A vehicle control system is provided which includes a travel controller working to execute a coasting mode to cut transmission of drive power, as produced by an engine to a drive wheel of the vehicle when a given execution condition is encountered while the vehicle is traveling. The travel controller determines a threshold value, as used for comparison with a position of an accelerator, based on the speed of the vehicle. When the position of the accelerator is determined to be smaller than the threshold value, the travel controller executes the coasting mode. This improves the fuel economy in the vehicle without sacrificing traveling of the vehicle according to a driver's operation on the accelerator.

A hybrid power supply system for an engine is disclosed. The hybrid power supply system includes a sensing unit to generate a signal indicative of a speed of the engine and a controller to determine the speed of the engine based on the signal received from the sensing unit. The controller compares the speed of the engine with a predefined maximum idle speed, and cuts off a supply of fuel to the engine, when the speed of the engine is greater than or equal to the predefined maximum idle speed. The controller shuts off an inlet valve and an exhaust valve associated with a cylinder of the engine. The closure of the inlet valve and the exhaust valve allow compression and expansion of air within the cylinder during supply of a rotational power by a flywheel.

A vehicle control system is provided which includes a travel controller working to execute a coasting mode to cut transmission of drive power, as produced by an engine to a drive wheel of the vehicle when a given execution condition is encountered while the vehicle is traveling. The travel controller determines a threshold value, as used for comparison with a position of an accelerator, based on the speed of the vehicle. When the position of the accelerator is determined to be smaller than the threshold value, the travel controller executes the coasting mode. This improves the fuel economy in the vehicle without sacrificing traveling of the vehicle according to a driver's operation on the accelerator.

A method for controlling engine revolution per minute (RPM) includes: a frequency deriving process for deriving a frequency from change in engine RPM detected by a detector by a controller during driving of the engine; a frequency conversion process for converting a derivation frequency derived in the frequency deriving process into a conversion frequency via a predetermined conversion process by the controller; a frequency comparison process for comparing an amplitude of the conversion frequency at which engine RPM is to be changed among conversion frequencies converted in the frequency conversion process with an amplitude of a reference frequency pre-inputted to the controller; and a fuel injection amount adjusting process for deriving a correction value based on a result derived in the frequency comparison process, for applying the derived correction value, and for controlling an injector by the controller to adjust a fuel injection amount.

A hybrid power supply system for an engine is disclosed. The hybrid power supply system includes a sensing unit to generate a signal indicative of a speed of the engine and a controller to determine the speed of the engine based on the signal received from the sensing unit. The controller compares the speed of the engine with a predefined maximum idle speed, and cuts off a supply of fuel to the engine, when the speed of the engine is greater than or equal to the predefined maximum idle speed. The controller shuts off an inlet valve and an exhaust valve associated with a cylinder of the engine. The closure of the inlet valve and the exhaust valve allow compression and expansion of air within the cylinder during supply of a rotational power by a flywheel.

The present disclosure relates to a system for controlling vibration of an engine including an engine inertia portion which rotates together with the engine and a sub-inertia portion which influences a rotation speed of the engine and is separately provided, and a damper which is disposed between the engine inertia portion and the sub-inertia portion for reducing a vibration. The present disclosure includes: determining whether a vehicle is in an idle state; sensing rotation speeds of the engine inertia portion and the sub-inertia portion, respectively; calculating an average value of the rotation speeds of the engine inertia portion and the sub-inertia portion; calculating an error value from the average value; and PI controlling by receiving the error value.

In a vehicle including a power supply network for electrical consumers, a battery, an engine, and a generator coupled to the engine to supply electrical energy to the battery and to the power supply network, an operation saving device includes an electronic processor configured to raise an idling speed of the engine when the battery is disconnected from the power supply network.

The engine device including a multi-fuel engine that is operated by burning a main fuel including a low GHG fuel, which emits less greenhouse gas than a petroleum-based fuel, and a hydrocarbon-based auxiliary fuel includes a main fuel injection unit of a fuel injection unit, which injects the main fuel by electric control, an auxiliary fuel injection unit of the fuel injection unit, which injects the auxiliary fuel by mechanical control, and a control device that electrically controls at least one of the injection volume, injection pressure, injection timing, and injection frequency of the main fuel by the main fuel injection unit. The control device controls the rotation speed of the multi-fuel engine at the time of idle operation.

A vehicle includes one or more processors configured to select an air/fuel ratio for the engine that is different from the stoichiometric air/fuel ratio. The one or more processors are further configured to select a torque request for the engine, determine a load request for the engine based on at least the torque request and the selected air/fuel ratio, and determine an output to a throttle actuator based on the load request for the engine.