Systems and methods for diagnosing a vehicle engine intake manifold and exhaust system

Abstract

The present invention relates to systems and methods for diagnosing intake manifolds and exhaust systems of vehicle engines. Methods and systems are provided for indicating the presence or absence of a source of degradation in one of an intake manifold, an exhaust system, or an engine of an engine system. In one example, a method includes rotating the engine without fuel being supplied thereto and indicating a source of degradation based on both intake flow and exhaust flow as compared to a baseline intake flow and a baseline exhaust flow. In this way, the source of degradation can be precisely located, which can increase the lifespan of the vehicle engine system, reduce undesirable emissions, and which can increase customer satisfaction due to the shorter time spent diagnosing such a source of degradation.

Description

Technical Field

[0001] The present invention generally relates to methods and systems for assessing the presence or absence of degradation in a vehicle engine, an engine intake manifold, or an engine exhaust system. Background Art

[0002] An internal combustion engine combusts a mixture of fuel and air in order to generate torque to propel a vehicle. Specifically, air is drawn into the engine via an engine intake manifold based on the position of a throttle, and then the air is mixed with fuel. The air-fuel mixture is combusted within one or more engine cylinders to drive one or more pistons within the one or more cylinders, thereby rotating an engine crankshaft. By-products of combustion within the engine cylinders are directed to one or more catalysts via an exhaust manifold before exiting to the atmosphere.

[0003] Over time, degradation can occur in both the engine intake and exhaust systems. The presence of any degradation in the intake system, exhaust system, or engine can result in a decrease in fuel economy and, in some examples, an increase in undesirable emissions. The inventors have recognized these problems herein.

[0004] Engine operation can be regulated based on a number of parameters such as the air flow rate provided to the engine. For example, a measurement of the air flow provided to the engine can be determined by a mass air flow (MAF) sensor. However, in the intake manifold, the presence of any degradation downstream of the MAF sensor can result in un-metered air being provided to the engine. As a result, the air-fuel ratio can shift lean. However, there are many other root causes for an engine to run lean, such as undesirable combustion, an exhaust oxygen sensor not operating as desired, valve timing issues, a MAF sensor not operating as desired, etc. Therefore, it is challenging to specifically diagnose the presence or absence of degradation in the intake system or intake manifold that originates downstream of the MAF sensor. Similarly, for example, if the degradation is downstream of the exhaust oxygen sensor, it can be difficult to precisely locate the degradation in the exhaust system.

[0005] U.S. Patent No. US20090187301 teaches a method for diagnosing the presence or absence of degradation in an engine intake manifold by comparing the manifold absolute pressure to the atmospheric pressure. In one example, a significant amount of degradation is indicated in response to the manifold absolute pressure being substantially equal to the atmospheric pressure. Summary of the Invention

[0006] However, the inventors have recognized herein potential problems with such an approach. For example, such an approach cannot be used to diagnose the presence or absence of degradation in a vehicle's exhaust system. Accordingly, the inventors have developed herein systems and methods for addressing these problems. In one example, a method is provided that includes performing an engine system diagnosis by rotating the vehicle's engine without fuel supply to draw intake air flow into the engine via an intake manifold and direct exhaust air flow to the atmosphere via an exhaust system, and indicating a source of degradation originating from one of the engine, the intake manifold, or the exhaust system based on both the intake air flow and the exhaust air flow during the rotation. In this way, the source of degradation is robustly determined in the case of an engine system diagnosis to be from the vehicle's intake manifold, engine, or exhaust system.

[0007] In one example, the method includes, prior to performing the diagnosis, obtaining a set of baseline comparator data that includes a baseline intake air flow and a baseline exhaust air flow under a set of conditions that are substantially equivalent to a set of conditions for performing the engine system diagnosis, the set of substantially equivalent conditions including rotating the engine without fuel supply by a battery-powered motor. In such an example, the set of substantially equivalent conditions further includes rotating the engine at a predetermined speed for a predetermined duration and controlling a throttle positioned in the intake manifold to a predetermined position to allow air to be drawn into the engine via the intake manifold.

[0008] In some examples, the intake air flow and the baseline intake air flow can be measured by a mass air flow sensor positioned in the intake manifold, and wherein the exhaust air flow and the baseline exhaust air flow are measured by a pressure sensor positioned in the exhaust system. In such an example, the pressure sensor can include a differential pressure sensor corresponding to a particulate filter positioned in the exhaust system. Additionally, obtaining the set of baseline comparator data is performed under conditions where the engine system does not have the source of degradation.

[0009] In one example, in response to the intake air flow during the engine system diagnosis being substantially equal to the baseline intake air flow, but where the exhaust air flow during the engine system diagnosis is greater than the baseline exhaust air flow, the source of degradation can be indicated in the intake manifold.

[0010] In another example, in response to the intake air flow during the engine system diagnosis being substantially equal to the baseline intake air flow, but where the exhaust air flow during the engine system diagnosis is lower compared to the baseline exhaust air flow, the source of degradation can be indicated in the exhaust system.

[0011] In another example, in response to both the intake flow rate and the exhaust flow rate being below the baseline intake flow rate and the baseline exhaust flow rate, respectively, during the engine system diagnosis, the degradation source may be indicated as originating from the engine.

[0012] In yet another example, in response to not only the intake flow rate being substantially equal to the baseline intake flow rate during the engine system diagnosis, but also the exhaust flow rate being substantially equal to the baseline exhaust flow rate during the engine system diagnosis, the degradation source does not exist in any of the intake manifold, the exhaust system, or the engine.

[0013] The above and other advantages and features of the present invention will be apparent when the following detailed description is considered alone or in conjunction with the accompanying drawings.

[0014] It should be understood that the above summary is provided to introduce in a simplified form a selection of concepts that are further described in the detailed description. This does not mean identifying the key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to embodiments that solve any of the above or any disadvantages mentioned in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An exemplary vehicle propulsion system is schematically illustrated.

[0016] Figure 2 An exemplary vehicle system having a fuel system and an evaporative emissions system is schematically illustrated.

[0017] Figures 3A - 3C A block diagram of a vehicle intake and exhaust system of an engine is schematically illustrated, where potential locations of degradation are illustrated.

[0018] Figure 4 A block diagram of an exemplary autonomous driving system is schematically illustrated.

[0019] Figure 5 A high-level flowchart showing the presence or absence of degradation originating from the intake manifold, the exhaust system, or the engine is shown.

[0020] Figure 6 Shows in detail for use in the above Figure 5 A high-level flowchart of the steps for obtaining baseline comparator data and for performing engine system diagnosis used in the method.

[0021] Figure 7 Shows an example look-up table that can be used to interpret the results of the Figure 5 method.

[0022] Figure 8 illustrates an example timeline for determining whether degradation exists in a vehicle intake manifold, exhaust system, or engine according to the method of Figures 5 - 6 . DETAILED DESCRIPTION

[0023] The following description relates to systems and methods for precisely locating a source of degradation originating from a vehicle's intake manifold, exhaust system, or engine. Such methods may include rotating or spinning the engine without fuel injection, where rotating the engine not supplied with fuel is carried out via an electric motor of a hybrid vehicle (such as the hybrid vehicle depicted at Figure 1 ). To diagnose a source of degradation in an engine system that includes an engine intake manifold, an engine exhaust system, and an engine, intake and exhaust flow rates may be monitored under a set of predetermined conditions and compared to a set of baseline intake and exhaust flow rates measured under a substantially equivalent set of predetermined conditions. As illustrated in Figure 2 , measuring the intake flow rate may be carried out via a mass air flow (MAF) sensor located in the intake manifold, while measuring the exhaust flow rate may be carried out via a gasoline particulate filter (GPF) differential pressure sensor located in the exhaust system downstream of the exhaust manifold. By comparing the intake and exhaust flow rate measurements to baseline measurements taken under conditions where no degradation exists in the engine system, the source of degradation can be precisely located as originating from the intake manifold, exhaust system, or engine, as shown at Figures 3A - 3C . In some examples, the set of predetermined conditions for making the baseline intake and exhaust flow rate measurements and the test intake and exhaust flow rate measurements may include an indication that the vehicle is unoccupied. Thus, in some examples, these measurements may be made in an unoccupied autonomous vehicle, where Figure 4 depicts an example autonomous vehicle control system. At Figure 5 , a method for precisely locating the source of degradation in the intake manifold, exhaust system, or engine is illustrated. As discussed, in addition to similar measurements under test conditions, such a method may include baseline measurements of intake flow rate and exhaust flow rate. Thus, at Figure 6 , a method for obtaining these measurements for use in the method depicted at Figure 5 is illustrated. To interpret the results of such a diagnostic test, the results may be analyzed via a look-up table (such as the look-up table depicted above at Figure 7 ). At Figure 8 , an example timeline for carrying out such an engine system test diagnostic procedure is illustrated.

[0024] Figure 1FIG. illustrates an example vehicle propulsion system 100. The vehicle propulsion system 100 includes an engine 110 that burns fuel and a motor 120. As a non-limiting example, the engine 110 includes an internal combustion engine, and the motor 120 includes an electric motor. The motor 120 can be configured to use or consume an energy source different from that of the engine 110. For example, the engine 110 can consume liquid fuel (e.g., gasoline) to produce an engine output, while the motor 120 can consume electrical energy to produce a motor output. Thus, a vehicle having the propulsion system 100 can be referred to as a hybrid electric vehicle (HEV).

[0025] The vehicle propulsion system 100 can use a variety of different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes can enable the engine 110 to be maintained in a shut-down state (i.e., set to a deactivated state), in which case fuel combustion at the engine is discontinuous. For example, under selected operating conditions, the motor 120 can propel the vehicle via the drive wheels 130 as shown by arrow 122, while the engine 110 is deactivated.

[0026] During some other operating conditions, the engine 110 can be set to a deactivated state (as described above), and the motor 120 can be operated to charge the energy storage device 150. For example, the motor 120 can receive wheel torque from the drive wheels 130 as shown by arrow 122, where the motor can convert the vehicle's kinetic energy into electrical energy as shown by arrow 124 for storage at the energy storage device 150. This operation can be referred to as regenerative braking of the vehicle. Thus, in some examples, the motor 120 is capable of providing a generator function. However, in some other examples, the generator 16 can instead receive wheel torque from the drive wheels 130, where the generator can convert the vehicle's kinetic energy into electrical energy as shown by arrow 162 for storage at the energy storage device 150.

[0027] During still other operating conditions, the engine 110 can operate by burning fuel received from the fuel system 140 as shown by arrow 142. For example, the engine 110 can be operated to propel the vehicle via the drive wheels 130 as shown by arrow 112, while the motor 120 is deactivated. During some other operating conditions, both the engine 110 and the motor 120 can be operated to propel the vehicle via the drive wheels 130, as shown by arrows 112 and 122, respectively. A configuration in which both the engine and the motor can selectively propel the vehicle can be referred to as a parallel 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.

[0028] In some other examples, the vehicle propulsion system 100 can be configured as a series vehicle propulsion system, whereby the engine does not directly propel the drive wheels. Instead, 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, and the generator 160 can then supply electrical power to one or more of the motor 120 (as indicated by arrow 114) or 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 power, where the electrical power can be stored in the energy storage device 150 for subsequent use by the motor.

[0029] In some other examples, which will be discussed in more detail below, the motor 120 can in some examples be used to rotate or spin the motor in a configuration where it is not being supplied with fuel. More specifically, the motor 120 can use power from an on-vehicle energy storage device 150 (e.g., which can include a battery) to rotate the engine that is not being supplied with fuel. In cases where the motor 120 is used to rotate the engine that is not being supplied with fuel, fuel injection into the engine cylinders can be prevented, and a spark can be withheld from each of the engine cylinders.

[0030] 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, the 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 arrow 142. Other suitable fuels or fuel blends can be supplied to the engine 110, where they can be burned at the engine to produce an engine output. The engine output can be used to propel the vehicle as indicated by arrow 112, or to recharge the energy storage device 150 via the motor 120 or the generator 160.

[0031] In some examples, the energy storage device 150 can be configured to store electrical power that can be supplied to other electrical loads located on the vehicle (other than the motor), including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, etc. As a non-limiting example, the energy storage device 150 can include one or more batteries and / or capacitors.

[0032] The control system 190 can communicate 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 sensed 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. Additionally, in response to the sensed feedback, 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. The control system 190 can receive an indication of a requested vehicle propulsion system output from the vehicle operator 102. For example, the control system 190 can receive sensed feedback from a pedal position sensor 194 in communication with a pedal 192. The pedal 192 can schematically represent a brake pedal and / or an accelerator pedal. Additionally, in some examples, the control system 190 can communicate with a remote engine start receiver 195 (or transceiver) that receives a wireless signal 106 from a remote key 104 having a remote start button 105. In other examples (not shown), remote engine start can be initiated via a mobile phone or a smartphone-based system where the user's mobile phone sends data to a server and the server communicates with the vehicle to start the engine.

[0033] The energy storage device 150 can periodically receive electrical energy from a power source 180 (e.g., not part of the vehicle) located external to the vehicle as shown 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. During a recharge operation of the energy storage device 150 from the power source 180, the electrical energy transfer cable 182 can electrically couple the energy storage device 150 to the power source 180. When the vehicle propulsion system is operated to propel the vehicle, the electrical energy transfer cable 182 can be disconnected between the power source 180 and the energy storage device 150. 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).

[0034] In other examples, the electrical energy 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, 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 is not part of the vehicle. In this manner, the motor 120 can propel the vehicle using an energy source different from the fuel used by the engine 110.

[0035] The fuel system 140 may periodically receive fuel from a fuel source located outside the vehicle. As a non-limiting example, as indicated by arrow 172, the vehicle propulsion system 100 may be refueled by receiving fuel via a fuel dispensing device 170, as indicated by arrow 172. In some examples, the fuel tank 144 may be configured to store fuel received from the fuel dispensing device 170 until it is supplied to the engine 110 for combustion. In some examples, the control system 190 may receive an indication of the level of fuel stored at the fuel tank 144 via a fuel level sensor. The level of fuel stored at the fuel tank 144 (e.g., as identified by the fuel level sensor) may be communicated to the vehicle operator, for example, via a fuel gauge or an indication in the vehicle instrument panel 196.

[0036] The vehicle propulsion system 100 may 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. The vehicle instrument panel 196 may include (one or more) indicator lights and / or a text-based display that presents messages to the operator. The vehicle instrument panel 196 may also include various input sections for receiving operator input, such as buttons, touchscreens, voice input / recognition, etc. For example, the vehicle instrument panel 196 may include a fuel fill button 197 that may be manually actuated or pressed by the vehicle operator to initiate fuel filling. For example, as described in more detail below, in response to the vehicle operator actuating the fuel fill button 197, the fuel tank in the vehicle may be depressurized so that fuel filling may be performed.

[0037] As is known in the art, the control system 190 can be communicatively coupled to other vehicles or infrastructure using suitable communication technologies. For example, the control system 190 can be coupled to other vehicles or infrastructure via a wireless network 131, which can include Wi-Fi, Bluetooth, a cellular service, a wireless data transfer protocol, and the like. The control system 190 can broadcast (and receive) information regarding 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) technologies. The communication and exchanged information between vehicles can be direct between vehicles or multi-hop. In some examples, a more remote communication (such as WiMax) can be used instead of or in combination with V2V or V2I2V to extend the coverage area by several miles. In other examples, the vehicle control system 190 can be communicatively coupled to other vehicles or infrastructure via the wireless network 131 and the Internet (e.g., the cloud), as is known in the art.

[0038] The vehicle system 100 can also include an on-vehicle navigation system 132 (e.g., a Global Positioning System (GPS)) with which an operator of the vehicle can interact. The navigation system 132 can include one or more position sensors for assisting in estimating vehicle speed, vehicle altitude, vehicle position / location, etc. This information can be used to infer engine operating parameters such as local atmospheric pressure. As described above, the control system 190 can be further configured to receive information via the Internet or other communication networks. The information received from the GPS can be cross-referenced with information available via the Internet to determine local weather conditions, local vehicle rules, etc. In one example, the information received from the GPS can be used in combination with a route learning method such that the routes that the vehicle typically travels can be learned by the vehicle control system 190. In some examples, other sensors (such as 133), such as lasers, radars, sonars, acoustic sensors, etc., can be additionally or alternatively used in combination with the on-vehicle navigation system for route learning of the routes that the vehicle typically travels.

[0039] The vehicle system 100 can also include sensors dedicated to indicating the occupancy status of the vehicle, such as a seat load unit 107, door sensing technology 108, and an on-vehicle camera 109.

[0040] Figure 2 A schematic diagram of the vehicle system 206 is shown. It can be understood that the vehicle system 206 can include the same as those in Figure 1The same vehicle system as the vehicle system 100 depicted herein. The vehicle system 206 includes an engine system 208 that is coupled to an emissions control system 251 and a fuel system 218. It will be appreciated that the fuel system 218 may include the same fuel system as the fuel system 140 depicted in Figure 1 herein. The emissions control system 251 includes a fuel vapor container or canister 222 that can be used to capture and store fuel vapor. In some examples, the vehicle system 206 may be a hybrid electric vehicle system.

[0041] The engine system 208 may include an engine 110 having a plurality of cylinders 230. Although not explicitly shown, it will be appreciated that each cylinder may include one or more intake valves and one or more exhaust valves. The engine 110 includes an engine intake 223 and an engine exhaust 225. The engine intake 223 includes a throttle 262 that is in fluid communication with an engine intake manifold 244 via an intake passage 242. The throttle 262 may include an electronic throttle that can be controlled by sending a signal to actuate the throttle to a desired position via a vehicle controller. In such an example where the throttle is electronic, the power to control the throttle to the desired position may come from an on-board energy storage device (e.g., 150), such as a battery. Additionally, the engine intake 223 may include an air box and filter 215 located upstream of the throttle 262. The engine exhaust system 225 includes an exhaust manifold 248 that leads to an exhaust passage 235 that directs exhaust to the atmosphere. The engine exhaust system 225 may include one or more exhaust catalysts 270 that may be mounted in the exhaust in a close-coupled state. One or more emissions control devices may include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, etc. It should be recognized that other components may be included in the engine, such as various valves and sensors. For example, an atmospheric pressure sensor 213 may be included in the engine intake. In one example, the atmospheric pressure sensor 213 may be a manifold absolute pressure (MAP) sensor and may be coupled to the engine intake downstream of the throttle 262. The atmospheric pressure sensor 213 may rely on a part-throttle or wide-open or wide-throttle condition (e.g., when the opening of the throttle 262 is greater than a threshold) in order to accurately determine BP. Alternatively, MAP may be inferred from an alternate engine condition (e.g., the mass air flow (MAF) measured by a MAF sensor 210 coupled to the intake manifold).

[0042] The engine exhaust system 225 may further include a gasoline particulate filter (GPF) 217. The GPF 217 may 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 may be periodically regenerated by operating at least one cylinder of the engine within a specific air-fuel ratio to increase the temperature of the GPF 217 such that the trapped hydrocarbons and soot particulates can be oxidized.

[0043] In some examples, a temperature sensor 226 may be positioned upstream of the inlet of the GPF 217, and a temperature sensor 229 may be positioned downstream of the GPF 217. For example, the temperature sensors 226 and 229 may be used to evaluate the temperature of the GPF 217 for regeneration purposes. Additionally, the pressure in the exhaust system may be evaluated by a pressure sensor 263. For example, the pressure sensor 263 may be a differential pressure sensor positioned upstream and downstream of the GPF 217. The pressure sensor 263 may be used to determine the pressure at the inlet of the GPF 217 in order to evaluate the condition of the air to be introduced to the inlet of the GPF 217 for regeneration. Additionally, in some examples, a soot sensor 268 may be positioned downstream of the GPF 217 to evaluate the level of soot released from the GPF 217. The soot sensor 268 may be used to diagnose the operation of the GPF 217 and other functions.

[0044] The fuel system 218 may include a fuel tank 220 coupled to a fuel pump system 221. It will be appreciated that the fuel tank 220 may include the same fuel tank as the fuel tank 144 depicted above at Figure 1 The fuel pump system 221 may include one or more pumps for pressurizing fuel delivered to an injector (such as the exemplary injector 266 shown) of the engine 110. Although only a single injector 266 is shown, additional injectors are provided for each cylinder. It should be recognized that the fuel system 218 may be a non-return fuel system, a return fuel system, or various other types of fuel systems. The fuel tank 220 may accommodate a variety of fuel blends, including fuels having a range of alcohol concentrations, such as various gasoline-ethanol blends, which include E10, E85, gasoline, etc. and combinations thereof. A fuel level sensor 234 located in the fuel tank 220 may provide an indication of the fuel level (“fuel level input”) to the controller 212. As depicted, the fuel level sensor 234 may include a float connected to a variable resistor. Alternatively, other types of fuel level sensors may be used.

[0045] The vapor generated in the fuel system 218 can be directed via a vapor recovery line 231 to an evaporative emissions control system 251 including a fuel vapor canister 222 and then drawn into the engine intake 223. The vapor recovery line 231 can be coupled to the fuel tank 220 via one or more conduits and can include one or more valves for isolating the fuel tank during certain conditions. For example, the vapor recovery line 231 can be coupled to the fuel tank 220 via one or more of conduits 271, 273, and 275 or a combination thereof.

[0046] Additionally, in some examples, one or more fuel tank vent valves can be located in conduits 271, 273, or 275. Among other functions, the fuel tank vent valves can also allow the fuel vapor canister of the emissions control system to be maintained at a low pressure or vacuum without increasing the fuel evaporation rate of the fuel tank (which would occur if the fuel tank pressure decreased). For example, conduit 271 can include a grade vent valve (GVV) 287, conduit 273 can include a fill limit vent valve (FLVV) 285, and conduit 275 can include a grade vent valve (GVV) 283. Additionally, in some examples, the recovery line 231 can be coupled to a fuel fill system 219. In some examples, the fuel fill system can include a fuel cap 205 for blocking the fuel fill system from the atmosphere. The fuel fill system 219 is coupled to the fuel tank 220 via a fuel fill tube or neck 211.

[0047] Additionally, the fuel fill system 219 can include a fuel fill lock 245. In some examples, the fuel fill lock 245 can be a fuel cap locking mechanism. The fuel cap locking mechanism can be configured to automatically lock the fuel cap in a closed position such that the fuel cap cannot be opened. For example, when the pressure or vacuum in the fuel tank is greater than a threshold, the fuel cap 205 can be held locked by the fuel fill lock 245. In response to a fuel fill request (e.g., a request initiated by a vehicle operator), the fuel tank can be depressurized and the fuel cap unlocked after the pressure or vacuum in the fuel tank drops below the threshold. The fuel cap locking mechanism can be a latch or a clutch device that, when engaged, prevents removal of the fuel cap. The latch or clutch device can be electrically locked, for example, by a solenoid, or can be mechanically locked, for example, by a pressure diaphragm.

[0048] In some examples, the fuel fill lock 245 can be a fill tube valve located at the mouth of the fuel fill tube 211. In such examples, the fuel fill lock 245 does not prevent removal of the fuel cap 205. Rather, the fuel fill lock 245 can prevent a fuel fill pump from being inserted into the fuel fill tube 211. The fill tube valve can be electrically locked, for example, by a solenoid, or can be mechanically locked, for example, by a pressure diaphragm.

[0049] In some examples, the fuel fill lock 245 can be a fuel fill door lock, such as a latch or clamping device that locks a fuel fill door located in a body panel of the vehicle. The fuel fill door lock can be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0050] In an example where the fuel fill lock 245 is locked using an electrical mechanism, the fuel fill lock 245 can be unlocked by a command from the controller 212, for example, when the fuel tank pressure drops below a pressure threshold. In an example where the fuel fill lock 245 is locked using a mechanical mechanism, the fuel fill lock 245 can be unlocked by a pressure gradient, for example, when the fuel tank pressure is reduced to atmospheric pressure.

[0051] The emissions control system 251 can include one or more emissions control devices, such as one or more fuel vapor canisters 222 filled with a suitable adsorbent 286b, which are configured to temporarily trap fuel vapor (including vaporized hydrocarbons) during fuel tank refilling operations and “running losses” (i.e., fuel vaporized during vehicle operation). In one example, the adsorbent 286b used can be activated carbon. The emissions control system 251 can also include a canister vent path or vent line 227 that can direct gas from the canister 222 to the atmosphere when storing or trapping fuel vapor from the fuel system 218.

[0052] The canister 222 can include a buffer 222a (or buffer zone), and each of the canister and the buffer 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 of the canister 222). The adsorbent 286a in the buffer 222a can be the same as or different from the adsorbent in the canister (e.g., both can include charcoal). The buffer 222a can be positioned within the canister 222 such that during canister loading, fuel tank vapor is first adsorbed within the buffer, and then when the buffer is saturated, additional fuel tank vapor is adsorbed in the canister. In contrast, during canister drawdown, fuel vapor is first desorbed from the canister (e.g., to a threshold amount) before being desorbed from the buffer. In other words, the loading and unloading of the buffer are not linearly related to the loading and unloading of the canister. Thus, the role of the canister buffer is to dampen any fuel vapor spikes flowing from the fuel tank to the canister, thereby reducing the likelihood of any fuel vapor spikes entering the engine. One or more temperature sensors 232 can be coupled to the canister 222 and / or within the canister 222. As fuel vapor is adsorbed by the adsorbent in the canister, heat is generated (heat of adsorption). Similarly, as fuel vapor is desorbed by the adsorbent in the canister, heat is consumed. In this way, the adsorption and desorption of fuel vapor by the canister can be monitored and estimated based on temperature changes within the canister.

[0053] When stored fuel vapor is drawn from the fuel system 218 to the engine intake 223 via the draw line 228 and the draw valve 261, the vent line 227 can also allow fresh air to be drawn into the canister 222. For example, the draw valve 261 can be normally closed, but can be opened under certain conditions such that vacuum from the engine intake manifold 244 is provided to the fuel vapor canister for drawing. In some examples, the vent line 227 can include an air filter 259 disposed therein, upstream of the canister 222.

[0054] In some examples, the flow of air and vapor between the canister 222 and the atmosphere can be regulated by a canister vent valve 297 coupled within the vent line 227. When included, the canister vent valve 297 can be a normally open valve such that the fuel tank isolation valve 252 (FTIV) can control the venting of the fuel tank 220 to the atmosphere. The FTIV 252 can be positioned between the fuel tank and the fuel vapor canister 222 within the conduit 278. The FTIV 252 can be a normally closed valve that, when opened, allows fuel vapor to be discharged from the fuel tank 220 to the fuel vapor canister 222. The fuel vapor can then be discharged to the atmosphere or drawn into the engine intake system 223 via the canister draw valve 261. As will be discussed in detail below, in some examples, the FTIV may not be included, while in other examples, the FTIV may be included.

[0055] By selectively adjusting various valves and solenoids, the fuel system 218 can be operated by the controller 212 in a variety of modes. It will be appreciated that the control system 214 can include the same control system as the control system 190 depicted above at Figure 1 For example, the fuel system can be operated in a fuel vapor storage mode (e.g., during a fuel tank fueling operation and when the engine is not combusting air and fuel), where the controller 212 can open the isolation valve 252 (when included) while closing the canister draw valve (CPV) 261 to direct fueling vapor into the canister 222 while preventing fuel vapor from being directed into the intake manifold.

[0056] As another example, the fuel system can be operated in a fueling mode (e.g., when a vehicle operator requests fuel tank fueling), where the controller 212 can open the isolation valve 252 (when included) while maintaining the canister draw valve 261 closed to depressurize the fuel tank before allowing fuel to be added therein. Thus, the isolation valve 252 (when included) can remain open during a fueling operation to allow fueling vapor to be stored in the canister. After fueling is complete, the isolation valve can be closed.

[0057] As another example, the fuel system can operate in a canister purge mode (e.g., after the light-off temperature of the emission control device has been reached and while the engine is combusting air and fuel), where the controller 212 can open the canister purge valve 261 while closing the isolation valve 252 (when included). Herein, the vacuum generated by the intake manifold of the running engine can be used to suck fresh air through the vent line 227 and through the fuel vapor canister 222 to purge the stored fuel vapor into the intake manifold 244. In this mode, the purged fuel vapor from the canister is burned in the engine. The purge can continue until the amount of stored fuel vapor in the canister is below a threshold.

[0058] The controller 212 can be part of the control system 214. In some examples, the control system 214 can be the same as the control system 190 illustrated in Figure 1 The control system 214 is shown receiving information from a plurality of sensors 216 (various examples of which are described in the text) and sending control signals to a plurality of actuators 281 (various examples of which are described in the text). In one example, the sensors 216 can include an exhaust sensor 237, a temperature sensor 233, a pressure sensor 291, a pressure sensor 282, and a canister temperature sensor 232, with the exhaust sensor 237 located downstream of the emission control device 270. Other sensors (such as pressure, temperature, air-fuel ratio, and component sensors) can be coupled to various locations of the vehicle system 206. As another example, the actuators can include a throttle 262, a fuel tank isolation valve 252, a canister purge valve 261, and a canister vent valve 297. The control system 214 can include the controller 212. The controller can receive input data from various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or code programmed therein corresponding to one or more programs. Examples of control programs are described herein with respect to Figures 5 - 6 the example control programs.

[0059] In some examples, the controller can be placed in a reduced power mode or a sleep mode, where the controller only maintains basic functions and operates with lower battery consumption than in the corresponding wake mode. For example, the controller can be placed in the sleep mode after a vehicle stop event to perform diagnostic programs for a duration after the vehicle stop event. Based on inputs received from one or more sensors, the controller can have a wake-up input that allows the controller to be returned to the wake mode. For example, the opening of a vehicle door can trigger a return to the wake mode. In other examples, specifically with respect to Figures 5 - 6The methods depicted would require the controller to be awake to execute these methods. For example, the wake-up ability can enable the circuit to wake up the controller to obtain baseline comparator data or perform engine system diagnostics, as will be discussed further in detail below.

[0060] The undesired evaporative emissions detection procedure can be intermittently performed by the controller 212 on the fuel system 218 and / or the evaporative emissions control system 251 to confirm the absence of undesired evaporative emissions in the fuel system and / or the evaporative emissions system. Thus, the evaporative emissions detection procedure can be performed while the engine is off (engine-off test) using the engine-off natural vacuum (EONV) generated due to the change in temperature and pressure at the fuel tank after the engine is off and / or the vacuum supplemented from a vacuum pump. Alternatively, the evaporative emissions detection procedure can be performed while the engine is running by operating the vacuum pump and / or using the engine intake manifold vacuum. In some configurations, the canister vent valve (CVV) 297 can be coupled within the vent line 227. The CVV 297 can be used to regulate the flow of air and vapor between the canister 222 and the atmosphere. The CVV can also be used for diagnostic procedures. When included, the CVV can be opened during fuel vapor storage operations (e.g., during fuel tank fueling and when the engine is not running) such that the air that has been stripped of fuel vapor after passing through the canister can be vented to the atmosphere. Similarly, during purge operations (e.g., during canister regeneration and when the engine is running), the CVV can be opened to allow fresh air flow to strip the fuel vapor stored in the canister. In some examples, the CVV 297 can be a solenoid valve, where the opening or closing of the valve is performed via the actuation of the canister vent solenoid. Specifically, the canister vent valve can be open and is closed after the actuation of the canister vent solenoid. In some examples, the CVV 297 can be configured as a latching solenoid valve. In other words, when the valve is placed in the closed configuration, it latches closed without the need for additional current or voltage. For example, the valve can be closed with a 100 ms pulse and then opened at a later time point with another 100 ms pulse. In this way, the battery power required to keep the CVV closed is reduced. Specifically, the CVV can be closed when the vehicle is stopped, thus maintaining battery power while maintaining the fuel emissions control system's barrier from the atmosphere.

[0061] In another example, engine system diagnostics can be performed to determine whether the source of degradation is from the engine's intake manifold, the engine's exhaust system, or the engine itself. Such an example will be described below with respect to Figures 5 - 6The methods depicted are discussed in detail. As discussed herein, degradation of the intake manifold can refer to perforations, cracks, degraded gaskets, loose connections, or air leaks in the intake manifold. Degradation of the exhaust system can similarly refer to perforations, cracks, degraded gaskets, loose connections, or exhaust leaks in the exhaust system. It can be understood that degradation of the exhaust system can refer to downstream of the engine system and the engine (such as 110) upstream of the GPF (such as 217). Finally, degradation of the engine can refer to improperly sealed intake / exhaust valves, undesirable camshaft timing, compression problems, or any other engine-specific problems that can cause the engine to not pump as effectively as expected or required.

[0062] Now turning to Figures 3A - 3C , which respectively illustrate examples of degradation sources originating from the intake manifold, the exhaust system, or the engine. Thus, Figures 3A - 3C illustrates a simplified block diagram of an engine system that includes a MAF sensor 210, an intake manifold 244, an engine 110, an exhaust system 225, a GPF 217, and a differential pressure sensor 263. Thus, Figures 3A - 3C represents a simplified block diagram of the engine system depicted above at Figure 2 . As will be detailed below, degradation sources are shown in each of Figures 3A - 3C , which are represented as 310a, 310b, and 310c.

[0063] Now turning to Figure 3A , which shows an example where the degradation source 310a originates from the intake manifold 244. In such an example, the degradation source 310a cannot be directly observed via the MAF sensor 210 because the degradation source is downstream of the MAF sensor 210. However, when the engine is running, un-metered air can be drawn into the engine via the degradation source. Thus, it can be understood that additional air (in addition to the air drawn in through the intake passage (such as 242)) can be drawn into the engine, and thus the pressure in the exhaust system will be greater than expected, as monitored by the differential pressure sensor 263. Thus, as will be discussed further below with respect to Figures 5 - 8 , if the mass air flow indicated by the MAF sensor 210 is substantially equal to the expected mass air flow under a set of predetermined conditions, but the exhaust flow (such as the pressure in the exhaust system) indicated by the differential pressure sensor 263 is greater than the expected exhaust flow under the same (or substantially equivalent) set of predetermined conditions, then the degradation source can be diagnosed in the intake manifold 244.

[0064] Now turning to Figure 3B, which shows an example where the degradation source 310b originates from the exhaust system 225. In such an example, the degradation source cannot be directly observed via the MAF sensor 210 or the differential pressure sensor 263. However, when the engine is running, the exhaust flow can be pushed or forced through the degradation source 310b to the atmosphere, resulting in a generally lower exhaust flow rate as monitored by the differential pressure sensor 263. Thus, as will be discussed in further detail below with respect to Figures 5 - 8 if the mass air flow rate indicated by the MAF sensor 210 is substantially equal to the expected mass air flow rate under a set of predetermined conditions, but the exhaust flow rate (e.g., the pressure in the exhaust system) indicated by the differential pressure sensor 263 is less than the expected exhaust flow rate under the same (or substantially equivalent) set of predetermined conditions, then a degradation source in the exhaust system 225 can be diagnosed.

[0065] Now turning to Figure 3C , which shows an example where the degradation source 310c originates from the engine 110. As mentioned above, the degradation source 310c originating from the engine 110 can include improperly sealed intake / exhaust valves, undesirable camshaft timing, compression problems, or any other engine-specific problems that can cause the engine to pump less effectively than expected or required. In such an example, the MAF sensor 210 cannot be directly used to infer a degradation source originating from the engine, and similarly the differential pressure sensor 263 cannot be directly used to infer such a degradation source. However, an engine with a degradation source will not pump as effectively as expected, so the amount of air drawn into the intake passage (e.g., 242) will be lower than expected under a set of predetermined conditions. Similarly, since less air is generally drawn into the engine via the intake passage, a smaller exhaust flow rate will result. Thus, as will be discussed in further detail below with respect to Figures 5 - 8 if the intake mass air flow rate indicated by the MAF sensor 210 is substantially equal to the exhaust flow rate indicated by the differential pressure sensor 263, but both the intake mass air flow rate and the exhaust flow rate are lower than expected under a set of predetermined conditions, then a degradation source originating from the engine 110 can be diagnosed.

[0066] As discussed above with respect to Figures 3A - 3C the set of predetermined conditions can include an engine speed at a predetermined RPM, the position of the throttle (e.g., 262) at a predetermined angle or open level, the engine being rotated or turned without fuel supply by power from an on-vehicle energy storage device (e.g., 150), etc. Additionally, as discussed above, the "expected" air flow rates in the intake manifold and the exhaust system can include the air flow rates that have been previously established without indicating a degradation source. In other words, as will be discussed in further detail below, the expected air flow rates in the intake manifold and the exhaust system can include those measured under conditions similar to those described above with respect toFigures 3A - 3C The baseline air flow rate in the intake manifold and the exhaust flow rate in the exhaust system under a set of predefined conditions substantially equivalent to the set of predefined conditions being discussed.

[0067] As discussed, one of the set of predefined conditions can include rotating or turning the engine without fuel being supplied to establish the baseline or expected air flow rates in the intake manifold and the exhaust system when no degradation is indicated. Additionally, when performing engine system diagnostics (including comparing values obtained via the MAF sensor 210 and the differential pressure sensor 263), the predefined conditions can similarly include rotating or turning the engine without fuel being supplied. Thus, to avoid customer dissatisfaction due to the engine turning without fuel being supplied, such engine system diagnostics can be performed under conditions where the vehicle operator and passengers are not alerted in the vehicle. Examples can include remote start events when the vehicle is unoccupied, "waking up" the vehicle controller for a certain predefined duration after a cut-off event when the vehicle is unoccupied, etc. In yet another example, engine system diagnostics can be performed in an autonomous vehicle that is indicated as unoccupied. In each of the examples mentioned above, vehicle occupancy can be indicated by one or more of a seat load unit (such as 107), door sensing technology (such as 108), and / or one or more on-board cameras (such as 109).

[0068] Since the engine system diagnostics discussed above can be performed in a vehicle configured as an autonomous vehicle, an example autonomous driving system is discussed below. Figure 4 An example autonomous driving system is discussed. Figure 4 Is a block diagram of an example autonomous driving system 400 that can operate the vehicle system 100 described above at [location]. In this document, the vehicle system 100 will be referred to simply as "the vehicle". As shown, the autonomous driving system 400 includes a user interface device 410, a navigation system 415, at least one autonomous driving sensor 420, and an autonomous mode controller 425. It can be understood that the on-board navigation system 415 can be the same as the on-board navigation system 132 depicted above at [location]. Figure 1 Figure 1

[0069]

[0070] The user interface device 410 can be configured to present information to vehicle passengers in the event that vehicle passengers may be present. However, it can be understood that under certain conditions, the vehicle can operate autonomously without vehicle passengers. The information presented can include audible information or visual information. Additionally, the user interface device 410 can be configured to receive user input. Thus, the user interface device 410 can be located in the passenger compartment of the vehicle (not shown). In some possible implementations, the user interface device 410 can include a touch-sensitive display screen.

[0070] The navigation system 415 can be configured to determine the current position of the vehicle using, for example, a Global Positioning System (GPS) receiver, which is configured to triangulate the position of the vehicle relative to satellites or land-based towers. The navigation system 415 can be further configured to develop a route from the current position to a selected destination and to display a map and present driving directions to the selected destination via, for example, the user interface device 410.

[0071] The autonomous driving sensor 420 can include any number of devices configured to generate signals that assist in navigating the vehicle. Examples of the autonomous driving sensor 420 can include radar sensors, lidar sensors, vision sensors (e.g., cameras), vehicle-to-vehicle infrastructure networks, and the like. When the vehicle 100 is operating in autonomous mode, the autonomous driving sensor 420 can enable the vehicle to "see" the road and the surrounding environment of the vehicle and / or bypass various obstacles. The autonomous driving sensor 420 can be configured to output sensor signals to, for example, the autonomous mode controller 425.

[0072] The autonomous mode controller 425 can be configured to control one or more subsystems 430 when the vehicle is operating in autonomous mode. Examples of subsystems 430 that can be controlled by the autonomous mode controller 425 can include a brake subsystem, a suspension subsystem, a steering subsystem, and a powertrain subsystem. The autonomous mode controller 425 can control any one or more of these subsystems 430 by outputting signals to the control units associated with the subsystems 430. In one example, the brake subsystem can include an antilock braking subsystem configured to apply braking force to one or more of the wheels (e.g., 135). Applying braking force to one or more of the vehicle wheels, as discussed herein, can be referred to as activating the brakes. To control the vehicle autonomously, the autonomous mode controller 425 can output appropriate commands to the subsystems 430. The commands can cause the subsystems to operate according to driving characteristics associated with the selected driving mode. For example, the driving characteristics can include how aggressively the vehicle accelerates and decelerates, how much space the vehicle leaves behind a vehicle in front, how frequently the autonomous vehicle changes lanes, and the like.

[0073] Accordingly, a system for a vehicle can include an engine system that includes an intake manifold, an exhaust system, and an engine. A mass air flow sensor can be positioned in the intake manifold, and a differential pressure sensor can be positioned in the exhaust system, the differential pressure sensor being configured to measure a differential pressure across a gasoline particulate filter positioned in the exhaust system. The system can include a motor that is capable of rotating the engine without fuel being supplied thereto. The system can further include a controller that stores instructions in a non-transitory memory, the instructions when executed causing the controller to: under a first condition, obtain a baseline measurement of intake air flow and a baseline measurement of exhaust air flow via the mass air flow sensor and the differential pressure sensor, respectively. Under a second condition, the system can obtain a test measurement of intake air flow and a test measurement of exhaust air flow during an engine system diagnosis that includes indicating the presence or absence of a degradation source originating from one of the intake manifold, the exhaust system, or the engine. In such an example, the presence or absence of the degradation source can be based on 1) comparing the baseline measurement of intake air flow and the test measurement of intake air flow obtained under the first condition and the second condition, respectively, and 2) comparing the baseline measurement of exhaust air flow and the test measurement of exhaust air flow obtained under the first condition and the second condition, respectively.

[0074] In such a system, the controller can include additional instructions to: 1) in response to the test measurement of intake air flow being substantially equal to the baseline measurement of intake air flow, but where the test measurement of exhaust air flow is greater than the baseline measurement of exhaust air flow, indicate that the degradation source is present in the intake manifold, 2) in response to the test measurement of intake air flow being substantially equal to the baseline measurement of intake air flow, but where the test measurement of exhaust air flow is lower than the baseline measurement of exhaust air flow, indicate that the degradation source is present in the exhaust system, and 3) in response to both the test measurement of intake air flow being lower than the baseline measurement of intake air flow and the test measurement of exhaust air flow being lower than the baseline measurement of exhaust air flow, indicate that the degradation source is present in the engine.

[0075] Such a system can further include a throttle positioned in the intake manifold, where the controller can store further instructions to: rotate the engine without fuel being supplied thereto by the motor for a predetermined duration not only under the first condition but also under the second condition, where the throttle is controlled to a predetermined position to allow air to be drawn into the engine while the engine is rotating without fuel being supplied thereto.

[0076] The system may further include an intake filter positioned upstream of the throttle, and wherein the controller stores additional instructions to: in response to an indication that a baseline measurement of the intake air flow rate and a baseline measurement of the exhaust air flow rate have been obtained under the first condition, and further in response to an indication that the gasoline particulate filter has not been regenerated and the intake filter has not been replaced since the baseline measurement of the intake air flow rate and the baseline measurement of the exhaust air flow rate were obtained under the first condition, obtain a test measurement of the intake air flow rate and a test measurement of the exhaust air flow rate under the second condition.

[0077] The system may further include additional instructions to: in response to an indication that the vehicle is unoccupied under both the first condition and the second condition, obtain a test measurement of the intake air flow rate and a test measurement of the exhaust air flow rate and obtain a baseline measurement of the intake air flow rate and a baseline measurement of the exhaust air flow rate.

[0078] The system may further include additional instructions to: if the pressure difference across the gasoline particulate filter does not exceed a threshold pressure difference, prevent regeneration of the gasoline particulate filter in response to obtaining a baseline measurement of the intake air flow rate and a baseline measurement of the exhaust air flow rate under the first condition.

[0079] The system may further include additional instructions to: in response to the gasoline particulate filter being regenerated after the first condition and before the second condition, obtain again a baseline measurement of the intake air flow rate and a baseline measurement of the exhaust air flow rate before the second condition.

[0080] It will be appreciated that in the above examples of the system, the two conditions are not mutually exclusive. In other words, in the absence of the purpose of performing the second condition, there would be no motivation to perform the first condition. More specifically, if the second condition is not subsequently performed, there would be no reason to obtain the baseline measurement of the intake air flow rate and the baseline measurement of the exhaust air flow rate under the conditions set forth herein for the first condition.

[0081] Now turning to Figure 5, shows a high-level example method 500 for performing engine system diagnostics. More specifically, method 500 can be used to diagnose the presence or absence of degradation originating from the vehicle's intake manifold, exhaust system, or engine by comparing the intake and exhaust flow rates under a set of predetermined conditions with baseline intake and exhaust flow rates (baseline intake and exhaust flow rates obtained under a substantially equivalent set of predetermined conditions). In this way, the source of degradation can be precisely located in the intake manifold, exhaust system, or engine compartment. By precisely locating the source of degradation, the repair procedure can be simplified, and problems related to the engine system can be diagnosed quickly and accurately, which can lead to an increase in the lifespan of the engine system components.

[0082] Method 500 will be described with reference to the system described herein and shown in Figures 1 - 4 , but it should be understood that similar methods can be applied to other systems without departing from the scope of the present disclosure. Method 500 can be executed by a controller (such as the controller 212 in Figure 2 ) and can be stored as executable instructions in a non-transitory memory at the controller. The instructions for executing method 500 and the remaining methods included herein can be executed by the controller based on the instructions stored on the controller's memory and in combination with signals received from sensors of the engine system (such as the sensors described above with reference to Figures 1 - 4 ). The controller can employ engine system actuators according to the following methods, such as a motor (e.g., 120), a throttle (e.g., 262), a canister purge valve (e.g., 261), etc.

[0083] Method 500 begins at 505 and can include indicating whether the conditions are met for obtaining baseline comparator data for engine system diagnostics. The conditions being met for obtaining baseline comparator data can include an indication that the vehicle is unoccupied. As discussed above, seat load units, in-vehicle camera(s), and / or door sensing techniques can be used to ensure that the vehicle is unoccupied. Thus, baseline comparator data can be obtained in response to a remote start event, or by waking up the controller within a predetermined duration after a shutdown event, or in the case where the vehicle contains an unoccupied autonomous vehicle. More specifically, if the vehicle is in operation, e.g., if the vehicle is being propelled via a motor (e.g., 120), an engine (e.g., 110), or some combination thereof, the conditions are not indicated as being met for obtaining baseline comparator data for engine system diagnostics. Further still, the conditions being indicated as met at 505 can include an indication that the source of degradation has not yet been indicated as present in the vehicle's intake manifold, exhaust system, or engine.

[0084] Additionally, the condition being met at 505 for obtaining baseline comparator data can include an indication that baseline comparator data has not been obtained within a predetermined duration since the previous baseline comparator data measurement. In some examples, such a predetermined duration can include 1 day, greater than 1 day but less than 2 days, greater than 2 days, etc. If at 505 the condition is indicated as being met for obtaining baseline comparator data, method 500 can proceed to 510, where baseline comparator data can be obtained according to method 600 depicted at Figure 6 therein.

[0085] Alternatively, if the condition is not indicated as being met at 505 for obtaining baseline comparator data, method 500 can proceed to 515 and can include indicating whether the condition is met for performing an engine system diagnosis. The condition being met for performing an engine system diagnosis can similarly include an indication that the vehicle is unoccupied, which can include a remote start event, waking up the controller within a predetermined duration after a shutdown event, or an unoccupied autonomous vehicle. Additionally, the condition being met at 515 for performing an engine system diagnosis can include an indication that baseline comparator data has been obtained within a threshold duration for the engine system diagnosis expected to be performed at 515. In some examples, the threshold duration since baseline comparator data has been obtained can include 1 day or less, greater than 1 day but less than 2 days, greater than 2 days but less than 3 days, etc. Further, the condition being met at 515 for performing an engine system diagnosis can include an indication that the intake system filter (e.g., 215) has not been replaced since baseline comparator data has been obtained, and can further include an indication that the GPF (e.g., 217) has not been regenerated since baseline comparator data has been obtained. Another example includes an indication that a degradation source has not been indicated as being present in the vehicle's intake manifold, exhaust system, or engine.

[0086] In some other examples, the condition being met for performing an engine system diagnosis can include an indication of a disturbance to the air-fuel ratio as monitored by an exhaust sensor (e.g., 237). For example, if during a driving cycle when the engine is running (e.g., combusting air and fuel), it is indicated that the engine system suddenly runs lean (or rich), then one possibility is that there is a degradation source originating from the intake manifold, exhaust system, or engine. Thus, if the engine system suddenly indicates an unexpected air-fuel ratio, then such an indication can be stored at the controller. Assuming that all conditions are met at step 515 of method 500 for performing an engine system diagnosis, such an indication stored at the controller will trigger the performance of an engine system diagnosis.

[0087] If it is indicated at step 515 that the conditions are not met for performing engine system diagnostics, method 500 can proceed to 520 and can include maintaining the current vehicle operating parameters. For example, if the vehicle is not running, where the engine is off (not combusting air and fuel), and where the motor is not being used to propel the vehicle, then these conditions can be maintained. Alternatively, if the vehicle is running, then the current vehicle operating parameters can be maintained. In an example case where an air-fuel ratio perturbation is shown and thus engine system diagnostics are needed but the conditions are not indicated as met at 515, such an indication can be stored at the controller such that engine system diagnostics can be triggered in response to the conditions being met for performing engine system diagnostics. In another example, where one of the conditions not indicated as met at 515 includes a lack of appropriate baseline comparator data (e.g., the obtained baseline comparator data is greater than a threshold duration before performing engine system diagnostics, or the intake filter (e.g., 215) was replaced or the GPF was regenerated after obtaining the baseline comparator data), the method can include setting a flag at the controller and illuminating a malfunction indicator lamp on the vehicle instrument panel. Such an indication can warn the vehicle operator that the vehicle needs to be serviced for potential sources of degradation, e.g., originating from the intake manifold, exhaust system, or engine compartment, because engine system diagnostics cannot be performed without appropriate baseline comparator data.

[0088] To prevent such a situation, in some examples, the vehicle controller can prevent GPF regeneration in response to obtaining baseline comparator data until engine system diagnostics have been performed. However, the controller can rely on pressure measurements indicated by a differential pressure sensor (e.g., 263) to determine whether it is important to regenerate the GPF at the expense of engine system diagnostics, or whether GPF regeneration can be prevented until engine system diagnostics have been performed. For example, if during engine operation, a threshold differential pressure is obtained by the differential pressure sensor (e.g., 263) corresponding to the GPF, then it can be determined that the GPF can be regenerated even though such an event will result in engine system diagnostics not being able to be performed until subsequent baseline comparator data is obtained.

[0089] In cases where GPF regeneration is enabled after obtaining baseline comparator data such that new baseline comparator data can be obtained, a flag can be set at the controller indicating that GPF regeneration occurred after obtaining baseline comparator data such that new baseline comparator data can be obtained at the next available opportunity (e.g., as discussed above, when the conditions are met for obtaining baseline comparator data).

[0090] Similar situations can occur if the intake filter (e.g., 215) is replaced after obtaining the baseline comparator data. For example, a flag can be set at the controller in these situations, commanding the vehicle controller to obtain the baseline comparator data at the next opportunity (when the condition is indicated as being met for obtaining the baseline comparator data).

[0091] Returning to step 515 of method 500, if the condition is indicated as being met for performing engine system diagnostics, method 500 can proceed to 525 and can include, according to Figure 6 performing engine system diagnostics. It can be understood that both obtaining the baseline comparator data and performing engine system diagnostics can include substantially equivalent methods included by method 600.

[0092] Now turning to Figure 6 , a high-level example method 600 for obtaining the baseline comparator data and / or performing a portion of the engine system diagnostics is shown. More specifically, method 600 can be used to obtain baseline comparator data that can be used in conjunction with the method 500 depicted at Figure 5 in order to perform engine system diagnostics relying on the baseline comparator data. In this way, the source of degradation can be precisely located as originating from the vehicle's intake manifold, exhaust system, or engine.

[0093] Method 600 will be described with reference to the system described herein and shown in Figures 1 - 4 , but it should be understood that similar methods can be applied to other systems without departing from the scope of the present disclosure. Method 600 can be executed by a controller (such as the controller 212 in Figure 2 ) and can be stored as executable instructions at the controller in non-transitory memory. The instructions for executing method 600 and the remaining methods included herein can be executed by the controller based on the instructions stored on the controller's memory and in combination with signals received from sensors of the engine system (such as the sensors described above with reference to Figures 1 - 4 ). The controller can employ engine system actuators, such as a motor (e.g., 120), throttle (e.g., 262), canister purge valve (e.g., 261), etc., according to the following method.

[0094] Method 600 begins at 605 and can include controlling the throttle (e.g., 262) to a predetermined throttle position. As discussed above, such a throttle can include an electronic throttle that can be actuated to open or close via the vehicle controller using power / electricity supplied by an on-vehicle energy storage device (e.g., 150), which can include, for example, a battery. The predetermined throttle position can include a position that is more open than the closed position to, for example, allow intake air to be drawn into the engine via the intake manifold.

[0095] In response to controlling the throttle to a predetermined throttle position, method 600 may proceed to 610. At 610, method 600 may include rotating the engine at a predetermined speed (e.g., a predetermined RPM) for a predetermined duration without fuel being supplied to the engine. Rotating the engine without fuel being supplied may include rotating the engine in the same direction as when the engine is operated to combust air and fuel. Rotating the engine without fuel being supplied may further include rotating the engine via a motor (e.g., 120), where the motor may be powered by an on-vehicle energy storage device (e.g., 150) such as a battery. The speed of the engine may be further controlled to a predetermined speed via the motor. The predetermined engine speed may include a speed at which a robust measurement of the air flow can be obtained by a MAF sensor (e.g., 210) and by a differential pressure sensor (e.g., 263) corresponding to the GPF (e.g., 217). Additionally, although not explicitly illustrated, it can be understood that the canister purge valve (e.g., 261) may remain closed during rotation of the engine to ensure that air is not sucked from the evaporative emissions system and / or the fuel system. Further still, although not explicitly shown, for a vehicle equipped with exhaust gas recirculation (EGR) (e.g., high-pressure EGR and / or low-pressure EGR), one or more valves controlling the exhaust gas recirculation may be commanded or held closed. Further still, in order to rotate the engine without fuel being supplied, the valve timing may be controlled to a default value.

[0096] In the case where the engine is rotated without fuel being supplied at a predetermined engine speed, method 600 may proceed to 615. At 615, method 600 may include obtaining an intake air flow measurement value and an exhaust gas flow measurement value. More specifically, the MAF sensor (e.g., 210) may be used at step 620 to obtain the intake air flow measurement value, while the differential pressure sensor (e.g., 263) may be used at step 625 to obtain the exhaust gas flow measurement value. These measurements may be obtained by making one or more individual measurements during the predetermined duration of rotation of the engine without fuel being supplied. In an example where more than one measurement is obtained while the engine is rotated without fuel being supplied, these measurements may be averaged or otherwise processed to obtain a high-confidence value of the desired measurement.

[0097] These obtained measurement values may be stored at the vehicle controller for engine system diagnosis, which is discussed in further detail at Figure 5 below.

[0098] In response to the intake air flow measurement and the exhaust air flow measurement obtained at steps 620 and 625 respectively, method 600 may proceed to 630. At 630, method 600 may include stopping the engine from rotating without fuel supply, and may further include returning the throttle to the default configuration. For example, the motor (e.g., 120) may be commanded to stop the engine, while the vehicle controller may send a signal to the electronic throttle to actuate the throttle to the default position.

[0099] As mentioned above, it can be understood that the method discussed at Figure 6 involves obtaining baseline comparator data and performing engine system diagnostics after obtaining the baseline comparator data. Therefore, for the sake of brevity, this method will not be discussed here again. Therefore, it can be understood that method 600 can be used in combination with Figure 5 to obtain baseline comparator data at step 510 and perform engine system diagnostics at step 525.

[0100] Therefore, returning to step 515 of method 500, in response to having obtained the baseline comparator data and the conditions are met for an indication to perform engine system diagnostics, method 500 may proceed to 525, where intake air flow measurement and exhaust air flow measurement are obtained according to Figure 6 . In response to obtaining these measurements, method 500 may proceed to 530. At step 530, method 500 may include interpreting the results of the engine system diagnostics performed at step 525 according to Figure 7 .

[0101] Therefore, proceeding to Figure 7 , which illustrates an example look-up table that can be used to interpret the results of engine system diagnostics. For example, such a look-up table may be stored at the vehicle controller. As illustrated at Figure 7 , there may be four distinct results (A - D) that may be produced by the engine system diagnostics.

[0102] Result A may include the situation where the measured value of the intake air flow as measured by the MAF sensor is substantially equal to the baseline measured value of the intake air flow as measured by the MAF sensor, but the exhaust air flow monitored by the differential pressure sensor is greater than the baseline measured value of the exhaust air flow as measured by the differential pressure sensor. In such an example, it may be indicated that there is a degradation source such as those depicted above at Figure 3A . As discussed, a degradation source from the intake manifold can thus cause un-metered air to be introduced into the engine, and thus the exhaust air flow will be greater than the exhaust air flow expected in the absence of a degradation source (e.g., in the baseline case).

[0103] Result B can include a situation where the measured value of the intake air flow as measured by the MAF sensor is substantially equal to the baseline measured value of the intake air flow as measured by the MAF sensor, but the exhaust air flow as monitored by the differential pressure sensor is less than the baseline measured value of the exhaust air flow as measured by the differential pressure sensor. In such an example, it can be indicated that there is a degradation source originating from the exhaust system such as depicted above at Figure 3B . As discussed, a degradation source originating from the exhaust system can thus cause the exhaust flow to be forced to the atmosphere via the degradation source before reaching the differential pressure sensor. Therefore, such a process can result in the differential pressure sensor reading being lower than the differential pressure sensor reading expected in the absence of a degradation source (e.g., in the baseline case).

[0104] Result C can include a situation where both the intake air flow as measured by the MAF sensor and the exhaust air flow as measured by the differential pressure sensor are less than the baseline measured values obtained by the MAF sensor and the differential pressure sensor. In such an example, it can be understood that there can be a degradation source originating from the engine compartment related to the engine operation. As discussed, such a degradation source can include an intake valve and / or an exhaust valve that is not properly sealed, compression problems related to the (one or more) engine cylinders, degraded piston rings, degraded cylinder head gaskets, an undesirable camshaft timing, etc. In such a case where the engine is identified as a degradation source, the engine does not pump as expected, thus resulting in generally less air being drawn into the engine via the intake manifold and a corresponding lower amount of exhaust flow being directed through the exhaust system.

[0105] Result D can include a situation where both the intake air flow as measured by the MAF sensor and the exhaust air flow as measured by the differential pressure sensor are substantially equal to the baseline measured values obtained by the MAF sensor and the differential pressure sensor. In such an example, it can be indicated that there is no degradation source originating from the intake manifold, the exhaust system, and / or the engine.

[0106] It can be understood that in any of the potential Results A - D discussed above, sensor readings that are substantially equal to their respective baseline measured values can include measured values within a certain range of each other, e.g., less than or equal to a 5% difference of the measured values within the engine system diagnostic span.

[0107] After interpreting the result of the engine system diagnosis at step 530 of method 500, method 500 can proceed to 535. At 535, method 500 can include adjusting vehicle operating parameters based on the result of the engine system diagnosis. As an example, assuming a degradation source is identified in the intake manifold, the exhaust system, and / or the engine, the MIL on the vehicle dashboard will be illuminated, warning the vehicle operator that the vehicle needs to be repaired.

[0108] If the degradation source is indicated as originating from the intake manifold, in some examples, the vehicle controller may adjust the throttle position during engine operation while fuel is being supplied, to account for unmetered air entering the engine via the degradation source.

[0109] In other examples where the degradation source is indicated as originating from the intake manifold, the exhaust system, or the engine compartment, adjusting the vehicle operating parameters may include the vehicle controller commanding an electric operating mode as frequently as possible, to mitigate a potential release of undesirable emissions to the atmosphere, and / or to mitigate potential mechanical problems with the engine in cases where the engine is inhaling a greater amount of air than desired, or to mitigate problems already present in the engine compartment.

[0110] Turning now to Figure 8 , an example timeline 800 is shown for obtaining baseline comparator measurements and for performing engine system diagnostics in accordance with the method depicted herein and with reference to Figures 5 - 6 the method depicted herein and with reference to Figures 1 - 4 the system depicted herein. Timeline 800 includes, over time, a graphical curve 805 indicating whether the engine is on or off, a graphical curve 810 indicating the fuel injection state (on or off) to the engine, and a graphical curve 815 indicating the position of the throttle (e.g., 262). The throttle can be open, closed, or somewhere in between.

[0111] Timeline 800 further includes a graphical curve 820 indicating engine speed (RPM) over time. The engine speed can be 0 (e.g., stopped), or greater than stopped (+). Timeline 800 further includes a graphical curve 825 indicating the airflow as monitored by a MAF sensor (e.g., 210) over time, and a graphical curve 830 indicating the exhaust flow as measured by a GFP differential pressure (dP) sensor (e.g., 263) over time. In both graphical curves 825 and 830, the sensor may not record any flow (0), or may record a flow above 0 (+). Timeline 800 further includes a graphical curve 835 indicating the air-fuel ratio as monitored via an exhaust sensor (e.g., 237) over time. The air-fuel ratio can be stoichiometric (the ideal ratio of air to fuel to burn all fuel without excess air), or can be richer or leaner than stoichiometric.

[0112] The timeline 800 further includes, over time, a graph 840 indicating whether a condition is indicated as being met for obtaining baseline comparator data, a graph 845 indicating whether a condition is indicated as being met for performing engine system diagnostics, a graph 850 indicating whether the vehicle is occupied, and a graph 855 indicating whether a degradation source is present in the engine system. The source can be the engine, the intake manifold (intake device), or the exhaust system (exhaust device).

[0113] At time t0, the engine is off, so fuel is not being injected into the engine cylinders and the engine speed is 0 RPM. Although not explicitly shown, it can be understood that at time t0, the vehicle is also not being propelled by the motor. The position of the throttle is substantially closed, reflecting the position of the throttle in the engine-off / vehicle-stopped state. With the engine off, there is no air-fuel ratio to measure, so the air-fuel ratio is not indicated at time t0. Similarly, the MAF sensor in the intake manifold located downstream of the throttle does not record any air flow, and the GPF differential pressure sensor does not record any exhaust flow. At time t0, the condition is not indicated as being met for obtaining baseline comparator data, and the condition is not further indicated as being met for performing an engine system diagnostic test. The vehicle is not indicated as being occupied, and degradation is not indicated in the engine system.

[0114] At time t1, the condition is indicated as being met for obtaining baseline comparator data, as discussed above with respect to step 505 of method 500. In this example timeline 800, it can be understood that condition satisfaction can include a situation where a predetermined duration has elapsed since a cutoff event, where the controller is awakened to obtain baseline comparator data. In other examples, the condition can be satisfied in response to a remote start event where the vehicle is not occupied or where the vehicle includes an autonomous vehicle that is not occupied.

[0115] Accordingly, at time t1, in response to the condition being indicated as being met for obtaining baseline comparator data, the engine is controlled to rotate without fuel injection, where rotating the engine without fuel supply can include rotating the engine via a motor (e.g., 120), powered by an on-board energy storage device (e.g., 150) such as a battery, as discussed above with respect to step 610 of method 600. The motor can control the engine speed to a predetermined engine speed, illustrated by graph 820. Additionally, at time t1, the position of the throttle is controlled to a predetermined throttle position, as discussed above with respect to step 605 of method 600.

[0116] Between times t1 and t2, with the engine rotating without fuel being supplied, due to no fuel injection, the air-fuel ratio as indicated by the exhaust sensor is indicated as lean. The intake air flow is monitored via the MAF sensor between times t1 and t2, and the exhaust gas flow is monitored via the GPF differential pressure sensor between times t1 and t2. As discussed, these measurements can be stored at the vehicle's controller such that subsequent measurements of the intake air flow and the exhaust gas flow can be compared to the baseline measurements in order to precisely locate potential sources of degradation originating from the vehicle's intake manifold, exhaust system, or engine.

[0117] After a predetermined duration at time t2, the engine is controlled to 0 RPM via the electric motor. In other words, the engine rotates to a stop. Although not explicitly illustrated, it can be understood that in the case of a remote start event, after obtaining the baseline comparator data (or after performing an engine system diagnosis), instead of rotating the engine to a stop, fuel is supplied to the engine in anticipation of the vehicle operator operating the vehicle. Additionally, the throttle position is controlled to a default configuration, which in this example includes the configuration in which the throttle was in prior to obtaining the baseline comparator data. Since the engine rotates to a stop, the air flow as measured by the MAF sensor drops to no flow, and the exhaust gas flow as measured by the GPF differential pressure sensor drops to no flow. Since the baseline comparator data has been obtained and stored at the controller, and a predetermined duration has elapsed at time t2, the condition is no longer indicated as being met for obtaining the baseline comparator data.

[0118] At time t3, the vehicle is occupied. This indication can be provided via a door sensor, a seat load cell, one or more on-board cameras, etc. At time t4, the engine is turned on, where fuel injection is provided to one or more engine cylinders. In other words, by time t4, the vehicle operator has entered the vehicle and started the engine with the intention of driving the vehicle.

[0119] Between times t4 and t5, the vehicle is driven, so the throttle position varies according to the driver's demand, and the engine speed is controlled according to the driver's demand. While the engine is running, both the MAF sensor and the GPF differential pressure sensor measure the intake air flow and the exhaust gas flow that vary according to the driver's demand, respectively.

[0120] Between times t4 and t5, the air-fuel ratio remains substantially equal to the stoichiometric air-fuel ratio. However, at time t5, the air-fuel ratio suddenly transitions to lean. As discussed above, a sudden or abrupt change in the air-fuel ratio can indicate potential degradation in the engine system. Thus, it is understood that in response to the change in the air-fuel ratio beginning at time t5, such results can be stored at the vehicle controller such that an engine system diagnosis can be initiated at the next opportunity (when conditions are indicated as being met for performing an engine system diagnosis).

[0121] Between times t5 and t6, the vehicle continues to operate with the engine combusting air and fuel. In some examples, in response to perturbations in the air-fuel ratio, adaptive fuel learning can correct the lean air-fuel ratio, indicated by the dashed line 836. However, in other examples, the vehicle may not include adaptive fuel learning and thus may not correct the lean air-fuel ratio.

[0122] At time t6, the engine is turned off and fuel supply to the engine is stopped. At time t7, the vehicle is unoccupied again.

[0123] After a period of time, at time t8, conditions are indicated as being met for performing an engine system diagnosis, as discussed above with respect to step 515 of method 500. Since conditions are indicated as being met for an engine system diagnosis, the engine is rotated again by the motor without fuel injection. The throttle is controlled to the same predetermined throttle position as the throttle position during acquisition of the baseline comparator data. Additionally, the engine speed (RPM) is controlled to the same engine speed as the engine speed during acquisition of the baseline comparator data.

[0124] Thus, between times t8 and t9, in addition to the GPF differential pressure sensor readings, MAF sensor readings are also obtained. With the engine being rotated without fuel supply, the air-fuel ratio is indicated as being lean during engine rotation. Line 826 indicates the baseline MAF sensor measurement obtained between times t1 and t2. Similarly, line 831 indicates the baseline GPF differential pressure sensor measurement obtained between times t1 and t2.

[0125] At time t9, with a predetermined duration having elapsed (the predetermined duration being substantially equal to the predetermined duration of engine rotation for obtaining baseline comparator data), the engine system diagnosis is complete. With the engine system diagnosis complete, the vehicle controller can compare the values obtained from the MAF sensor and the GPF differential pressure sensor during the engine system diagnosis with the corresponding values obtained during acquisition of the baseline comparator data. As discussed above, a look-up table (such as the one above in Figure 7The lookup table 700 depicted herein can be used to interpret the results of engine system diagnostics. In this example timeline, the MAF sensor readings during engine system diagnostics are indicated as being substantially equal to the corresponding MAF sensor readings obtained during acquisition of baseline comparator data. Additionally, the GPF differential pressure sensor readings during engine system diagnostics are indicated as being substantially equal to the corresponding GPF differential pressure sensor readings obtained during acquisition of baseline comparator data. Such an example thus represents result A as discussed above with respect to Figure 7 wherein it is indicated in Figure 7 that the degradation originates from the intake manifold.

[0126] In this manner, degradation originating from the intake manifold of the engine system, the exhaust system (upstream of the GPF differential pressure sensor and downstream of the engine), or the engine can be precisely located by comparing intake flow measurements and exhaust flow measurements with baseline intake flow measurements and baseline exhaust flow measurements, where the baseline intake flow measurements and baseline exhaust flow measurements are obtained when the engine system is not degraded. By precisely locating the source of degradation, customer satisfaction can be improved as the time spent by technicians on the vehicle can be reduced.

[0127] The technical effect is realized that a mass air flow sensor located in the intake manifold of the engine cannot effectively diagnose the source of degradation originating from the intake manifold unless such a measurement of mass air flow is considered in conjunction with a pressure sensor in the exhaust system. Similarly, the source of degradation originating from the engine or the exhaust system is not directly specifiable unless the measured values of intake flow and exhaust flow are considered together. In all examples (e.g., the source of degradation is from the intake manifold, the exhaust system, or the engine), a further technical effect is realized that the measured values of intake flow and exhaust flow can be compared with the baseline measured values of intake flow and exhaust flow such that determination of the source of degradation can be achieved by separately comparing both the intake flow and exhaust flow with the baseline intake flow measurement and baseline exhaust flow measurement. A still further technical effect is realized that by rotating the engine without fuel being supplied at a predetermined engine speed for a predetermined duration and with the throttle controlled to a predetermined open position, the conditions for baseline measurement and for measurement of intake flow and exhaust flow during actual test diagnostics can be substantially equivalent. In this manner, the source of degradation originating from the intake manifold, the exhaust system, or the engine can be conclusively diagnosed.

[0128] In this document and with reference to Figures 1 - 4 the system described herein and with reference to Figures 5 - 6The described method can implement one or more systems and one or more methods. In one example, a method includes performing engine system diagnostics by rotating the engine of a vehicle without fuel supply to draw intake air flow into the engine via an intake manifold and direct exhaust air flow to the atmosphere via an exhaust system; and indicating a source of degradation originating from one of the engine, the intake manifold, or the exhaust system based on both the intake air flow and the exhaust air flow during the rotation. In a first example of the method, the method further includes, prior to performing the engine system diagnostics, obtaining a set of baseline comparator data including a baseline intake air flow and a baseline exhaust air flow under a set of conditions substantially equivalent to a set of conditions for performing the engine system diagnostics, the set of substantially equivalent conditions including rotating the engine without fuel supply by a battery-powered motor. A second example of the method optionally includes the first example and further includes, wherein the set of substantially equivalent conditions further includes rotating the engine at a predetermined speed for a predetermined duration and controlling a throttle positioned in the intake manifold to a predetermined position to allow air to be drawn into the engine via the intake manifold. A third example of the method optionally includes any one or more or each of the first to second examples and further includes, wherein the intake air flow and the baseline intake air flow are measured by a mass air flow sensor positioned in the intake manifold, and wherein the exhaust air flow and the baseline exhaust air flow are measured by a pressure sensor positioned in the exhaust system. A fourth example of the method optionally includes any one or more or each of the first to third examples and further includes, wherein the pressure sensor includes a differential pressure sensor corresponding to a particulate filter positioned in the exhaust system. A fifth example of the method optionally includes any one or more or each of the first to fourth examples and further includes, wherein obtaining the set of baseline comparator data is performed under conditions where the engine system does not have the source of degradation. A sixth example of the method optionally includes any one or more or each of the first to fifth examples and further includes, wherein in response to the intake air flow being substantially equal to the baseline intake air flow during the engine system diagnostics, but wherein the exhaust air flow is greater than the baseline exhaust air flow during the engine system diagnostics, the source of degradation is indicated in the intake manifold. A seventh example of the method optionally includes any one or more or each of the first to sixth examples and further includes, wherein in response to the intake air flow being substantially equal to the baseline intake air flow during the engine system diagnostics, but wherein the exhaust air flow is lower compared to the baseline exhaust air flow during the engine system diagnostics, the source of degradation is indicated in the exhaust system.An eighth example of the method optionally includes any one or more or each of the first through seventh examples, and further includes, wherein in response to both the intake flow rate and the exhaust flow rate being respectively below the baseline intake flow rate and the baseline exhaust flow rate during the engine system diagnosis, the source of degradation is indicated as originating from the engine. A ninth example of the method optionally includes any one or more or each of the first through eighth examples, and further includes, wherein in response to both the intake flow rate being substantially equal to the baseline intake flow rate and the exhaust flow rate being substantially equal to the baseline exhaust flow rate during the engine system diagnosis, the source of degradation does not exist in any of the intake manifold, the exhaust system, or the engine.

[0129] An example of a system for a vehicle includes: an engine system including an intake manifold, an exhaust system, and an engine; a mass air flow sensor positioned in the intake manifold; a differential pressure sensor positioned in the exhaust system and configured to measure a pressure difference across a gasoline particulate filter positioned in the exhaust system; a motor capable of rotating the engine; and a controller storing instructions in a non-transitory memory, the instructions when executed causing the controller to: under a first condition, obtain a set of baseline measurements of intake flow and a set of baseline measurements of exhaust flow via the mass air flow sensor and the differential pressure sensor respectively; under a second condition, obtain a set of test measurements of intake flow and a set of test measurements of exhaust flow during an engine system diagnosis, the engine system diagnosis including indicating the presence or absence of a degradation source originating from one of the intake manifold, the exhaust system, or the engine; and wherein the presence or absence of the degradation source is based on both: 1) comparing the baseline measurement of intake flow and the test measurement of intake flow obtained under the first condition and the second condition respectively with each other, and 2) comparing the baseline measurement of exhaust flow and the test measurement of exhaust flow obtained under the first condition and the second condition respectively with each other. In a first example of the system, the system further includes additional instructions to: in response to the test measurement of intake flow being substantially equal to the baseline measurement of intake flow, but wherein the test measurement of exhaust flow is greater than the baseline measurement of exhaust flow, indicate that the degradation source is present in the intake manifold; in response to the test measurement of intake flow being substantially equal to the baseline measurement of intake flow, but wherein the test measurement of exhaust flow is lower than the baseline measurement of exhaust flow, indicate that the degradation source is present in the exhaust system; and in response to not only the test measurement of intake flow being lower than the baseline measurement of intake flow, but also the test measurement of exhaust flow being lower than the baseline measurement of exhaust flow, indicate that the degradation source is present in the engine. A second example of the system optionally includes the first example and further includes: a throttle positioned in the intake manifold; and wherein the controller stores further instructions to: rotate the engine un-fueled by the motor for a predetermined duration not only under the first condition but also under the second condition, wherein the throttle is controlled to a predetermined position to allow air to be drawn into the engine while the engine is rotating un-fueled.A third example of the system optionally includes any one or more or each of the first and second examples, and further includes an intake filter positioned upstream of the throttle, and wherein the controller stores additional instructions to: in response to an indication that a baseline measurement of the set of intake air flow rates and a baseline measurement of the exhaust gas flow rate have been obtained under the first condition, and further in response to an indication that the gasoline particulate filter has not been regenerated and the intake filter has not been replaced since the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate were obtained under the first condition, obtain a test measurement of the set of intake air flow rates and a test measurement of the exhaust gas flow rate under the second condition. A fourth example of the system optionally includes any one or more or each of the first through third examples, and further includes additional instructions to: in response to an indication that the vehicle is unoccupied under both the first condition and the second condition, obtain a test measurement of the set of intake air flow rates and a test measurement of the exhaust gas flow rate and obtain a baseline measurement of the set of intake air flow rates and a baseline measurement of the exhaust gas flow rate. A fifth example of the system optionally includes any one or more or each of the first through fourth examples, and further includes additional instructions to: if the pressure difference across the gasoline particulate filter does not exceed a threshold pressure difference, prevent regeneration of the gasoline particulate filter in response to obtaining the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate under the first condition. A sixth example of the system optionally includes any one or more or each of the first through fifth examples, and further includes additional instructions to: in response to the gasoline particulate filter being regenerated after the first condition and before the second condition, obtain again the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate before the second condition.

[0130] Another example of the method includes rotating the vehicle's engine without fuel supply to draw air into the engine via the intake manifold and then discharging the air to the atmosphere via the exhaust system to obtain a set of baseline measurements of the intake air flow and a set of baseline measurements of the exhaust air flow, wherein the set of baseline measurements of the intake air flow and the set of baseline measurements of the exhaust air flow are subsequently compared with a set of test measurements of the intake air flow and a set of test measurements of the exhaust air flow under a set of conditions that are substantially equivalent to those for obtaining the set of baseline measurements of the intake air flow and the set of baseline measurements of the exhaust air flow; and indicating the presence or absence of a degradation source originating from one of the intake manifold, the exhaust system, or the engine based on comparing the set of baseline measurements of the intake air flow and the set of baseline measurements of the exhaust air flow with the set of test measurements of the intake air flow and the set of test measurements of the exhaust air flow. In a first example of the method, the method further includes, in response to the test measurement of the intake air flow being substantially equal to the baseline measurement of the intake air flow but where the test measurement of the exhaust air flow is greater than the baseline measurement of the exhaust air flow, indicating that the degradation source is present in the intake manifold; in response to the test measurement of the intake air flow being substantially equal to the baseline measurement of the intake air flow but where the test measurement of the exhaust air flow is below the baseline measurement of the exhaust air flow, indicating that the degradation source is present in the exhaust system; and in response to both the test measurement of the intake air flow being below the baseline measurement of the intake air flow and the test measurement of the exhaust air flow being below the baseline measurement of the exhaust air flow, indicating the presence of the degradation source originating from the engine. A second example of the method optionally includes the first example and further includes that rotating the engine without fuel supply is performed under the condition that the vehicle is unoccupied and the vehicle is not in motion; and that the set of conditions that are substantially equivalent to those for obtaining the set of test measurements of the intake air flow and the set of test measurements of the exhaust air flow and the set of baseline measurements of the intake air flow and the set of baseline measurements of the exhaust air flow includes rotating the engine at a predetermined speed for a predetermined duration, where a throttle positioned in the engine intake device is controlled to a predetermined position, and further in response to an indication that a filter positioned upstream of the throttle or a particulate filter positioned in the exhaust system has not been replaced or regenerated, respectively, after obtaining the set of baseline measurements of the intake air flow and the set of baseline measurements of the exhaust air flow.

[0131] Note that the example control and estimation routines included herein can be used with a variety of engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and executed by a control system including a controller combined with 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, multi-tasking, multi-threading, etc. Accordingly, the various acts, operations, and / or functions described can be executed in the illustrated order, in parallel, or in some cases omitted. Likewise, the features and advantages of the example embodiments of the invention described herein are not necessarily required to be in the described processing order, but are provided for ease of illustration and description. Depending on the particular strategy employed, one or more of the acts, operations, and / or functions shown can be repeated. Additionally, the acts, operations, and / or functions described can be graphically represented as code in a non-transitory memory of a computer-readable storage medium incorporated into the engine control system, where the described acts are implemented by executing instructions in a system including various engine hardware components in combination with an electronic controller.

[0132] It should be recognized that the configurations and routines disclosed herein are exemplary in nature and these specific embodiments are not to be considered limiting as many variations are possible. For example, the above techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of the present 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.

[0133] The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to "a" element or "a first" element or the equivalent thereof. These claims should be understood to include the combination of one or more such elements, neither requiring nor precluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or characteristics can be claimed by modifying the existing claims or by presenting new claims in this or a related application. These claims, whether broader, narrower, the same, or different in scope from the original claims, are regarded as included within the subject matter of the present disclosure.

Claims

1. A method for a vehicle, comprising: Obtaining a set of baseline comparator data before performing an engine system diagnosis of the vehicle, the set of baseline comparator data including a baseline intake air flow rate and a baseline exhaust gas flow rate under a set of conditions that are substantially equivalent to a set of conditions for performing the engine system diagnosis; Performing the engine system diagnosis by rotating the engine of the engine system without fuel supply to suck in the intake air flow rate via the intake manifold and direct the exhaust gas flow rate to the atmosphere via the exhaust system; and Indicating a source of degradation originating from one of the engine, the intake manifold, or the exhaust system based on both a comparison of the intake air flow rate during the rotation with the baseline intake air flow rate and a comparison of the exhaust gas flow rate during the rotation with the baseline exhaust gas flow rate.

2. The method according to claim 1, wherein the set of substantially equivalent conditions includes rotating the engine without fuel supply by a motor powered by a battery.

3. The method according to claim 2, wherein the set of substantially equivalent conditions further includes rotating the engine at a predetermined rotational speed for a predetermined duration and controlling a throttle positioned in the intake manifold to a predetermined position to allow air to be sucked into the engine via the intake manifold.

4. The method according to claim 2, wherein the intake air flow rate and the baseline intake air flow rate are measured by a mass air flow sensor positioned in the intake manifold, and wherein the exhaust gas flow rate and the baseline exhaust gas flow rate are measured by a pressure sensor positioned in the exhaust system.

5. The method according to claim 4, wherein the pressure sensor includes a differential pressure sensor corresponding to a particulate filter positioned in the exhaust system.

6. The method according to claim 2, wherein obtaining the set of baseline comparator data is performed under conditions where the engine system has no source of degradation.

7. The method according to claim 2, wherein in response to the intake air flow rate being substantially equal to the baseline intake air flow rate during the engine system diagnosis, but wherein the exhaust gas flow rate is greater than the baseline exhaust gas flow rate during the engine system diagnosis, the source of degradation is indicated in the intake manifold.

8. The method according to claim 2, wherein in response to the intake air flow rate being substantially equal to the baseline intake air flow rate during the engine system diagnosis, but wherein the exhaust gas flow rate is lower than the baseline exhaust gas flow rate during the engine system diagnosis, the source of degradation is indicated in the exhaust system.

9. The method according to claim 2, wherein in response to both the intake air flow rate and the exhaust gas flow rate being lower than the baseline intake air flow rate and the baseline exhaust gas flow rate, respectively, during the engine system diagnosis, the source of degradation is indicated as originating from the engine.

10. The method according to claim 2, wherein in response to not only the intake air flow rate being substantially equal to the baseline intake air flow rate during the engine system diagnosis, but also the exhaust gas flow rate being substantially equal to the baseline exhaust gas flow rate during the engine system diagnosis, the degradation source does not exist in any one of the intake manifold, the exhaust system, or the engine.

11. A system for a vehicle, comprising: An engine system including an intake manifold, an exhaust system, and an engine; A mass air flow sensor positioned in the intake manifold; A differential pressure sensor positioned in the exhaust system and configured to measure a pressure difference across a gasoline particulate filter positioned in the exhaust system; A motor capable of rotating the engine; And A controller storing instructions in a non-transitory memory, the instructions when executed causing the controller to: Obtain a baseline measurement of an intake air flow rate and a baseline measurement of an exhaust gas flow rate via the mass air flow sensor and the differential pressure sensor, respectively, under a first condition for obtaining baseline comparator data; Obtain a test measurement of an intake air flow rate and a test measurement of an exhaust gas flow rate during the engine system diagnosis under a second condition for performing the engine system diagnosis, the engine system diagnosis including indicating the presence or absence of a degradation source originating from one of the intake manifold, the exhaust system, or the engine; and Wherein the presence or absence of the degradation source is based on both: 1) comparing the baseline measurement of the intake air flow rate and the test measurement of the intake air flow rate obtained under the first condition and the second condition, respectively, and 2) comparing the baseline measurement of the exhaust gas flow rate and the test measurement of the exhaust gas flow rate obtained under the first condition and the second condition, respectively.

12. The system according to claim 11, further comprising additional instructions to: Indicate that the degradation source exists in the intake manifold in response to the test measurement of the intake air flow rate being substantially equal to the baseline measurement of the intake air flow rate, but wherein the test measurement of the exhaust gas flow rate is greater than the baseline measurement of the exhaust gas flow rate; Indicate that the degradation source exists in the exhaust system in response to the test measurement of the intake air flow rate being substantially equal to the baseline measurement of the intake air flow rate, but wherein the test measurement of the exhaust gas flow rate is lower than the baseline measurement of the exhaust gas flow rate; And Indicate that the degradation source exists in the engine in response to not only the test measurement of the intake air flow rate being lower than the baseline measurement of the intake air flow rate, but also the test measurement of the exhaust gas flow rate being lower than the baseline measurement of the exhaust gas flow rate.

13. The system according to claim 11, further comprising: A throttle positioned in the intake manifold; and The controller stores further instructions to: rotate the engine un-fueled by the motor for a predetermined duration not only under the first condition but also under the second condition, wherein the throttle valve is controlled to a predetermined position to allow air to be drawn into the engine while the engine is rotating un-fueled.

14. The system of claim 13, further comprising an intake filter positioned upstream of the throttle valve, and wherein the controller stores additional instructions to: in response to an indication that a baseline measurement of the set of intake air flow rates and a baseline measurement of the exhaust gas flow rate have been obtained under the first condition, and further in response to an indication that the gasoline particulate filter has not been regenerated and the intake filter has not been replaced since the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate were obtained under the first condition, obtain a test measurement of the set of intake air flow rates and a test measurement of the exhaust gas flow rate under the second condition.

15. The system of claim 11, further comprising additional instructions to: in response to an indication that the vehicle is unoccupied under both the first condition and the second condition, obtain a test measurement of the set of intake air flow rates and a test measurement of the exhaust gas flow rate and obtain a baseline measurement of the set of intake air flow rates and a baseline measurement of the exhaust gas flow rate; if the pressure difference across the gasoline particulate filter does not exceed a threshold pressure difference, prevent regeneration of the gasoline particulate filter in response to obtaining the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate under the first condition; and in response to the gasoline particulate filter being regenerated after the first condition and before the second condition, obtain again the baseline measurement of the set of intake air flow rates and the baseline measurement of the exhaust gas flow rate before the second condition.

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