Methods and systems are provided for providing compression release during a stop/start event in an engine. In one example, a method includes: responsive to a request for a stop/start event in an engine with a continuously variable valve lift (CVVL) system including a compression release hydraulic valve actuator coupled to a valve of a first cylinder, determining a desired stop position of the engine; and prior to restarting the engine during the stop/start event, adjusting the compression release hydraulic valve actuator to open the valve during a compression stroke of the first cylinder. In this way, an amount of torque used to restart the engine may be reduced.

In the case of restarting an internal combustion engine that has been automatically stopped during running, the internal combustion engine is restarted by combustion recovery starting when the rotation speed of the internal combustion engine under the input of a restart request is greater than or equal to a predetermined first rotation speed. In the case of restarting the internal combustion engine that has been automatically stopped during running, the internal combustion engine is restarted by cranking recovery starting when the rotation speed of the internal combustion engine under the input of the restart request is lower than the predetermined first rotation speed. The first rotation speed is set lower at the restart of the internal combustion engine in a sailing stop state than at the restart of the internal combustion engine in a coast stop state.

A method of controlling engine restart may include selecting, by a start controller, a first start situation and a second start situation for restarting an engine; determining a current possible start-up through the first and second start situations; prioritizing possible start-ups; and attempting to restart the engine by setting the first and second start situations as first start control and second start control, respectively, based on the priorities of the start-ups.

A method for controlling a start of a vehicle using a controller includes: determining whether revolutions per minute (RPM) of an engine is within a reference range when start of the vehicle is requested; determining whether state data for controlling the vehicle satisfies a control condition for controlling a start of the vehicle when RPM of the engine is within the reference range; determining whether a position value of an accelerator pedal is less than or equal to a reference position value when the state data satisfies the control condition; determining whether a speed of the vehicle is greater than or equal to a reference speed when the position value of the accelerator pedal is less than or equal to the reference position value; and controlling a brake device when speed of the vehicle is greater than or equal to the reference speed.

A method and system for operating a vehicle that includes feedback of operating status of an engine starting system is described. In one example, the method inhibits automatic engine pull-down in response to feedback from an engine starting system that does not meet expectations. The system and method may provide diagnostics for the engine starting system.

Methods and systems are provided for performing expansion combustion in an engine of a start-stop vehicle. In one example, a method may include, responsive to receiving an auto-start request to restart an engine from an auto-stop, determining a fuel mass to inject into a cylinder for an expansion combustion event based on a duration of the auto-stop, and actuating a spark plug of the cylinder after injecting the determined fuel mass to perform the expansion combustion event. In this way, an air-fuel ratio of the expansion combustion event may be more accurately controlled, resulting in more robust expansion combustion engine restarts.

A system for controlling a compression ignition engine includes: a speed obtaining section which detects or estimates an engine speed achieved by combustion in an n-th cycle; and an injection amount setting section which sets, in a start period after the start of cranking, a fuel injection amount to be injected by injectors in an (n+1)-th cycle. If the engine speed achieved by the combustion in the n-th cycle falls in the resonance range, the injection amount setting section sets the fuel injection amount for an (n+1)-th cycle to be larger than the fuel injection amount injected when the engine speed is higher than or equal to an upper limit of the resonance range.

A method actuates a starter of an internal combustion engine by way of a starter relay. The starter relay is configured to supply the starter optionally with current via an on-board electrical system. The method has the following steps: determining an error status of the internal combustion engine; commencing repeated actuations of the starter relay; determining a current status of the internal combustion engine, wherein the current status of the internal combustion engine displays at least one error status or at least one operating status; and, if the current status displays at least one operating status, ending the repeated actuation of the starter relay, otherwise once again determining the current status. A system for actuating a starter of an internal combustion engine includes a control device, a power source, a starter relay, connected to the control device and configured to supply the starter of the internal combustion engine optionally with current from the power source via an on-board electrical system, wherein the control device is configured to carry out the method.

The present disclosure provides a method in a vehicle, comprising detecting an engine stop opportunity and recording, in a memory, data corresponding to a first engine stop that occurred in response to detection of the engine stop opportunity. The method further includes detecting an engine stop inhibit, and recording, in a memory, data corresponding to a first missed engine stop wherein the first missed engine stop indicates detection of the engine stop opportunity without an engine stop in response to the detection of the engine stop opportunity.

Systems and methods for operating a hybrid vehicle are presented. In one example, an integrated starter/generator (ISG) is operated in a speed control mode after an engine stop request. The ISG is prevented from stopping while engine rotational speed is greater than a threshold engine rotational speed so that the engine may be restarted via the ISG.