Abstract: When an actual output power level of an engine is greater than a preset engine power demand due to the higher density of intake air in a cold environment, the control procedure of the invention controls a motor to raise a rotation speed of the engine with a throttle opening TH kept at a current level, so as to make the actual output power level of the engine substantially equal to the engine power demand (this is attained by, for example, a change of a target drive point from a point A to a point B). This arrangement effectively restrains a battery from being charged with an unexpectedly large electric power and prevents frequent changeover between the stop and the start of the engine with a significant variation in current state of charge (SOC) of the battery.

Abstract: When an actual output power level of an engine is greater than a preset engine power demand due to the higher density of intake air in a cold environment, the control procedure of the invention controls a motor to raise a rotation speed of the engine with a throttle opening TH kept at a current level, so as to make the actual output power level of the engine substantially equal to the engine power demand (this is attained by, for example, a change of a target drive point from a point A to a point B). This arrangement effectively restrains a battery from being charged with an unexpectedly large electric power and prevents frequent changeover between the stop and the start of the engine with a significant variation in current state of charge (SOC) of the battery.

Abstract: A valve opening/closing timing control apparatus and method can be used with a camshaft whose rotation is synchronized with opening/closing timing of an intake valve or an exhaust valve in an internal combustion engine; a relative rotation angle adjustment mechanism which transmits torque of a crankshaft in the internal combustion engine to the camshaft and which adjusts a relative rotation angle between the crankshaft and the camshaft; and a lock mechanism which depends on hydraulic fluid, and which mechanically locks or unlocks the relative rotation angle that is adjusted by the relative rotation angle adjustment mechanism. The apparatus and method determine the duration of a time period from a start of the internal combustion engine until a start of relative rotation angle adjustment, based upon an unlocking force of the hydraulic fluid that is applied to the lock mechanism when the lock mechanism is locked and the internal combustion engine is started.

Abstract: A valve opening/closing timing control apparatus and method can be used with a camshaft whose rotation is synchronized with opening/closing timing of an intake valve or an exhaust valve in an internal combustion engine; a relative rotation angle adjustment mechanism which transmits torque of a crankshaft in the internal combustion engine to the camshaft and which adjusts a relative rotation angle between the crankshaft and the camshaft; and a lock mechanism which depends on hydraulic fluid, and which mechanically locks or unlocks the relative rotation angle that is adjusted by the relative rotation angle adjustment mechanism. The apparatus and method determine the duration of a time period from a start of the internal combustion engine until a start of relative rotation angle adjustment, based upon an unlocking force of the hydraulic fluid that is applied to the lock mechanism when the lock mechanism is locked and the internal combustion engine is started.

Abstract: An engine performs a combustion mode selected from a plurality of combustion modes. The combustion modes include stratified-charge combustion and homogeneous-charge combustion. A electronic control unit switches the combustion mode in accordance with the current running conditions of the engine. The electronic control unit limits a running area in which stratified-charge combustion is performed in accordance with the frequency of engine knocking occurrences. This properly executes knocking control without adversely affecting the execution of is stratified-charge combustion.

Abstract: In a high-pressure pump for an internal combustion engine, a spill valve is inhibited from being stopped frequently. If the fuel injection amount becomes smaller than a predetermined amount, a method of determination is changed so that a feedforward term for duty control increases. This makes it unlikely that the duty ratio will become equal to zero. Operation resulting from a closing motion of the spill valve occurs substantially regularly. As a result, the circumstance where operation noise is generated irregularly is avoided, and a sense of incongruity given to the driver is reduced.