Methods and systems are provided for pinpointing a source of degradation in a vehicle engine system. In one example, a method includes spinning an engine of a vehicle unfueled in a forward and a reverse direction, in no particular order, and recording a first intake air flow and a second intake air flow, respectively, in an intake of the engine, and where the source of degradation is indicated as a function of both the first air flow and the second air flow. In this way, the degradation of the vehicle engine system may be pinpointed as to being located in the intake manifold, the exhaust system, or the engine.

The invention relates to an internal combustion engine with an air intake system and an exhaust system is embodied as an internal combustion engine, in particular a gasoline engine, that is charged by means of an exhaust gas turbocharger. At least one three-way catalytic converter is arranged in the exhaust system of the internal combustion engine. Furthermore, a low-pressure exhaust gas recirculation system is provided that connects the exhaust system downstream from a turbine of the exhaust gas turbocharger and upstream from the at least one three-way catalytic converter to the air intake system upstream from a compressor of the exhaust gas turbocharger. The invention further relates to a method for exhaust aftertreatment of such an internal combustion engine.

A Purge Control Solenoid Valve (PCSV) control method for preventing malfunction may include: starting-up by a starting motor a crankshaft of an engine, and opening PCSV by a duty-control, wherein in the starting-up step, the PCSV is opened to eliminate foreign substances stained on the PCSV.

An automobile power system in a vehicle may include an intake pipe supplying external air to an engine supplying power to driving wheels, a canister connected with a fuel tank to absorb evaporation gas produced in the fuel tank, an active purging system compressing and supplying the evaporation gas absorbed in the canister to the intake pipe, a diverging line extending from the active purging system to the engine, a diverging valve mounted on the diverging line, and a starting motor rotating a crankshaft when the engine is started. In addition, the evaporation gas absorbed in the canister is supplied to the engine through the diverging line before the engine is restarted, and then the starting motor is operated.

A method of controlling oxygen purge of a three-way catalyst may include: performing a fuel cut-off; determining whether a fuel cut-in condition is satisfied after the fuel cut-off; calculating an optimum valve overlap according to an intake amount, an engine rotation speed, and an ignition timing if the fuel cut-in condition is satisfied after the fuel cut-off; controlling a CVVD apparatus to be at the optimum valve overlap; and performing the oxygen purge at the optimum valve overlap.

A vehicle includes a controller programmed to activate a fuel savings feature upon satisfaction of transition conditions and inhibit the transition according to satisfaction of inhibit conditions. The controller is further programmed to accumulate data indicative of the inhibit conditions and a time associated with the conditions being satisfied over a drive cycle.

A method of controlling a hybrid electric vehicle is provided. The method includes determining whether a condition for turning off an engine is satisfied and determining engine clutch disengaging time and residual purge gas consuming time from engine driving status information when the condition is satisfied. Engine clutch-engaged charging control time is determined from the engine clutch disengaging time and the residual purge gas consuming time. The method includes closing a purge control solenoid valve and starting to perform engine clutch-engaged charging control. The engine clutch-engaged charging control is maintained for the determined engine clutch-engaged charging control time and then engine clutch disengaging control is performed for the determined engine clutch disengaging time. The engine is stopped after the engine clutch disengaging control is performed.

A fuel injection valve drive control device includes a boost circuit having a boost coil, a switching component (FFT or the like) supplying a switching current from a battery source voltage to the boost coil, and a boost capacitor accumulating a boosted voltage generated by the operation of the switching component; a discharge circuit for discharging the accumulated electric charge via a current limiter (e.g. discharge resistor, constant current source) and a discharge switch (FET or the like); and a monitoring circuit for monitoring the accumulated voltage. The discharge circuit is caused to operate when the control device is shutting down and performs a deterioration/failure diagnosis of the boost capacitor and an operation check of the discharge circuit on the basis of a monitored voltage value of the boost capacitor at starting the discharge operation and a monitored voltage value of the boost capacitor after a predetermined time has elapsed.

In some embodiments, a vehicle includes a temperature monitoring controller. The temperature monitoring controller is a processor, control module, or other suitable hardware that is configured to receive temperature sensor values from an engine control module (ECM) when an ignition bus is in a powered on state, and to decide when the engine should be automatically started in order to maintain a temperature above a low temperature threshold. The temperature monitoring controller periodically causes an ignition bus of the vehicle to be placed in the powered on state when the engine is shut down in order to collect temperature sensor values. The temperature monitoring controller determines whether to automatically start the engine, and if not, determines how long to wait before collecting temperature sensor values again based on a rate of change of the temperature sensor values.

A control device for an internal combustion engine executes an automatic stop control and automatic start-up control for an intermittent operation of the internal combustion engine. In the automatic start-up control, the control device is configured to commence a restart by starting fuel injection from a fuel-injection-start cylinder. In the automatic stop control, the control device is configured to: execute an air-fuel-ratio rich processing that controls an air-fuel ratio such that the air-fuel ratio becomes richer than the stoichiometric air-fuel ratio before a start of the fuel cut; execute a throttle closing processing that closes a throttle valve in synchronization with the fuel cut; and execute a throttle opening processing approaches the atmospheric air pressure before a cylinder destined to be the fuel-injection-start cylinder later completes the last intake stroke in the course of the engine stop after execution of the throttle closing processing.