Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, an amount of opening overlap between a plurality of intake valves and a first set of exhaust valves coupled to the first exhaust manifold may be adjusted responsive to a transition from an estimated combustion air-fuel content to a leaner air-fuel content of the blowthrough air on a cylinder to cylinder basis. As one example, the transition may be determined from an output of an oxygen sensor positioned within the first exhaust manifold or an exhaust runner of each of the first set of exhaust valves.

A torque request module is configured to, while a vehicle speed is greater than a predetermined speed, decrease a torque request in response to a first signal from a start/stop switch being in a first state continuously for greater than a first predetermined period and less than a second predetermined period. A control module is configured to, as the torque request decreases, decrease torque output of at least one of an engine and an electric motor. A light control module is configured to: selectively turn exterior hazard lights on and off in response to a second signal from a hazard light switch being in a first state; and selectively turn the exterior hazard lights on and off in response to the first signal from the start/stop switch being in the first state continuously for greater than the first predetermined period.

Provided are methods for warming up a vehicle exhaust treatment system prior to an engine start, wherein the vehicle includes an internal combustion engine (ICE), a supercharger capable of delivering air to an ICE intake, an exhaust gas treatment system including an exhaust gas treatment device and an upstream electric heating device and capable of accepting exhaust gas from the ICE, and optionally a turbocharger having a turbine in fluid communication with the exhaust gas treatment system. Methods include establishing fluid communication between the supercharger and the exhaust gas treatment system, engaging the supercharger to communicate air to the exhaust gas treatment system via the supercharger, and engaging the heating device. The method can further comprise reducing turbine resistance by reducing the power position of the turbine or opening a wastegate. The methods can further include first satisfying a start condition, and/or subsequently detecting a termination condition.

The method determines whether soot loading of a gas particulate filter (GPF) requires regeneration. If it does, the temperature of the GPF is read to determine whether it is sufficiently high to achieve particulate (soot) burning. If it is not, an engine control module is commanded to adjust variables such as spark timing, fuel injection timing and valve timing. If the temperature of the particulate filter is sufficiently high that regeneration can occur, other variables may be adjusted such as leaning the air/fuel mixture, retarding the spark timing, the fuel injection and valve timing. Because the latter adjustments may limit or reduce either engine speed or power, messages in a message center are provided indicating, first, that the driver should continue driving for GPF regeneration and, subsequently, under certain conditions, that the engine power has been reduced. Operation of the motor vehicle proceeds until, based upon sensed conditions or pre-determined experimental or empirical data, the filter has been regenerated.

Methods and systems are provided for indicating whether a canister purge valve in a vehicle evaporative emissions control system is degraded. In one example, an air intake system hydrocarbon (AIS HC) trap temperature may be monitored during a refueling event, and responsive to an indication that the AIS HC trap temperature change is greater than a predetermined threshold, it may be indicated that the canister purge valve is degraded. In this way, diagnosis of whether a vehicle canister purge valve is degraded may be indicated without the use of engine manifold vacuum, and may be advantageous for vehicles configured to operate for significant amounts of time without engine operation, or without intake manifold vacuum.

An engine system includes an intake line, an exhaust line, an exhaust gas recirculation (EGR) system, a turbocharger including a turbine provided in the exhaust line, and a compressor provided in the intake line, wherein the compressor compresses outside air, an intake bypass line which branches off from the intake line at a rear end of the compressor and merges into the intake line at the front end of the compressor, a recirculation valve installed at a point at which the intake bypass line and the intake line merge together, and a controller which controls operations of opening and closing the recirculation valve so that a portion of the intake gas compressed by the compressor is supplied into the intake line at the front end of the compressor through the intake bypass line, or the intake gas is supplied into the combustion chamber through the intake bypass line.

A cooling time computing unit computes, based on a temperature detected by a temperature detection unit, a cooling time during which an injection unit is cooled by driving of an engine. A notification control unit uses a notification unit to notify an operator of a necessity of cooling before the engine is stopped, during the cooling time computed by the cooling time computing unit.

A vehicle method for gaseous fuel loss detection, including for each of a high and low pressure portion of a fuel system including a gaseous fuel, indicating degradation based on a loss of mass from the fuel system, the loss of mass based on separately tracking fuel mass in each of the portions based on respective temperatures and pressures at a first and second instance following an engine off condition. The method may utilize the respective pressures and temperatures to determine which portions of the fuel system are losing mass and further identify degradation of fuel system valves.

Methods and systems are provided for mitigating the effects of a leaky fuel injector during vehicle idle stop conditions. In one example, a method may include identifying the cylinder with a leaky fuel injector, and at or during engine shutdown, positioning the engine to a selected position based on the identified cylinder such that an exhaust valve of the identified cylinder is at least partly open.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, in response to a request to shut down the split exhaust engine system, an intake throttle may be closed and a first valve disposed in a secondary flow passage coupled between the intake manifold, downstream of the intake throttle, and a first exhaust manifold coupled to a first set of exhaust valves, may be opened. As a result, unburned hydrocarbons may be routed to a catalyst disposed in the exhaust passage.