System and method for mitigating wet fouling of a spark plug

Abstract

The present disclosure provides "Systems and methods for mitigating spark plug wet fouling." Methods and systems for drying a wet-fouled spark plug during an engine floodback condition are provided. In one example, a method can include causing the engine to reverse direction without fueling, and activating heating elements of an exhaust catalyst to cause heated ambient air to flow through a combustion chamber to dry the wet-fouled spark plug.

Description

Technical Field

[0001] This manual generally relates to methods and systems for drying wet-sludge spark plugs in engines. Background Technology

[0002] An engine ignition system may include spark plugs for delivering electric current to the combustion chamber of a spark-ignition engine (such as a gasoline engine) to ignite the air-fuel mixture and initiate combustion. Spark plug fouling can occur, where the ignition tip of the spark plug insulator is coated with foreign matter, such as fuel or soot particles. Spark plugs fouled by soot particles include carbon deposits on the spark plug electrodes, while wet-fouled spark plugs include liquid fuel accumulating around the electrodes. For example, spark plugs may have wet fouling due to engine overflow. During extreme temperature weather conditions, the engine may overflow due to rich fuel or excessive fuel inside the cylinder (e.g., due to fuel injector degradation) when the driver repeatedly presses / pumps the accelerator pedal during cranking. When spark plugs have wet fouling, they cannot produce a spark at the electrodes, thus delaying or preventing the engine from starting. In some cases, engine overflow may cause a frustrated vehicle driver to continue cranking the engine until the battery is depleted. Furthermore, vehicle emissions may increase due to repeated unsuccessful cranking attempts during engine overflow.

[0003] Dudar discloses an exemplary method for resolving wet spark plug deposits in U.S. Patent No. 9,790,874. In this method, when deposited spark plugs are detected before engine start, ambient air can be drawn in and directed to one or more engine cylinders via an evaporative emission control (EVAP) system. The ambient air can be drawn in by a pump operating the EVAP system, and can be heated via a heater connected to the fuel vapor filter canister of the EVAP system. The heated ambient air flowing through the engine cylinders promotes the drying of the spark plugs.

[0004] However, the inventors in this paper have recognized the potential problems of such systems. As an example, the fuel vapor filter of an EVAP system can become saturated with fuel vapor, and by drawing ambient air through the fuel vapor filter, unwanted amounts of fuel vapor can be directed into the engine cylinders during the engine's non-combustion period. Because the fuel vapor is unburned, vehicle evaporative emissions may increase. Furthermore, fuel vapor may hinder the drying of wet spark plugs. Turning the starter without providing additional airflow to dry the spark plugs may be inefficient, leading to increased engine start-up time. Increased engine start-up time may increase driver frustration and excessive battery drain. Summary of the Invention

[0005] In one example, the aforementioned problem can be addressed by an engine method comprising: in response to fuel overflow in the combustion chamber of a spark-ignition engine during an engine start-up attempt, cutting off fuel supply to the combustion chamber, activating a heating element of a catalyst connected to the engine's exhaust manifold, and reversing the engine to allow air heated by the heating element to flow through the exhaust manifold into the combustion chamber. In this way, by reversing the engine and directing the heated air from the electrically heated catalyst into the engine cylinders, deposited spark plugs can be dried.

[0006] In one example, in an electrically heated catalytic converter (EHC), a heating element connected to the catalytic converter can be activated to heat the catalytic converter during engine start-up to accelerate catalytic ignition. When a wet spark plug is detected, the engine can be rotated in the reverse direction without fuel via the engine motor. Because the engine is rotating in reverse, ambient air can be drawn into the engine system via the exhaust manifold. The heating element connected to the EHC can be activated to heat the ambient air flowing to the engine cylinders via the EHC. The heated air dries the wet spark plug as it enters the engine cylinders. After the heated air has been directed through the engine cylinders for more than a threshold duration, the spark plugs connected to one or more cylinders can be activated to generate a spark. If a characteristic secondary waveform is detected for each generated spark, it can be confirmed that the spark plug is dry. Upon confirmation that the spark plug is dry, the engine can be stopped from rotating in reverse and fuel can be resumed for engine start-up.

[0007] In this way, by utilizing existing engine components, such as electrically heated catalysts, as needed, the need for additional equipment or external intervention for spark plug drying can be reduced or eliminated. By reversing the engine rotation, the drop in exhaust pressure can be used to draw in ambient air and dry the spark plugs. The advantage of using heated airflow to dry spark plugs is that multiple spark plugs can be dried simultaneously as the engine rotates and the cylinder valves of each cylinder periodically open and close. In short, wet spark plugs can dry faster than without additional airflow, thus shortening engine start-up time and thereby reducing driver frustration.

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

[0009] Figure 1An exemplary vehicle system including spark plugs is schematically shown.

[0010] Figures 2A to 2B An exemplary H-bridge circuit is schematically shown, which can be used to rotate a vehicle engine in a forward or reverse direction.

[0011] Figure 3 A flowchart illustrating an exemplary method for drying wet-smudge spark plugs is shown.

[0012] Figure 4 A flowchart illustrating an exemplary method for determining whether a wet spark plug is dry is shown.

[0013] Figure 5 An exemplary secondary ignition pulse emitted by a functioning spark plug is shown.

[0014] Figure 6 An exemplary drying of a wet-smudged spark plug is shown according to this disclosure. Detailed Implementation

[0015] The following description relates to methods for mitigating the effects of engine systems (such as) by providing on-demand heated airflow. Figure 1 The system and method for preventing spark plug wet deposits in the engine system shown. To enable the engine to rotate in both forward and reverse directions without fuel, an H-bridge circuit, such as in... Figures 2A to 2B The H-bridge circuit is depicted in the diagram. In response to an indication of spark plug wetness, the vehicle's engine controller can be configured, for example, according to... Figure 3 and Figure 4 The method described herein performs an exemplary procedure to dry one or more spark plugs. During drying, the active spark plugs can generate secondary ignition pulses (waveforms), such as... Figure 5 The pulse shown can be used to verify that the spark plug has dried successfully. Figure 6 An exemplary engine operation for drying wet-sludge spark plugs is shown.

[0016] Figure 1An example of a cylinder 14 of an internal combustion engine 10, which may be included in a vehicle 5, is depicted. The engine 10 may be controlled at least in part by a control system including a controller 12 and by input from a vehicle driver 130 via an input device 132. In this example, the input device 132 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. The cylinder 14 of the engine 10 (also referred to herein as a “combustion chamber”) may include a combustion chamber wall 136 in which a piston 138 is located. The piston 138 may be connected to a crankshaft 140 such that the reciprocating motion of the piston is converted into rotational motion of the crankshaft. The crankshaft 140 may be connected to at least one wheel 55 via a transmission 54, as further described below. Furthermore, a starter motor (not shown) may be connected to the crankshaft 140 via a flywheel to enable starting operation of the engine 10.

[0017] In some examples, vehicle 5 may include an autonomous vehicle and / or a hybrid vehicle having multiple torque sources available for one or more wheels 55. In other examples, vehicle 5 is a conventional vehicle with only an engine or an electric vehicle with only one or more electric motors. In the example shown, vehicle 5 includes an engine 10 and an electric motor 52. The electric motor 52 may be a motor or an electric motor / generator. When one or more clutches 56 are engaged, the crankshaft 140 of engine 10 and the electric motor 52 are connected to the wheels 55 via a transmission 54. In the depicted example, a first clutch 56 is disposed between the crankshaft 140 and the electric motor 52, while a second clutch 56 is disposed between the electric motor 52 and the transmission 54. Controller 12 may send signals to the actuators of each clutch 56 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 140 from the electric motor 52 and its connected components, and / or connecting or disconnecting the electric motor 52 from the transmission 54 and its connected components. The transmission 54 may be a gearbox, a planetary gear system, or other type of transmission.

[0018] The powertrain can be configured in various ways, including parallel, series, or series-parallel hybrid vehicles. In an electric vehicle embodiment, the system battery 58 may be a traction battery that delivers power to the motor 52 to provide torque to the wheels 55. In some embodiments, the motor 52 may also function as a generator to provide power, for example, to charge the system battery 58 during braking operations. It should be understood that in other embodiments, including non-electric vehicle embodiments, the system battery 58 may be a typical starter-light-ignition (SLI) battery connected to the alternator 46.

[0019] Alternator 46 can be configured to charge system battery 58 via crankshaft 140 using engine torque during engine operation. Additionally, alternator 46 can supply power to one or more electrical systems based on corresponding electrical requirements of the engine's electrical systems, such as one or more auxiliary systems (including heating, ventilation, and air conditioning (HVAC) systems, electric heaters connected to the electric heated catalytic converter (EHC), headlights, in-vehicle entertainment systems, and other auxiliary systems). In one example, the current drawn from the alternator can vary based on each of cabin cooling requirements, battery charging needs, other auxiliary vehicle system requirements, and motor torque. A voltage regulator can be connected to alternator 46 to regulate the alternator's power output based on system usage requirements, including auxiliary system requirements.

[0020] Cylinder 14 of engine 10 can receive intake air via a series of intake ports 142 and 144 and an intake manifold 146. In addition to cylinder 14, the intake manifold 146 can also communicate with other cylinders of engine 10. One or more of the intake ports may include one or more supercharging devices, such as turbochargers or superchargers. For example, Figure 1 An engine 10 equipped with a turbocharger is shown, the turbocharger including a compressor 174 disposed between intake manifolds 142 and 144 and an exhaust turbine 176 disposed along an exhaust manifold 135. When the supercharging device is configured as a turbocharger, the compressor 174 may be powered at least partially via the exhaust turbine 176 through a shaft 180. However, in other examples, such as when the engine 10 is equipped with a mechanical supercharger, the compressor 174 may be powered by mechanical input from a motor or the engine, and the exhaust turbine 176 may optionally be omitted. In yet another example, the engine 10 may be equipped with an electromechanical supercharger (e.g., an "eBooster"), and the compressor 174 may be driven by an electric motor.

[0021] A throttle valve 162, including a throttle plate 164, can be disposed in the engine intake manifold to change the flow rate and / or pressure of the intake air supplied to the engine cylinders. For example, the throttle valve 162 can be located downstream of the compressor 174, such as... Figure 1 As shown, or alternatively, it can be located upstream of compressor 174.

[0022] In addition to cylinder 14, exhaust manifold 148 can also receive exhaust gas from other cylinders of engine 10. Exhaust sensor 126 is shown connected upstream of emission control device 178 to exhaust manifold 148. Exhaust sensor 126 can be selected from a variety of suitable sensors for providing an indication of exhaust air-fuel ratio (AFR), such as, for example, a linear oxygen sensor or UEGO (universal or wide-range exhaust oxygen sensor), a dual-state oxygen sensor or EGO, HEGO (heated EGO), nitrogen oxides (NOx), hydrocarbons (HC), or carbon monoxide (CO) sensors. Figure 1 In the example, exhaust sensor 126 is a UEGO. Emission control device 178 can be a three-way catalytic converter, a NOx trap, various other emission control devices, or a combination thereof. Figure 1 In the example, emission control device 178 is an electrically heated catalyst (EHC). An electric heater (also referred to herein as a heating element) 179 may be connected to EHC 178 to electrically heat the catalyst during cold start conditions. By actively heating EHC 178, catalyst ignition can be accelerated, thereby improving emission quality during cold start conditions.

[0023] An exhaust gas recirculation (EGR) delivery passage may be connected upstream of the turbine 176 to the exhaust port to provide high-pressure EGR (HP-EGR) to the engine intake manifold downstream of the compressor 174. An EGR valve may be connected to the EGR passage at its junction with the intake port. The EGR valve may be opened to allow a controlled amount of exhaust gas to reach the compressor outlet to achieve desired combustion and emission control performance. The EGR valve may be configured as a continuously variable valve or an on / off valve. In other embodiments, the engine system may include a low-pressure EGR (LP-EGR) flow path, wherein exhaust gas is drawn downstream of the turbine 176 and recirculated upstream of the compressor 174 to the engine intake manifold.

[0024] Each cylinder of engine 10 may include one or more intake valves and one or more exhaust valves. For example, cylinder 14 is shown to include at least one intake lift valve 150 and at least one exhaust lift valve 156 located in the upper region of cylinder 14. In some examples, each cylinder of engine 10 including cylinder 14 may include at least two intake lift valves and at least two exhaust lift valves located in the upper region of the cylinder. Intake valve 150 may be controlled by controller 12 via actuator 152. Similarly, exhaust valve 156 may be controlled by controller 12 via actuator 154. The positions of intake valve 150 and exhaust valve 156 may be determined by corresponding valve position sensors (not shown).

[0025] During certain states, controller 12 can modify the signals provided to actuators 152 and 154 to control the opening and closing of the corresponding intake and exhaust valves. The valve actuators can be electrically actuated, cam-actuated, or a combination thereof. Intake and exhaust valve timing can be controlled simultaneously, or any of the following possibilities can be used: variable intake cam timing, variable exhaust cam timing, dual independent variable cam timing, or fixed cam timing. Each cam-actuated system can include one or more cams and can utilize one or more of a cam profile changing (CPS) system, variable cam timing (VCT) system, variable valve timing (VVT) system, and / or variable valve lift (VVL) system that can be operated by controller 12 to change valve operation. For example, cylinder 14 may optionally include an intake valve controlled by electric valve actuation and an exhaust valve controlled by cam actuation (including CPS and / or VCT). In other examples, the intake and exhaust valves may be controlled by a common valve actuator (or actuation system) or a variable valve timing actuator (or actuation system).

[0026] Cylinder 14 may have a compression ratio, which is the volume ratio when piston 138 is at bottom dead center (BDC) to top dead center (TDC). In one example, the compression ratio is in the range of 9:1 to 10:1. However, in some examples using different fuels, the compression ratio may be increased. This may happen, for example, when using fuels with higher octane ratings or fuels with higher potential enthalpy of vaporization. The compression ratio may also be increased if direct injection is used due to its effect on engine knock.

[0027] In some examples, each cylinder of engine 10 may be configured with one or more fuel injectors for supplying fuel thereto. As a non-limiting example, cylinder 14 is shown including a fuel injector 166. Fuel injector 166 may be configured to deliver fuel received from fuel system 8. Fuel system 8 may include one or more fuel tanks, fuel pumps, and fuel rails. Fuel injector 166 is shown directly connected to cylinder 14 for injecting fuel therein in proportion to the pulse width of the signal FPW received from controller 12 via electronic actuator 168. In this way, fuel injector 166 provides so-called direct fuel injection (hereinafter also referred to as "DI") into cylinder 14. Although Figure 1A fuel injector 166 is shown located on one side of cylinder 14, but the fuel injector 166 may optionally be located on top of the piston, such as near spark plug 192. Due to the lower volatility of some alcohol-based fuels, such a location may increase mixing and combustion when the engine is operated with alcohol-based fuels. Alternatively, the injector may be located on top and near the intake valve to increase mixing. Fuel can be delivered from the fuel tank of fuel system 8 to the fuel injector 166 via a high-pressure fuel pump and fuel rail. Furthermore, the fuel tank may have a pressure sensor that provides a signal to controller 12.

[0028] In an alternative example, fuel injector 166 may be configured to be located in the intake manifold rather than directly connected to cylinder 14, providing so-called port fuel injection (hereinafter also referred to as "PFI") to the intake manifold upstream of cylinder 14. In other examples, cylinder 14 may include multiple injectors, which may be configured as direct fuel injectors, port fuel injectors, or combinations thereof. Therefore, it should be understood that the fuel system described herein should not be limited to the specific fuel injector configurations described herein by way of example.

[0029] Fuel injector 166 can be configured to receive different fuels as fuel mixtures from fuel system 8 in different relative amounts, and is also configured to inject the fuel mixture directly into the cylinder. Furthermore, fuel can be delivered to cylinder 14 during different strokes of a single cycle of the cylinder. For example, directly injected fuel can be delivered at least partially during the previous exhaust stroke, during the intake stroke, and / or during the compression stroke. Thus, for a single combustion event, one or more fuel injections can be performed per cycle. Multiple injections can be performed during the compression stroke, intake stroke, or any suitable combination thereof; this is known as split fuel injection.

[0030] Each cylinder of engine 10 may include a spark plug 192 for initiating combustion. In a selected operating mode, ignition system 190 may provide an ignition spark to combustion chamber 14 via spark plug 192 in response to a spark advance signal SA from controller 12. The timing of signal SA can be adjusted based on engine operating conditions and driver torque requirements. For example, a spark can be provided at maximum braking torque (MBT) timing to maximize engine power and efficiency. Controller 12 can input engine operating conditions (including engine speed, engine load, and exhaust AFR) into a lookup table and output the corresponding MBT timing for the input engine operating conditions. In other examples, the spark can be delayed from the MBT, such as to accelerate catalyst preheating during engine start-up or reduce engine knock.

[0031] During engine overflow, spark plug 192 may be wet and may not produce a spark. Engine overflow can be determined based on at least one of the following: the position of throttle 162 during engine start-up attempts, the output of exhaust sensor 126 during engine start-up attempts, and the number of engine start-up attempts reaching a threshold without combustion in the combustion chamber. In one example, during engine overflow, throttle 162 is fully open, and the output of exhaust sensor 126 is rich in stoichiometric air-fuel ratio. To dry the wet spark plug, fuel delivery to the combustion chamber can be cut off, the electric heater 179 of catalyst 178 can be activated, and the engine can be reversed via motor 52 to allow air heated by electric heater 179 to flow through exhaust manifold 148 and catalyst 178 into combustion chamber 14. After the heated air has flowed through combustion chamber 14 for more than a threshold duration, spark plug 192 can be activated, and / or a secondary pulse detected from spark plug 192 can indicate that the combustion chamber is dry. In response to the detection of a secondary pulse from spark plug 192, the engine may cease rotating via the electric motor, and the vehicle driver may be notified to start the engine. In response to an instruction to dry combustion chamber 14, and upon reaching the ignition temperature of catalyst 178, operation of electric heater 179 may be suspended.

[0032] Controller 12 in Figure 1The controller 12, shown as a microcomputer, includes a microprocessor unit 106, an input / output port 108, an electronic storage medium (shown in this particular example as a non-transitory read-only memory chip 110) for executable programs (e.g., executable instructions) and calibration values, random access memory 112, keep-alive memory 114, and a data bus. The controller 12 can receive various signals from sensors connected to the engine 10, including those previously discussed and additionally including measurements of intake mass airflow (MAF) from mass airflow sensor 122; engine coolant temperature (ECT) from temperature sensor 116 connected to cooling manifold 118; exhaust temperature from temperature sensor 158 connected to exhaust manifold 135; surface ignition sensing signal (PIP) from Hall effect sensor 120 (or other type of sensor) connected to crankshaft 140; throttle position (TP) from throttle position sensor; signal UEGO from exhaust sensor 126, which can be used by the controller 12 to determine exhaust AFR; and absolute manifold pressure signal (MAP) from MAP sensor 124. The controller 12 can generate an engine speed signal (RPM) from the PIP signal. The manifold pressure signal (MAP) from the MAP sensor 124 can be used to provide an indication of vacuum or pressure in the intake manifold. The controller 12 can infer the engine temperature based on the engine coolant temperature and infer the temperature of the emission control unit 178 based on the signal received from the temperature sensor 158.

[0033] Controller 12 from Figure 1 Various sensors receive signals and employ Figure 1 Various actuators adjust engine operation based on received signals and instructions stored in the controller's memory. For example, the controller can detect an indication of spark plug wetness based on a signal TP from the throttle position sensor during an engine start-up attempt. In response to the spark plug wetness indication, the controller can activate the electric heater 179 and reverse the engine rotation via the motor 52 to allow heated air to flow through the cylinder 14 until the spark plugs are dry, as referenced... Figure 3 As described.

[0034] As mentioned above, Figure 1 Only one cylinder of a multi-cylinder engine is shown. Therefore, each cylinder can similarly include its own set of intake / exhaust valves, one or more fuel injectors, spark plugs, etc. It should be understood that engine 10 can include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders. Furthermore, each of these cylinders can include components manufactured by… Figure 1 Some or all of the various components described and depicted with reference to cylinder 14.

[0035] Figure 2A and Figure 2B An exemplary circuit 200 is shown that can be used to reverse the rotational orientation of an electric motor. Circuit 200 schematically depicts an H-bridge circuit that can be used to alternately operate the motor 210 in a first (forward) direction and a second (reverse) direction. Circuit 200 includes a first (LO) side 220 and a second (HI) side 230. Side 220 includes transistors 221 and 222, while side 230 includes transistors 231 and 232. Circuit 200 also includes a power supply 240.

[0036] exist Figure 2A In this configuration, transistors 221 and 232 are activated (excited), while transistors 222 and 231 are deactivated. In this configuration, the left lead 251 of motor 210 is connected to power supply 240, while the right lead 252 of motor 210 is connected to ground. In this way, motor 200 can operate in the forward (or default) direction. When the engine is operated in the forward direction via the motor, the engine can be in a rotation start mode for initial combustion initiation. Additionally and / or alternatively, when the engine is operated in the forward direction via the motor, the engine (and the motor or another motor) can be in a drive mode to drive the vehicle. It is understood that in some examples, the engine can rotate in the forward (e.g., default) direction while the vehicle is stationary, and it is desirable for the engine to rotate or spin in the forward direction without combustion.

[0037] exist Figure 2B In this configuration, transistors 222 and 231 are activated (energized), while transistors 221 and 232 are deactivated. In this configuration, the right lead 252 of motor 210 is connected to power supply 240, while the left lead 251 of motor 210 is connected to ground. In this way, motor 210 can run in the opposite direction.

[0038] In this way, Figures 1 to 2B The components provide a system comprising: a vehicle, including autonomous vehicles and / or hybrid vehicles; an electric motor; an engine including one or more cylinders, an intake manifold, and an exhaust manifold, each cylinder including a spark plug; an intake throttle valve connected to the intake manifold; an electrically heated catalyst (EHC) including an electric heater and an oxygen sensor connected to the exhaust manifold; and a controller having computer-readable instructions stored in a non-transitory memory, the computer-readable instructions, when executed during engine off and during engine overflow indication and before engine start, causing the controller to: activate the electric heater of the EHC, simultaneously dry each cylinder by providing a heated airflow from the exhaust manifold via the EHC, and deactivate the electric heater in response to each of a secondary pulse generated by a spark plug connected to each cylinder and the electric heater temperature of the EHC rising above the ignition temperature.

[0039] Figure 3 An exemplary method 300 is shown that can be implemented to dry wet spark plugs during engine overflow conditions. The instructions for performing method 300 and the remaining methods included herein can be obtained by a controller based on instructions stored in the controller's memory and in conjunction with data from sensors in the engine system (such as those referenced above). Figure 1 The controller uses signals received by the described sensor to perform the operation. According to the method described below, the controller can employ the engine actuator of the engine system to adjust engine operation. For example, method 300 can be performed before an engine start attempt, such that a wet spark plug can be detected during the engine start attempt and subsequently dried using a heated airflow.

[0040] Method 300 begins at 302 and includes estimating and / or measuring operating conditions. Operating conditions may include, for example, ambient temperature, ambient pressure, ambient humidity, throttle position (e.g., signal TP from the throttle position sensor output), accelerator pedal position (e.g., signal PP from the pedal position sensor output), exhaust air-fuel ratio (e.g., determined by signal UEGO from the exhaust sensor output), engine coolant temperature, engine state, and vehicle ignition state. Engine state may refer to whether the engine is on (e.g., operating at a non-zero speed, with combustion occurring in the engine cylinders) or off (e.g., stationary, with no combustion occurring in the engine cylinders). Vehicle ignition state may refer to the position of the ignition switch. As an example, the ignition switch may be in the "off" position, indicating that the vehicle is off (e.g., power is off, vehicle speed is zero), but (e.g., by the vehicle driver) the ignition key is inserted, indicating that the vehicle may soon be requested to start. As another example, the vehicle may be on and operating in a purely electric mode, where the electric motor (e.g., Figure 1 The motor 52) supplies torque to propel the vehicle, and the engine is turned off and does not supply torque to propel the vehicle.

[0041] At 304, method 300 includes starting the engine in response to an engine start request. In one example, the engine starts in response to a vehicle driver (such as by turning the ignition key, pressing the ignition button, or requesting engine start from a remote control device (such as a key fob, smartphone, tablet, etc.)) switching the ignition switch to the "on" position. In another example, the engine starts in response to the vehicle switching from a pure electric mode to an engine mode, in which combustion occurs in the engine and the vehicle is propelled at least partially by torque derived from the engine. For example, when the system battery (e.g., Figure 1When the state of charge (SOC) of the system battery (58) drops below a threshold SOC, the vehicle can switch to engine mode. The threshold SOC can be a positive, non-zero battery SOC level below which the system battery may be unable to support or perform additional vehicle functions while propelling the vehicle via torque derived from the electric motor. As another example, if the vehicle driver's torque demand rises above a threshold torque, the vehicle can switch to engine mode. For example, the threshold torque can be a positive, non-zero torque amount that the electric motor alone cannot meet or maintain. Starting the engine can include turning the starter engine with an electric motor (such as a starter motor or electric motor). The engine can be turned at a speed that allows combustion to begin and maintains momentum during starting (e.g., a speed in the range of 50 RPM to 100 RPM).

[0042] At point 306, it is determined whether spark plug wetness is detected. For example, spark plug wetness can be detected if there is an indication of engine overflow. Engine overflow can be indicated by a fully open throttle (WOT) signal, which is generated when the vehicle driver depresses the accelerator pedal to its maximum extent during engine start-up. In some examples, the controller can be configured to prevent spark plugs from being coated with fuel in response to the WOT signal, such as by reducing or completely suppressing fuel injection pulses during start-up. In other examples, the WOT signal during start-up is an indication of spark plug wetness. As another example, engine overflow can be inferred from an exhaust sensor indicating a rich AFR during start-up (e.g., an AFR determined from the exhaust sensor output is less than a threshold AFR). As yet another example, engine overflow (and therefore spark plug wetness) can be inferred from a lack of engine start-up after a predetermined number of engine start-up attempts.

[0043] If, for example, spark plug wet deposits are not detected when a WOT signal is absent during engine start-up, the determined AFR is not less than a threshold AFR, or the engine starts within a predetermined number of engine start-up attempts, then method 300 proceeds to 308 to include delivering fuel to the engine cylinders and providing a spark to initiate combustion. For example, fuel can be delivered to the engine cylinders by actuating the fuel injector at a nominal fuel pulse width for engine start-up and a given operating condition. The controller can control the operating conditions (including ambient humidity, MAF (as determined by a MAF sensor such as...)). Figure 1The MAF sensor 122 outputs the determined AFR and the desired AFR, which are input into one or more lookup tables, algorithms, and / or maps to determine the fuel pulse width and output the fuel pulse width to be sent to the fuel injectors. Similarly, a spark can be provided at the nominal spark timing (such as at or near the maximum braking torque (MBT) timing) used for starting operation and a given operating condition. The controller can input operating conditions (such as engine speed and load, engine coolant temperature, ambient temperature, exhaust temperature, MAP, etc.) into one or more lookup tables, algorithms, and / or maps and output the spark timing. The determined spark timing is sent to the ignition system (e.g., Figure 1 The signal SA from the ignition system 190 can trigger the spark plug to ignite the air-fuel mixture. After 308, method 300 ends.

[0044] If wet deposits are detected on the spark plug at 306, method 300 proceeds to 310 and optionally includes notifying the vehicle driver that a drying procedure is being performed. For example, a message may be displayed to the driver on a human-machine interface on the vehicle's dashboard, indicating that a drying procedure is being performed and that no further attempts to start the engine should be made until prompted. Upon notification to the driver, the driver can stop further engine starting attempts, thereby preventing potential depletion of the system battery.

[0045] At 312, method 300 includes disabling fuel delivery and spark. Additional fuel delivery, due to engine overflow, can exacerbate wet deposits, increase vehicle emissions, and affect emission controls (e.g., ...). Figure 1 Emission control devices (178) deteriorate and reduce fuel economy. Further wet fouling, emission control device deterioration, increased vehicle emissions, and reduced fuel economy can be avoided by disabling fuel delivery (e.g., by keeping fuel injectors closed). When wet fouling occurs, spark plugs may fail to generate a spark at their electrodes, thus actuating the spark plugs may be inefficient. For example, disabling the spark in response to an indication of spark plug wet fouling can reduce energy consumption and prevent excessive spark plug wear.

[0046] At 314, the controller can direct power to an electrically heated catalyst (such as...). Figure 1 The electric heater (EHC178 in the system) sends a signal to activate the electric heater. This can be done via the system battery (such as...) Figure 1 The battery 58 in the battery supplies power to the electric heater. In one example, if an engine start is requested during a period below the EHC threshold temperature (such as the ignition temperature), the electric heater may already be operational and remain operational. The electric heater actively heats the EHC during cold starts to accelerate the attainment of the catalyst ignition temperature.

[0047] At 316, the procedure includes rotating or turning the engine in the opposite direction without fuel at a predetermined speed (e.g., a predetermined RPM). Rotating the engine in the opposite direction can include rotating the engine in the opposite direction to when the engine operates to burn air and fuel. Rotating the engine in the opposite direction without fuel can include directing airflow sequentially through the exhaust system, engine cylinders, and intake manifold. Rotating the engine in the opposite direction without fuel can include via a motor (such as...) Figure 1 The motor 52 in the motor rotates the engine, wherein the motor can transmit energy via an onboard energy storage device such as a battery. Figure 1 The battery (58) in the middle is powered. In non-hybrid vehicles, the engine can be reversed via the vehicle's starter motor and the battery. To reverse the engine's rotation, an H-bridge circuit (such as...) can be used. Figures 2A to 2B (The circuit depicted in the diagram). The engine speed can be controlled to a predetermined speed via a motor. The predetermined engine speed can include the speed at which a strong airflow is generated through the cylinders when the engine is reversed. In one example, the predetermined speed can be below 500 rpm.

[0048] At point 318, the controller can signal the throttle plate connected to the intake throttle valve to open the intake throttle valve, signal the wastegate valve connected to the exhaust turbine's wastegate passage to actuate the wastegate valve to the open position, and signal the EGR valve connected to the exhaust gas recirculation (EGR) passage to actuate the EGR valve to the fully closed position, allowing a larger amount of ambient air to enter the engine system via the exhaust system for guidance to the engine cylinders via the EHC. In one example, the intake throttle valve can be fully open, the wastegate valve can be fully open, and the EGR valve can be fully closed. By opening the intake throttle valve, a larger amount of ambient air can be drawn in by rotating the engine. Because the wastegate passage provides a lower resistance path for airflow relative to the exhaust turbine by opening the wastegate valve, at least a portion of the ambient air can flow from the EHC to the engine cylinders via the path of least resistance (through the wastegate passage), thus bypassing the turbine. When the EGR valve is closed, ambient air cannot flow from the exhaust manifold through the EGR passage to the intake manifold, and the entire air volume can be guided through the engine cylinders. Additionally, the fuel vapor filter extraction valve connecting the engine intake manifold to the evaporative emission control (EVAP) system can be actuated to the closed position to isolate the engine intake manifold from the fuel vapor system.

[0049] When ambient air entering the engine system via the exhaust manifold is guided to the engine cylinders through the EHC, the ambient air can be heated by an electric heater. As the engine rotates, the exhaust and intake valves of each cylinder can periodically open and close. The heated air from the EHC can enter the engine cylinder through the corresponding exhaust valve and exit through the corresponding intake valve. As the heated air flows through the engine cylinders, the heat from the air dries the cylinder interior, including the spark plugs.

[0050] At 320, the procedure includes determining whether the spark plugs for each engine cylinder are dry. Figure 4 An exemplary procedure 400 for determining whether the spark plugs in each cylinder are dry is shown. If it is determined that one or more spark plugs are not dry, heated air can continue to be directed through the engine cylinders. At 322, the engine can continue to rotate in reverse and the electric heater connected to the EHC is activated. If it is determined that each spark plug connected to one or more engine cylinders is dry, at 324, the controller can send a signal to the actuator connected to the motor to stop the engine from rotating. In this way, engine reverse rotation can be deactivated when a predetermined number of spark plugs are indicated to be dry. In one example, the predetermined number of spark plugs can be the total number of spark plugs in the engine. At 326, the controller can send a signal to the electric heater connected to the EHC to deactivate the heater when it is confirmed that the EHC has reached its ignition temperature. If, after drying the spark plugs, the catalyst temperature is observed to be below the ignition temperature, the electric heater can operate until the catalyst temperature rises above the ignition temperature.

[0051] At point 328, fuel delivery and spark can be activated. Activating fuel delivery and spark may include actuating the fuel pump to supply fuel to the fuel injectors at high pressure. However, the fuel injectors may not yet be actuated to open. In this way, fuel can be prepared for injection in response to an engine start request (such as an engine start request from the vehicle driver). Similarly, activating spark may include enabling a spark advance signal to be transmitted from the controller to the ignition system (e.g., when an engine start request is anticipated but has not yet been transmitted) in the event of such a request. Figure 1 The ignition system 190 can initiate combustion in the engine cylinders in response to an engine start request by activating fuel delivery and spark.

[0052] At 320, method 300 optionally includes informing the vehicle driver that it is permissible to attempt to start the engine. For example, a message may be displayed to the vehicle driver on a human-machine interface on the vehicle's dashboard, indicating that it is permissible to attempt to start the engine.

[0053] In this way, before starting an engine with one or more cylinders each connected to a spark plug, while the spark plugs are in a wet, sludge-covered state, the spark plugs can be dried by directing heated air through one or more cylinders as the engine rotates in the reverse direction. This air is heated by a heater connected to an electrically heated catalyst (EHC).

[0054] Figure 4 An exemplary method 400 is shown that can be implemented to confirm whether each spark plug connected to each of the cylinders in an engine has dried. Method 400 may be part of method 300 and may be used in... Figure 3 Execute step 320 in method 300.

[0055] At 402, the controller can estimate the time elapsed since the engine reverse rotation was initiated. In one example, a timer can be started when the engine reverse rotation is initiated, and the time elapsed since the engine reverse rotation was initiated can be estimated from the timer. As described in step 316 of method 300, because the engine reverse rotation was initiated, heated air can circulate through the engine cylinders, thereby drying the spark plugs. At 404, the procedure includes determining whether the time since the engine reverse rotation was initiated is greater than a first threshold duration. The first threshold duration can be a non-zero predetermined duration predicted to dry spark plugs with more severe wet deposits via heated air when the engine is reversed without fuel.

[0056] If it is determined that the elapsed time since the engine started reversing is less than a first threshold duration, then at 406, the engine can continue to reverse and the electric heater connected to the electrically heated catalyst will activate. Heated air can then continue to flow through the overflowing engine cylinders. If it is determined that the elapsed time since the engine started reversing is greater than the first threshold duration, the controller can infer that the spark plugs connected to each engine cylinder have dried out.

[0057] The controller can also individually determine whether each spark plug is dry. At 408, the controller can send a signal to the first spark plug connected to the first cylinder to actuate the spark plug without fuel, and can monitor the secondary ignition pulse of the spark plug coil via an ammeter connected to the activated spark plug.

[0058] Figure 5An exemplary secondary ignition pulse (waveform) generated by an active, dry spark plug is shown. The x-axis represents time, and the y-axis represents the amplitude of the current flowing through the primary circuit of the spark plug (recorded by an ammeter connected to the spark plug). Before time t1, no current flows through the primary circuit. At time t1, current may begin to flow through the primary circuit. At time t2, the current through the primary circuit may be limited, and at time t3, a spark may be ignited. The residence time of the current flowing through the primary circuit is between times t1 and t3. Between times t3 and t4, the spark may ignite, causing the air-fuel mixture in the cylinder to ignite. At 410, the procedure includes determining whether a secondary ignition pulse is detected from the activated spark plug (first spark plug). If it is determined that no secondary ignition pulse is detected, it can be inferred that the activated spark plug may not be dry at this time and may require further drying. At 412, the activated spark plug may be deactivated, and the engine may continue to rotate in reverse while the electric heater is activated for a second threshold duration. By continuing to rotate the engine in reverse, further heated air can be supplied to the spark plugs to dry them. The second threshold duration can be a predetermined, non-zero duration predicted to remove any residual moisture from the engine cylinders. After the second threshold duration has elapsed, the procedure can return to step 408 to activate the spark plugs and monitor the secondary ignition pulse.

[0059] If a secondary ignition pulse is detected at 410, it can be inferred at 414 that the last spark plug activated is dry. At 416, the procedure includes determining whether each spark plug connected to each of the engine cylinders has been activated (and a secondary ignition pulse is detected) to ensure that each spark plug is dry. If it is determined that all spark plugs have not been activated, the second spark plug connected to the second cylinder can be activated at 418. In the cylinder bank, the second cylinder may immediately follow the first cylinder (the first spark plug connected to the first cylinder is activated last). The procedure can proceed to step 410, where the secondary ignition pulse corresponding to the second spark plug can be monitored. In this way, the spark plugs connected to each cylinder can be activated sequentially without fuel injection, and the secondary ignition pulse corresponding to each spark plug can be monitored via one or more ammeters connected to each spark plug to confirm that the individual spark plug is dry.

[0060] If it is determined that all spark plugs have been activated, then at 420, it can be inferred that a secondary waveform has been obtained when each spark plug in the engine is actuated (in sequence), and that all spark plugs are dry. The procedure can then proceed to... Figure 3 Step 324 of program 300.

[0061] In this way, heated air is guided through one or more cylinders until a threshold duration has elapsed, and after the threshold duration has elapsed, a first spark plug connected to the first cylinder can be activated. In response to the second spark plug generating a secondary pulse, a second spark plug connected to a different cylinder can be activated, and in response to the second spark plug generating a secondary pulse, it can be indicated that each of the first and second spark plugs is dry.

[0062] Figure 6 An exemplary timeline 600 is shown, illustrating the connection to an engine cylinder (such as...). Figure 1 Cylinder 14) wet scale on spark plugs (such as Figure 1 The drying process is performed on spark plug 192. The horizontal axis (x-axis) represents time, while the vertical markers t0 to t4 indicate critical times in the spark plug drying procedure. Wet spark plugs can be dried by allowing heated air to flow through the engine cylinders for a threshold duration d1. The threshold duration can be calibrated based on a predicted time for drying severely wet spark plugs.

[0063] The first graph (line 602) shows an electric motor (such as...) Figure 1 The first graph (line 604) shows the operating status of the electric motor (52). In one example, the electric motor could be a starter motor. The second graph (line 604) shows the direction of engine rotation. The engine can rotate via the electric motor in the default forward direction or in the reverse direction, which is opposite to the forward direction. The third graph (line 605) shows the opening of the intake throttle valve connected to the engine intake manifold. In the third graph, the vertical axis represents the position of the throttle valve from "closed" (meaning the throttle valve is fully closed) to "open" (meaning the throttle valve is fully open). The fourth graph (line 606) shows the operating status of the electric heater connected to the electrically heated catalyst (EHC) housed in the engine exhaust manifold. The electric heater can operate to heat the EHC during cold starts to accelerate catalyst ignition. The fifth graph (line 608) shows the piston position of the cylinder. In the fifth graph, the vertical axis shows the piston position from bottom dead center ("BDC") to top dead center ("TDC"). The sixth graph (line 610) shows the temperature of the EHC estimated via an exhaust temperature sensor. The dashed line 611 represents the threshold temperature; below this temperature, the catalyst needs to be heated. The threshold 611 can be calibrated based on the catalyst ignition temperature.

[0064] Before time t1, the electric motor activates to rotate the engine crankshaft in response to an engine start request from the vehicle driver. When the engine is rotating (e.g., during a turn start), the pistons in the engine cylinders travel between the BDC and TDC. During a turn start, the throttle valve fully opens, for example, due to the vehicle driver fully depressing the accelerator pedal. As a result, engine overflow occurs, and spark plug sludge forms. Due to the spark plug sludge, the engine does not start, and the starting attempt ceases at time t1 when the electric motor is deactivated. Based on a catalytic converter temperature below threshold 611, the electric heater is activated to actively provide heat to the catalytic converter.

[0065] At time t1, in response to the spark plug wetness (e.g., based on throttle position determination and engine not started), the controller initiates a spark plug drying procedure. The intake throttle is actuated to the closed position. After the electric motor is deactivated and the engine crankshaft stops rotating, the piston may briefly continue moving due to momentum before coming to a complete stop between time t1 and time t2.

[0066] At time t2, the controller sends a signal to the electric motor to reverse the engine rotation. As the engine rotates, the piston moves from the BDC to the TDC, and correspondingly, the exhaust and intake valves open and close. Because the engine is rotating in reverse, ambient air is drawn into the engine system through the exhaust manifold, and then flows through the EHC to the engine cylinders. The controller sends a signal to the throttle plate of the intake throttle valve to fully open the throttle valve to increase the volume of air flowing through the engine system. Between t2 and t3, as the ambient air flows through the EHC, the air is heated by the active electric heater, and the heated air is then directed through the cylinders to the intake manifold. The heat from the air causes the fuel overflowing from the cylinders to evaporate, thereby drying the cylinders.

[0067] At time t3, the EHC temperature rises above the threshold temperature 411, indicating that the catalyst has reached its ignition temperature. However, it is observed that the threshold duration d1 has not elapsed since the engine reverses its rotation after initiation. Therefore, even after the EHC has reached its ignition temperature, the electric heater remains active between times t3 and t4, while the engine reverses its rotation to allow heated air to flow through the cylinders.

[0068] At time t4, in response to the completion of the threshold duration d1, the controller sends a signal to the electric motor to pause engine rotation. The controller also sends a signal to the electric heater to deactivate it. The throttle is also actuated to the closed position. If the spark plugs are dry, the vehicle driver is notified that the engine can be started.

[0069] In this way, by identifying spark plug deposits and utilizing existing engine components, spark plugs can be dried and engine starting can be accelerated without external intervention. The effect of the engine's reverse rotation is that ambient air can be guided to the cylinders via an electrically heated catalyst, and the heated airflow can be used to dry the engine cylinders. In summary, by using heated airflow to dry the wet spark plugs more quickly, engine start-up time can be shortened and emissions quality can be improved.

[0070] An exemplary engine method includes: in response to overflow of the combustion chamber of a spark-ignition engine due to fuel during an engine start-up attempt, cutting off fuel delivery to the combustion chamber, activating a heating element of a catalyst connected to an exhaust manifold of the engine, and reversing the engine to allow air heated by the heating element to flow through the exhaust manifold to the combustion chamber. In any of the foregoing examples, additionally or optionally, the spark-ignition engine includes an intake manifold having a throttle valve connected therein and an exhaust sensor connected to the exhaust manifold, and the overflow is determined based on at least one of the position of the throttle valve during the engine start-up attempt, the output of the exhaust sensor during the engine start-up attempt, and a threshold number of engine start-up attempts reached without combustion occurring in the combustion chamber. In any or all of the foregoing examples, additionally or optionally, the throttle valve position is fully open, and the exhaust sensor output is rich in stoichiometric air-fuel ratio. In any or all of the foregoing examples, additionally or optionally, the air heated by the heating element is drawn from the atmosphere into the engine via the exhaust manifold, and the air flows to the combustion chamber via the catalyst. In any or all of the foregoing examples, additionally or optionally, the combustion chamber includes a spark plug for supplying a spark to the combustion chamber for combustion. In any or all of the foregoing examples, additionally or optionally, the method further includes, immediately before reversing the engine, opening the throttle to the fully open position, opening an exhaust valve housed in an exhaust gas valve passage connected to the exhaust turbine, and closing an EGR valve connected to an exhaust gas recirculation (EGR) passage. In any or all of the foregoing examples, additionally or optionally, the method further includes, after allowing the heated air to flow through the combustion chamber for more than a threshold duration, activating the spark plug, and, in response to detecting a secondary pulse from the spark plug, indicating that the combustion chamber is dry. In any or all of the foregoing examples, additionally or optionally, the method further includes interrupting engine rotation in response to detecting a secondary pulse from the spark plug, and continuing engine rotation in reverse in response to the absence of the secondary pulse. In any or all of the foregoing examples, additionally or optionally, the method further includes suspending operation of the heating element in response to an instruction to dry the combustion chamber and upon reaching the ignition temperature of the catalyst. In any or all of the foregoing examples, additionally or optionally, the engine is rotated in reverse without fuel via an electric motor.

[0071] Another exemplary engine method includes drying the spark plugs by directing heated air, heated by a heater connected to an electrically heated catalytic converter (EHC), through the one or more cylinders while the engine is in a wet-sludge state, prior to starting an engine having one or more cylinders each connected to a spark plug. In any of the foregoing examples, additionally or optionally, the spark plug wet-sludge state includes an engine overflow state when no spark is generated. In any or all of the foregoing examples, additionally or optionally, the air is drawn into the engine via an exhaust manifold, and the air flows from the exhaust manifold to the one or more cylinders via the EHC housed downstream of the one or more cylinders. In any or all of the foregoing examples, additionally or optionally, the heater is powered by a battery connected to the heater, and the heater operates during cold starts to heat the EHC until the EHC reaches its ignition temperature. In any or all of the foregoing examples, additionally or optionally, the heated air is directed through the one or more cylinders until a threshold duration has elapsed, the method further comprising: after the threshold duration has elapsed, activating a first spark plug connected to a first cylinder; activating a second spark plug connected to a different cylinder in response to a secondary pulse generated by the first spark plug; and indicating that each of the first and second spark plugs is dry in response to the secondary pulse generated by the second spark plug; and deactivating engine reverse rotation when a predetermined number of spark plugs are indicated to be dry. In any or all of the foregoing examples, additionally or optionally, the engine propels a vehicle including autonomous vehicles and / or hybrid vehicles, and wherein the engine is started by rotating via an electric motor.

[0072] In yet another example, a system includes: a vehicle, including autonomous vehicles and / or hybrid vehicles; an electric motor; an engine including one or more cylinders, an intake manifold, and an exhaust manifold, each cylinder including a spark plug; an intake throttle valve connected to the intake manifold; an electrically heated catalyst (EHC) including an electric heater and an oxygen sensor connected to the exhaust manifold; and a controller having computer-readable instructions stored in a non-transitory memory, the computer-readable instructions causing the controller, when executed during engine off and during engine overflow indication and before engine start, to: activate the electric heater of the EHC, simultaneously dry each cylinder by providing a heated airflow from the exhaust manifold to the one or more cylinders via the EHC, and deactivate the electric heater in response to each of a secondary pulse generated by a spark plug connected to each cylinder and the electric heater temperature of the EHC rising above the ignition temperature. In any of the foregoing examples, additionally or optionally, the indication of engine overflow includes each of the stoichiometric air-fuel ratio in the exhaust manifold estimated via the oxygen sensor and the fully open position of the intake throttle. In any or all of the foregoing examples, additionally or optionally, the heated airflow is generated by reversing the engine via the electric motor to draw ambient air through the exhaust manifold, the ambient air being heated by the electric heater en route to the one or more cylinders. In any or all of the foregoing examples, additionally or optionally, generating the secondary pulse includes sequentially activating the spark plugs connected to each cylinder without injecting fuel into the one or more cylinders, and monitoring the secondary pulse via one or more ammeters connected to each of the spark plugs.

[0073] Note that the exemplary control and estimation programs included herein can be used in conjunction with various engine and / or vehicle system configurations. The control methods and programs disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific programs described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threaded processing strategies, etc. Therefore, the various actions, operations, or functions shown may be executed sequentially, in parallel, or in some cases omitted. Similarly, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations, and / or functions shown may be repeatedly executed depending on the specific strategy used. Furthermore, the actions, operations, and / or functions can be graphically represented as code programmed into a non-transitory memory of a computer-readable storage medium in an engine control system, wherein the actions are performed by executing instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0074] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments should not be considered limiting, as many variations are possible. For example, the above-described techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations disclosed herein, as well as other features, functions, and / or properties.

[0075] The following claims specifically point to certain combinations and sub-combinations considered novel and non-obvious. These claims may relate to an “a” element or a “first” element or its equivalent. These claims should be understood to include the introduction of one or more such elements, thus neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment to these claims or by setting new claims in this application or related applications. Such claims, whether broader, narrower, equivalent, or different in scope from the original claims, are considered to be included within the subject matter of this disclosure.

[0076] According to the present invention, a method includes: in response to a spark-ignition engine combustion chamber overflowing due to fuel during an engine start-up attempt, cutting off fuel delivery to the combustion chamber, activating a heating element of a catalyst connected to an exhaust manifold of the engine, and reversing the engine to allow air heated by the heating element to flow through the exhaust manifold to the combustion chamber.

[0077] According to one embodiment, the spark-ignition engine includes an intake manifold having a throttle valve connected therein and an exhaust sensor connected to the exhaust manifold, and the overflow is determined based on at least one of the position of the throttle valve during the engine start-up attempt, the output of the exhaust sensor during the engine start-up attempt, and the number of engine start-up attempts reached without combustion occurring in the combustion chamber.

[0078] According to one embodiment, the throttle position is fully open, and the exhaust sensor output is rich in stoichiometric air-fuel ratio.

[0079] According to one embodiment, the air heated by the heating element is drawn from the atmosphere into the engine via the exhaust manifold, and the air flows through the catalyst into the combustion chamber.

[0080] According to one embodiment, the combustion chamber includes a spark plug for supplying a spark to the combustion chamber for combustion.

[0081] According to one embodiment, the invention is further characterized in that, immediately before the engine is reversed, the throttle is opened to the fully open position, the exhaust valve housed in the exhaust valve passage connected to the exhaust turbine is opened, and the EGR valve connected to the exhaust gas recirculation (EGR) passage is closed.

[0082] According to one embodiment, after the heated air flows through the combustion chamber for more than a threshold duration, the spark plug is activated, and in response to the detection of a secondary pulse from the spark plug, the combustion chamber is indicated to be dry.

[0083] According to one embodiment, in response to detecting a secondary pulse from the spark plug, the engine is stopped from rotating, and in response to the absence of the secondary pulse, the engine continues to rotate in the reverse direction.

[0084] According to one embodiment, the operation of the heating element is suspended in response to an instruction to dry the combustion chamber and when the ignition temperature of the catalyst is reached.

[0085] According to one embodiment, the engine is reversed without fuel via an electric motor.

[0086] According to the invention, a method includes: drying the spark plugs in a wet, sludge-covered state before starting an engine having one or more cylinders, each having a spark plug connected to it, by directing heated air through the one or more cylinders while the engine is rotating in the reverse direction, the air being heated by a heater connected to an electrically heated catalyst (EHC) located in the exhaust manifold of the engine.

[0087] According to one embodiment, the spark plug wet deposit state includes the engine overflow state when no spark is generated.

[0088] According to one embodiment, the air is drawn into the engine via the exhaust port, and the air flows from the exhaust port to the one or more cylinders via the EHC housed downstream of the one or more cylinders.

[0089] According to one embodiment, the heater is powered by a battery connected to the heater, and the heater operates during cold start to heat the EHC until the EHC reaches the ignition temperature.

[0090] According to one embodiment, the heated air is directed through the one or more cylinders until a threshold duration has elapsed, the method further comprising: after the threshold duration has elapsed, activating a first spark plug connected to a first cylinder; activating a second spark plug connected to a different cylinder in response to a secondary pulse generated by the first spark plug; and indicating that each of the first and second spark plugs is dry in response to the second spark plug generating the secondary pulse; and deactivating engine reverse rotation when a predetermined number of spark plugs are indicated to be dry.

[0091] According to one embodiment, the engine propels a vehicle including autonomous vehicles and / or hybrid vehicles, and wherein the engine is started by rotating via an electric motor.

[0092] According to the present invention, a system is provided comprising: a vehicle, including an autonomous vehicle and / or a hybrid vehicle; an electric motor; an engine including one or more cylinders, an intake manifold, and an exhaust manifold, each cylinder including a spark plug; an intake throttle valve connected to the intake manifold; an electrically heated catalyst (EHC) including an electric heater and an oxygen sensor connected to the exhaust manifold; and a controller having computer-readable instructions stored in a non-transitory memory, the computer-readable instructions, when executed during engine off and during engine overflow indication and before engine start, causing the controller to: activate the electric heater of the EHC, simultaneously dry each cylinder by providing a heated airflow from the exhaust manifold to the one or more cylinders via the EHC, and deactivate the electric heater in response to each of a secondary pulse generated by a spark plug connected to each cylinder and the electric heater temperature of the EHC rising above the ignition temperature.

[0093] According to one embodiment, the indication of engine overflow includes each of the stoichiometric air-fuel ratio in the exhaust manifold estimated via the oxygen sensor and the fully open position of the intake throttle.

[0094] According to one embodiment, the heated airflow is generated by reversing the engine via the motor to draw ambient air through the exhaust manifold, the ambient air being heated by the electric heater en route to the one or more cylinders.

[0095] According to one embodiment, generating the secondary pulse includes sequentially activating the spark plugs connected to each cylinder without injecting fuel into the one or more cylinders, and monitoring the secondary pulse via one or more ammeters connected to each of the spark plugs.

Claims

1. A method comprising: In response to fuel overflow in the combustion chamber of a spark-ignited engine during an engine start-up attempt, the fuel supply to the combustion chamber is cut off, a heating element of a catalyst connected to the engine's exhaust manifold is activated, and the engine is reversed so that air heated by the heating element flows through the exhaust manifold to the combustion chamber.

2. The method of claim 1, wherein the spark-ignition engine includes an intake manifold having a throttle valve connected therein and an exhaust sensor connected to the exhaust manifold, and the overflow is determined based on at least one of the position of the throttle valve during the engine start attempt, the output of the exhaust sensor during the engine start attempt, and the number of engine start attempts reached without combustion occurring in the combustion chamber.

3. The method of claim 2, wherein the throttle position is fully open, and the exhaust sensor output is rich in stoichiometric air-fuel ratio.

4. The method of claim 1, wherein the air heated by the heating element is drawn from the atmosphere into the engine via the exhaust manifold, and the air flows to the combustion chamber via the catalyst.

5. The method of claim 1, wherein the combustion chamber includes a spark plug for supplying a spark to the combustion chamber for combustion.

6. The method of claim 2, further comprising, immediately before reversing the engine, opening the throttle to the fully open position, opening an exhaust valve housed in an exhaust valve passage connected to the exhaust turbine, and closing an exhaust gas recirculation (EGR) valve connected to the exhaust gas recirculation (EGR) passage.

7. The method of claim 5, further comprising activating the spark plug after allowing the heated air to flow through the combustion chamber for a duration exceeding a threshold, and indicating that the combustion chamber is dry in response to detecting a secondary pulse from the spark plug.

8. The method of claim 7, further comprising, in response to detecting a secondary pulse from the spark plug, stopping the engine from rotating, and in response to the absence of the secondary pulse, allowing the engine to continue rotating in the reverse direction.

9. The method of claim 7, further comprising suspending operation of the heating element in response to an instruction to dry the combustion chamber and upon reaching the ignition temperature of the catalyst.

10. The method of claim 1, wherein the engine is reversed without fuel via an electric motor.

11. A system comprising: Vehicles, including autonomous vehicles; Electric motor; An engine, the engine including one or more cylinders, an intake manifold and an exhaust manifold, each cylinder including a spark plug; An intake throttle valve, the intake throttle valve being connected to the intake manifold; An electrically heated catalyst (EHC), the EHC comprising an electric heater and an oxygen sensor connected to the exhaust port; and The controller has computer-readable instructions stored in non-transitory memory, the computer-readable instructions enabling the controller to: Before starting the engine, while the spark plugs are wet and sludge-covered, the spark plugs are dried by directing heated air through the one or more cylinders as the engine rotates in the reverse direction; the heated air is provided by an electric heater connected to the electrically heated catalyst EHC.

12. The system of claim 11, wherein the spark plug wet state includes the engine overflow state when no spark is generated.

13. The system of claim 11, wherein the air is drawn into the engine via the exhaust manifold, and the air flows from the exhaust manifold to the one or more cylinders via the electrically heated catalyst (EHC).

14. The system of claim 11, wherein the electric heater is powered by a battery connected to the heater, and the heater operates during cold start to heat the electrically heated catalyst EHC until the electrically heated catalyst EHC reaches the ignition temperature.

15. The system of claim 11, wherein the heated air is directed through the one or more cylinders until a threshold duration has elapsed, after which a first spark plug connected to a first cylinder is activated; and in response to a secondary pulse generated by the first spark plug, a second spark plug connected to a different cylinder is activated. And in response to the second spark plug generating the secondary pulse, indicating that each of the first spark plug and the second spark plug is dry; And when a predetermined number of spark plugs are indicated to be dry, the engine is deactivated and rotated in reverse.

16. A system comprising: Vehicles, including hybrid vehicles; Electric motor; An engine, the engine including one or more cylinders, an intake manifold and an exhaust manifold, each cylinder including a spark plug; An intake throttle valve, the intake throttle valve being connected to the intake manifold; An electrically heated catalyst (EHC), the EHC comprising an electric heater and an oxygen sensor connected to the exhaust port; and The controller has computer-readable instructions stored in non-transitory memory, the computer-readable instructions enabling the controller to: Before starting the engine, while the spark plugs are wet and sludge-covered, the spark plugs are dried by directing heated air through the one or more cylinders as the engine rotates in the reverse direction; the heated air is provided by an electric heater connected to the electrically heated catalyst EHC.

17. The system of claim 16, wherein the spark plug wet state includes the engine overflow state when no spark is generated.

18. The system of claim 16, wherein the air is drawn into the engine via the exhaust manifold, and the air flows from the exhaust manifold to the one or more cylinders via the electrically heated catalyst (EHC).

19. The system of claim 16, wherein the electric heater is powered by a battery connected to the heater, and the heater operates during cold start to heat the electrically heated catalyst EHC until the electrically heated catalyst EHC reaches the ignition temperature.

20. The system of claim 16, wherein the heated air is directed through the one or more cylinders until a threshold duration has elapsed, after which a first spark plug connected to a first cylinder is activated; and a second spark plug connected to a different cylinder is activated in response to a secondary pulse generated by the first spark plug. And in response to the second spark plug generating the secondary pulse, indicating that each of the first spark plug and the second spark plug is dry; And when a predetermined number of spark plugs are indicated to be dry, the engine is deactivated and rotated in reverse.

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