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 to 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.

A controller for an internal combustion engine includes processing circuitry configured to execute: a dither control process of operating fuel injection valves to designate at least one of cylinders as a lean combustion cylinder, in which an air-fuel ratio is leaner than a stoichiometric air-fuel ratio, and to designate at least another one of the cylinders as a rich combustion cylinder, in which an air-fuel ratio is richer than the stoichiometric air-fuel ratio; and an idle-time limiting process of causing an absolute value of a difference between the air-fuel ratio in the lean combustion cylinder and the air-fuel ratio in the rich combustion cylinder to be smaller when the internal combustion engine is idling than when the internal combustion engine is not idling.

When atmospheric pressure (Pa) which varies according to altitude is higher than a predetermined pressure threshold (Path) during idle operation in which catalyst warm-up request is issued, an intake pressure is controlled, through a throttle valve (19), to an intake pressure at which an intake air amount required to promote the warm-up of a catalyst converter (26) is obtained. When the atmospheric pressure (Pa) is lower than the predetermined pressure threshold (Path), the intake pressure is controlled, through a throttle valve (19), to an intake pressure (PaPb) at which a differential pressure (Pb) required by a brake booster (8) is obtained. Accordingly, negative pressure in the brake booster (8) can be secured while promoting the warm-up of the catalyst during the idle operation.

A waste gate valve (7) of a turbocharger (3) is fully opened during idling after warm-up is completed in order to reduce exhaust resistance. However, during idling in an engine cold state when a cooling water temperature (TW) is below a threshold value (TW1), the waste gate valve (7) is open-loop controlled to an intermediate opening degree that is smaller than full opening. An ignition timing is delayed (retarded) for catalyst warm-up. When the cooling water temperature (TW) reaches (t3) the threshold value (TW1), the opening degree of the waste gate valve (7) is set to full opening. When an accelerator opening degree (APO) becomes large (t4) before warm-up is completed, the limitation of the opening degree is released.

An outboard motor having an idling stop function, which includes a starter motor configured to start up an engine, a capacitor configured to serve as a power source of the starter motor, a restarting circuit that includes a restart switch configured to activate the starter motor by electric power supplied from the capacitor in conjunction with a shift lever directly operated by a ship operator at a time of restarting after idling stop, a changeover switch configured to switch to an idling stop mode that enables the restarting circuit, and an engine control device configured to control shifting to the idling stop in the idling stop mode. The capacitor is disposed in an engine compartment of the outboard motor.

An engine-driven working machine according to the present invention has a controller and a muffler. The controller is operated from starting of the engine in a rotational speed limitation mode in which the engine is prevented from rotating at a rotational speed that is higher than the predetermined limitation rotational speed. The controller forces to stop the engine, after a predetermined period has passed, during which the engine operates in the rotational speed limitation mode.

A method for controlling the operation of a spark ignition internal combustion engine is described. The engine includes: a combustion chamber, an intake duct for placing the combustion chamber in communication with the external, a throttle valve arranged inside the intake duct, a carburetor for introducing fuel into the intake duct to form an air/fuel mixture to be intaken into the combustion chamber, and a spark plug arranged inside the combustion chamber to generate a spark for igniting the combustion of the air/fuel mixture. The method includes: monitoring the opening degree of the throttle valve; monitoring the speed of the engine, preventing the spark plug from generating the spark, if the opening degree of the throttle valve drops below a first opening degree threshold value and the speed of the engine is greater than a first engine speed threshold value.

When a request for temperature increase of a three-way catalyst is made, a CPU executes dither control in which one of a plurality of cylinders is set as a rich combustion cylinder with a richer air-fuel ratio than a stoichiometric air-fuel ratio and the remaining cylinders are set as lean combustion cylinders with a leaner air-fuel ratio than the stoichiometric air-fuel ratio. When not executing the dither control, the CPU learns a rich learning value that is a learning value of a degree of a rich imbalance based on an upstream-side air-fuel ratio. When the rich learning value is greater than or equal to a predetermined value, the CPU prohibits the dither control.

A control apparatus configured to control a power unit of a vehicle includes an electronic control unit configured to i) store a set of measurement values of at least one physical parameter representing a plurality of conditions of the power unit; ii) approximate the stored set of the measurement values, by mixed probability distribution, so as to obtain a first probability distribution of the measurement values representing a first condition, and a second probability distribution of the measurement values representing a second condition; iii) set a discrimination boundary between values representing the first condition and values representing the second condition, between mean values of the first probability distribution and the second probability distribution; and iv) control the power unit, according to a result of comparison between a measurement value and the discrimination boundary.

The present invention provides a cooling device for an internal combustion engine of a vehicle. While the vehicle is in a decelerating state and while the internal combustion engine is in an idle reduction state, the cooling device increases the ratio of the cooling water circulation rate through a first path which extends through a heater core and a radiator while reducing the ratio of the cooling water circulation rate through a second path which bypasses the heater core and radiator. In addition, the cooling device increases the discharge flow rate of the electric water pump while the vehicle is in a decelerating state, and maintains the electric water pump in an operating state during idle reduction. Thus, the present invention allows accelerating the temperature decrease of the cylinder head during idle reduction, as well as improving fuel economy during acceleration when the vehicle is started.