Abstract: Methods and systems are provided for detection of cylinder misfire in an engine. In one example, a system may comprise a first cylinder and second cylinder of the engine having exhaust flows combined together in an exhaust system before being combined with other cylinders of the engine. The first cylinder and second cylinder may share an exhaust gas sensor mounted in the exhaust in a position to sense exhaust from the first cylinder and second cylinder, and being positioned before exhaust from other cylinders is combined with sensed exhaust from the first cylinder and second cylinder. The system may further include a control system with instructions stored therein to indicate detected misfire in one or more of the first and second sensors based on an output from the exhaust gas sensor.

Abstract: Methods and systems are provided for detection of cylinder misfire in an engine. In one example, a system may comprise a first cylinder and second cylinder of the engine having exhaust flows combined together in an exhaust system before being combined with other cylinders of the engine. The first cylinder and second cylinder may share an exhaust gas sensor mounted in the exhaust in a position to sense exhaust from the first cylinder and second cylinder, and being positioned before exhaust from other cylinders is combined with sensed exhaust from the first cylinder and second cylinder. The system may further include a control system with instructions stored therein to indicate detected misfire in one or more of the first and second sensors based on an output from the exhaust gas sensor.

Abstract: Methods and systems to determine a presence or absence of engine misfire or spark plug fouling are presented. In one example, rates of change in engine speed are arranged in engine data blocks and root mean square values for the rates of change in engine speed are determined. The presence or absence of engine misfire or spark plug fouling may be based at least in part on the root mean square values.

Abstract: Methods and systems are provided for controlling spark plug fouling in newly manufactured vehicles. In one example, an engine is operated with a first, more aggressive spark discharge schedule when in a pre-delivery state and transitioned to a second, less aggressive spark discharge schedule when in a post-delivery state. In each spark discharge schedule, a spark plug ignition coil is repeatedly discharged when the engine is off, such as when the engine is spinning down to rest on a shutdown event or before the engine is fueled on an engine restart event.

Abstract: Methods and systems are provided for detecting spark plug fouling and cleaning up fouled spark plug during pre-delivery phase of a vehicle. In one example, a method may include updating a spark plug fouling index saved in the non-volatile memory of the vehicle based on engine operating parameters, and indicating spark plug fouling based on the updated index. The method may further include cleaning the fouled spark plug by driving the vehicle along a planned route.

Abstract: Methods and systems are provided for restarting an engine when a high pressure fuel pump is degraded. In response to an indication of high pressure fuel pump degradation, fuel may be injected during an intake stroke, rather than a compression stroke, for a selected number of combustion events since the engine restart. By shifting to an intake stroke injection, the engine may be started even when sufficient fuel rail pressures are not available.

Abstract: Methods and systems are provided for mitigating knock and/or pre-ignition. Each of a spark timing retard, cylinder enrichment, and engine load limiting is adjusted based on a knock sensor output generated in a single defined crank angle window, and not based on knock sensor output generated outside the defined crank angle window. A severity of the mitigating actions is adjusted in proportion to the knock sensor output intensity with the severity of the mitigating action increased as the knock sensor output intensity increases.

Abstract: Methods and systems are provided for detecting cylinder misfire in a vehicle engine via a plurality of sensors, based on dual mass flywheel (DMF) operating frequency. In response to detection of a misfire event, the misfiring cylinders may be deactivated and upon confirmation of DMF operation out of a resonant frequency range, the deactivated cylinder(s) may be sequentially reactivated.

Abstract: Methods and systems are provided for restarting an engine when a high pressure fuel pump is degraded. In response to an indication of high pressure fuel pump degradation, fuel may be injected during an intake stroke, rather than a compression stroke, for a selected number of combustion events since the engine restart. By shifting to an intake stroke injection, the engine may be started even when sufficient fuel rail pressures are not available.

Abstract: Methods and systems are provided for controlling spark plug fouling in newly manufactured vehicles. In one example, an engine is operated with a first, more aggressive spark discharge schedule when in a pre-delivery state and transitioned to a second, less aggressive spark discharge schedule when in a post-delivery state. In each spark discharge schedule, a spark plug ignition coil is repeatedly discharged when the engine is off, such as when the engine is spinning down to rest on a shutdown event or before the engine is fueled on an engine restart event.

Abstract: Methods and systems are provided for restarting an engine when a high pressure fuel pump is degraded. In response to an indication of high pressure fuel pump degradation, fuel may be injected during an intake stroke, rather than a compression stroke, for a selected number of combustion events since the engine restart. By shifting to an intake stroke injection, the engine may be started even when sufficient fuel rail pressures are not available.

Abstract: Methods and systems are provided for detecting spark plug fouling and cleaning up fouled spark plug during pre-delivery phase of a vehicle. In one example, a method may include updating a spark plug fouling index saved in the non-volatile memory of the vehicle based on engine operating parameters, and indicating spark plug fouling based on the updated index. The method may further include cleaning the fouled spark plug by driving the vehicle along a planned route.

Abstract: Methods and systems are provided for detecting cylinder misfire in a vehicle engine via a plurality of sensors, based on dual mass flywheel (DMF) operating frequency. In response to detection of a misfire event, the misfiring cylinders may be deactivated and upon confirmation of DMF operation out of a resonant frequency range, the deactivated cylinder(s) may be sequentially reactivated.

Abstract: Methods and systems are provided for addressing pre-ignition that may be induced in response to actions taken to mitigate a cylinder misfire. An amount of engine load limiting applied may be adjusted to reduce the likelihood pre-ignition while also addressing component over-temperature issues. By limiting an engine load while shutting off fuel in a misfiring cylinder, and while combusting a lean air-fuel mixture in the remaining cylinders, pre-ignition induced by the misfire-mitigating lean combustion conditions can be reduced.

Abstract: Methods and systems are provided for addressing pre-ignition that may be induced in response to actions taken to mitigate a cylinder misfire. An amount of engine load limiting applied may be adjusted to reduce the likelihood pre-ignition while also addressing component over-temperature issues. By limiting an engine load while shutting off fuel in a misfiring cylinder, and while combusting a lean air-fuel mixture in the remaining cylinders, pre-ignition induced by the misfire-mitigating lean combustion conditions can be reduced.

Abstract: Methods and systems are provided for addressing pre-ignition occurring while operating with blow-though air delivery. A variable cam timing device used to provide positive intake to exhaust valve overlap is adjusted in response to an indication of pre-ignition to transiently reduce valve overlap. Pre-ignition mitigating load limiting and enrichment applied during a blow-through mode is adjusted differently from those applied when blow-through air is not being delivered.

Abstract: Methods and systems are provided for addressing pre-ignition that may be induced in response to actions taken to mitigate a cylinder misfire. An amount of engine load limiting applied may be adjusted to reduce the likelihood pre-ignition while also addressing component over-temperature issues. By limiting an engine load while shutting off fuel in a misfiring cylinder, and while combusting a lean air-fuel mixture in the remaining cylinders, pre-ignition induced by the misfire-mitigating lean combustion conditions can be reduced.

Abstract: Various systems and methods are described for deactivation and reactivation of a cylinder bank in a V-engine. In one example, the cylinder bank is deactivated responsive to an indication of misfire based on crankshaft acceleration and exhaust air fuel ratio. The cylinder bank is reactivated sequentially based on exhaust catalyst temperature.

Abstract: Methods and systems are provided for addressing pre-ignition occurring while operating with blow-though air delivery. A variable cam timing device used to provide positive intake to exhaust valve overlap is adjusted in response to an indication of pre-ignition to transiently reduce valve overlap. Pre-ignition mitigating load limiting and enrichment applied during a blow-through mode is adjusted differently from those applied when blow-through air is not being delivered.

Abstract: Methods and systems are provided for addressing pre-ignition occurring while operating with blow-though air delivery. A variable cam timing device used to provide positive intake to exhaust valve overlap is adjusted in response to an indication of pre-ignition to transiently reduce valve overlap. Pre-ignition mitigating load limiting and enrichment applied during a blow-through mode is adjusted differently from those applied when blow-through air is not being delivered.