In an exhaust gas control system for an internal combustion engine operable at a lean air-fuel ratio, after a request to stop the internal combustion engine has been issued, the internal combustion engine is operated at a stoichiometric air-fuel ratio or lower until an air-fuel ratio in an SCR catalyst becomes lower than or equal to the stoichiometric air-fuel ratio, and then supply of fuel to the internal combustion engine is stopped.

A method controls a system for supplying diesel fuel on a motor vehicle. The system includes a fuel tank, a first pump that is a low-pressure pump taking fuel from the tank and delivering the fuel to a second pump that is a high-pressure pump. The method includes controlling the first pump to regulate the quantity of fuel provided as a function of the needs of the second pump, and determining a geographical position of the vehicle. The first pump is controlled to a maximum pressure level when the vehicle is in one of several predefined probable stopping zones.

Various methods and systems are provided for diagnosing an engine component based on a measured engine speed during an engine shutdown event. As one embodiment, a method for an engine includes measuring an engine speed drop rate, via an engine speed sensor, during an engine shutdown event; and indicating a change in performance of one of the engine speed sensor or an additional engine component in response to the measured engine speed drop rate deviating from a reference engine speed drop rate by a pre-set or pre-defined threshold rate.

Methods and systems are provided for determining a load of a canister included in an evaporative emissions system of a vehicle. One example method comprises flowing each of purge vapors, refueling vapors, and breakthrough vapors through a common hydrocarbon sensor and using output from the hydrocarbon sensor based on the flowing of different vapors to estimate the load of the canister.

Methods and systems are provided for adjusting a compression ratio of a variable compression ratio (VCR) engine during engine shutdown. In one example, a method (or system) may include actuating a VCR mechanism from a higher compression ratio setting to a lower compression ratio setting after a last combustion event and before the engine spins down to rest. In this way, engine shake, for example, due to piston bounce-back, may be reduced.

Methods and systems are provided for controlling an aspirator shut-off valve in an engine of a hybrid vehicle. One example method includes opening the aspirator shut-off valve following a shut-down command to the engine when engine speed is between a first engine speed and a second engine speed, the first engine speed being lower than an idle speed and the second engine speed occurring before an imminent engine stop. The example method further includes not opening the aspirator shut-off valve between the first engine speed and the second engine speed if an oxygen content of an emission control device is at or near a threshold.

While a vehicle is coasting with an engine being automatically stopped and a power transmission path between the engine and wheels being disengaged, when a deceleration request is made and the engine is restarted with the power transmission path being engaged, a deceleration level increases relative to the deceleration level required by a driver or the vehicle, thereby lowering drivability. A vehicle control apparatus includes a deceleration level control unit that controls the deceleration level of the vehicle such that, during travelling of the vehicle continuing to travel with a power transmission mechanism between the engine and the wheels being disengaged, when the deceleration request is made and the engine is started by an engagement of the power transmission mechanism, the deceleration level becomes a target deceleration level calculated from a first target deceleration level generated after the engagement of the power transmission mechanism is complete and a second target deceleration level generated in response to the deceleration request.

A kill switch assembly for an internal combustion engine may include a housing, a first terminal carried by the housing and connected to a ground wire, a second terminal carried by the housing and connected to an engine microcontroller communication wire, and a kill switch. The kill switch may be carried by the housing, electrically connected to the first and second terminals, and manually operable by an operator to change the state of the electric switch to provide an engine stop signal to the engine microcontroller. The assembly may also include an electronic circuit carried by the housing, connected to the first and second terminals, and through the wires communicating with the engine microcontroller.

A method of diagnosing a high pressure fuel delivery system includes sensing an after shutdown fuel pressure in the fuel rail. An after shutdown leak rate is calculated from the after shutdown fuel pressure, and compared to a shutdown leak threshold. The high pressure fuel delivery system is analyzed to detect a leak in one of the fuel rail or the fuel injector when the after shutdown leak rate is greater than the shutdown leak threshold. A cranking fuel pressure in the fuel rail is also sensed. A cranking leak rate is calculated from the cranking fuel pressure, and compared to a cranking leak threshold. The high pressure fuel delivery system is analyzed to detect a leak in the high pressure fuel pump when the cranking leak rate is greater than the cranking leak threshold.

An internal combustion engine having: at least one piston-cylinder unit, a turbocharger having an exhaust gas turbine, a catalytic converter connected between the at least one piston-cylinder unit and the exhaust gas turbine, and a control device, wherein the control device is designed to control a fluid-delivery device such that, when the internal combustion engine is in a state in which no combustion and/or ignition takes place in the at least one piston-cylinder unit, the fluid-delivery device delivers fuel-air mixture through the catalytic converter.