Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, inhibiting of automatic engine stopping and starting may be withdrawn in response to a change in driver vehicle settings or when a temperature of an engine is less than a threshold temperature.

A control device estimates a leakage gas amount with respect to gas that leaks to an upstream side from a downstream side of a fresh air introduction valve when the fresh air introduction valve is closed. If the leakage gas amount is equal to or greater than a predetermined value when there is a request to open the fresh air introduction valve, a target opening degree of the fresh air introduction valve is determined based on the engine speed and intake pressure, and also a correction opening degree with respect to the target opening degree is calculated based on the leakage gas amount. The fresh air introduction valve is opened to an opening degree greater than the target opening degree by an amount corresponding to the correction opening degree, to thereby cause leakage gas that is accumulated in a fresh air introduction passage to flow into an intake passage together with a required amount of fresh air.

Systems and methods are provided for cooling an overheated engine using a combination of variable displacement engine (VDE) technology and direct injection technology. In one example, a method may include deactivating a subset of engine cylinders based on an engine temperature and directly injecting liquid fuel into the deactivated cylinders. In this way, an increased thermal conductivity of the liquid fuel compared to air decreases the engine temperature at a faster rate than when air-based engine cooling methods are used, thereby preventing overheating-related engine degradation.

Methods and systems are provided for partially regenerating a lean NO.sub.x trap in response to an engine shutdown request. In one example, an engine shutdown is delayed so that a low-temperature storing region of the lean NO.sub.x trap is regenerated without regenerating a high-temperature storing region of the lean NO.sub.x trap. A battery charge is replenished during the shutdown, wherein the charge may be consumed during a subsequent engine operation.

A transmission controller increases a load applied on an engine when a start condition of a sailing-stop control is met.

A system is provided for automatically shutting down an engine of a portable or handheld device in response to the engine operating while in an enclosed space, such as a garage, shed, room, etc. to prevent dangers associated with carbon monoxide accumulating in the enclosed space. The engine has an oxygen sensor in its exhaust that is configured to detect the presence or absence of oxygen in the exhaust. Fuel can be removed from the air/fuel mixture (e.g., less fuel being injected) based on the output of the oxygen sensor to maintain a given desired air/fuel ratio. If the amount of fuel provided continues to decrease over time in order to maintain the air/fuel ratio, the controller can assume the engine is operating in confined spaces and can shut down the engine.

A method (300) of controlling an internal combustion engine (3) of a vehicle (1), comprising: receiving at least one input (301) indicative of a current external environment proximal to the vehicle (1); determining (305) in dependence on the at least one input (301) whether a hazard is present; determining a current propulsion demand (303) of the vehicle (1); if it is determined that the current propulsion demand (303) is low, either commanding switching of the internal combustion engine (3) to an off state (307) if it is determined that a hazard is not present, or not commanding switching of the internal combustion engine (3) to the off state if it is determined that a hazard is present; and if it is determined that the current propulsion demand (303) is high, commanding switching of the internal combustion engine (3) to an on state if the internal combustion engine (3) is in the off state.

A vibration reduction device upon KEY-OFF of an engine may include a fuel injection device for injecting fuel stored in a fuel tank into a combustion chamber of an engine depending upon a target torque value, a measurement device for measuring the RPM and the rotational torque of the engine, and an controller for detecting whether or not an engine becomes KEY-OFF and when it is determined to be in KEY-OFF state, setting a reference torque value, and setting a torque value changing the reference torque value depending upon a predetermined reference as the target torque value and controlling the fuel injection device to finely inject fuel into the engine depending upon the target torque, thus reducing engine vibration.

A method for functional monitoring of an apparatus for variable setting of a cylinder compression in a reciprocating-piston internal combustion engine is described, including ascertaining a value of an engine parameter which is indicative of an engine position of the internal combustion engine at a defined cylinder compression; comparing the ascertained value with a further value of the engine parameter; and determining, depending on a result of the comparison, whether the apparatus for variable setting of the cylinder compression is functioning correctly.

Methods and systems are provided for rationalizing a hydrocarbon sensor in a hybrid vehicle, the hydrocarbon sensor used for feed-forward air/fuel ratio control during fuel vapor canister purging events. In one example, a method comprises routing blow-by gasses from a crankcase of an engine of the vehicle to an intake manifold of the engine and then to a fuel vapor storage canister, and indicating whether the hydrocarbon sensor is functioning as desired based on a magnitude of a response of the hydrocarbon sensor during the routing. In this way, the hydrocarbon sensor may be diagnosed under conditions when the canister is substantially free from fuel vapors, and where engine run-time is limited.