A pre-stoppage ignition control unit defines, as a stoppage transition air amount, an intake air amount of the engine with which the engine torque becomes the stoppage transition torque in a state in which an ignition timing of the engine is set to a predetermined self-sustaining operation ignition timing, defines, as an intermediate timing, a predetermined timing earlier than timing at which the intake air amount converges to the stoppage transition air amount during an execution period of the pre-stoppage self-sustaining operation control, sets the ignition timing of the engine in a period from the start of the pre-stoppage self-sustaining operation control to the intermediate timing to timing earlier than the self-sustaining operation ignition timing, and sets the ignition timing of the engine in the period after the intermediate timing to the self-sustaining operation ignition timing.

A system and method for enhancing spark generation in an ignition coil of an internal combustion engine at low rotational speeds of the flywheel. The method and system monitor the rotational speed of the flywheel and, when the rotational speed of the flywheel is below a threshold rotational speed, the system and method supplies voltage pulses to the primary winding. The timing of the voltage pulses supplied to the primary winding are triggered off of voltage transitions in pulses induced in the primary winding upon rotation of the flywheel. Once the internal combustion engine has started, the switching device transitions into a second condition to disconnect the electrical storage device from the primary winding. The spark generation system of the present disclosure allows for starting of an internal combustion engine upon slower initial rotational speeds.

An apparatus, method, and system for controlling an idle speed of an internal combustion engine during certain vehicle component operations to minimize unwanted motion and vibration. A transmission neutral engagement, a transmission forward or reverse gear engagement, and a vehicle speed are detected. An engine target idle speed is set to a first speed during the neutral engagement. An engine target idle speed is set to a second idle speed when a vehicle speed is less than a threshold speed and the forward or reverse gear is activated. The vehicle target idle speed is set a third idle speed when the vehicle speed is greater than a threshold speed while the forward or reverse gear is activated, wherein the first target idle speed, second target idle speed and third target idle speed are different engine speeds.

Systems and methods for operating an internal combustion engine that is coupled to a power split transmission are described. In one example, the internal combustion engine is operated in a speed control mode or a torque control mode in response to a braking torque and a transmission shift command. Operating the engine in the torque control mode may allow the engine to charge a battery while a neutral transmission state is selected.

Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, an electric machine, and a transmission are described. In one example, values of an engine spark to engine torque relationship are adjusted to improve engine torque control. The engine is subsequently operated responsive to adjusted values of the engine spark to engine torque relationship.

A rotational speed control apparatus for an engine is provided. The engine configured to drive a compressor that compresses a cooling medium for air conditioning. The rotational speed control apparatus includes electronic control unit. The electronic control unit is configured to: (a) correct a torque of the engine through feedback in accordance with a deviation between a rotational speed during idle operation and a target rotational speed; (b) (i) calculate a load torque of the compressor, and (ii) correct the calculated load torque through feedback in accordance with a deviation between the rotational speed of the engine and the target rotational speed and correct a required value of the torque of the engine in accordance with the corrected load torque, in a predetermined period from a start of a changeover between a driven state of the compressor and a stopped state of the compressor.

In at least some implementations, a method of maintaining an engine speed below a first threshold, includes: (a) determining an engine speed; (b) comparing the engine speed to a second threshold that is less than the first threshold; (c) allowing an engine ignition event to occur during a subsequent engine cycle if the engine speed is less than the second threshold; and (d) skipping at least one subsequent engine ignition event if the engine speed is greater than the second threshold. In at least some implementations, the second threshold is less than the first threshold by a maximum acceleration of the engine after one ignition event so that an ignition event when the engine speed is less than the second threshold does not cause the engine speed to increase above the first threshold.

A PCM (60) performs a catalyst early warming control (AWS control) for accelerating warm-up of a catalytic device. When the catalytic device (35) is not in an activated state and a vehicle is traveling, the PCM (60) is configured to perform: a fuel injection control to inject fuel such that a homogeneous fuel-air mixture can be formed in a combustion chamber (11) of an engine (10) so as to generate a homogeneous combustion; an intake air amount control to increase intake air amount; and an ignition control to retard ignition timing from a reference ignition timing. In addition, the PCM (60) is configured to vary ignition timing retard amount corresponding to a difference between the ignition timing retarded by the ignition timing control and the reference ignition timing, in accordance with engine speed and/or engine load.

Methods and systems are provided for an exhaust catalyst heating strategy that uses spark retard to increase an amount of heat output by an engine without a combustion stability limit. In one example, a method may include, during an engine cold start, applying an ignition spark at a timing that produces substantially zero combustion torque while maintaining an engine speed greater than a threshold speed via electric motor torque. Furthermore, an amount of heat output by the engine may be controlled by adjusting an airflow through the engine, such as by adjusting one or more of a throttle position and the engine speed.

A method and apparatus controlling the fuel-to-air ratio of a fuel and air mixture supplied to an operating engine includes the steps of determining a first engine speed before enleanment of the mixture, determining a second engine speed near or at the end of a period of enleanment of the mixture, and after ending the enleanment, determining whether the engine speed recovers within a predetermined range of the first engine speed and if so determining a delta speed difference between the first and second speeds and using this delta speed difference as a factor in determining a change in the fuel-to-air ratio of the fuel mixture supplied to the engine.