Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, an amount of time to start an engine and a rate of engine acceleration are adjusted in response to what type of event triggered an automatic engine start.

A method for starting a hybrid vehicle 100 comprising an internal combustion engine 301, an electric motor 320 coupled to a driveline of the hybrid vehicle, a traction battery 302 configured to supply energy to the electric motor, and an open clutch 310 decoupling the internal combustion engine from the driveline, the method comprising: determining s503, s505 whether a temperature-dependent parameter associated with the traction battery satisfies a first condition; starting s535 the electric motor; monitoring s541 satisfaction of a second condition while internal combustion engine speed is greater than zero; and attempting s545 to close the clutch to couple the internal combustion engine to the driveline if the second condition is satisfied.

Systems and methods for operating a spark ignition engine that includes a particulate filter in the engine's exhaust system are described. In one example, a threshold temperature at which the spark ignition engine may be automatically stopped is adjusted according to an amount of soot that is stored in the particulate filter.

A method for slow starting a reciprocating engine having a crankshaft, piston, and piston chamber is disclosed. The method includes applying a force to the crankshaft, sensing an engine characteristic, and determining if an error or fault is present in the engine.

Methods and systems are provided for dealing with a change of mind event during an automatic shut-down of an engine in which the speed at which a starter motor used to restart the engine is disengaged is based upon the comparison of current engine speed (N) with a cranking speed limit (S.sub.LIM). In one example, during an engine restart while the engine is spinning down, the starter motor may crank the engine to a threshold cranking engine speed adjusted based on a position of the gear.

Methods and systems are provided for extending a duration of engine idle-stop while reducing a frequency of engine restart from idle-stop. In one example, in response to engine restart conditions where combustion torque is not necessary, an engine can be rotated electrically, without fuel delivery, via an electric motor. The unfueled engine spinning via the motor drives an FEAD which in turns drives an actuator coupled to the FEAD, such as an AC compressor or an automatic transmission oil pump.

Systems and methods for operating a spark ignition engine that includes a particulate filter in the engine's exhaust system are described. In one example, a threshold temperature at which the spark ignition engine may be automatically stopped is adjusted according to an amount of soot that is stored in the particulate filter.

In response to a restarting request generated during a stopping period, in which fuel injection is stopped to automatically stop engine operation, either starter starting or combustion starting is selected. In the starter starting, the engine is restarted using a starter motor. In the combustion starting, the engine is restarted through fuel injection and ignition without using the starter motor. If the rotational resistance acting on the crankshaft is determined to be of such a magnitude that the combustion starting is impossible, the starter starting is carried out in response to the restarting request generated during the stopping period.

Systems and methods for operating a spark ignition engine that includes a particulate filter in the engine's exhaust system are described. In one example, a threshold temperature at which the spark ignition engine may be automatically stopped is adjusted according to an amount of soot that is stored in the particulate filter.

A control device for a multi-stage automatic transmission-equipped vehicle includes a hydraulic power controller, a combustion controller configured to, if a predetermined combustion stop condition is satisfied when the vehicle is traveling, perform deceleration-period combustion stop control, and limit combustion restart triggered by a reduction in rotational speed of an internal combustion engine, during execution of the deceleration-period combustion stop control, and a motoring controller configured to control the rotational drive of the internal combustion engine by a motor during execution of the deceleration-period combustion stop control so that the rotational speed of the internal combustion engine is maintained at a predetermined rotational speed during a period of time from the time that the rotational speed of the internal combustion engine decreases to the predetermined rotational speed until downshifting to a predetermined gear ratio is completed.