The control system 190 can be in communication with one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. The control system 190 can receive sensory feedback information from one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. In addition, the control system 190 can send control signals to one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160 in response to the sensory feedback. The control system 190 can receive an indication of an operator-requested output of the vehicle propulsion system from the vehicle operator 102. For example, the control system 190 can receive sensory feedback from a pedal position sensor 194 that is in communication with a pedal 192. The pedal 192 can illustratively refer to a brake pedal and / or an accelerator pedal. In addition, in some examples, the control system 190 can be in communication with a remote engine start receiver 195 (or transceiver) that receives the wireless signal 106 from the key fob 104 having the remote start button 105. In other examples (not shown), the remote engine start can be initiated via a cellular phone or smart phone-based system, where the user's cellular phone sends data to a server and the server communicates with the vehicle to start the engine.

[0027] The vehicle system 100 can include a human-machine interface (HMI) 133 coupled to a vehicle dashboard via which an operator can communicate with the control system 190. The HMI 133 can include a touch-sensitive display screen. In one example, via input to the HMI 133, the operator can specify a desired level of engine exhaust noise. The operator can also desire to adjust the level of exhaust noise based on the time of day. In one example, the operator can set the exhaust noise to a lower level in the early morning hours and then change the noise level to a higher level later in the day. In another example, the operator can desire a constant level of exhaust noise and can not frequently change the setting of the desired exhaust noise level. Based on the desired level of exhaust noise, the position of the butterfly plate of the exhaust regulation valve can be adjusted to change the exhaust flow via the exhaust muffler. With respect to Figure 2 An exhaust system and an exhaust regulation valve are described.

[0028] The energy storage device 150 can periodically receive electrical energy from a power source 180 that resides outside of the vehicle (e.g., is not part of the vehicle) as indicated by arrow 184. As a non-limiting example, the vehicle propulsion system 100 can be configured as a plug-in hybrid electric vehicle (HEV), whereby electrical energy can be supplied from the power source 180 to the energy storage device 150 via an electrical energy transfer cable 182. The electrical power transfer cable 182 can electrically couple the energy storage device 150 and the power source 180 during a recharging operation of the energy storage device 150 from the power source 180. The electrical power transfer cable 182 can be disconnected between the power source 180 and the energy storage device 150 when the vehicle propulsion system is operating to propel the vehicle. The control system 190 can identify and / or control the amount of electrical energy stored at the energy storage device, which can be referred to as the state of charge (SOC).

[0029] In other examples, the electrical power transfer cable 182 can be omitted, where electrical energy can be received wirelessly at the energy storage device 150 from the power source 180. For example, the energy storage device 150 can receive electrical energy from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. Thus, it should be appreciated that any suitable method can be used to recharge the energy storage device 150 from a power source that does not form part of the vehicle. In this way, the motor 120 can propel the vehicle by utilizing an energy source other than the fuel utilized by the engine 110.

[0030] Fuel system 140 can periodically receive fuel from a fuel source that resides outside of the vehicle. As a non-limiting example, vehicle propulsion system 100 can be refueled via a fuel dispensing device 170 as indicated by arrow 172. In some examples, fuel tank 144 can be configured to store fuel received from fuel dispensing device 170 until the fuel is supplied to engine 110 for combustion. In some examples, control system 190 can receive an indication of a fuel level stored at fuel tank 144 via a fuel level sensor. The fuel level stored at fuel tank 144 (e.g., as identified by the fuel level sensor) can be communicated to a vehicle operator, for example, via a fuel gauge or an indication in a vehicle dashboard 196.

[0031] Vehicle propulsion system 100 can also include an ambient temperature / humidity sensor 198 and roll stability control sensors, such as one or more lateral and / or longitudinal and / or yaw rate sensors 199. Vehicle dashboard 196 can include one or more indicator lights and / or text-based displays on which messages are displayed to an operator. Vehicle dashboard 196 can also include various input portions for receiving operator input, such as buttons, touchscreens, voice input / recognition, etc. For example, vehicle dashboard 196 can include a refueling button 197 that can be manually actuated or pressed by a vehicle operator to initiate refueling. For example, as described in more detail below, in response to a vehicle operator actuating refueling button 197, a fuel tank in the vehicle can be depressurized such that refueling can be performed.

[0032] Control system 190 can be communicatively coupled to other vehicles or infrastructure using appropriate communication technology, as known in the art. For example, control system 190 can be coupled to other vehicles or infrastructure via a wireless network 131, which can include Wi-Fi, Bluetooth, a type of cellular service, a wireless data transfer protocol, etc. Control system 190 can broadcast (and receive) information about vehicle data, vehicle diagnostics, traffic conditions, vehicle location information, vehicle operating procedures, etc. via vehicle-to-vehicle (V2V), vehicle-to-infrastructure-to-vehicle (V2I2V), and / or vehicle-to-infrastructure (V2I) technology. Communications and information exchanged between vehicles can be directly between vehicles or can be multiple hops. In some examples, long-range communications (e.g., WiMax) can be used instead of or in conjunction with V2V or V2I2V to extend the coverage area several miles. In other examples, vehicle control system 190 can be communicatively coupled to other vehicles or infrastructure via wireless network 131 and the Internet (e.g., the cloud), as commonly known in the art.

[0033] The vehicle system 100 can also include an on-board navigation system 132 (e.g., a global positioning system) that can interact with a vehicle operator. The navigation system 132 can include one or more position sensors to assist in estimating vehicle speed, vehicle height, vehicle position / location, etc. This information can be used to infer engine operating parameters, such as local atmospheric pressure. As discussed above, the control system 190 can also be configured to receive information via the internet or other communication network. Information received from the GPS can be cross-referenced with information available via the internet to determine local weather conditions, local vehicle regulations, etc. In one example, information received from the GPS can be utilized in conjunction with a route learning method such that the vehicle control system 190 can learn the routes that the vehicle typically travels. In some examples, other sensors, such as lasers, radar, sonar, acoustic sensors, etc. can additionally or alternatively be utilized in conjunction with the on-board navigation system to route learn the routes that the vehicle typically travels.

[0034] The vehicle system 100 can also include sensors specific to indicating the occupancy status of the vehicle, such as seat load sensors 107, door sensing technology 108, and on-board cameras 109.

[0035] Figure 2 A schematic diagram 200 of a vehicle system 206 is shown. It can be appreciated that the vehicle system 206 can include the same vehicle system as the vehicle system 100 depicted. Figure 1 The vehicle system 206 includes an engine system 208 coupled to an emissions control system 251 and a fuel system 219. It can be appreciated that the fuel system 219 can include the same fuel system as the fuel system 140 depicted. Figure 1 The emissions control system 251 includes a fuel vapor container or canister 222, which can be used to capture and store fuel vapor. In some examples, the vehicle system 206 can be a hybrid electric vehicle system.

[0036] The engine system 208 can include an engine 110 having a plurality of cylinders 230. While not explicitly shown, it can be appreciated that each cylinder can include one or more intake valves and one or more exhaust valves. The engine 110 includes an engine air intake 223 and an engine air exhaust 225. The engine air intake 223 includes a throttle valve 262 in fluid communication with an engine intake manifold 244 via an intake passage 242. The throttle valve 262 can include an electronic throttle valve, which can be controlled via a vehicle controller sending a signal to actuate the throttle valve to a desired position. In such examples where the throttle valve is an electronic throttle valve, the power to control the throttle valve to the desired position can come from an on-board energy storage device (e.g., 150), such as a battery. Further, the engine air intake 223 can include an air box and an intake air filter 215 located upstream of the throttle valve 262.

[0037] In the depicted embodiment, the engine 110 is a supercharged engine coupled to a turbocharger that includes a compressor 114 driven by a turbine 116. Specifically, fresh air is introduced to the engine 110 along an intake tract 242 via an intake air filter 215 and flows to the compressor 114. The compressor can be any suitable intake compressor, such as a motor-driven or drive shaft-driven mechanical supercharger compressor. In the engine system 110, the compressor is a turbocharger compressor that is mechanically coupled to the turbine 116 via a shaft 19, which is driven by the expanding engine exhaust.

[0038] As shown in FIG. 1, the engine 110 is coupled to a vehicle transmission 220. The transmission 220 is coupled to a drive shaft 222, which is coupled to a pair of front wheels 224. The engine 110 is also coupled to a rear axle 226, which is coupled to a pair of rear wheels 228. The vehicle transmission 220 can be any suitable transmission, such as a continuously variable transmission (CVT), a multi-speed transmission, a dual clutch transmission, a manual transmission, an automated manual transmission, etc. Figure 2 As shown in FIG. 1, the engine 110 is coupled to a vehicle transmission 220. The transmission 220 is coupled to a drive shaft 222, which is coupled to a pair of front wheels 224. The engine 110 is also coupled to a rear axle 226, which is coupled to a pair of rear wheels 228. The vehicle transmission 220 can be any suitable transmission, such as a continuously variable transmission (CVT), a multi-speed transmission, a dual clutch transmission, a manual transmission, an automated manual transmission, etc.

[0039] To assist the turbocharger, an electric supercharger 155 (eBooster) can be incorporated into the vehicle propulsion system. The electric supercharger 155 can be powered via an on-board energy storage device 250, which can include a battery, a capacitor, a super capacitor, etc. In one example, the electric supercharger 155 can be activated (actuated on) in response to a demand for wheel torque in order to quickly provide the desired boost air to the engine without a delay that can otherwise occur if the turbocharger is utilized without the electric supercharger. In such an example, the electric supercharger 155 can be actuated off or deactivated in response to the turbocharger accelerating to a threshold speed (e.g., 70,000 rpm). More specifically, operation control of the electric supercharger 155 can be under the control of a vehicle controller (e.g., controller 12). For example, the controller can send a signal to the electric supercharger actuator 155b that can actuate on the electric supercharger. In another example, the controller can send a signal to the electric supercharger actuator 155b that can actuate off the electric supercharger. In one example, the electric supercharger actuator can contain a motor that drives air compression.

[0040] The electric supercharger 155 can be positioned between the first electric supercharger conduit 159a and the second electric supercharger conduit 159b. The first electric supercharger conduit 159a can fluidly couple the intake tract 42 to the electric supercharger 155 upstream of the electric supercharger bypass valve 161. The second electric supercharger conduit 159b can fluidly couple the electric supercharger 155 to the intake tract 42 downstream of the electric supercharger bypass valve 161. By way of example, air can be drawn into the electric supercharger 155 via the first electric supercharger conduit 159a upstream of the electric supercharger bypass valve 161, and compressed air can exit the electric supercharger 155 and be directed to the intake tract 42 via the second electric supercharger conduit downstream of the electric supercharger bypass valve 161. In this way, compressed air can be directed to the engine intake 244.

[0041] In the event that the electric supercharger 155 is activated to provide supercharging more quickly than relying on the turbocharger alone, it can be appreciated that the electric supercharger bypass valve 161 can be commanded closed while the electric supercharger 155 is activated. In this way, intake air can flow through the turbocharger and through the electric supercharger 155. Once the turbocharger reaches a threshold speed, the electric supercharger 155 can be closed, and the electric supercharger bypass valve 161 can be commanded open. In one example, when the engine is rotating in a reverse direction, the electric supercharger can also rotate in a direction opposite the default rotational direction in order to produce air flow from the exhaust tract to the engine cylinders 230.

[0042] The engine exhaust system 225 includes an exhaust manifold 248 leading to an exhaust tract 235 that directs exhaust gases to the atmosphere. The engine exhaust system 225 can include one or more exhaust catalysts 270, which can be installed at a close coupled position in the exhaust. The one or more emission control devices can include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, etc. It will be appreciated that other components, such as various valves and sensors, can be included in the engine. For example, an atmospheric pressure sensor 213 can be included in the engine intake. In one example, the atmospheric pressure sensor 213 can be a manifold air pressure (MAP) sensor, and can be coupled to the engine intake downstream of the throttle valve 262. Alternatively, the MAP can be inferred from an alternative engine operating condition, such as mass air flow (MAF) measured by a MAF sensor 210 coupled to the intake manifold.

[0043] The engine exhaust system 225 can also include a gasoline particulate filter (GPF) 217. The GPF 217 can include a particulate filter, a hydrocarbon trap, a catalytic coating, or a combination thereof. In some examples, during operation of the engine 110, the GPF 217 can be periodically regenerated by operating at least one cylinder of the engine within a certain air-to-fuel ratio to increase the temperature of the GPF 217, such that retained hydrocarbons and soot particulates can be oxidized.

[0044] In some examples, a temperature sensor 226 can be located upstream of the inlet of the GPF 217, while a temperature sensor 229 can be located downstream of the GPF 217. For example, the temperature sensors 226 and 229 can be used to assess the temperature of the GPF 217 for regeneration purposes. Further, a pressure sensor 263 can assess the pressure in the exhaust system. For example, the pressure sensor 263 can be a sensor located upstream and downstream of the GPF 217. The pressure sensor 263 can be used to determine the pressure at the inlet of the GPF 217 in order to assess the working conditions of the air to be introduced into the inlet of the GPF 217 for regeneration. Further, in some examples, a soot sensor can be located downstream of the GPF 217 to assess the level of soot released from the GPF 217.

[0045] A muffler 220 is also located downstream of the GPF 217. The muffler 220 can reduce the amplitude of the sound pressure produced by the exhaust gases before the exhaust gases exit into the atmosphere. The exhaust gases can pass through one or more chambers or other sound-attenuating structures within the muffler 220 before exiting the muffler via a muffler outlet to an exhaust tailpipe 231 of the exhaust system, which leads to the atmosphere.

[0046] The exhaust system includes an exhaust regulation valve 218 that is controlled to regulate the portion of the exhaust gases that flow through the muffler 220. The exhaust regulation valve 218 is installed in the exhaust system, downstream of the GPF 217 and upstream of the exhaust tailpipe 231, with the exhaust regulation valve 218 coupled to the muffler 220 in a bypass passage 224 that is parallel to the exhaust passage 235. Exhaust gases exiting via the exhaust system of the internal combustion engine 110 can pass through the exhaust regulation valve 218 under certain conditions, depending on whether the valve is in an open position or a closed position. In one embodiment, when the exhaust regulation valve 218 is in the closed position, the exhaust gases can exit (e.g., to the atmosphere) only by passing through the muffler 220. When the exhaust regulation valve 218 is in the open position, at least a portion of the exhaust gases can pass through the bypass passage 224, thereby bypassing the muffler 220. In some examples, the exhaust regulation valve can be operated partially open or partially closed, thereby allowing the exhaust gases to be partially directed through the muffler and partially through the exhaust regulation valve and into the bypass passage 224 before exiting into the atmosphere. Figure 2 The exhaust system includes an exhaust regulation valve 218 that is controlled to regulate the portion of the exhaust gases that flow through the muffler 220. The exhaust regulation valve 218 is installed in the exhaust system, downstream of the GPF 217 and upstream of the exhaust tailpipe 231, with the exhaust regulation valve 218 coupled to the muffler 220 in a bypass passage 224 that is parallel to the exhaust passage 235. Exhaust gases exiting via the exhaust system of the internal combustion engine 110 can pass through the exhaust regulation valve 218 under certain conditions, depending on whether the valve is in an open position or a closed position. In one embodiment, when the exhaust regulation valve 218 is in the closed position, the exhaust gases can exit (e.g., to the atmosphere) only by passing through the muffler 220. When the exhaust regulation valve 218 is in the open position, at least a portion of the exhaust gases can pass through the bypass passage 224, thereby bypassing the muffler 220. In some examples, the exhaust regulation valve can be operated partially open or partially closed, thereby allowing the exhaust gases to be partially directed through the muffler and partially through the exhaust regulation valve and into the bypass passage 224 before exiting into the atmosphere.

[0047] Engine exhaust noise can be regulated by adjusting the opening of exhaust regulation valve 218. An operator can indicate a desired engine noise level via input to an HMI coupled to a vehicle dashboard and controller 212, such as HMI 133 in Figure 1 When a higher level of exhaust noise is desired, the controller can increase the opening of exhaust regulation valve 218 to increase the volume of exhaust gas flowing from downstream of GPF 217 to the exhaust tailpipe via exhaust regulation valve 218. As the exhaust gas flowing via exhaust regulation valve 218 bypasses muffler 220, the amplitude of the sound pressure generated by the exhaust gas can not be significantly reduced and the perceived engine exhaust noise increases. Similarly, when a higher level of exhaust noise is desired, the controller can close exhaust regulation valve 218 to direct the entire volume of exhaust gas to the exhaust tailpipe via muffler 220, where the amplitude of the sound pressure can be attenuated and the operator perceives a lower engine exhaust sound.

[0048] During conditions when the vehicle (vehicle system 206) is unoccupied and the vehicle is not in motion, the controller can periodically or opportunistically perform a diagnosis of exhaust regulation valve 218. The engine is reversed with no fuel via a battery-powered motor, the position of exhaust regulation valve 218 is changed from a fully closed position to a fully open position at a constant rate, and the intake air flow at each position of the exhaust regulation valve is estimated via MAF sensor 210. The exhaust regulation valve can be indicated as non-deteriorated in response to the intake air flow at each position of the exhaust regulation valve decreasing from a highest intake air flow at the fully open position to a lowest intake air flow at the fully closed position. Accordingly, deterioration of the exhaust regulation valve can be indicated in response to the intake air flow at each position of the exhaust regulation valve not being constant. Further, when the engine is reversed, intake electric supercharger 155 operates in a reverse direction to increase the flow of ambient air from engine exhaust passage 235 to engine intake manifold 244 via one or more engine cylinders 230.

[0049] The MAP sensor 213 can also be used for diagnostics of the exhaust regulation valve 218 during reverse rotation of the engine. In one example, during reverse rotation of the engine, the exhaust regulation valve 218 can first be commanded to the closed position, and after a threshold duration has elapsed since the exhaust regulation valve 218 was closed, the valve can be actuated to the fully open position. The threshold duration can be calibrated based on stabilization of intake manifold air pressure during reverse rotation of the engine. When the exhaust regulation valve 218 is opened, the amount of air directed into the engine system increases, resulting in a corresponding increase in intake manifold pressure. If a corresponding increase, such as greater than 5%, is observed in the MAP sensor 213 reading upon opening of the exhaust regulation valve 218, it can be inferred that the exhaust regulation valve 218 can have actuated from the closed position to the open position and not stuck. However, if no significant change, such as greater than 5%, is observed in the MAP sensor 213 reading after opening of the exhaust regulation valve 218, it can be inferred that the exhaust regulation valve 218 is stuck and can not actuate. When the engine is reverse rotated, the exhaust valve can be open for a longer duration, thereby allowing higher pressurization of the intake manifold at lower engine speeds. By operating the engine at lower engine speeds, power consumption from the electric motor can be reduced, and the diagnostics can be performed at lower engine noise generation. In this way, during a first engine operating condition, the engine can be rotated in the forward direction with fuel injected via the fuel injectors 266, and the electric supercharger 155 can be rotated in the forward direction based on torque demand, while during a second engine operating condition, the engine can be rotated in the reverse direction without fuel via the electric motor, and the electric supercharger 155 can be rotated in the reverse direction during diagnostics of the exhaust regulation valve. Details of the diagnostic method of the exhaust regulation valve 218 are described in detail in Figure 5 .

[0050] The fuel system 219 can include a fuel tank coupled to a fuel pump system 221. It can be appreciated that the fuel tank can be the same fuel tank as the fuel tank 144 described above in Figure 1 . The fuel pump system 221 can include one or more pumps for pressurizing fuel delivered to the injectors, such as the example injectors 266 shown. While only a single injector 266 is shown, additional injectors are provided for each cylinder. It should be appreciated that the fuel system 219 can be a returnless fuel system, a return fuel system, or various other types of fuel systems. The fuel tank can hold a variety of fuel blends, including fuels with a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, and the like, and combinations thereof.

[0051] Vapors generated in the fuel system 219 can be directed to a vapor emission control system 251 via a vapor recovery line 278 before being purged to the engine intake 223, which includes a fuel vapor canister 222. The vapor recovery line 278 can be coupled to the fuel tank via one or more conduits and can include one or more valves for isolating the fuel tank under certain conditions.

[0052] The emission control system 251 can include one or more emission control devices, such as one or more fuel vapor canisters 222 filled with a suitable adsorbent 286b configured to temporarily trap fuel vapors (including vaporized hydrocarbons) and “run losses” (i.e., vaporized fuel during vehicle operation) during fuel tank refilling operations. In one example, the adsorbent 286b used is activated carbon. The emission control system 251 can also include a canister vent path or vent line 227 that can vent gas from the canister 222 to the atmosphere when storing or trapping fuel vapors from the fuel system 219.

[0053] The canister 222 can include a buffer 222a (or buffer zone), each of which contains an adsorbent. As shown, the volume of the buffer 222a can be less than the volume of the canister 222 (e.g., a fraction of the volume). The adsorbent 286a in the buffer 222a can be the same or different than the adsorbent in the canister (e.g., both can include carbon). The buffer 222a can be positioned within the canister 222 such that during canister loading, fuel tank vapors are first adsorbed within the buffer, and then when the buffer is saturated, additional fuel tank vapors are adsorbed in the canister. In contrast, during canister purging, fuel vapors are first desorbed from the canister (e.g., to a threshold amount), and then from the buffer. In other words, the loading and unloading of the buffer is not linear with the loading and unloading of the canister. As a result, the effect of the canister buffer is to dampen any fuel vapor peaks flowing from the fuel tank to the canister, thereby reducing the likelihood of any fuel vapor peaks entering the engine. One or more temperature sensors 232 can be coupled to the canister 222 and / or within the canister. As fuel vapors are adsorbed by the adsorbent in the canister, heat is generated (heat of adsorption). Likewise, as fuel vapors are desorbed by the adsorbent in the canister, heat is consumed. In this way, the adsorption and desorption of fuel vapors by the canister can be monitored and estimated based on temperature changes within the canister.

[0054] Vent line 227 can also allow fresh air to be drawn into canister 222 when stored fuel vapor is purged from fuel system 219 to engine air intake 223 via purge line 228 and purge valve 261. For example, purge valve 261 can be normally closed, but can be opened during certain conditions so that a vacuum from engine air intake manifold 244 is provided to the fuel vapor canister for purging. In some examples, vent line 227 can include an air filter 259 disposed upstream of canister 222 therein.

[0055] In some examples, the flow of air and vapor between canister 222 and atmosphere can be regulated by a canister vent valve 297 coupled within vent line 227. When included, canister vent valve 297 can be a normally open valve so that fuel tank isolation valve 252 (FTIV) can control venting of the fuel tank to atmosphere. FTIV 252 can be positioned between the fuel tank and fuel vapor canister 222 within vapor recovery line 278. FTIV 252 can be a normally closed valve that, when opened, allows fuel vapor to be vented from the fuel tank to fuel vapor canister 222. The fuel vapor can then be vented to atmosphere or purged to engine air intake system 223 via canister purge valve 261.

[0056] By selectively adjusting the various valves and solenoids, fuel system 219 can be operated in a variety of modes by controller 212. It can be appreciated that control system 214 can include the same control system as control system 190 depicted above in Figure 1 For example, the fuel system can be operated in a fuel vapor storage mode (e.g., during a fuel tank refueling operation and the engine is not combusting air and fuel), where controller 212 can open FTIV 252 while closing canister purge valve (CPV) 261 to direct refueling vapors into canister 222 while preventing fuel vapors from being directed into the intake manifold.

[0057] As another example, the fuel system can be operated in a refueling mode (e.g., when a vehicle operator requests refueling of the fuel tank), where controller 212 can open isolation FTIV 252 while keeping canister purge valve 261 closed to depressurize the fuel tank before allowing fuel to be added in the fuel tank. FTIV 252 can therefore remain open during refueling operations to allow refueling vapors to be stored in the canister. FTIV 252 can be closed after refueling is complete.

[0058] As another example, the fuel system can operate in a filter canister flushing mode (e.g., after the emission control ignition temperature has been reached and the engine is burning air and fuel), where controller 212 can open filter canister flushing valve 261 while simultaneously closing FTIV 252. In this document, the vacuum generated by the intake manifold of the operating engine can be used to draw in fresh air through ventilation line 227 and fuel vapor filter canister 222 to flush stored fuel vapor into intake manifold 244. In this mode, the fuel vapor flushed from the filter canister is burned in the engine. Flushing can continue until the amount of fuel vapor stored in the filter canister is below a threshold.

[0059] Controller 212 may include a portion of control system 214. In some examples, control system 214 may be integrated with... Figure 1 The control system 190 shown is identical. Control system 214 is shown receiving information from multiple sensors 216 (various examples of which are described herein) and sending control signals to multiple actuators 281 (various examples of which are described herein). As an example, sensors 216 may include an exhaust gas sensor 237 located upstream of emission control unit 270, a pressure sensor 263 coupled to both ends of particulate filter 217, temperature sensors 233, 226, and 229, a MAP sensor 213, a MAF sensor 210, and a filter canister temperature sensor 232. Other sensors, such as pressure, temperature, air-fuel ratio, and composition sensors, may be coupled to various locations within vehicle system 206. As another example, actuators may include a throttle valve 262, a fuel tank isolation valve 252, a filter canister flush valve 261 and a filter canister vent valve 297, an exhaust gas regulating valve 218, and an electric supercharger actuator 155b. The controller can receive input data from various sensors, process the input data, and trigger actuators in response to the processed input data based on instructions corresponding to one or more programs or codes programmed into those instructions. In one example, during vehicle-off conditions, the controller can perform diagnostics on the exhaust regulating valve 218. The controller can send a signal to each electric supercharger actuator 155b to rotate the electric supercharger in the opposite direction to allow ambient air to flow into the environment via the exhaust tailpipe 231, while continuously changing the opening of the exhaust regulating valve 218 and monitoring airflow via the MAF sensor 210. In another example, during vehicle-off conditions, the controller can perform diagnostics on the intake air filter 215. The controller can send a signal to each electric supercharger actuator 155b to rotate the electric supercharger in the opposite direction to allow ambient air to flow into the environment via the exhaust tailpipe 231, while monitoring airflow via the pressure sensor 263 and the MAF sensor 210.

[0060] In some examples, the controller can be placed in a reduced power mode or sleep mode in which the controller maintains only basic functions and operates with lower battery consumption than a corresponding wake mode. For example, the controller can be placed in a sleep mode after a vehicle off event in order to perform a diagnostic procedure for a certain duration after the vehicle off event. The controller can have a wake input that allows the controller to return to a wake mode based on input received from one or more sensors. For example, opening of a vehicle door can trigger a return to a wake mode.

[0061] For example, the wake capability can enable the circuit to wake the controller in order to timely perform a diagnostic of the intake air filter 215. During a vehicle off state, the engine can be running without fuel, the air flow through the exhaust system and the air flow through the intake system can be compared to each other and to a baseline air flow, and in response to the air flow through the exhaust system being substantially equal to the air flow through the intake system and each of the air flow through the exhaust system and the air flow through the intake system being lower than the baseline air flow, an air flow obstruction can be indicated. The air flow obstruction can be indicated as the intake air filter 215 being clogged based on the air flow through the exhaust system increasing to the baseline air flow upon opening a secondary path to atmosphere. The secondary path to atmosphere can be from downstream of the MAF sensor 210 via the canister purge line 228, the canister 222, and the canister vent path 227 of the evaporative emission control system 251 to atmosphere, and the secondary path can be opened by each of actuating the canister purge valve 261 to an open position and actuating the canister vent valve 297 to an open position.

[0062] The air flow through the exhaust system is estimated via a differential pressure (dP) sensor 263 coupled across the particulate filter 217, and the air flow through the intake system is estimated via the MAF sensor 210. During the diagnostic of the intake air filter 215, the intake electric supercharger 155 can also be operated in a reverse direction to direct ambient air from the engine exhaust tract 235 to the engine intake manifold 244 via one or more engine cylinders.

[0063] The diagnostic procedure for the exhaust regulation valve and the air filter can be performed in a vehicle configured as an autonomous vehicle, and an example autonomous driving system is discussed below with reference to Figure 3 . Figure 3 may be operated on the vehicle discussed above in Figure 1A block diagram of an exemplary autonomous driving system 300 of the vehicle system 100 described in FIG. 1. Herein, the vehicle system 100 will be referred to simply as the "vehicle." As shown, the autonomous driving system 300 includes a user interface device 310, a navigation system 315, at least one autonomous driving sensor 320, and an autonomous mode controller 325. It can be appreciated that the in-vehicle navigation system 315 can be the same as the in-vehicle navigation system 132 depicted in FIG. 1, and the user interface device 310 can be the same as the HMI 133 depicted in FIG. 1. Figure 1 Figure 1

[0064] The user interface device 310 can be configured to present information to a vehicle occupant under conditions in which a vehicle occupant can be present. However, it can be appreciated that under certain conditions, the vehicle can operate autonomously without a vehicle occupant. The presented information can include audible or visual information. Further, the user interface device 310 can be configured to receive user input. Thus, the user interface device 310 can be located in a passenger compartment (not shown) of the vehicle. In some possible approaches, the user interface device 310 can include a touch-sensitive display screen.

[0065] The navigation system 315 can be configured to determine a current location of the vehicle using, for example, a global positioning system (GPS) receiver configured to triangulate a position of the vehicle relative to satellites or ground-based transmission towers. The navigation system 315 can also be configured to develop a route from the current location to a selected destination, and to display a map and present a driving route to the selected destination via, for example, the user interface device 310.

[0066] The autonomous driving sensor 320 can include any number of devices configured to produce signals that aid in navigating the vehicle. Examples of autonomous driving sensors 320 can include radar sensors, lidar sensors, vision sensors (e.g., video cameras), vehicle-to-vehicle infrastructure networks, etc. The autonomous driving sensors 320 can enable the vehicle to "see" the road and vehicle surroundings, and / or to navigate over various obstacles while the vehicle 100 is operating in autonomous mode. The autonomous driving sensors 320 can be configured to output sensor signals to, for example, the autonomous mode controller 325.

[0067] ​​The autonomous mode controller 325 can be configured to control one or more subsystems 330 when the vehicle is operating in autonomous mode. Examples of subsystems 330 that can be controlled by the autonomous mode controller 325 can include a braking subsystem, a suspension subsystem, a steering subsystem, and a powertrain subsystem. The autonomous mode controller 325 can control any one or more of these subsystems 330 by outputting signals to control units associated with the subsystems 330. In one example, the braking subsystem can include an anti-lock braking subsystem configured to apply a braking force to one or more wheels. It is discussed herein that applying a braking force to one or more wheels can be referred to as activating the brakes. To autonomously control the vehicle, the autonomous mode controller 325 can output appropriate commands to the subsystems 330. These commands can cause the subsystems to operate in accordance with the driving characteristics associated with the selected driving mode. For example, the driving characteristics can include how aggressive the vehicle accelerates and decelerates, how much space the autonomous vehicle leaves in front of the preceding vehicle, how often the autonomous vehicle changes lanes, etc.

[0068] Figure 4A and Figure 4B An exemplary circuit 400 that can be used to reverse the rotational orientation of an electric motor is shown. The circuit 400 schematically depicts an H-bridge circuit that can be used to run a motor 410 in a first (forward) direction and, alternatively, in a second (reverse) direction. The circuit 400 includes a first (LO) side 420 and a second (HI) side 430. Side 420 includes transistors 421 and 422, while side 430 includes transistors 431 and 432. The circuit 400 also includes a power source 440.

[0069] In Figure 4A transistors 421 and 432 are activated (energized), while transistors 422 and 431 are turned off. In this configuration, the left lead 451 of the motor 410 is connected to the power source 440, while the right lead 452 of the motor 410 is connected to ground. In this way, the motor 400 can be run in the forward (or default) direction. When the engine is being operated via the motor in the forward direction, the engine can be in a cranking mode for initial combustion start. Additionally and / or alternatively, when the engine is being operated via the motor in the forward direction, the engine (and motor or another motor) can be in a drive mode to drive the vehicle. It can be appreciated that in some examples, the engine can be cranked in the forward (e.g., default) direction under conditions where the vehicle is stationary, and only the engine is expected to be cranked or rotated in the forward direction without combustion.

[0070] In Figure 4BIn this configuration, transistors 422 and 431 are activated (energized), while transistors 421 and 432 are turned off. In this configuration, the right lead 452 of the motor 410 is connected to the power supply 440, while the left lead 451 of the motor 410 is connected to ground. In this way, the motor 410 can be run in the reverse direction.

[0071] In this way, Figures 1-4A To Figure 4B The components of 1 provide a system for a hybrid vehicle, the system comprising: a vehicle; an engine; an electric machine coupled to a battery capable of rotating the engine; an intake tract comprising an intake air filter and a compressor; an exhaust tract comprising a particulate filter; a manifold air flow (MAF) sensor coupled to the intake tract; a differential pressure sensor coupled across the particulate filter; a canister purge line; and a ventilation path coupling the intake tract to the atmosphere via a canister, the canister purge line comprising a canister purge valve (CPV), and the ventilation path comprising a canister ventilation valve (CVV). The vehicle further comprises a controller having computer readable instructions stored on a non-transitory memory for: obtaining a baseline air flow via the MAF sensor by counter-rotating the engine with the electric machine when the intake air filter is first installed; and after a threshold duration of use of the intake air filter since the intake air filter was installed and while the engine is counter-rotated by the electric machine, obtaining a first intake air flow via the MAF sensor and a first exhaust air flow via the differential pressure sensor; comparing the first intake air flow, the first exhaust air flow, and the baseline air flow; and in response to the first intake air flow and the first exhaust air flow being equal to each other and lower than the baseline air flow, diagnosing the intake air filter in response to a change in the first exhaust air flow after the CPV and the CVV are opened.

[0072] Figure 5 An exemplary method 500 that can be implemented to perform a diagnosis of an exhaust regulation valve during an engine non-combustion state is shown. The instructions for performing the method 500 and the remaining methods included herein can be performed by a controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of an engine system, such as the sensors described above with reference to Figure 2 The controller can employ engine actuators of the engine system to adjust engine operation in accordance with the methods described below.

[0073] At 502, the method includes determining whether a condition for initiating a diagnosis of an exhaust regulation valve (such as an exhaust gas recirculation valve) is satisfied. Figure 2Conditions for diagnosing the exhaust regulating valve (218) in the system. In one example, conditions for initiating exhaust regulating valve diagnosis may include the vehicle being in a closed state when the vehicle is not occupied (no passengers are in the vehicle). Seat force sensors, one or more onboard cameras, and / or door sensing technologies may be used to ensure the vehicle is not occupied. In another example, the regulating valve diagnosis may be performed during autonomous vehicle mode when the vehicle is operated without a driver and when the vehicle is not propelled by engine torque. Vehicle operation may be controlled from a remote location or may be pre-programmed in the controller memory. During vehicle operation in autonomous mode, the diagnosis may be performed as appropriate when the vehicle stops at a traffic signal or immediately after completing a driving cycle. In yet another example, the regulating valve diagnosis may be performed in response to the controller waking up after a predetermined duration following an engine shutdown event. Conditions for initiating exhaust regulating valve diagnosis include confirming that engine sensors such as the MAF sensor and oxygen sensor are not deteriorated and that diagnostic codes (flags) indicating deterioration of any engine components are generally not set. Furthermore, before initiating the regulating valve diagnosis, the controller may verify that a predetermined duration has elapsed since the previous exhaust regulating valve diagnosis procedure was performed. In some examples, such a scheduled duration can include one day, more than one day but less than two days, more than two days, etc. In other examples, the scheduled duration can include miles traveled, vehicle operating hours, or other parameters.

[0074] If it is determined that the conditions for initiating exhaust control valve diagnostics are not met, at point 503, the exhaust control valve diagnostic procedure can be postponed until the conditions are met. In some examples, if the exhaust control valve diagnostic conditions are not met, the current operating parameters can continue until the exhaust control valve diagnostic conditions are met. Such operating parameters may include fuel being transported via the fuel system (such as fuel lines) when the vehicle is operating. Figure 2 The fuel system 219 delivers fuel to one or more engine cylinders via fuel injectors, where combustion of air and fuel is performed. The engine torque generated by combustion in the engine cylinders can be used to propel the vehicle. Vapor generated in the fuel system can be guided via vapor recovery lines to an evaporative emission control system (such as...). Figure 2 The EVAP system 251 in the model includes an evaporative emission control system comprising a fuel vapor filter canister. Vapor stored in the canister can be flushed into the engine intake manifold via a flushing line and a filter canister flushing valve (CPV), which regulates the vapor flow from the filter canister to the engine intake. While the stored fuel vapor is flushed into the engine intake, the ventilation lines allow fresh air to be drawn into the filter canister.

[0075] Electric superchargers (such as) Figure 2The electric supercharger 155 in the middle can be connected to a duct in parallel with the intake manifold, and by operating the 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 pressure.

[0076] The opening of the exhaust regulating valve can be adjusted based on the desired engine noise level selected by the operator (e.g., via a human-machine interface). When a higher level of exhaust noise is required, the controller can increase the opening of the exhaust regulating valve to increase the volume of exhaust flowing through the exhaust regulating valve around the muffler to the exhaust tailpipe. When the exhaust flowing through the exhaust regulating valve bypasses the muffler, the sound pressure amplitude generated by the exhaust may not be significantly reduced, thereby causing an increase in perceived engine exhaust noise.

[0077] If the conditions for initiating exhaust control valve diagnostics are determined to be met, at 504, 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 is operated to burn air and fuel. Rotating the engine in the reverse direction without fuel can include directing air flow sequentially through the exhaust system, the engine, and the intake manifold. Rotating the engine in the reverse direction without fuel can include via a motor (such as...) Figure 1 The motor 120 in the motor rotates the engine, wherein the motor can be connected to an onboard energy storage device such as a battery. Figure 1 The energy storage device 150 in the battery is powered. In non-hybrid vehicles, the engine can be reversed via the vehicle's starter motor and battery. To reverse the engine's rotation, an H-bridge circuit (such as...) can be used. Figures 4A-4B The circuit shown can be used to control the engine speed to a predetermined speed via a motor. The predetermined engine speed can be included when the engine is rotating in the reverse direction, and can be controlled via a MAF sensor (such as...). Figure 2 The MAF sensor 210 in the filter canister obtains a robust airflow measurement at a given speed. In one example, the predetermined speed can be below 500 rpm. Furthermore, although not explicitly shown, it is understood that the filter canister flushing valve (such as...) is activated during engine rotation. Figure 2 The CPV 261 in the figure can remain closed to ensure that air is not directed to the evaporative emission system and / or the fuel system. Furthermore, although not explicitly shown, for vehicles equipped with exhaust gas recirculation (EGR) (e.g., high-pressure EGR and / or low-pressure EGR), one or more valves controlling exhaust gas recirculation can be commanded or kept closed.

[0078] At 506, the electric supercharger (such as...) Figure 2The 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 default forward direction to provide the desired boost. The reverse rotation of the electric supercharger generates lower pressure at the exhaust manifold, thereby promoting airflow through the exhaust system, engine, and 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 supercharger. Figure 1 The energy stored in the energy storage device 250 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 can be reduced, and noise generation during operation can also be reduced. In one example, step 506 of method 500 can be optional, and the exhaust regulating valve diagnostic can be performed without rotating the electric supercharger. During the exhaust regulating valve diagnostic procedure, the electric supercharger can remain in a deactivated state while the engine rotates in reverse. At 508, the exhaust regulating valve opening can be changed from a fully open position (throttle fully open) to a fully closed position. The controller can send a signal to the actuator coupled to the exhaust regulating valve to actuate the exhaust regulating valve to the fully open position, and then actuate the valve from the fully open position to the fully closed position. The exhaust regulating valve opening can decrease from the fully open position to the fully closed position at a constant rate (dE / dt). In one example, the sweep rate of the disc in the exhaust regulating valve can be more than 90 degrees in 5 seconds.

[0079] As the position of the exhaust regulating valve changes, the airflow into the exhaust system can change. In one example, when the exhaust regulating valve is fully open, ambient air can flow through the muffler and bypass channels (such as...) due to the low pressure generated in the engine intake manifold by the counter-rotation of the engine and electric supercharger. Figure 2 Each of the bypass passages (224) flows into the exhaust manifold. Air entering the exhaust manifold can continue to flow through the engine cylinders and then into the intake manifold. Ambient air can then exit the engine system via the intake manifold. As the exhaust regulating valve opening decreases, the path of air flow through the bypass passages becomes narrower, and the airflow is restricted to a path through the muffler, and the total volume of air entering the exhaust manifold may decrease. When the exhaust regulating valve is fully closed, air can no longer flow into the exhaust manifold through the bypass passages, so the total volume of air entering the exhaust manifold can be further reduced.

[0080] Alternatively, the controller can send a signal to an actuator coupled to the exhaust regulation valve to first actuate the position of the exhaust regulation valve to a fully closed position and then actuate the position of the valve from the fully closed position to a fully open position. The opening of the exhaust regulation valve can increase at a constant rate from the fully closed position to the fully open position.

[0081] At 510, for each position of the exhaust regulation valve, the amount of air flowing through the exhaust manifold, and then through the cylinders and intake manifold, can be estimated via a manifold air flow sensor, such as MAF sensor 210 in FIG. 2. The amount of air flowing through the engine components can be directly proportional to the opening of the exhaust regulation valve. In one example, the amount of air entering the exhaust manifold can increase as the exhaust regulation valve opening increases, and correspondingly, the amount of air entering the exhaust manifold can decrease as the exhaust regulation valve opening decreases. Thus, as the opening of the exhaust regulation valve decreases from the fully open position to the fully closed position, the MAF sensor reading indicative of the intake manifold air flow can proportionally decrease. Figure 2

[0082] At 511, the rate of change of the intake air flow estimated based on the MAF sensor reading over time (dF / dt) is estimated. The estimation of dF / dt can be performed during the time period in which the opening of the exhaust regulation valve decreases from the fully open position to the fully closed position at a constant rate. In one example, the MAF sensor output can be periodically sampled (e.g., at evenly spaced time intervals), starting when the exhaust regulation valve is at the fully open position (e.g., 100% open) and continuing until the exhaust regulation valve is at the fully closed position (e.g., 0% open). The MAF sensor output can be sampled when the exhaust regulation valve is 90% open, 80% open, 70% open, etc. during this time. Each time the MAF sensor output is sampled, the sampled output can be stored in the memory of the controller. In some examples, the corresponding position of the exhaust regulation valve can also be stored with the MAF output at that exhaust regulation valve position.

[0083] At 512, the routine includes determining whether the rate of change of the intake air flow (dF / dt) is related to the rate of change of the opening of the exhaust regulation valve (dE / dt). The intake air flow can proportionally decrease as the opening of the exhaust regulation valve decreases from the fully open position to the fully closed position at a constant rate (dE / dt). In one example, the routine can determine whether dF / dt is directly proportional to dE / dt.

[0084] ​​In another example, the procedure can include determining whether the MAF sensor reading is highest at a full open position of the exhaust regulation valve and whether the MAF sensor reading is lowest at a closed position of the exhaust regulation valve. As described above, at the full open position of the exhaust regulation valve, the highest MAF sensor reading is expected to correspond to the highest volume of ambient air entering the engine system. Also, at the closed position of the exhaust regulation valve, the lowest MAF sensor reading is expected to correspond to the lowest volume of ambient air entering the engine system.

[0085] The highest MAF sensor reading described above can be a sampled MAF sensor output having a highest value of all sampled MAF sensor outputs collected during a sweep of the exhaust regulation valve from the full open position to the full closed position. The lowest MAF sensor reading described above can be a sampled MAF sensor output having a lowest value of all sampled MAF sensor outputs collected during a sweep of the exhaust regulation valve from the full open position to the full closed position.

[0086] In yet another example, the procedure can include determining whether the MAF sensor reading at each position of the exhaust regulation valve reading (e.g., when the regulation valve is at 100%, 75%, 50%, 25%, and 0% open) is substantially equal to an expected intake air flow. In one example, substantially equal can include the MAF sensor reading being within 5% of the expected intake air flow. The controller can use a lookup table to determine the expected intake air flow corresponding to the exhaust regulation valve opening. As an example, the input to the lookup table can be the exhaust regulation valve opening, and the output is the intake air flow. As the regulation valve opening decreases, the expected intake air flow can proportionally decrease.

[0087] If it is determined that the rate of change of intake air flow (dF / dt) and the rate of change of the opening of the exhaust regulation valve (dE / dt) are related (proportional), it can be inferred that the exhaust regulation valve successfully actuated from the full open position to the full closed position and did not get stuck in any position between the full open position and the closed position.

[0088] If it is determined that the MAF sensor reading at the full open position of the exhaust regulation valve is the highest and the MAF sensor reading at the closed position of the exhaust regulation valve is the lowest, it can also be inferred that the exhaust regulation valve successfully actuated from the full open position to the full closed position. Also, if the MAF sensor reading is substantially equal to the expected intake air flow for each position of the exhaust regulation valve, it can be inferred that the exhaust regulation valve is not stuck at any position between the full open position and the full closed position. Accordingly, at 514, the exhaust regulation valve can be indicated as not deteriorated. At 516, the diagnostic procedure is completed and each of the engine and the electric supercharger can be de-rotated. The controller can send a signal to a motor powering the engine to stop the engine from rotating. The controller can also send a signal to an actuator coupled to the electric supercharger to pause operation of the electric supercharger.

[0089] If it is determined at 512 that the rate of change of intake air flow (dF / dt) and the rate of change of the opening of the exhaust regulation valve (dE / dt) are not proportional, it can be inferred that the exhaust regulation valve can not be able to actuate from the full open position to the full closed position. If it is determined that the MAF sensor reading at the full open position of the exhaust regulation valve is not the highest and / or the MAF sensor reading at the closed position of the exhaust regulation valve is not the lowest, and / or the MAF sensor reading is not substantially equal to the expected intake air flow for each position of the exhaust regulation valve, it can be inferred that the exhaust regulation valve is deteriorated. At 518, a diagnostic code (flag) indicating that the exhaust regulation valve is deteriorated can be set. In one example, the deterioration of the valve can include the valve being stuck at a fixed position, such as the full open position, the full closed position, or a position between the full open position and the full closed position, even though it is actuated to move to another position. In another example, the deterioration of the valve can include the valve leaking, causing air to flow via the bypass passage and the valve even when the valve is commanded to the full closed position.

[0090] Because of the deterioration of the valve, the valve position corresponding to the desired exhaust noise setting can not be properly adjusted, thereby adversely affecting the driving experience. Accordingly, in response to the indication of the deterioration of the exhaust regulation valve, at 520, the engine exhaust noise regulation via adjustment of the exhaust regulation valve can be prohibited until the valve has been serviced.

[0091] In this way, when the vehicle is operated without a driver and when the vehicle is not propelled by engine torque, during a first engine operating condition, the position of the exhaust regulation valve can be adjusted based on an operator-selected noise mode, and during a second engine operating condition, the opening of the exhaust regulation valve can be adjusted from a fully closed position to a fully open position, the intake air flow corresponding to each opening of the exhaust regulation valve can be estimated via the MAF sensor, and the exhaust regulation valve can be diagnosed based on changes in the intake air flow as the opening of the exhaust regulation valve increases. The first engine operating condition includes the engine rotating in a forward direction with fuel injected via fuel injectors, and the electric supercharger rotating in the forward direction based on torque demand, while the second engine operating condition includes the engine rotating in a reverse direction without fuel via the electric machine.

[0092] Figure 6 An example timeline 600 is shown that illustrates a diagnosis of an exhaust regulation valve, such as exhaust regulation valve 218 in Figure 2 The horizontal line (x-axis) represents time, while the vertical markers tl through t4 represent important times in the operation of the electric supercharger.

[0093] The first graph (line 602) illustrates a change in vehicle speed over time. The second graph (line 604) illustrates a direction of rotation of the engine. For example, during engine operation, the engine can rotate in a default direction of forward, where air-fuel combustion in the engine cylinders, with fuel supplied to the engine cylinders via fuel injectors. Alternatively, the engine can rotate in a reverse direction without fuel, such as via an electric machine coupled to a hybrid electric vehicle (HEV). The third graph (line 606) illustrates an operation of the electric supercharger, such as electric supercharger 216 in Figure 1The fourth plot (line 608) shows operation of an electric motor coupled to a hybrid electric vehicle (HEV). The electric motor can be operated to provide motor torque to propel the HEV. The fifth plot (line 610) shows the opening of the exhaust regulation valve. The sixth plot (line 612) shows the volume of intake air flow estimated based on input from a manifold air flow (MAF) sensor. The dotted line 613 shows the expected intake air flow corresponding to the opening of the exhaust regulation valve at any given point in time. The controller uses a lookup table to estimate the expected intake air flow corresponding to each opening of the exhaust regulation valve (e.g., when the regulation valve is at 100%, 75%, 50%, 25%, and 0% open), where the exhaust valve opening is an input to the lookup table and the expected intake air flow is an output of the lookup table. The seventh plot (dashed line 616) shows a flag representing a diagnostic code set to indicate that the exhaust regulation valve is deteriorating.

[0094] Prior to time tl, the vehicle is operated via engine torque. The engine is driven by combustion and rotates in the forward direction. Based on the torque demand, the electric supercharger rotates in the forward direction to provide the desired boost pressure. The intake manifold air flow during engine combustion is estimated based on the reading of the MAF sensor. The HEV electric motor is not operated for engine rotation or vehicle propulsion. Based on the desired engine exhaust noise setting (by the operator via the on-board human machine interface), the exhaust regulation valve is held at a fixed position between the fully open and fully closed positions accordingly. Because the exhaust regulation valve is not indicated to be deteriorating, the flag is held in the closed position.

[0095] At time tl, the vehicle speed decreases to zero and between times tl and t2, the vehicle is no longer operated using engine torque and / or electric motor torque (the vehicle off state begins). Accordingly, at time tl, the engine is turned off by pausing fuel injection and spark to the engine cylinders. The electric supercharger is no longer operated between times tl and t2. When the engine is turned off, the intake air flow is no longer monitored via the MAF sensor.

[0096] At time t2, after a threshold duration has elapsed since the vehicle was turned off at time tl, a diagnosis of the exhaust regulation valve is initiated by the wake-up controller. The controller sends a signal to the HEV motor to turn the engine in a reverse direction without fueling. Also, the controller sends a signal to the actuator coupled to the electric supercharger to spin the electric supercharger in a reverse direction. When the engine and electric supercharger are spinning in their respective reverse directions, a lower pressure is created at the engine exhaust manifold, and ambient air can enter the engine system via the exhaust passage. The controller then sends a signal to the actuator coupled to the exhaust regulation valve to move the exhaust regulation valve to a fully closed position between t2 and t3, and air flows into the engine system via the muffler (exhaust regulation valve closed) and the MAF reading can stabilize.

[0097] At time t3, the controller sends a signal to the actuator coupled to the exhaust regulation valve to gradually increase the opening of the exhaust regulation valve from the fully closed position at a constant rate. The rate of increase of the exhaust regulation valve opening is 18 degrees / second. Between times t3 and t4, as the position of the exhaust regulation valve increases, the air flow into the engine system via the exhaust passage and then to the intake manifold via the engine cylinders increases correspondingly. The actual air flow through the engine system is monitored via the MAF sensor corresponding to each position of the exhaust regulation valve. The actual air flow (line 612) is compared to the expected air flow (line 613) corresponding to the opening of the exhaust regulation valve at any given point in time. It has been observed that the actual air flow correlates to the expected air flow and the MAF sensor reading increases proportionally to the opening of the exhaust regulation valve.

[0098] Therefore, at the end of the diagnostic procedure, at time t4, based on the observation that the actual air flow correlates to the expected air flow and the MAF sensor reading is highest corresponding to the fully open position of the exhaust regulation valve and lowest corresponding to the fully closed position of the exhaust regulation valve, it is concluded that the exhaust regulation valve is not deteriorated (not stuck anywhere and / or not leaking). Because it is concluded that the exhaust regulation valve is not deteriorated, the flag remains in the off state.

[0099] At time t4, at the end of the diagnostic procedure, the exhaust regulation valve is actuated back to the position of the valve prior to the initiation of the diagnostic procedure, such as the position of the valve prior to time t3. Also, at time t4, the controller sends a signal to each of the HEV motor and the electric supercharger actuator to pause operation and stop spinning the engine and the electric supercharger, respectively. After time t4, the vehicle is not propelled using engine torque and / or motor torque, and the engine remains in the off state until a subsequent vehicle key-on.

[0100] If the exhaust regulation valve deteriorates between times t3 and t4, the MAF sensor reading will not increase in proportion to the increase in exhaust regulation valve opening. If the exhaust regulation valve is stuck at a particular open position, as shown by dashed line 611, the valve opening will not change significantly even if the controller sends a signal to an actuator coupled to the exhaust regulation valve to gradually actuate the valve from a fully closed position to a fully open position. Accordingly, as shown by dashed line 614, the MAF reading remains substantially constant for the duration of the diagnostic procedure between times t3 and t4. From the substantially constant MAF sensor reading, it can be inferred that the exhaust regulation valve is deteriorating and a flag indicating deterioration of the exhaust regulation valve is set at time t4.

[0101] In this way, the engine is rotated in a reverse direction and the intake electric supercharger is rotated in a reverse direction to draw air through the exhaust passage into the engine and then direct the air through the intake passage to the atmosphere, the opening of the exhaust regulation valve is changed, and the presence or absence of deterioration of the exhaust regulation valve is diagnosed based on the correlation between the opening of the exhaust regulation valve and the air flow through the intake passage.

[0102] Figures 7A-7B An exemplary method 700 that can be implemented to perform a diagnosis of the air cleaner is shown. Similar to the diagnosis of the exhaust regulation valve, the diagnosis of the intake air cleaner can be performed by reversing the engine without fueling during an engine non-combustion state. In one example, during a vehicle off state, the intake air cleaner diagnosis and the exhaust regulation valve diagnosis can be performed continuously.

[0103] At 702, the procedure includes determining whether a condition for initiating a diagnosis of an intake air cleaner, such as the air cleaner 102, is met. In one example, the condition is met when the engine is in a non-combustion state, such as when the engine is off. In another example, the condition is met when the engine is in a non-combustion state and the engine is not being fueled. In one example, the condition is met when the engine is in a non-combustion state and the engine is not being fueled and the engine is not being rotated in a reverse direction. In another example, the condition is met when the engine is in a non-combustion state and the engine is not being fueled and the engine is not being rotated in a reverse direction and the engine is not being rotated in a forward direction. Figure 2diagnosed. In one example, the condition for initiating the intake air filter diagnosis can include a vehicle off state (absence of any occupants in the vehicle) when the vehicle is unoccupied. Seat force sensors, one or more on-board vehicle cameras, and / or door sensing technology can be used to ensure that the vehicle is unoccupied. In another example, the intake air filter diagnosis can be performed during autonomous vehicle mode when the vehicle is operated without a driver and when the vehicle is not propelled by engine torque. The vehicle operation can be controlled from a remote location or can be pre-programmed in the controller memory. The diagnosis can be performed opportunistically during vehicle operation in autonomous mode when the vehicle is stopped at a traffic signal or shortly after completing a drive cycle. In yet another example, the intake air filter diagnosis can be performed in response to the controller waking up after a predetermined duration of time after an engine off event. Another condition for initiating the intake air filter diagnosis is that the soot load on the exhaust particulate filter (PF) is below a threshold soot load. The threshold soot load can correspond to a load on the PF that can not affect the output of a differential pressure (dP) sensor coupled across the PF. As an example, the threshold soot load can correspond to the soot load remaining on the PF at the end of PF regeneration.

[0104] The expected air flow through the intake manifold can be estimated as a function of the intake throttle opening, and the actual air flow through the intake manifold can be estimated based on input from a manifold air flow (MAF) sensor. Due to blockage in the intake air filter, the actual air flow through the intake manifold can be reduced below the expected air flow. If the actual air flow is detected to be below the expected air flow, the diagnosis of the intake air filter can be performed opportunistically.

[0105] The expected engine torque output can be estimated based on engine operating conditions, including engine speed, engine load, engine temperature, etc. A blocked intake air filter can reduce the amount of air entering the cylinders for combustion, thereby adversely affecting the engine torque output. Thus, a reduced engine output (a sluggish engine) compared to the expected engine output can trigger the intake air filter diagnosis.

[0106] Conditions for initiating an intake air filter diagnosis include confirming that engine sensors, such as a MAF sensor, a dP sensor, an oxygen sensor, etc., are not deteriorated, and generally no diagnostic codes (flags) are set indicating deterioration of any engine components. In addition, prior to initiating an intake air filter diagnosis, the controller can verify whether a predetermined duration has elapsed since a previous intake air filter diagnosis procedure. In some examples, such a predetermined duration can include one day, more than one day but less than two days, more than two days, etc. In other examples, the predetermined duration can include a number of miles traveled, a number of hours of vehicle operation, or other parameters.

[0107] If it is determined that the conditions for initiating an intake air filter diagnosis are not satisfied, at 704, the intake air filter diagnosis procedure can be postponed until the conditions are satisfied. In some examples, if the intake air filter diagnosis conditions are not satisfied, the current operating parameters can continue until the intake air filter diagnosis conditions are satisfied. During combustion, the intake air throttle can be opened to allow air to flow into the intake manifold via the intake air filter. The air filter can remove dust, dirt, and other airborne particulates from the air entering the intake manifold. Fuel can be delivered to one or more engine cylinders via fuel injectors of a fuel system, such as fuel system 219 in FIG. 2, and engine torque generated by combustion in the engine cylinders can be used to propel the vehicle. Vapors generated in the fuel system can be directed to a vapor emission control system, such as EVAP system 251 in FIG. 2, which includes a fuel vapor canister. Vapors stored in the canister can be purged to the engine intake manifold via a purge line, a canister purge valve (CPV) that regulates the flow of vapors from the canister to the engine intake, and a vent line that allows fresh air to be drawn into the canister when stored fuel vapors are purged to the engine intake. Figure 2 Figure 2

[0108] An electric supercharger, such as electric supercharger 155 in FIG. 1, coupled to a conduit in parallel with an intake passage, can be used to provide a desired boost pressure during conditions when the boost pressure provided by operating a turbocharger, such as intake compressor 114 and exhaust turbine 116 in FIG. 1, is below the desired boost pressure. Figure 2 Figure 1

[0109] ​​​​If it is determined that the conditions for initiating the intake air filter diagnosis are met, the method 700 proceeds to 706 and includes un-fueled rotating or turning the engine in a reverse direction at a predetermined speed (e.g., a predetermined RPM). Un-fueled rotating the engine can include rotating the engine in an opposite direction as when the engine is operated to combust air and fuel. Un-fueled rotating the engine in the reverse direction can include directing air to flow through the exhaust system, the engine, and the intake manifold in sequence. Un-fueled rotating the engine in the reverse direction can include rotating the engine via a motor (such as motor 120 in Figure 1 ) that can be powered via an on-board energy storage device (such as energy storage device 150 in Figures 4A-4B ) such as a battery. To reverse-rotate the engine, a H-bridge circuit (such as the circuit shown in Figure 2 ) can be utilized. Un-fueled turning the engine while the engine is reverse-rotated is initiated under a set of predetermined conditions including engine speed, duration of engine turn initiation, intake throttle position, and exhaust regulation valve position. The engine speed can be controlled to a predetermined speed via the motor. In one example, the predetermined speed can be below 500 rpm. The predetermined engine conditions can include a set of conditions when robust air flow measurements can be obtained via a MAF sensor (such as MAF sensor 210 in Figure 2 ) while the engine is reverse-rotated. In one example, the predetermined conditions can be calibrated by the controller via the MAF sensor based on expected air flow prior to initiating the diagnostic procedure. Further, to un-fueled rotate the engine in the reverse direction, valve timing can be controlled to default values.

[0110] While not explicitly shown, for vehicles equipped with exhaust gas recirculation (EGR) (e.g., high pressure EGR and / or low pressure EGR), one or more valves controlling exhaust gas recirculation can be commanded or held closed.

[0111] At 708, an electric supercharger can be rotated in a reverse direction. The electric supercharger can be coupled to a conduit in parallel with the intake tract, the conduit coupled to the intake tract downstream of the intake compressor and upstream of the charge air cooler. The electric supercharger can operate in a default direction of forward to provide a desired boost pressure during conditions when the boost pressure provided by operating the turbocharger (such as intake compressor 114 and exhaust turbine 116 in Figure 1 ) is below the desired boost pressure. Reverse rotation of the electric supercharger creates a lower pressure at the exhaust manifold, thereby facilitating air to flow through the exhaust system, the engine, and the intake manifold in sequence. The controller can send a signal to an electric supercharger actuator (such as actuator 155b in Figure 1 ) to use energy from an energy storage device (such as energy storage device 150 in Figure 2The electric supercharger can be actuated by energy stored in the energy storage device 250) of the vehicle. The electric supercharger can be operated at a predetermined speed at which a robust air flow measurement can be obtained via the MAF sensor when the engine is running in reverse and the electric supercharger is rotating in reverse. In one example, the predetermined speed of the electric supercharger can be calibrated by the controller via the MAF sensor based on a desired air flow prior to initiating the diagnostic procedure. During the no-fuel run start of the engine, when the engine is running in reverse and the electric supercharger is rotating in reverse, a low pressure area is created within the exhaust manifold and ambient air can enter and flow through the exhaust manifold, engine cylinder, and intake manifold in sequence via the exhaust tailpipe, and then the air can escape to the atmosphere via the intake tract. In one example, step 708 of the method 700 can be optional and the diagnostic of the intake air filter can be performed without running the electric supercharger. During the intake air filter diagnostic procedure, the electric supercharger can remain in a deactivated state while the engine is running in reverse to direct ambient air into the exhaust manifold via the exhaust tailpipe.

[0112] At 710, the controller can retrieve a baseline air flow from an on-board database. In one example, the baseline air flow can be estimated via the MAF sensor by no-fuel run starting the engine in a reverse direction and rotating the electric supercharger in a reverse direction at the time of installation of the air filter. In one example, the installation of the air filter can include assembling the air filter in the engine at a manufacturing plant. In another example, the installation of the air filter can include replacing an old air filter with a new air filter at a service location. The baseline air flow can be estimated for a first threshold duration of time since installation of the intake air filter, while the diagnostic of the air filter can be performed when the intake air filter has been in use for more than a second threshold duration of time, which is longer than the first threshold duration of time. In one example, the first threshold duration of time can be 1 day since installation of the air filter. In another example, the second threshold duration of time can be 30 days since installation of the air filter. Alternatively, the baseline air flow can be estimated for a first threshold distance of travel (of the vehicle) since installation of the intake air filter, while the diagnostic of the air filter can be performed when the intake air filter has been in use for more than a second threshold distance of travel, which is longer than the first threshold distance. In one example, the first threshold distance can be 30 miles since installation of the air filter. In another example, the second threshold distance can be 300 miles since installation of the air filter.

[0113] A baseline air flow can be obtained when operating the engine and electric supercharger under a set of predetermined conditions, including engine speed, engine run-up duration, intake throttle position, exhaust regulator valve position, and electric supercharger speed. As an example, the set of predetermined conditions when estimating the baseline air flow is the same as the set of predetermined conditions when the engine is run up in step 706 and the electric supercharger is spun in step 708.

[0114] In one example, the baseline air flow can be a single baseline air flow estimated via the intake MAF sensor during engine operation under the set of predetermined conditions. In another example, there can be two separate baseline air flows: a first baseline intake air flow estimated via the intake MAF sensor and a second baseline exhaust air flow estimated via an exhaust differential pressure (dP) sensor coupled across the exhaust particulate filter. Each of the first baseline intake air flow and the second baseline exhaust air flow can be estimated during engine operation under the set of predetermined conditions. For a non-deteriorated engine system, because the same ambient air flow flows through each of the exhaust tract and the intake manifold during engine reverse rotation (during non-combustion states), the air flow estimated by the dP sensor can be substantially equal to the air flow estimated by the MAF sensor. Thus, the first baseline intake air flow and the second baseline exhaust air flow can be substantially equal to each other. In one example, substantially equal includes the first baseline intake air flow being within a threshold margin of the second baseline exhaust air flow. As an example, the threshold margin can be 5%. Also, the first baseline intake air flow can be equal to the second baseline exhaust air flow.

[0115] At 712, the method continues the intake air filter diagnostic procedure and estimates the air flow through the intake system via the MAF sensor (intake air flow) and estimates the air flow through the exhaust system via the dP sensor (exhaust air flow). In the absence of blockages or leaks in the engine system, the same amount of air can flow through each of the exhaust manifold, the engine cylinders, and the intake manifold.

[0116] At 714, the method includes determining whether there is a correlation between the intake air flow, the exhaust air flow, and the baseline air flow. In one example, the controller can determine whether the intake air flow, the exhaust air flow, and the baseline air flow are substantially equal to each other. As previously described, substantially equal can include each factor being within a threshold margin of the other two factors, the factors being the intake air flow, the exhaust air flow, and the baseline air flow. In one example, the threshold margin can be 5%. In another example, it can be determined whether the intake air flow, the exhaust air flow, and the baseline air flow are equal to each other.

[0117] In one example, if there are separate intake baseline air flow and exhaust baseline air flow, the controller can determine whether the intake air flow, exhaust air flow, intake baseline air flow, and exhaust baseline air flow are substantially equal to each other.

[0118] If it is determined that there is a correlation between the intake air flow, exhaust air flow, and baseline air flow and that they are substantially equal to each other, it can be inferred that the amount of ambient air flowing through the engine components at the time of diagnosis is substantially equal to the amount of ambient air flowing through the engine components at the time of installation of the air cleaner. Thus, it can be inferred that the air cleaner is not clogged and, at 716, the controller can indicate that the air cleaner is not degraded. The controller can also indicate that the intake air cleaner is not degraded if the intake air flow, exhaust air flow, intake baseline air flow, and exhaust baseline air flow are substantially equal to each other. Also, because the intake air flow is substantially equal to the exhaust air flow, it can be inferred that there is no loss of air between the dP sensor and the MAF sensor when ambient air flows from the exhaust manifold through the engine components to the intake manifold, thereby indicating that there is no leak or clog in the engine components between the dP sensor and the MAF sensor.

[0119] If it is determined that there is no correlation between the intake air flow, exhaust air flow, and baseline air flow, at 720, the routine includes determining whether the intake air flow and exhaust air flow are converging but each of the intake air flow and exhaust air flow is lower than the baseline air flow. In one example, the controller can determine whether the intake air flow is substantially equal to the exhaust air flow but each of the intake air flow and exhaust air flow is lower than the baseline air flow. In another example, the controller can determine whether the intake air flow is substantially equal to the exhaust air flow but the intake air flow and exhaust air flow are lower than the intake baseline air flow and exhaust baseline air flow, respectively.

[0120] If it is determined that the intake air flow rate and the exhaust air flow rate are not converging, then at 721, it can be inferred that the intake air flow rate and the exhaust air flow rate are diverging. In one example, divergence between the intake air flow rate and the exhaust air flow rate can be inferred based on the intake air flow rate being significantly different from the exhaust air flow rate. As an example, the difference between the intake air flow rate and the exhaust air flow rate can be higher than 5%. The difference between the intake air flow rate and the exhaust air flow rate indicates that the entire volume of ambient air that enters the engine system through the exhaust tailpipe flows through the exhaust manifold, but the same volume of air can not flow through the intake manifold. Thus, it can be inferred that there can be a leak in the engine system between the dP sensor housed in the exhaust manifold and the MAF sensor housed in the intake manifold, and when air flows from the dP sensor to the MAF sensor, a portion of the air is lost from the flow path (between the dP sensor and the MAF sensor) through the leak. The controller can also make a diagnosis of the engine system to identify the location of the leak. In one example, the leak in the intake manifold can be confirmed based on the engine air-fuel ratio change estimated via an oxygen sensor coupled to the exhaust passage upstream of the exhaust catalyst. If the leak is confirmed to exist, the controller can adjust the air-fuel ratio to compensate for the air loss from the intake manifold. In one example, a leak in the evaporative emission control system coupled to the engine intake manifold can cause air to be directed to the EVAP system when flowing from the exhaust manifold to the intake manifold, thereby causing the intake air flow rate (as estimated via the MAF) to be lower than the exhaust air flow rate (as estimated via the dP). A canister purge valve (such as CPV 261 in Figure 2 ) is housed in a canister purge line (such as purge line 228 in Figure 2 ) of the EVAP system, while a canister vent valve (such as CVV 297 in Figure 2 ) is housed in a canister vent path (such as vent path 227 in Figure 7B ) of the EVAP system. The canister purge line couples the intake system to the canister of the EVAP system, while the canister vent path couples the canister to the atmosphere, the canister purge line being coupled to the intake manifold downstream of the MAF sensor. A leak in the CPV can cause air to flow from the intake manifold to the canister via the purge line.

[0121] If it is determined at 720 that the intake air flow rate and the exhaust air flow rate are converging but each of the intake air flow rate and the exhaust air flow rate is lower than the baseline air flow rate, then it can be inferred that there is an obstruction in the air flow. It can be determined that the intake air flow rate and the exhaust air flow rate are converging, but the intake air flow rate is lower than the intake baseline air flow rate and the exhaust air flow rate is lower than the baseline exhaust air flow rate. A secondary flow path for air can be opened to determine the location of the obstruction. The method continues to Step A as described in detail in Figure 7B .

[0122] At 722 ( Figure 8 As shown in the diagram, method 700 includes opening the CPV and opening (or keeping open) the CVV. The controller can send signals to each actuator connected to the CPV and CVV to actuate each of the CPV and CVV to the open position. When the CPV and CVV are open, a secondary path connecting the engine exhaust manifold to the atmosphere can be established via flushing lines and ventilation paths. In one example, if the CVV is already in the open position during a diagnostic procedure, the CVV can be kept in the open position.

[0123] At 724, method 700 includes determining whether the exhaust airflow increases to the baseline airflow when the secondary path to the atmosphere is opened. In one example, the controller may determine whether the exhaust airflow increases to the baseline exhaust airflow when the secondary path to the atmosphere is opened. If, for example, the intake air filter is not blocked when the air filter is installed, a first amount of ambient air can enter the exhaust manifold due to the lower pressure at the exhaust manifold (generated by the counter-rotation of the engine and the electric supercharger), and then flow to the atmosphere via the intake manifold (baseline airflow). However, if the intake air filter is blocked, the main path of air escaping to the atmosphere through the exhaust duct (exhaust tailpipe) into the engine system can be restricted, thereby reducing the airflow through the main path relative to the baseline airflow. If the unobstructed secondary path to the atmosphere is opened, a higher amount of air can enter the exhaust manifold and flow to the atmosphere via the secondary path. As an example, if the flush line and ventilation path of the EVAP system provide a secondary path, a first amount of ambient air can enter the exhaust manifold and then flow to the atmosphere via the flush line and ventilation path of the EVAP system. When the flush line is connected to the intake manifold downstream of the MAF sensor, the increase in airflow through the exhaust manifold can be detected by the dP sensor but may not be detected by the MAF sensor.

[0124] Therefore, if it is determined that the exhaust airflow increases to the baseline airflow (or exhaust baseline airflow) when the CPV and CVV are turned on, a limitation in the main path can be inferred. At point 726, a diagnostic code (flag) indicating blockage or deterioration of the intake air filter can be set.

[0125] Because the intake air filter is deteriorating, less than desired amounts of air can flow into the intake manifold during subsequent engine combustion, resulting in a richer-than-stoichiometric air-fuel mixture in the engine. During subsequent engine combustion, to provide the desired air-fuel ratio for combustion, the throttle opening can be adjusted at 730 based on the filter blockage. In one example, the controller cannot increase the intake throttle opening to compensate for the blockage in the intake air filter until the blocked air filter is replaced.

[0126] If it is determined at 724 that the exhaust air flow has not increased to the baseline air flow (or to the exhaust baseline air flow) even after the CPV and CVV are opened, it can be inferred that there can be an obstruction in the exhaust system or intake system of the engine at a location other than the intake air filter. Due to the obstruction, even when the second path to atmosphere is opened, a lower amount of air (relative to the amount of air that flows through the engine when the air filter is installed) can flow through the engine components. In one example, the obstruction can include a foreign object in the muffler or a degraded exhaust aftertreatment device. At 732, the possible obstruction can be indicated by setting a diagnostic code, and the controller can conduct further diagnostics of the engine system to identify the location of the obstruction. In one example, if the catalyst monitoring sensor (oxygen sensor) does not alternate between rich and lean, it can be inferred that the exhaust catalyst is obstructed. The obstruction in the exhaust catalyst can result in reduced fuel economy and increased incidence of misfires.

[0127] In this way, it can be indicated that the air filter is obstructed in response to an increase in the exhaust air flow after the CPV and CVV are opened, and the air filter is not obstructed in response to no change in the exhaust air flow after the CPV and CVV are opened.

[0128] At 718, the diagnostic procedure is completed and each of the engine and the electric supercharger can no longer be rotated. The controller can send a signal to the motor that powers the engine to stop the engine from rotating. The controller can also send a signal to the actuator coupled to the electric supercharger to pause operation of the electric supercharger.

[0129] In this way, during a first engine condition, the engine can be rotated in reverse without fuel, and a first baseline intake air flow and a second baseline exhaust air flow can be recorded, the first engine condition including an engine condition when a first threshold duration has passed since the intake air filter was installed. During a second engine condition, the engine can be rotated in reverse without fuel, and an updated intake air flow and an updated exhaust air flow can be recorded, and a presence or absence of degradation of the intake air filter can be diagnosed based on a correlation between each of the first baseline intake air flow, the second baseline exhaust air flow, the updated intake air flow, and the updated exhaust air flow with each other. The second engine condition includes an engine condition when the intake air filter has been used for more than a second threshold duration, the second threshold duration being longer than the first threshold duration.

[0130] Figure 2 An example timeline 800 is shown, which illustrates an intake air filter (such as Figure 1diagnosis of the air filter 215 in the intake air filter 215). The horizontal line (x-axis) represents time, while the vertical markers ti through t6 represent important times in the procedure for diagnosing the intake air filter.

[0131] The first graph (line 802) shows vehicle speed as a function of time. The second graph (line 804) shows the rotational direction of the engine. For example, during engine operation, the engine can rotate in a default direction of forward, where air-fuel combustion in the engine cylinders, fuel is supplied to the engine cylinders via fuel injectors. Alternatively, the engine can rotate in a reverse direction without fuel, such as via an electric motor coupled to a hybrid electric vehicle (HEV) or via a starter motor. The third graph (line 806) shows the rotational direction of the electric supercharger (such as the electric supercharger 155 in the intake air filter 215) coupled to a conduit that is parallel to the intake manifold downstream of the intake compressor and upstream of the charge air cooler (CAC). The electric supercharger can rotate in a forward direction or a reverse direction by reversing the circuitry of an actuator coupled to the electric supercharger, which is powered via an on-board energy storage device. The forward rotational direction of the electric supercharger is opposite the reverse rotational direction of the electric supercharger. The fourth graph (line 808) shows the operation of an electric motor coupled to a hybrid electric vehicle (HEV). The electric motor can be operated to provide motor torque to propel the HEV. The fifth graph (line 811) shows the reading of a dP sensor (such as the dP sensor 263 in the intake air filter 215) coupled across a particulate filter housed in an exhaust passage. During the diagnosis of the intake air filter, the dP sensor reading corresponds to exhaust air flow. The sixth graph (line 814) shows the reading of a MAF sensor (such as the MAF sensor 210 in the intake air filter 215) coupled to the intake manifold. During the diagnosis of the intake air filter, the MAF sensor reading corresponds to intake air flow. The seventh graph (line 818) shows the opening of a canister purge valve (CPV) coupled to a canister purge line of an evaporative emission control system. The canister purge line couples the intake passage (downstream from the MAF sensor) to a canister of the EVAP system. In addition, a canister vent path housing a canister vent valve (CVV) couples the canister to atmosphere. If each of the CPV and CVV are open, a flow path is established between the intake manifold and atmosphere through the canister purge line and the canister vent path. The eighth graph (dashed line 820) shows a flag representing a diagnostic code set to indicate exhaust gas recirculation valve deterioration. Figure 2 Figure 2 ​

[0132] ​​​Prior to time tO, a new (unused) intake air filter is installed in the intake manifold of the vehicle at the manufacturing plant. At the time of installation of the air filter, between times tO and tl, when the vehicle is not propelled via engine or motor torque, and optionally when the vehicle is confirmed to be unoccupied based on input from a vehicle camera, a baseline air flow is estimated. At time tl, the controller sends a signal to the HEV motor to spin the engine in a reverse direction at a first engine speed without fueling.

[0133] Also, the controller sends a signal to the actuator coupled to the electric supercharger to spin the electric supercharger in a reverse direction at a first electric supercharger speed. When the engine and electric supercharger are spinning in their respective reverse directions, a lower pressure is generated at the engine exhaust manifold, and ambient air enters the engine system via the exhaust passage. The ambient air then flows through the engine cylinders, intake manifold, and then is directed to the atmosphere via the intake passage. During the measurement of the baseline air flow, the CPV valve remains in the closed position. Between times tO and tl, the intake air flow estimated via the MAF sensor is saved in the on-board database as the baseline air flow corresponding to the unused (unobstructed) air filter, as shown by line 810. This baseline air flow 810 is used later during the diagnosis of the intake air filter. Because the intake air filter is not indicated to be deteriorated, the flag remains in the closed position.

[0134] At time tl, once the baseline air flow is saved in memory, the controller sends a signal to each of the HEV motor and electric supercharger actuator to pause operation and stop spinning the engine and electric supercharger, respectively (for the purpose of the diagnostic procedure). The duration between times tl and t2 corresponds to a threshold duration of time after which it is desired to timely perform the diagnostic procedure for the intake air filter. The duration between times tl and t2 includes a number of drive cycles and periods of time when the vehicle is not operated (not propelled via engine or motor torque).

[0135] At time t2, the vehicle is started from rest and operated via engine torque. The engine is driven by combustion and spins in a forward direction. Based on the torque demand, the electric supercharger spins in a forward direction to provide the desired boost pressure. The HEV motor is not operated for engine rotation or vehicle propulsion. Between times t2 and t3, the MAF reading represents the amount of air that enters the engine for combustion via the intake passage. The amount of air that enters the intake passage is proportional to the throttle opening. The dP sensor reading corresponds to the soot load accumulated on the particulate filter having the dP sensor coupled across both ends. Between t2 and t3, the particulate filter is regenerated. During the regeneration of the particulate filter, heat from the exhaust combust the soot deposited on the particulate filter, and as the soot load on the particulate filter decreases, a corresponding decrease in the differential pressure across the particulate filter is observed.

[0136] At time t3, the vehicle speed decreases to zero, and between times t3 and t4, the engine torque and / or motor torque is no longer used to operate the vehicle (the vehicle off state begins). Thus, at time t3, the engine is turned off by pausing fuel injection and spark to the engine cylinders. Also, the electric supercharger is paused. Between times t3 and t4, the engine remains in the off state.

[0137] At time t4, after a threshold duration has elapsed since the vehicle off at time t3 and when it is confirmed that the vehicle is unoccupied, optionally based on input from the on-board camera, a diagnosis of the intake air filter is initiated by the wake-up controller. The controller sends a signal to the HEV motor to turn the engine in a reverse direction at a first engine speed without fueling. Also, the controller sends a signal to the actuator coupled to the electric supercharger to spin the electric supercharger in a reverse direction at a first electric supercharger speed. When the engine and electric supercharger spin in their respective reverse directions, a lower pressure is created at the engine exhaust manifold, and ambient air can enter the engine system via the exhaust passage. Between times t4 and t5, ambient air flows through the exhaust manifold, engine cylinders, and intake manifold in sequence. The baseline air flow 813 estimated between times tO and ti is retrieved from the on-board database and compared to each of the intake air flow estimated based on the MAF reading and the exhaust air flow estimated based on the dP sensor reading.

[0138] Between times t4 and t5, it is observed that the intake air flow is equal to the exhaust air flow, but each of the intake air flow and the exhaust air flow is lower than the baseline air flow 813. Thus, it is inferred that an equal amount of air is flowing through the exhaust manifold and the intake manifold, but due to the obstruction of the engine system, the amount of air entering the engine system during this period is lower compared to the amount of air entering the engine when the intake air filter was installed (between times tO and ti).

[0139] At time t5, the controller sends a signal to the CPV to actuate the valve to the open position. Also, the CVV remains in the open position to establish fluid communication between the intake manifold and the atmosphere via the canister purge line and the canister vent path. Upon opening the CPV, between times t5 and t6, it is observed that the dP sensor reading increases without any significant change (more than 5% change) in the MAF sensor reading. The increased exhaust air flow is equal to the baseline air flow 813. Based on the increase in the exhaust air flow to the baseline air flow, it is inferred that there is an obstruction in the intake air filter, and when the unobstructed flow path to the atmosphere via the canister purge line and the canister vent path is opened, the air flow into the exhaust manifold increases.

[0140] In response to detecting the obstruction in the intake air filter, a flag is set to notify the operator after time t5. At time t6, at the end of the diagnostic procedure, the controller sends a signal to each of the HEV motor and electric supercharger actuator to pause operation and stop rotating the engine and electric supercharger, respectively. Also, the CPV is actuated to the closed position to seal the EVAP system. After time t6, no engine torque and / or motor torque is used to propel the vehicle, and the engine remains in the off state until the subsequent vehicle key-on. The flag indicating the intake air filter obstruction (deterioration) is maintained until the air filter is replaced or serviced.

[0141] In this way, existing engine components such as the differential pressure sensor and MAF sensor can be repurposed as exhaust air flow meter and intake air flow meter, respectively, for the diagnosis of the intake air filter. The technical effect of confirming the obstruction in the intake air filter by opening the secondary path to atmosphere via the EVAP system is that the obstruction in the intake air filter can be distinguished from obstructions in other intake and exhaust components such as the exhaust catalyst. By detecting the deterioration of the intake air filter, the desired air-fuel ratio can be adjusted, and the combustion of a richer air-fuel mixture can be reduced. In summary, by monitoring the health of the intake air filter in a timely manner, deterioration of the air filter can be detected in time, and the obstructed intake air filter can be replaced soon.

[0142] An example engine method includes changing a position of an exhaust regulation valve during a reverse rotation of an engine while the engine is not fueling for a start, and diagnosing the exhaust regulation valve based on intake air flow at one or more positions of the exhaust regulation valve. In any of the foregoing examples, additionally or alternatively, changing the position of the exhaust regulation valve includes fully closing the exhaust regulation valve, and then increasing an opening of the exhaust regulation valve from a fully closed position to a fully open position at a constant rate. In any or all of the foregoing examples, additionally or alternatively, diagnosing the exhaust regulation valve based on the intake air flow further includes indicating that the exhaust regulation valve is not deteriorated in response to the intake air flow at multiple positions of the exhaust regulation valve decreasing from a highest intake air flow at the fully open position to a lowest intake air flow at the fully closed position. In any or all of the foregoing examples, additionally or alternatively, diagnosing the exhaust regulation valve based on the intake air flow includes indicating deterioration of the exhaust regulation valve in response to the intake air flow at multiple positions of the exhaust regulation valve not changing, the intake air flow at each of the multiple positions of the exhaust regulation valve being estimated via a mass air flow (MAF) sensor coupled to an engine intake manifold. In any or all of the foregoing examples, additionally or alternatively, the deterioration of the exhaust regulation valve includes the exhaust regulation valve being stuck at a position between the fully closed position and the fully open position. In any or all of the foregoing examples, additionally or alternatively, the engine is reverse rotated via a motor powered by a battery. In any or all of the foregoing examples, additionally or alternatively, the engine is coupled in a vehicle, and the engine is reverse rotated under a condition that the vehicle is unoccupied and the vehicle is not in motion. In any or all of the foregoing examples, the method further includes, additionally or alternatively, operating an intake electric supercharger in a reverse direction to direct ambient air from an engine exhaust passage to the engine intake manifold via one or more engine cylinders when the engine is reverse rotated. In any or all of the foregoing examples, additionally or alternatively, the intake electric supercharger is coupled to a conduit in parallel with an intake passage, the conduit being coupled to the intake passage downstream of an intake compressor and upstream of a charge air cooler, the method further including opening an electric supercharger bypass valve coupled to the intake passage downstream of the intake compressor when the intake electric supercharger is operated to direct air through the electric supercharger. In any or all of the foregoing examples, additionally or alternatively, the exhaust regulation valve is coupled to a bypass passage in parallel with the exhaust passage, the bypass passage being positioned across a muffler contained in the exhaust passage downstream of a particulate filter. In any or all of the foregoing examples, the method further includes, additionally or alternatively, in response to detecting deterioration of the exhaust regulation valve, inhibiting an operator from adjusting engine exhaust noise regulation via a human-machine interface coupled to the vehicle.

[0143] Another engine example method includes, during an autonomous vehicle mode in which a vehicle is operated without a human driver and when the vehicle is not propelled by engine torque, rotating each of an engine and an intake electric supercharger in a reverse direction to draw air into the engine through an exhaust passage and then direct the air to atmosphere through an intake passage; varying an opening of an exhaust regulation valve; and diagnosing a presence or absence of a deterioration of the exhaust regulation valve based on a correlation between the opening of the exhaust regulation valve and an air flow through the intake passage. In any of the foregoing examples, additionally or alternatively, varying the opening of the exhaust regulation valve includes increasing the opening of the exhaust regulation valve from a fully closed position to a fully open position in equal increments over a limited duration. In any or all of the foregoing examples, additionally or alternatively, the diagnosing includes indicating a presence of the deterioration of the exhaust regulation valve in response to the air flow through the intake passage not increasing proportionally to the increase in the opening of the exhaust regulation valve from the fully closed position to the fully open position. In any or all of the foregoing examples, additionally or alternatively, the diagnosing includes indicating an absence of the deterioration of the exhaust regulation valve in response to the air flow through the intake passage increasing proportionally to the increase in the opening of the exhaust regulation valve from the fully closed position to the fully open position. In any or all of the foregoing examples, additionally or alternatively, the engine is coupled to the vehicle, and rotating the engine in the reverse direction includes rotating the engine without fueling via an electric machine when the vehicle is stationary and unoccupied.

[0144] In yet another example, a hybrid vehicle system includes: a vehicle including an engine; a mass air flow (MAF) sensor located in an intake manifold of the engine; an exhaust regulation valve coupled across a muffler in an exhaust passage downstream of a particulate filter; and a controller having computer readable instructions stored on a non-transitory memory for: during a first engine operating condition, adjusting a position of the exhaust regulation valve based on an operator selected noise mode, during a second engine operating condition, adjusting an opening of the exhaust regulation valve from a fully closed position to a fully open position; estimating an intake air flow corresponding to each opening of the exhaust regulation valve via the MAF sensor; and diagnosing the exhaust regulation valve based on a change in intake air flow as the opening of the exhaust regulation valve increases. In any of the foregoing examples, additionally or alternatively, the first engine operating condition includes the engine rotating in a forward direction with fuel injected via a fuel injector and the electric supercharger rotating in the forward direction based on a torque demand, and wherein the second engine operating condition includes the engine counter rotating without fuel via an electric machine and the electric supercharger rotating in a reverse direction during diagnosis of the exhaust regulation valve. In any or all of the foregoing examples, additionally or alternatively, diagnosing the exhaust regulation valve includes indicating no degradation of the exhaust regulation valve in response to the intake air flow increasing proportionally as the opening of the exhaust regulation valve increases from the fully closed position to the fully open position, and indicating degradation of the exhaust regulation valve in response to the intake air flow remaining substantially constant as the opening of the exhaust regulation valve increases from the fully closed position to the open position. In any or all of the foregoing examples, additionally or alternatively, the operator selected noise mode is selected via an input to a human machine interface (HMI) coupled to a dashboard in a passenger cabin, and wherein the controller further includes instructions for: disabling further selection of the noise mode in response to an indication of degradation of the exhaust regulation valve.

[0145] Note that the example control and estimation procedures included herein can be used with various engine and / or vehicle system configurations. The control methods and procedures disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by control systems comprising controllers in combination with various sensors, actuators, and other engine hardware. The specific procedures described herein can represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and so on. As such, various actions, operations, or functions illustrated can be performed in the manner shown, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily restricted to that shown unless specifically stated. One or more actions, operations, or functions can be repeated depending on the particular strategy being used. Further, the described actions, operations, and / or functions can be coded as a set of instructions readable by a computer system functioning to instruct a controller to coordinate the functionality taught by the procedures described herein.

[0146] It should be understood that the arrangements and routines disclosed herein are exemplary in nature, and that these specific embodiments should not be taken as limiting the scope of the disclosure. For example, the above techniques can be applied to V-6, I-4, I-6, V-12, opposed 4 cylinder, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations disclosed herein, as well as other features, functions, and / or properties noted herein.

[0147] The following claims particularly point out certain combinations and subcombinations that are regarded as novel and nonobvious. These claims can refer to "a" or "an" element, or to "first" or "second" elements or the equivalent thereof. Such claims should be understood to include one or more elements having that name, either alone or in multiple arrangements, unless otherwise indicated herein. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties can be claimed through amendment of the following claims or through presentation of additional claims in the application. Such amended or new claims, which are to be accepted as included within the subject matter of the application being resubmitted, are also intended to be covered herein. Such amended or new claims may be

[0148] According to the present disclosure, an example engine method includes changing a position of an exhaust regulation valve during a reverse rotation of an engine while the engine is not fuelled for a start, and diagnosing the exhaust regulation valve based on intake air flow at one or more positions of the exhaust regulation valve.

[0149] According to embodiments, changing the position of the exhaust regulation valve includes fully closing the exhaust regulation valve and then increasing the opening of the exhaust regulation valve from the fully closed position to the fully open position at a constant rate.

[0150] According to embodiments, diagnosing the exhaust regulation valve based on the intake air flow further includes indicating that the exhaust regulation valve is not deteriorated in response to the intake air flow at a plurality of positions of the exhaust regulation valve decreasing from a highest intake air flow at the fully open position to a lowest intake air flow at the fully closed position.

[0151] According to embodiments, diagnosing the exhaust regulation valve based on the intake air flow includes indicating deterioration of the exhaust regulation valve in response to the intake air flow at a plurality of positions of the exhaust regulation valve not changing, the intake air flow at each of the plurality of positions of the exhaust regulation valve being estimated via a mass air flow (MAF) sensor coupled to an engine intake manifold.

[0152] According to embodiments, the deterioration of the exhaust regulation valve includes the exhaust regulation valve being stuck at a position between the fully closed position and the fully open position.

[0153] According to embodiments, the engine is reversed via a motor powered by a battery.

[0154] According to embodiments, the engine is coupled in a vehicle, and the engine is reversed under conditions that the vehicle is unoccupied and the vehicle is not in motion.

[0155] According to embodiments, when the engine is reversed, an intake electric supercharger is operated in a reverse direction to direct ambient air from an engine exhaust passage to the engine intake manifold via one or more engine cylinders.

[0156] According to embodiments, the intake electric supercharger is coupled to a conduit in parallel with an intake passage, the conduit being coupled to the intake passage downstream of an intake compressor and upstream of a charge air cooler, the method further comprising opening an electric supercharger bypass valve coupled to the intake passage downstream of the intake compressor when the intake electric supercharger is operated to direct air through the electric supercharger.

[0157] According to embodiments, the exhaust regulation valve is coupled to a bypass passage in parallel with the exhaust passage, the bypass passage being positioned across a muffler contained in the exhaust passage downstream of a particulate filter.

[0158] According to embodiments, the above invention is further characterized by, in response to detecting deterioration of the exhaust regulation valve, inhibiting an operator from adjusting engine exhaust noise via a human-machine interface coupled to the vehicle.

[0159] According to the invention, an engine method includes: during an autonomous vehicle mode in which a vehicle is operated without a driver and when the vehicle is not propelled by engine torque, rotating each of an engine and an intake electric supercharger in a reverse direction to draw air into the engine through an exhaust passage and then direct the air to atmosphere through an intake passage; changing an opening of an exhaust regulation valve; and diagnosing a presence or absence of deterioration of the exhaust regulation valve based on a correlation between the opening of the exhaust regulation valve and an air flow through the intake passage.

[0160] According to an embodiment, changing the opening of the exhaust regulation valve includes increasing the opening of the exhaust regulation valve from a fully closed position to a fully open position in equal increments over a limited duration.

[0161] According to an embodiment, the diagnosing includes indicating a presence of deterioration of the exhaust regulation valve in response to the air flow through the intake passage not increasing proportionally to the increase of the opening of the exhaust regulation valve from the fully closed position to the fully open position.

[0162] According to an embodiment, the diagnosing includes indicating an absence of deterioration of the exhaust regulation valve in response to the air flow through the intake passage increasing proportionally to the increase of the opening of the exhaust regulation valve from the fully closed position to the fully open position.

[0163] According to an embodiment, the engine is coupled to a vehicle, and rotating the engine in the reverse direction includes rotating the engine without fuel via an electric machine when the vehicle is stationary and unoccupied.

[0164] According to the invention, a hybrid vehicle system is provided having: a vehicle including an engine; a mass air flow (MAF) sensor located in an intake manifold of the engine; an exhaust regulation valve coupled across a muffler in an exhaust passage downstream of a particulate filter; and a controller having computer readable instructions stored on a non-transitory memory for: during a first engine operating condition, adjusting a position of the exhaust regulation valve based on an operator selected noise mode, during a second engine operating condition, adjusting an opening of the exhaust regulation valve from a fully closed position to a fully open position; estimating an intake air flow corresponding to each opening of the exhaust regulation valve via the MAF sensor; and diagnosing the exhaust regulation valve based on a change in the intake air flow as the opening of the exhaust regulation valve increases.

[0165] According to an embodiment, the first engine operating condition includes the engine rotating in a forward direction with fuel injected via a fuel injector, and the electric supercharger rotating in a forward direction based on a torque demand, and wherein the second engine operating condition includes the engine rotating in reverse via an electric machine without fuel, and the electric supercharger rotating in a reverse direction during the diagnosing of the exhaust regulation valve.

[0166] According to embodiments, diagnosing the exhaust regulation valve includes indicating that the exhaust regulation valve is not deteriorated in response to the intake air flow increasing in proportion to an increase in an opening of the exhaust regulation valve from the fully closed position to the fully open position, and indicating deterioration of the exhaust regulation valve in response to the intake air flow remaining substantially constant with an increase in the opening of the exhaust regulation valve from the fully closed position to the open position.

[0167] According to embodiments, the operator-selected noise mode is selected via input to a human-machine interface (HMI) coupled to an instrument panel in the vehicle cabin, and wherein the controller further includes instructions to prohibit further selection of the noise mode in response to an indication of deterioration of the exhaust regulation valve.

Claims

1. An engine method comprising: during reverse rotation of the engine by a motor while the engine is not fuelled for cranking, varying a position of an exhaust regulation valve, and diagnosing the exhaust regulation valve based on intake air flow at one or more positions of the exhaust regulation valve, wherein the exhaust regulation valve is coupled across a muffler positioned in an exhaust passage downstream of a particulate filter to control back pressure in the system and / or exhaust flow through the muffler, and wherein the intake air flow is estimated by a mass air flow sensor positioned in an intake manifold of the engine.

2. The method of claim 1, wherein varying the position of the exhaust regulation valve comprises fully closing the exhaust regulation valve and then increasing an opening of the exhaust regulation valve from a fully closed position to a fully open position at a constant rate.

3. The method of claim 2, wherein diagnosing the exhaust regulation valve based on the intake air flow further comprises indicating that the exhaust regulation valve is not deteriorated in response to the intake air flow at multiple positions of the exhaust regulation valve decreasing from a highest intake air flow at the fully open position to a lowest intake air flow at the fully closed position.

4. The method of claim 1, wherein diagnosing the exhaust regulation valve based on the intake air flow comprises indicating deterioration of the exhaust regulation valve in response to the intake air flow at multiple positions of the exhaust regulation valve not changing, the intake air flow at each of the multiple positions of the exhaust regulation valve being estimated via a mass air flow sensor coupled to an engine intake manifold.

5. The method of claim 4, wherein the deterioration of the exhaust regulation valve comprises the exhaust regulation valve sticking at a position between a fully closed position and a fully open position.

6. The method of claim 1, wherein the engine is reverse rotated via a motor powered by a battery.

7. The method of claim 1, wherein the engine is coupled in a vehicle, and the engine is reverse rotated under conditions that the vehicle is unoccupied and the vehicle is not moving.

8. The method of claim 1, further comprising operating an intake electric supercharger in a reverse direction to direct ambient air from an engine exhaust passage to the engine intake manifold via one or more engine cylinders when the engine is reverse rotated.

9. The method of claim 8, wherein the intake electric supercharger is coupled to a conduit in parallel with an intake passage, the conduit being coupled to the intake passage downstream of an intake compressor and upstream of a charge air cooler, the method further comprising closing an electric supercharger bypass valve coupled to the intake passage downstream of the intake compressor when the intake electric supercharger is operated to direct air through the intake electric supercharger.

10. The method of claim 9, wherein the exhaust regulation valve is coupled to a bypass passage in parallel with the exhaust passage, the bypass passage being positioned across a muffler housed in the exhaust passage downstream of a particulate filter.

11. The method of claim 4, further comprising, in response to detecting degradation of the exhaust regulation valve, inhibiting an operator from adjusting engine exhaust noise via a human-machine interface coupled to the vehicle.

12. A hybrid vehicle system, comprising: a vehicle including an engine; a mass air flow sensor positioned in an intake manifold of the engine; an exhaust regulation valve coupled across a muffler positioned in an exhaust passage downstream of a particulate filter; and a controller having computer readable instructions stored on a non-transitory memory for: during a first engine operating condition, adjusting a position of the exhaust regulation valve based on an operator selected noise mode; during a second engine operating condition, adjusting an opening of the exhaust regulation valve from a fully closed position to a fully open position; estimating an intake air flow corresponding to each opening of the exhaust regulation valve via the mass air flow sensor; and diagnosing the exhaust regulation valve based on a change in the intake air flow as the opening of the exhaust regulation valve increases.

13. The system of claim 12, wherein the engine includes an electric supercharger, the first engine operating condition includes the engine rotating in a forward direction with fuel injected via a fuel injector and the electric supercharger rotating in a forward direction based on a torque demand, and wherein the second engine operating condition includes the engine rotating in a reverse direction without fuel via an electric machine and the electric supercharger rotating in a reverse direction during the diagnosis of the exhaust regulation valve.

14. The system of claim 12, wherein diagnosing the exhaust regulation valve includes indicating the exhaust regulation valve is not degraded in response to the intake air flow increasing proportionally as the opening of the exhaust regulation valve increases from the fully closed position to the fully open position and indicating degradation of the exhaust regulation valve in response to the intake air flow remaining substantially constant as the opening of the exhaust regulation valve increases from the fully closed position to the fully open position.

15. The system of claim 14, wherein the operator selected noise mode is selected via an input to a human-machine interface coupled to a dashboard in a passenger compartment, and wherein the controller further includes instructions for inhibiting further selection of the noise mode in response to the indication of degradation of the exhaust regulation valve. ​

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