Performing a diagnosis on an air filter with an electric charging device

Abstract

Methods for an engine, including: Opening a high-pressure exhaust gas recirculation (HP-EGR) valve while the engine is off; Guiding air through an air filter by operating an electric motor coupled to a compressor; Measuring air pressure; and Displays the status of the air filter based on air pressure.

Description

AREA

[0001] The present description generally relates to methods and systems for performing a diagnosis on an intake air filter in a vehicle system by operating an electrical charging device while the engine is off. GENERAL STATE OF THE ART / BRIEF OVERVIEW

[0002] Air filters are used in vehicles to provide clean air for intake into the engine system. An air filter can become clogged due to a buildup of dirt and debris. A clogged air filter can increase the pressure drop of the intake air and restrict airflow to the engine. This restricted airflow can affect the engine's performance and efficiency. To replace or clean a clogged air filter, its status can be regularly monitored and displayed to the driver.

[0003] Attempts to diagnose air filter status include diagnosing the air filter based on a pressure drop across the filter. An exemplary approach is described by Pago et al. in US Patent US 5,606,311 A. In this method, a pressure drop across the air filter and the corresponding airflow are measured during engine operation, and filter restriction is then estimated by comparing the measured pressure drop with a reference pressure drop. Further prior art is known from US Patents US 8,573,040 B2 and US 2011 / 0308308 A1.

[0004] However, the inventors of the present invention have recognized potential problems with such an approach. For example, air filter diagnostics based on a pressure drop during engine operation may be inaccurate due to a low signal-to-noise ratio. In particular, the signal amplitude of the pressure drop may be small, as the pressure drop may not be significant relative to the sensor sensitivity, even with a clogged filter, depending on the vehicle's operating conditions. Furthermore, high noise levels can be generated by the alternating movements during engine operation. Consequently, Pago's method may produce false positives, indicating to the driver that the air filter needs to be changed before this is actually necessary. Moreover, engine running time may be limited in hybrid vehicles.Diagnosing the air filter status while the engine is running is often insufficient to detect a blockage. Furthermore, the duration of stable engine operation in a hybrid vehicle may not be long enough to obtain reliable pressure measurements.

[0005] The object of the present invention is therefore to solve these problems, at least in part.

[0006] This problem is solved by the features of the independent patent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0007] In one example, the problems described above can be solved by a procedure comprising: opening a high-pressure exhaust gas recirculation (HPEGR) valve while the engine is off; passing air through an air filter by actuating an electric motor coupled to a compressor; measuring air pressure; and displaying the status of the air filter based on the air pressure. In this way, a clogged air filter can be detected in a timely and reliable manner.

[0008] As an example, in an engine system equipped with an electric charging device, an electric motor coupled to the charging device can be operated while the engine is off, drawing ambient air into the engine system through the intake air filter. One or more valves, such as a high-pressure EGR valve, can be opened to direct the air further from the air filter, bypassing the cylinder, to an exhaust port. The air filter status can be diagnosed based on a pressure measurement related to the airflow through the air filter. For example, the pressure could be a pressure drop across the air filter. Another example would be the pressure downstream of the air filter in the direction of airflow. By directing the air from the filter to the exhaust port, bypassing the cylinder, the air can flow through the engine system with minimal resistance.Therefore, pressure measurement can accurately reflect flow restrictions caused by air filter clogging. Potential interference from other vehicle system components during measurement can be avoided. Furthermore, the time required for air filter diagnostics can be reduced because the airflow can be fully controlled and quickly stabilized by operating the electric charging device. By performing diagnostics on the air filter with the engine off, the air filter status can be checked frequently during automatic engine start-stop cycles, thus avoiding noise from the alternating movements during engine operation. Moreover, by using the electric motor coupled to the electric charging device for air filter diagnostics, the diagnostics can be performed with existing engine components.

[0009] As another example, during a first state, a first air pressure can be measured while air is directed from the atmosphere to the compressor through the air filter. Subsequently, a second air pressure can be measured while the air is directed from the compressor to the atmosphere through the air filter in a second direction, opposite to the first. A diagnosis of the air filter can be performed based on the first and second air pressures. By directing the air in the reverse direction, a diagnosis of the air filter can be performed when the high-pressure EGR valve is not present in the engine system. In one embodiment, the first state can occur while the engine is running, and the second state can occur while the engine is off.The electric motor can be operated in such a way that it directs air through the air filter in a second direction while the engine is off, in response to the initial air pressure measurement taken while the engine is running. For example, the initial air pressure reading might indicate a possible air filter blockage, and further diagnostic testing while the engine is off can improve diagnostic accuracy.

[0010] It is understood that the foregoing summary is provided to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to identify important or essential features of the claimed subject matter, the scope of which is defined solely by the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that eliminate the disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows an embodiment of a vehicle system that includes an electric charging device. Fig. Figure 2 shows an embodiment of a cylinder of an engine made of Fig. 1. Fig. Figure 3 shows another embodiment of a vehicle system that includes an electric charging device. Fig. Figure 4 shows an exemplary procedure for performing a diagnosis on an intake air filter. Fig. Figure 5 shows the status of motor actuators and operating parameters over time when implementing the procedure. Fig. 4. Fig. Figure 6 shows another exemplary procedure for performing a diagnosis on an intake air filter. Fig. Figure 7 shows the status of motor actuators and operating parameters over time during an implementation of the procedure. Fig. 6. DETAILED DESCRIPTION

[0011] The following description concerns systems and methods for diagnosing the status of an intake air filter in a vehicle system equipped with an electric charging device, such as a compressor. The electric charging device may be an electrically charged turbocharger, as is the case, for example, in one embodiment of the vehicle system described in Fig. Figure 1 shows the electric charging device. Alternatively, the electric charging device can be an electric compressor, as is used, for example, in another exemplary vehicle system in Figure 1. Fig. 3 is shown. Fig. Figure 2 shows exemplary components of an engine made of Fig. 1. A diagnosis of the air filter can be performed based on air pressure measurements while the engine is off, and an electric motor coupled to the electric charging device is operated to force air through the air filter. An exemplary procedure for filter diagnosis is described in Fig. Figure 4 shows the ambient air flowing through the air filter into the engine system while the engine is off. Another exemplary method for filter diagnostics is shown in Fig. Figure 6 shows the air flowing in opposite directions through the air filter when the engine is off. Fig. 5 and Fig. Figure 7 illustrates the variation of actuator status and operating parameters when implementing the procedures from Fig. 4 or Fig. 6.

[0012] Now, with reference to Fig. Figure 1 schematically illustrates an embodiment of a vehicle system 100. In one example, the vehicle system 100 may be designed as a motor vehicle for road traffic. However, it is understood that in other examples the vehicle system 100 may be designed as an off-road vehicle. In some examples, the vehicle system 100 may be a hybrid vehicle with multiple torque sources available to one or more vehicle wheels 76. In other examples, the vehicle system 100 is a conventional vehicle with only one engine. In the illustrated example, the vehicle system 100 includes an engine 10 and an electric machine 72. The electric machine 72 may be an electric motor or a motor-generator. A crankshaft 40 of the engine 10 and the electric machine 72 are connected to the vehicle wheels 76 via a transmission 74 when one or more clutches 73 are engaged.In the illustrated example, a first clutch 73 is provided between the crankshaft 40 and the electric machine 72, and a second clutch 73 is provided between the electric machine 72 and the transmission 74. The control unit 12 discussed here can send a signal to an actuator of each clutch 73 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 40 from the electric machine 72 and its associated components, and / or connecting or disconnecting the electric machine 72 from the transmission 74 and its associated components. The transmission 74 can be a manual transmission, a planetary gear system, or another type of transmission. The powertrain can be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle.

[0013] The electric machine 72 receives electrical power from a traction battery 75 to provide torque to the vehicle wheels 76. The electric machine 72 can also be operated as a generator to provide electrical power for charging the battery 75, for example, during braking. In other examples, where the vehicle system 100 is a conventional vehicle with only one engine, the traction battery 75 can be a starter, light, and ignition battery (e.g., SLI) that supplies electrical energy to the vehicle system 100.

[0014] The engine 10 can be a turbocharged engine that includes a turbocharger 13. The turbocharger 13 comprises a turbine 116, which is positioned in the exhaust port 35, and is coupled to a compressor 110, which is positioned in an intake port 42. According to the illustration, the compressor 110 is coupled to the turbine 116 via a shaft 119. The turbine 116 is driven by expanding engine exhaust gas. In the illustrated example, the turbocharger 13 is an electric turbocharger that includes an electric motor 111, which provides electrical assistance to the turbocharger's performance. A battery 158 is coupled to the electric motor 111 to provide power. In one example, the electric motor 111 can be coupled to the compressor via a shaft 119. In other examples, however, the electric motor can be coupled directly to the compressor or the turbine.By adjusting the power output of the electric motor 111, the amount of compressed air supplied by the compressor can be set. In one example, the compressor and turbine can be coupled within a twin-scroll turbocharger. In another example, the turbocharger can be a variable geometry turbocharger (VGT), where the turbine geometry is actively varied depending on the motor speed and other operating conditions. In yet another example, the geometry of the compressor 110 can be set by operating a compressor actuator 118. For example, the compressor 110 is a variable geometry compressor (VGC) that has blades which are moved according to a desired blade angle to direct an intake airflow into the compressor in various patterns.

[0015] During engine operation (engine speed greater than zero), the engine 10 receives ambient air along the intake duct 42 via an air filter 112, as indicated by arrow 130. The air is compressed by the compressor 110 of the turbocharger 13 and fed into the intake duct 43. The compressed air flows through the intake duct 43, through the charge air cooler (CAC) 18 for cooling, and through the throttle 20 before entering the intake manifold 22, where it enters the engine 10. In other words, the compressor 110 is coupled to the intake throttle 20 via the CAC 18, and the intake throttle 20 is coupled downstream of the intake manifold 22. The charge air cooler can be, for example, an air-to-air or water-to-air heat exchanger. In the Fig. In the embodiment shown in Figure 1, the pressure of the air charge in the intake manifold is measured by a manifold air pressure (MAP) sensor 124.

[0016] It is understood that other combinations and configurations of charging devices are possible. In one embodiment, the motor system 100 can include a compressor, wherein the compressor 110 can be driven at least partially by an electric machine and / or the motor 10, and the motor system may not include a turbine 116. In still other examples, several charging devices can be arranged in series, as in Fig. Figure 3 shows that both a compressor and a turbocharger are coupled to the intake port.

[0017] The compressor 110 can include a recirculation channel 80. The illustrated example shows a compressor recirculation valve (CRV) 82 coupled to the recirculation channel 80, whereby actuation of the CRV 82 adjusts the flow through the recirculation channel 80. Warm, compressed air from the compressor outlet can be returned to the compressor inlet via the recirculation channel 80. In some embodiments, the compressor recirculation system can alternatively or additionally include a recirculation channel for returning (cooled) compressed air from the compressor outlet, downstream to the charge air cooler, to the compressor inlet, or a compressor bypass for discharging compressed air to the atmosphere (not shown).The CRV 82 can be a continuously adjustable valve, with a position of the valve continuously adjustable from a fully closed position to a fully open position. In some embodiments, the compressor return valve 82 can be held partially open during operation of the supercharged engine to provide a pumping threshold. In this case, the partially open position can be a standard valve position. Increasing the opening of the compressor return valve can involve actuating (or applying a voltage to) a solenoid coil of the valve. Further discussion of exemplary CRV operation follows.

[0018] One or more sensors can be coupled to an inlet of the compressor 110 to determine the composition and condition of the air charge entering the compressor. For example, a pressure sensor 55 can be coupled between the air filter 112 and the compressor inlet to estimate the pressure of the air charge entering the compressor. In another example, a mass airflow (MAF) sensor 57 can also be coupled to the compressor inlet to estimate the amount of air entering the engine. Other sensors may include, for example, air-fuel ratio sensors, humidity sensors, etc. In other examples, one or more of the compressor inlet conditions (such as humidity, temperature, etc.) can be derived based on engine operating conditions.The sensors can estimate the condition of the intake air received at the compressor inlet from the intake duct, as well as the air charge returned from upstream to the CAC. A throttle inlet pressure (TIP) sensor 58, or another suitable sensor, can be coupled upstream of compressor 110 and downstream of throttle 20 to measure the boost pressure at a point downstream of compressor 110 and upstream of throttle 20. In this way, a compressor outlet pressure can be determined. A compressor pressure ratio can be calculated by dividing the compressor outlet pressure by the compressor inlet pressure (such as the pressure measured by sensor 55).

[0019] The intake manifold 22 is divided by a series of intake valves (hereinafter referred to as Fig. 2 described in more detail) are connected to a series of combustion chambers 30. The combustion chambers are further connected via a series of exhaust valves (hereinafter referred to in relation to Fig. 2 (described in more detail) is coupled to the exhaust manifold 36. In the illustrated embodiment, a single exhaust manifold 36 is shown. In other embodiments, however, the exhaust manifold 36 can comprise a plurality of exhaust manifold sections. Designs featuring a plurality of exhaust manifold sections can allow exhaust gas from different combustion chambers to be routed to different locations in the engine system 10. The sensor 125 can be coupled to the exhaust manifold to measure the exhaust pressure.

[0020] The combustion chambers 30 can be supplied by a fuel system with one or more fuels, such as gasoline, alcohol-fuel mixtures, diesel, biodiesel, compressed natural gas, etc. Fuel can be supplied to the combustion chambers by direct injection, port injection, throttle body injection, or any combination thereof. Direct injection involves injecting the fuel directly into the combustion chamber, while port injection directs the fuel mist to the intake ports, where it mixes with the intake air before entering the combustion chamber. The present example can include a variety of direct fuel injection devices 66 and port fuel injection devices 67. Combustion can be initiated in the combustion chambers by spark ignition and / or compression ignition.

[0021] As in Fig. As shown in Figure 1, exhaust gas is directed from one or more sections of the exhaust manifold 36 to the turbine 116 to drive the turbine. If a reduced turbine torque is desired, a portion of the exhaust gas can instead be directed through a wastegate 90, thus bypassing the turbine 116. A wastegate valve 92 coupled to the wastegate 90 can be actuated to open, allowing at least a portion of the exhaust pressure from upstream of the turbine 116 to be released via the wastegate 90 to a point downstream of the turbine. By reducing the exhaust pressure upstream of the turbine 116, the turbine speed can be reduced. In one embodiment, the wastegate valve 92 can be vacuum-actuated, that is, it can be actuated by applying a vacuum. The combined flow from the turbine 116 and the wastegate 90 then flows through an emission control device 70 (hereinafter referred to in Figure 1). Fig. 2 described in more detail), before all or part of the treated exhaust gas can be released to the atmosphere via the exhaust duct 35, as indicated by arrow 133.

[0022] The engine 10 can further include one or more exhaust gas recirculation (EGR) channels for recirculating a portion of the exhaust gas from the exhaust manifold to the intake manifold. By recirculating a portion of the exhaust gas, dilution can be achieved in the engine, which can improve engine performance by reducing engine knock, peak combustion temperatures and pressures of cylinders, throttling losses, and NOx emissions. In the illustrated example, exhaust gas can be recirculated from the exhaust manifold 36 upstream of the turbine 116 via a high-pressure EGR channel 84 to the intake manifold 22, downstream to the compressor 110, and the throttle 20. This configuration can be referred to as a high-pressure (HP) EGR system. The EGR channel 84 can include an HP EGR valve 86 for controlling an HP EGR flow and an EGR cooler for cooling the exhaust gas before it is fed to the intake manifold.In further examples, exhaust gas from the exhaust channel 35 upstream of the turbine 116 can be recirculated via a low-pressure EGR channel (not shown) to the intake channel 42 upstream of the compressor 110. The amount of EGR supplied to the intake channel can be varied by the control unit 12 via the high-pressure EGR valve 86.

[0023] The engine system 100 can further include a control system 14, which includes the control unit 12. According to the illustration, the control unit 12 receives information from a variety of sensors 16 (various examples of which are described here) and sends control signals to a variety of actuators 81 (various examples of which are described here). For example, the sensors 16 can include a MAP sensor 124, exhaust pressure sensor 125, exhaust temperature sensor 128, exhaust pressure sensor 129, compressor inlet pressure sensor 55, manifold airflow sensor 57, and throttle inlet pressure sensor 58. Other sensors, such as additional pressure, temperature, air-fuel ratio, and composition sensors, can be coupled at various points in the engine system 10. The actuators 81 can, for example,include the electric motor 111, the throttle 20, the compressor recirculation valve 82, the wastegate valve 92, the high-pressure EGR valve 86, the direct fuel injection device 66 and the intake manifold fuel injection device 67.

[0024] Now, with reference to Fig. 2 an embodiment of a combustion chamber (e.g. of a cylinder) of an internal combustion engine (such as engine 10 from Fig. 1) shown. Already in Fig. The components presented can be numbered similarly. The motor 10 can receive control parameters from a control system, which includes the controller 12, and input from a vehicle operator 230 via an input device 232. In this example, the input device 232 includes an accelerator pedal and a pedal position sensor 234 for generating a proportional pedal position signal PP. The cylinder (here also referred to as the "combustion chamber") 30 of the motor 10 can have combustion chamber walls 236 in which a piston 238 is positioned. The piston 238 can be coupled to the crankshaft 40, so that a reciprocating motion of the piston is translated into a rotary motion of the crankshaft. The crankshaft 40 can be coupled to at least one drive wheel of the vehicle system via a transmission system.

[0025] Cylinder 30 can draw in intake air via an intake port 42, an intake port 43, and an intake manifold 22. The intake manifold 22 can be connected to other cylinders of engine 10 in addition to cylinder 30. In some embodiments, one or more of the intake ports can include a charging device such as a turbocharger or a supercharger. For example, engine 10 is in Fig. 2 is designed with a turbocharger 13 comprising a compressor 110 arranged between the inlet port 42 and the intake port 43, and an exhaust turbine 116 arranged between an exhaust manifold 36 and an exhaust port 35. The compressor 110 can be driven, at least partially, by the exhaust turbine 116 via a shaft 119 when the charging device is designed as a turbocharger. The compressor can also be driven by the electric motor 111. As described above, in examples where the engine 10 is equipped with a compressor, the exhaust turbine 116 can optionally be omitted, in which case the compressor 110 can be driven by a mechanical input from an electric motor or the engine 10. The throttle 20 can include a throttle valve 264 and can be provided along an inlet port of the engine to vary the flow rate and / or pressure of the intake air supplied to the engine cylinders.For example, the throttle 20 can be arranged downstream of the compressor 110.

[0026] The exhaust manifold 36 can receive exhaust gases from other cylinders of the engine 10 in addition to those from cylinder 30. An exhaust gas sensor 228 is shown to be coupled to the exhaust manifold 36 upstream of the emission control device 70; however, it is understood that it can be located elsewhere in the exhaust system. The exhaust gas sensor 228 can be selected from various suitable sensors for providing an indication of the air / fuel ratio of the exhaust gas, such as a linear lambda sensor or UEGO sensor (Universal or Wide-Range Exhaust Gas Oxygen Sensor), a binary lambda sensor or EGO sensor (as shown), a HEGO sensor (heated EGO sensor), a NOx, HC, or CO sensor. The emission control device 70 can be a three-way catalytic converter (TWC), a NOx trap, various other emission control devices, or combinations thereof.

[0027] Each cylinder of the engine 10 can have one or more intake valves and one or more exhaust valves. For example, cylinder 30, as shown, includes at least one disc-shaped intake valve 250 and at least one disc-shaped exhaust valve 256, which are arranged in an upper region of cylinder 30. In some embodiments, each cylinder of the engine 10 containing cylinder 30 can include at least two intake control valves and at least two exhaust control valves, which are arranged in an upper region of the cylinder.

[0028] The intake valve 250 can be controlled by the controller 12 via cam actuation through a cam actuation system 251. Likewise, the exhaust valve 256 can be controlled by the controller 12 via the cam actuation system 253. The cam actuation systems 251 and 253 can each include one or more cams and utilize one or more of the following systems: cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL), which can be operated by the controller 12 to vary the valve operation. Regardless of whether the actuation is electronic or cam-based, the control for opening and closing the exhaust and intake valves can be set as specified for the desired combustion and emissions control performance.The operation of the intake valve 250 and exhaust valve 256 can be determined by valve position sensors (not shown) and / or camshaft position sensors 255 and 257, respectively. In alternative embodiments, the intake and / or exhaust valve can be controlled by an electric valve actuator. For example, cylinder 30 can alternatively include an intake valve controlled by an electric valve actuator and an exhaust valve controlled by cam actuators, including CPS and / or VCT systems. Furthermore, a VCT system can include one or more VCT devices (not shown) that can be actuated to adjust the actuation of the intake and exhaust valves to provide reduced positive overlap between the intake and exhaust valves.This means that the intake and exhaust valves open for a shorter period, moving away from opening simultaneously for a portion of the intake stroke. In other embodiments, the intake and exhaust valves can be controlled by a common valve actuator or actuator system, or by a variable valve actuation actuator or system.

[0029] In some embodiments, each cylinder of the engine 10 can include a spark plug 292 to initiate combustion. The ignition system 290 can provide a spark to the cylinder 30 via the spark plug 292 in response to a pre-ignition signal SA from the control unit 12 during selected operating modes. In other embodiments, compression-ignition engines can use a glow plug instead of the spark plug 292.

[0030] In some embodiments, each cylinder of the engine 10 can be equipped with one or more fuel injection devices for supplying fuel to the cylinder 30. As a non-limiting example, the cylinder 30 shown includes two fuel injection devices 66 and 67. The fuel injection devices 66 and 67 can be configured to supply fuel received from a fuel system (not shown) via a high-pressure fuel pump and a fuel distributor. Alternatively, the fuel can be supplied at a lower pressure by a single-stage fuel pump, in which case the control of the direct fuel injection during the compression stroke may be more limited than when using a high-pressure fuel system. Furthermore, the fuel tank can include a pressure converter that provides a signal to the control unit 12.

[0031] According to the illustration, the fuel injection device 66 is directly coupled to the cylinder 30 in order to inject fuel directly into it in proportion to the pulse width of the signal FPW-1, which is received by the control unit 12 via an electronic driver. Thus, the fuel injection device 66 provides a so-called direct injection (hereinafter referred to as "DI") of fuel into the combustion cylinder 30. While the injection device 66 according to Fig. The injector 2 is positioned on one side of cylinder 30, or alternatively, it can be located above the piston, such as near the position of spark plug 292. Such a position can improve mixing and combustion when the engine is operated with an alcohol-based fuel, as some alcohol-based fuels have lower volatility. Alternatively, the injector can be located above and near the intake valve to improve mixing.

[0032] According to the illustration, the fuel injection device 67 is arranged in the intake port 22 and not in the cylinder 30 in a configuration known as port fuel injection (hereinafter referred to as "PFI") into the intake port upstream of the cylinder 30. The fuel injection device 67 can inject fuel received from the fuel system 288 proportionally to the pulse width of the signal FPW-2, which is received by the controller 12 via an electronic driver.

[0033] Fuel can be supplied to the cylinder by either injection device during a single cylinder cycle. For example, each injection device can provide a portion of the total fuel injection that will be burned in cylinder 30. Thus, even in the case of a single combustion event, injected fuel can be delivered by the port and direct injection devices at different times. Furthermore, multiple injections of the delivered fuel can be performed per cycle during a single combustion event. These multiple injections can occur during the compression stroke, intake stroke, or any suitable combination thereof.

[0034] As described above, shows Fig. 2 merely one cylinder of a multi-cylinder engine. Thus, each cylinder can likewise have its own set of intake / exhaust valves, fuel injection device(s), spark plug, etc. It is understood that the engine 10 can include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12 or more cylinders. Furthermore, each of these cylinders can contain some or all of the various components that are in Fig. 2 are described and illustrated with reference to cylinder 30.

[0035] The engine may further include one or more exhaust gas recirculation channels for returning a portion of the exhaust gas from the engine outlet to the engine intake. In the illustrated embodiment, exhaust gas can be recirculated from the exhaust manifold 36 to the intake manifold 22 via a high-pressure EGR channel 84. Furthermore, an EGR sensor 88 may be arranged within the high-pressure EGR channel 84 and provide information on one or more aspects of the exhaust gas pressure, temperature, and concentration. Other non-restrictive exemplary EGR configurations may include low-pressure EGR.

[0036] According to the diagram, the exhaust gas sensor 226 is coupled to the exhaust gas channel 35 downstream of the turbine 116. The sensor 226 can be any suitable sensor for providing an indication of the air-fuel ratio of the exhaust gas, such as a linear lambda sensor or UEGO (wideband or wide-range lambda sensor), a binary lambda sensor or EGO, a HEGO (heated EGO), or a NO sensor. x-, HC or CO sensor.

[0037] The emission control device 70 can be arranged downstream of the exhaust gas sensor 226 and the turbine along the exhaust gas duct 35. In the illustrated example, the emission control device can include devices 271 and 272, where device 271 can be a gas particulate filter and device 272 can be a three-way catalytic converter.

[0038] The controller 12 is represented as a microcomputer, which includes a microprocessor unit 206, input / output ports 208, an electronic storage medium for executable programs and calibration values, which in this specific example is represented as a read-only memory chip 210, a direct access memory 212, a keep-alive memory 214 and a data bus.In addition to the signals discussed previously, the control unit 12 can receive various signals from sensors coupled to the engine 10, including an engine coolant temperature (ECT) measurement from temperature sensor 216, which is coupled to the cooling sleeve 218; a profile ignition pickup (PIP) signal from a Hall-effect sensor 220 (or other type), which is coupled to the crankshaft 40; the throttle position (TPS) from a throttle position sensor; and a manifold absolute pressure (MAP) signal from sensor 124. An engine speed (RPM) signal can be generated by the control unit 12 from the PIP signal. The manifold pressure (MAP) signal from a manifold pressure sensor can be used to provide an indication of vacuum or pressure in the intake manifold.Other sensors may include fuel level sensors and fuel composition sensors that are coupled to the fuel tank(s) of the fuel system.

[0039] A read-only memory chip 210 can be programmed as a storage medium and can contain computer-readable data representing instructions which can be executed by a microprocessor unit 206 to carry out the procedures described below, as well as other variants which are anticipated but not listed in detail.

[0040] The controller 12 can control the actuators in response to the processed input data received from the various sensors, based on instructions stored in the controller's memory or code programmed therein, according to one or more routines, such as the exemplary procedure 400 from Fig. 4 and the procedure 600 from Fig. 6. As an example, the controller 12 can determine the engine speed based on outputs from a Hall effect sensor 220. In response to an engine speed of zero, the controller 12 can actuate the electric motor 111, the high-pressure EGR valve 86, and the wastegate valve 92 so that ambient air flows through the air filter to the exhaust duct 35.

[0041] Fig. Figure 3 shows another embodiment of a vehicle system 300. Already in vehicle system 100 of Fig. The components presented may be numbered similarly. Like vehicle system 100, vehicle system 300 includes a motor 10 and a high-pressure EGR channel 84 coupled to the motor 10. Vehicle system 300 includes a turbocharger 313. The turbocharger 313 includes a compressor 310, which is driven by a turbine 316 via a shaft 319. A CRV valve 382 and a wastegate valve 392 are coupled to a compressor recirculation channel 380 and a wastegate 390, respectively.

[0042] The vehicle system 300 can further include a compressor 113 for further charging the intake air. According to the present illustration, the compressor 113 is coupled to the inlet channel 42 between the air filter 112 and the compressor 310. In another embodiment, the compressor 113 can be coupled between the compressor 310 and a cylinder. The compressor 113 can be an electric compressor driven by an electric motor 114 by signals from the control unit 12. A battery 159 can be coupled to the electric motor 114 to supply electrical power to the electric motor 114. The compressor 113 can include a bypass channel 85 for directing air between the air filter 112 and the compressor 310 without it flowing through the compressor. An airflow through the compressor bypass channel 85 can be regulated by a compressor bypass valve 83.Sensors 355 and 357 can be coupled to the intake channel 42 between the air filter and the compressor to measure air pressure and airflow rate, respectively.

[0043] In relation to Fig. 4. Procedure 400 presents an exemplary procedure for diagnosing the air filter status using an electrical charging device while the engine is off. In one example, the electrical charging device could be an electrically assisted turbocharger, as shown in Fig. 1 shown. In another example, the electric charging device could be an electric compressor coupled to a turbocharger, as in Fig. 3 shown.

[0044] Instructions for executing procedure 400 and the other procedures contained herein may be issued by a controller based on instructions stored in a memory of the controller and in conjunction with signals from sensors of the engine system, such as those mentioned above in relation to Fig. The sensors described in points 1-3 receive data and execute commands. The controller can use motor actuators of the motor system to adjust motor operation according to the procedures described below.

[0045] At 402, the procedure estimates and / or measures 400 engine operating conditions, including but not limited to engine speed, fuel quantity, fuel pressure, driver torque demand, engine coolant temperature (ECT), ambient air pressure (barometric pressure - BP), boost pressure, intake manifold pressure (boost pressure), exhaust manifold pressure, mass airflow rate (MAF), exhaust flow rate, accelerator pedal position (PP), EGR flow, and EGR rates, based on the output of appropriate values ​​related to the Fig. The sensors described in 1-3 can be measured and / or estimated.

[0046] At 404, air from the atmosphere flows to the engine through the air filter in a first direction during engine operation (as indicated by arrow 130 in Fig. 1 and Fig. 3 shown). The air can flow due to the vacuum created by operating the engine. The air can also be made to flow by the air charging device, such as a compressor. Step 404 can further include measuring a first air pressure related to the air flowing through the air filter. In one embodiment, the air pressure can be measured by a pressure sensor coupled downstream of the air filter (such as the pressure sensor 55 from Fig. 1 and the pressure sensor 355 from Fig. 3).

[0047] In another embodiment, the air pressure can be a pressure difference or a pressure drop across the air filter. In one example, the pressure drop can be measured by a sensor. In another example, the pressure drop can be calculated from the absolute value of the difference between the pressure downstream of the air filter and atmospheric pressure.

[0048] At procedure 408, the control unit checks whether the engine is switched off. For example, the engine's off state can be determined when the engine speed is zero with no piston movement. Another example is when no air enters the cylinder. Yet another example is when the engine's intake valves remain closed. If the engine is switched off, procedure 400 proceeds to 410. Otherwise, procedure 400 continues to monitor the engine operating conditions at procedure 406.

[0049] At 410, the controller determines whether the air filter status should be diagnosed. In one embodiment, the controller can determine whether the air filter status should be diagnosed in response to the air pressure measurement taken during engine operation at 404. For example, the controller can determine whether to perform further diagnostics on the air filter when the pressure drop across the air filter exceeds a threshold pressure during engine operation if the engine is off. The threshold pressure can be specified by operating or modeling a model engine system.

[0050] In another embodiment, the air filter status can be diagnosed after a predetermined time period since the last diagnosis or filter change. Alternatively, the air filter status can be diagnosed at predetermined intervals after a filter change. For example, the time period or predetermined intervals can be set based on engine operating conditions, such as weather and / or road conditions. For instance, an air filter diagnosis can be performed more frequently in response to extended engine operation in rural areas.

[0051] If the control unit determines that a diagnostic check of the air filter is required, procedure 400 transitions to 411. Otherwise, procedure 400 continues to monitor engine operating conditions at 406.

[0052] In figure 411, the control unit actuates the electric motor, which is coupled to the electric charging device, to direct air through the air filter. In one embodiment, the engine system includes a high-pressure exhaust gas recirculation (HPGR) system. The electric motor can be actuated to direct air in the first direction, from the atmosphere to the engine cylinder through the air filter, as indicated by arrow 130 in figure 411. Fig. 1 and Fig. Figure 3 shows the high-pressure EGR valve opening to allow airflow from the air filter to the exhaust manifold, bypassing the engine cylinder. One or more other valves, such as the wastegate valve (92 from Fig. 1 and Fig. 392 out Fig. 3) and the CRV valve (382 from Fig. 3) can be opened to allow airflow from the air filter to the exhaust duct, bypassing the turbine and / or compressor, in order to reduce airflow restriction. Furthermore, the compressor bypass valve (such as valve 83 from Fig. 3) be closed. In another example, the geometry of the compressor 310 can be adjusted to allow an airflow through the compressor with minimal flow restriction. In another embodiment, the electric motor can be operated in a motor system without high-pressure EGR, so that it draws air through the air filter in the reverse direction from the compressor to the atmosphere (as indicated by arrow 131 in Fig. 1 and Fig. 3 shown), which is directed in the opposite direction to the airflow during engine operation.

[0053] The speed of the electric motor can be set based on operating conditions, such as ambient pressure and temperature, to achieve increased reproducibility when averaging pressure over multiple motor-off events, thus improving the determination of the filter charge status. For example, the electric motor can be set to a desired speed, with the speed determined for each motor-off state based on ambient pressure and temperature, and potentially also on the temperature under the hood when air is drawn from under the hood to the intake (since the mass flow, and therefore the resistance, can be affected by air density). Furthermore, the speed can be determined based on the flow path of the gases in the motor system, e.g.,...based on the position of an EGR valve, and taking into account the fluctuations in flow resistance caused by the different valve positions, in order to have a more reproducible pressure drop at a given filter resistance.

[0054] At 412, a second air pressure can be measured during electric motor operation, which is related to the airflow through the air filter. This air pressure can be measured using the same approach as at 404. Specifically, the air pressure can be measured by the sensor coupled between the air filter and the compressor of an electrically assisted turbocharger or an electric compressor (such as sensor 55 from [reference missing]). Fig. 1 and sensor 355 from Fig. 3) is measured. Alternatively, the pressure drop at the air filter can be measured.

[0055] In 414, the first and second measured air pressures are compared to a characterized air pressure to determine air filter clogging. As an example, the characterized air pressure could be a threshold air pressure calibrated by operating or modeling a model engine system. Alternatively, the characterized air pressure could be a pressure profile calibrated by operating or modeling the model engine system. In one embodiment, filter clogging can be determined by comparing the second air pressure to the characterized air pressure. In another embodiment, both the first and second air pressures can be used to determine filter clogging. For example, a weighted sum of the first and second air pressures can be calculated before being compared to the characterized air pressure.The first and second atmospheric pressures can be weighted using differential weighting factors. In one example, the weighting factor for the second atmospheric pressure can be higher than the weighting factor for the first atmospheric pressure. In another example, the weighting factor for the first atmospheric pressure can be zero.

[0056] At 416, the controller determines whether the filter is clogged based on the comparison at 414. For example, the controller may determine that the air filter is clogged if the pressure drop across the air filter during an off-state of the engine exceeds a threshold. Alternatively, the controller may determine that the air filter is clogged if the pressure drop during engine operation exceeds a first threshold and the pressure drop during the off-state of the engine exceeds a second threshold. If the filter is not clogged, procedure 400 returns to 406 to continue monitoring the engine operating status. If the filter is clogged, procedure 400 proceeds to 418. Otherwise, procedure 400 continues to monitor the engine operating conditions at 406.

[0057] Error code 418 indicates a filter blockage. A filter change request can be sent to the driver. For example, the control unit can activate a display on the dashboard to show the driver this information. Additionally, registers in the control unit can be configured to record the filter status.

[0058] Fig. Figure 5 illustrates the status of several actuators and motor operating parameters over time when implementing procedure 400. Fig. 4. Graph 510 shows the status of the vehicle key. The key can be on or off, as indicated by the y-axis. Graph 520 shows the engine speed. The engine speed increases, as indicated by the arrow on the y-axis. Graph 530 shows the opening angle of the EGR valve. The opening degree increases, as indicated by the y-axis. Graph 540 shows the speed of the electric motor coupled to the compressor. The electric motor speed can be positive or negative, with the airflow being driven through the air filter in opposite directions. As an example, if the electric motor speed is positive, the airflow rate 550 through the air filter is positive, and air flows in a first direction from the atmosphere to the compressor through the air filter (represented as 130 in ). Fig. 1 and Fig. 3) If the electric motor speed is negative, the airflow rate 550 is negative and air flows in a second direction from the compressor to the atmosphere through the air filter (shown as 131 in Fig. 1 and Fig. 3) Graph 560 shows the pressure drop at the air filter. The pressure drop is the absolute value of the pressure difference at the air filter. The pressure drop increases, as indicated by the arrow on the y-axis. Graph 570 shows the air filter change request. The air filter change request can be on or off.

[0059] From t0 to t1, the vehicle key is switched on. The engine is operated at a non-zero engine speed. The EGR valve can be actuated based on parameters, including the engine speed. For example, the opening of the EGR valve can increase as the engine speed decreases. The electric motor speed 540 is set based on parameters such as charge air demand. The airflow rate 550 through the air filter is unidirectional. The pressure drop 560 at the filter varies in response to the airflow rate.

[0060] At time t1, the motor is switched off with a motor speed of zero. The electric motor speed and the airflow rate through the air filter into the motor are both zero. The pressure drop across the air filter is also zero, as no air is flowing through the filter. For example, the electric motor speed can be adjusted based on the ambient pressure. As another example, the electric motor speed can be increased as the ambient pressure decreases.

[0061] At t2, the controller determines whether to initiate a diagnostic check on the air filter. For example, the controller might determine to perform a diagnostic check on the filter if the pressure drop during t0-t1 exceeds a threshold of 561. The threshold of 561 can be predefined based on the operation or modeling of a model engine system. The threshold can also be set based on the airflow rate. Another example is that the controller might determine to perform a diagnostic check on the filter after a predetermined time period.

[0062] In one embodiment, the electric motor speed 540 begins to increase from zero, as shown in 541. The EGR valve opens to allow airflow from the air filter to the exhaust duct of the vehicle system. The pressure drop increases. At t3, in response to the pressure drop 564 exceeding a threshold value 563, the filter change request 570 is activated.

[0063] In another embodiment, the electric motor can be actuated at t2 such that it directs air in a second direction from the motor to the atmosphere through the filter. The electric motor speed increases in the negative direction from zero, as shown in 542. The airflow rate 551 also increases in the negative direction from t2. The corresponding pressure drop due to the airflow in the second direction is shown in 565. The filter change request is triggered at t3 in response to the pressure drop 565 exceeding a threshold value 562. In one example, if the vehicle system includes a high-pressure EGR channel, the high-pressure EGR valve can be closed without high-pressure EGR flow, as shown in 531.

[0064] At t4, the air filter diagnostics end. The electric motor speed and airflow rate return to zero. The pressure drop is also zero. From t2 to t4, while the electric motor speed is not zero, the EGR valve remains wide open.

[0065] At t5, the engine speed increases from zero. The opening of the EGR valve and the electric motor speed are adjusted based on engine operating parameters. The airflow rate 550 and the pressure drop 560 vary in response to engine operating conditions.

[0066] In T6 mode, the engine speed drops to zero when the key is switched off. The electric motor speed also drops to zero. The pressure drop is zero in response to the airflow rate decreasing from zero. The filter change indicator may remain on to signal the driver.

[0067] In another embodiment, a diagnosis of the air filter can be performed based on air pressure measured during several different engine off periods, separated by running engine states. The filter change requirement can be set based on several of the measured air pressures. For example, the filter status can be diagnosed by comparing an average of the measured air pressures during the several different engine off periods. Alternatively, the filter status can be diagnosed by comparing a weighted average of the measured air pressures during the several different engine off periods. The weighting factor can be determined based on the airflow rate through the air filter. For example, the weighting factor can be increased with increasing airflow rate.The airflow rate can be estimated based on ambient conditions and motor operating conditions. For example, the airflow rate can be high at high ambient pressure and high electric motor speed.

[0068] Fig. Figure 6 shows another exemplary method 600 for diagnosing the air filter status without operating the high-pressure EGR valve. Method 600 can be applied to a vehicle system without a high-pressure EGR channel. Method 600 operates the electric motor coupled to the electric charging device, so that it directs air through the air filter in opposite directions when the engine is off, and detects air filter clogging based on an air pressure measurement when the engine is running.

[0069] In case 602, the procedure estimates and / or measures 400 similarly to case 402. Fig. 4 Engine operating conditions, including but not limited to engine speed, fuel quantity, fuel pressure, driver torque demand, engine coolant temperature (ECT), ambient air pressure (barometric pressure - BP), boost pressure, intake manifold pressure (boost pressure), exhaust manifold pressure, mass airflow rate (MAF), exhaust flow rate, accelerator pedal position (PP), EGR flow and EGR rates, which are determined by the output of corresponding values ​​in relation to the Fig. The sensors described in 1-3 can be measured and / or estimated.

[0070] At 604, air flows out in a similar way to 404. Fig. 4 through the air filter in the first direction, and the first air pressure is measured. This air pressure can be the air pressure between the air filter and the compressor (such as the pressure measured by sensor 55). Fig. 1 or sensor 355 from Fig. 3 is measured). Alternatively, the air pressure can be the pressure drop at the air filter.

[0071] In the case of 608, the procedure determines 600 similarly to that in the case of 408. Fig. 4. Whether the engine is switched off. If the engine is switched off, procedure 600 proceeds to 610. For example, the procedure may involve the occurrence of an off state of the engine with no combustion at rest and an on state of the engine with combustion and rotation. Otherwise, procedure 600 continues to monitor engine operation at 606.

[0072] In the case of 610, the procedure determines 600 similarly to that in the case of 410. Fig. 4. Whether the air filter status should be diagnosed. The control unit can determine whether the air filter status should be diagnosed based on the initial air pressure and / or the time elapsed since the last filter diagnosis. If the control unit determines that a diagnosis should be performed on the filter, procedure 600 proceeds to 612. Otherwise, procedure 600 continues to monitor the engine operating conditions at 606.

[0073] At 612, the electric motor is operated in such a way that it directs the air through the air filter in a first direction (such as the one in Fig. 1 and Fig. 3 (direction 130) to feed ambient air into the engine system.

[0074] At 614, the second air pressure can be measured, which is related to the airflow in the first direction. The second air pressure can be measured with the same sensor as the first air pressure.

[0075] In 616, after the air has been directed through the air filter in the first direction, the electric motor is actuated and the air is directed by the compressor in a second direction, opposite to the first direction, to the atmosphere through the air filter (as in 131 from Fig. 1 and Fig. 3 shown). Furthermore, while the air is directed in the second direction, the air filter can be cleaned by blowing some of the dirt and dust that has been collected in the air filter into a compartment of an air box.

[0076] At 618, the third air pressure can be measured, which is related to the airflow in the second direction. By allowing the air to flow in the second direction after it has flowed in the first direction, the airflow rate through the air filter can be increased to ensure a high signal-to-noise ratio.

[0077] At 620, the measured air pressures are compared to a characterized air pressure to determine the filter status. For example, the characterized air pressure could be threshold air pressures calibrated by operating or modeling a model engine system by passing air through the air filter. Alternatively, the characterized air pressure could be a pressure profile calibrated by operating or modeling the model engine system to pass air through the air filter. In one embodiment, the third air pressure can be used to determine filter clogging. For example, it can be determined that the filter is clogged if the third pressure drop is higher than a threshold value. In another embodiment, filter clogging can be determined based on both the second and third air pressure measurements.As one example, the filter can be determined to be clogged if a weighted sum of the second and third atmospheric pressures exceeds a threshold value. As another example, the weighting factor for the third atmospheric pressure can be higher than the weighting factor for the second atmospheric pressure. In yet another embodiment, filter clogging can be determined based on a weighted sum of the first, second, and third pressures.

[0078] At 622, if the filter is clogged, procedure 600 proceeds to 624 to indicate a filter change request. Otherwise, procedure 600 continues monitoring engine operation at 606.

[0079] Fig. Figure 7 illustrates the status of several actuators and motor operating parameters over time when implementing procedure 600. Fig. 6. Trajectory 710 shows the status of the vehicle key. The key can be on or off, as indicated by the y-axis. Trajectory 720 shows the engine speed. The engine speed increases, as indicated by the y-axis arrow. Trajectory 730 shows the speed of the electric motor coupled to the compressor. The electric motor speed can be positive or negative to the airflow in opposite directions through the air filter. For example, if the electric motor speed is positive, the airflow rate 740 through the air filter is also positive, and air flows in a first direction from the atmosphere to the compressor through the air filter (represented as 130 in [reference missing]). Fig. 1 and Fig. 3) If the electric motor speed is negative, the airflow rate 740 is negative and air flows in a second direction from the compressor to the atmosphere through the air filter (shown as 131 in Fig. 1 and Fig.3) Graph 750 shows the pressure drop at the air filter. The pressure drop is the absolute value of the pressure difference at the air filter. The pressure drop increases as indicated by the arrow on the y-axis. Graph 760 shows the status of the air filter change request. The air filter change request can be on or off.

[0080] From t0 to t1, the vehicle key is switched on. The engine speed is not zero. The electric motor speed is set based on engine operating parameters, including engine speed. The airflow rate and pressure drop vary based on engine operation.

[0081] At t1, the engine speed reaches zero and the engine is off.

[0082] At t2, the controller begins to perform a diagnostic check on the air filter by activating the electric motor. In one example, the controller might determine that a diagnostic check should be performed on the filter in response to the pressure drop 750 (from t0 to t1) exceeding a threshold value 751 while the motor is running. In another example, the controller might determine that a diagnostic check should be performed on the filter based on the time elapsed since the last filter diagnostic check. The electric motor speed increases in the positive direction, causing the air to flow in the first direction, as indicated by the positive increase in the airflow rate 740.

[0083] At t3, the electric motor speed exceeds zero as it transitions from a positive to a negative speed. The airflow rate also exceeds zero as it transitions from a positive to a negative speed. Thus, the air begins to flow in a second direction after having been directed in the first. A diagnosis of the air filter can be performed based on a mean pressure drop measured while air is passed through the filter in both directions, in order to increase the statistical significance of the diagnosis.

[0084] At t4, in response to the mean pressure drop exceeding a threshold of 752, the filter change request is switched off. The electric motor is switched off at t5.

[0085] At t6, the motor speed increases from zero and the electric motor is operated based on motor operating conditions.

[0086] At t7, the engine and the electric motor are switched off in response to a key switching event.

[0087] In this way, the air filter status can be diagnosed while the engine is off by operating the electric motor connected to the charging device. The diagnosis is based on a pressure measurement while air is passed through the air filter and over the electric motor. The technical benefit of filter diagnostics while the engine is off is that the signal-to-noise ratio can be improved. Furthermore, air filter diagnostics can be performed in a timely manner in hybrid vehicles where engine running time is limited. The technical benefit of opening the high-pressure EGR valve and directing air from the air filter to the exhaust manifold, bypassing the cylinder, is that air restriction caused by engine components other than the air filter is avoided. Additionally, emissions due to air flowing through the cylinder can be prevented.The technical benefit of running the engine to direct air in the opposite direction to normal engine operation is that air filter diagnostics can be performed in vehicle systems without a high-pressure EGR channel. The technical benefit of directing air in both directions while the engine is off is that the diagnostic results may be statistically more significant.

[0088] In one embodiment, a method for an engine comprises: opening a high-pressure exhaust gas recirculation (HPEGR) valve while the engine is off; directing air through an air filter by actuating an electric motor coupled to a compressor; measuring an air pressure; and indicating the status of the air filter based on the air pressure. In a first example of the method, the method further comprises directing the air from the air filter to an exhaust duct of the engine, bypassing the cylinder. A second example of the method optionally includes the first example and further comprises: wherein the compressor is further coupled to a turbine. A third example of the method optionally includes one or more from the first and second examples and further comprises directing the air from the air filter to an exhaust duct, bypassing the turbine.A fourth example of the method optionally includes one or more from the first and third examples and further includes opening a compressor return valve coupled to a second compressor while the electric motor is operated. A fifth example of the method optionally includes one or more from the first and fourth examples and further includes: wherein the second compressor is coupled between the compressor and the motor.A sixth example of the method optionally includes one or more from the first and fifth examples and further includes: wherein the air pressure is an air pressure differential at the air filter, and wherein the conduction and measurement are carried out during several different off-periods of the engine, separated by running-engine states, and the indication is based on several of the measured air pressures, the electric motor being operated at a speed set on the basis of the ambient pressure during each of the flow conditions. A seventh example of the method optionally includes one or more from the first and sixth examples and further includes: wherein the air pressure is measured between the air filter and the compressor.An eighth example of the procedure may include one or more from the first and seventh examples and further includes indicating the status of the air filter by comparing the air pressure with a characterized air pressure.

[0089] In another embodiment, a method comprises: during a first state, directing air through an air filter in a first direction and measuring a first air pressure; during a second state, actuating an electric motor to direct air through the air filter in a second direction opposite to the first direction and measuring a second air pressure; and indicating a filter change request based on the first and second air pressures. In a first example of the method, the first state is present during engine operation, and the second state is present during an off-state of the engine. A second example of the method optionally includes the first example and further comprises: wherein the first and second states are present during an off-state of the engine, and further comprising directing the air through the air filter in a first direction by actuating the electric motor.A third example of the method may include one or more of the elements from the first and second examples and further includes: wherein the first and second air pressures are measured by a sensor. A fourth example of the method may include one or more of the elements from the first and third examples and further includes: wherein the sensor is located between the air filter and a compressor. A fifth example of the method may include one or more of the elements from the first and fourth examples and further includes indications of the filter change requirement based on a weighted sum of the first and second air pressures.

[0090] In yet another embodiment, a vehicle system comprises: an engine containing one cylinder; an intake air duct for drawing ambient air into the engine; an exhaust duct coupled to an engine exhaust manifold; an air filter coupled to the intake air duct; a compressor coupled to the intake air duct for supplying supercharged air to the engine; an electric motor coupled to the compressor; an EGR valve coupled to a high-pressure EGR duct for recirculating exhaust gas from the engine exhaust manifold to an engine intake manifold; and a control unit with computer-readable instructions stored in non-volatile memory.The system performs the following actions: switching off the engine while the key is in the ignition state; actuating the electric motor to direct air through the air filter to the compressor; opening the EGR valve to direct air from the compressor to the exhaust manifold, bypassing the cylinder; determining an air pressure; and indicating an air filter change based on the determined air pressure. In a first example of the method, the air pressure is a pressure drop across the air filter, and the control is further used to indicate an air filter change in response to the pressure drop exceeding a threshold value.A second example of the method optionally includes the first example and further includes: wherein the compressor is an electric compressor and the system further includes a turbocharger coupled to the engine. A third example of the method optionally includes one or more from the first and second examples and further includes: wherein the control is further designed to open a compressor return valve and a turbocharger wastegate valve while the electric motor is actuated. A fourth example of the method further includes one or more from the first and third examples and further includes: wherein the control is further designed to adjust the turbocharger geometry while the electric motor is actuated.

[0091] In another description, a method for an engine of a hybrid vehicle comprises: opening a high-pressure exhaust gas recirculation (HPEGR) valve while the engine is off; passing air through an air filter by actuating an electric motor coupled to a compressor; measuring an air pressure; and indicating an air filter status based on the air pressure.

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

[0093] It is understood that the interpretations and routines disclosed herein are exemplary in nature and that these specific embodiments are not to be interpreted in a restrictive sense, as numerous variations are possible. For example, the foregoing technology can be applied to V-6, I-4, I-6, V-12, 4-cylinder boxer, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0094] The following claims, in particular, describe certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element, "a first" element, or the equivalent thereof. Such claims are to be understood as including one or more such elements, without requiring or excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Regardless of whether they have a broader, narrower, identical, or different scope of protection compared to the original claims, such claims are also considered to be included in the subject matter of the present disclosure.

Claims

[1] Method for an engine, comprising: Opening a high-pressure exhaust gas recirculation (HP-EGR) valve while the engine is off; Guiding air through an air filter by operating an electric motor coupled to a compressor; Measuring air pressure; and Displays the status of the air filter based on air pressure. [2] Method according to claim 1, further comprising directing the air from the air filter to an exhaust duct of the engine, bypassing a cylinder. [3] Method according to claim 1, wherein the compressor is further coupled to a turbine. [4] Method according to claim 3, further comprising directing the air from the air filter to an exhaust duct, bypassing the turbine. [5] Method according to claim 1, further comprising opening a compressor return valve coupled to a second compressor while the motor is being operated. [6] Method according to claim 5, wherein the second compressor is coupled between the compressor and the motor. [7] Method according to claim 1, wherein the air pressure is an air pressure difference at the air filter and wherein the guiding and measuring are carried out during several different off-times of the engine, which are separated by states with the engine running, and the indication is based on several of the measured air pressures, wherein the engine is operated at a speed which is set on the basis of the ambient pressure during each of the flow conditions. [8] Method according to claim 1, wherein the air pressure is measured between the air filter and the compressor. [9] Method according to claim 1, further comprising indicating the status of the air filter by comparing the air pressure with a characterized air pressure. [10] Vehicle system, comprising: an engine that includes one cylinder; an intake air duct for drawing ambient air into the engine; an exhaust duct that is coupled to an engine exhaust manifold; an air filter that is coupled to the intake air duct; a compressor coupled to the intake air duct to supply charged air to the engine; a motor that is coupled to the compressor; an EGR valve coupled to a high-pressure EGR channel for recirculating exhaust gas from the engine exhaust manifold to an engine intake manifold; a controller with computer-readable instructions stored in non-volatile memory for: Switching off the engine while the key is off; Activating the electric motor to direct air through the air filter to the compressor; Opening the EGR valve to direct air from the compressor to the exhaust manifold, bypassing the cylinder; Determining air pressure; and Indicates when an air filter needs to be changed based on the specified air pressure. [11] Vehicle system according to claim 10, wherein the air pressure is a pressure drop at the air filter and the control is further designed to indicate an air filter change in response to the pressure drop being higher than a threshold value. [12] Vehicle system according to claim 10, wherein the compressor is an electric compressor and the system further comprises a turbocharger coupled to the engine. [13] Vehicle system according to claim 12, wherein the control system is further designed to open a compressor recirculation valve and a wastegate valve of the turbocharger while the engine is being operated. [14] Vehicle system according to claim 12, wherein the control system is further designed to adjust the geometry of the turbocharger while the engine is being operated. [15] Procedures, including: During a first state, air is directed through an air filter in a first direction and a first air pressure is measured; During a second state, an electric motor is operated to direct air through the air filter in a second direction opposite to the first direction, and a second air pressure is measured; and Displays a filter change request based on the first and second air pressures.

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