Abstract: In a fuel supply system for an internal combustion engine, there is provided a technology capable of keeping the pressure of fuel constant. Fuel pumps are provided in which the pressure of fuel to be discharged therefrom can be adjusted due to an increase and a decrease in the amount of the fuel discharged, and the discharge of fuel therefrom can be stopped. Fuel injection valves serve as a fuel pressure reducing device that reduces the fuel pressure raised by the fuel pumps. A fuel pressure adjusting section changes the number of operations of the fuel pumps and the amounts of fuel discharged from the fuel pumps in such a manner that an average value of the fuel pressure from after the fuel pressure has once been raised until the fuel pressure is again raised becomes substantially constant before and after the number of operations of said fuel pumps is changed.

Abstract: An internal combustion engine is capable of changing a compression ratio according to an output torque. A motor is connected with an output shaft of the internal combustion engine to transmit torque to and from the output shaft. The internal combustion engine detects a torque demand required to the internal combustion engine. When the torque demand exceeds a threshold torque, which is set in advance for changeover of setting of the compression ratio in the internal combustion engine, the motor is controlled to output a torque to the output shaft. The torque output from the motor restricts the output torque of the internal combustion engine to be not greater than the threshold torque. Such control effectively prevents frequent changeover of the setting of the compression ratio in the internal combustion engine. This arrangement desirably saves energy required for the frequent changeover of the compression ratio and thus enhances the total efficiency of the internal combustion engine.

Abstract: An exhaust passageway of an engine is provided with a NOx storage-reduction catalyst for trapping and storing NOx from an exhaust gas lean of a stoichiometric air-fuel ratio. When the storage of the NOx in the catalyst becomes large, the engine is operated at a rich air-fuel ratio for a short time so that NOx is released from the catalyst and is removed by reduction. An electronic unit of the engine estimates the amount of storage of NOx in the catalyst through the use of NOx counters that are incremented at a predetermined rate during a lean air-fuel ratio operation of the engine, and that are decremented at a predetermined rate during a rich air-fuel ratio operation of the engine. Independent NOx counters are provided for at least two divided portions of the catalyst in a one-to-one correspondence.

Abstract: In an in-cylinder injection spark-ignition internal combustion engine including a plurality of cylinders and a catalyst device disposed in an exhaust system of the engine, a fuel is injected to at least one selected cylinder selected from the plurality of cylinders to be operated, and subsequently the fuel is injected to all cylinders to be operated. At this time, a warm-up controlled variable for the at least one selected cylinder is smaller than the warm-up controlled variable used when all cylinders are operated. In the in-cylinder injection spark-ignition internal combustion engine, the all cylinder operation is started and the warm-up control is started for all cylinders to warm up the catalyst device disposed in the exhaust system of the engine preferably when a fuel injection pressure exceeds a target value.

Abstract: In an in-cylinder injection spark-ignition internal combustion engine including a plurality of cylinders and a catalyst device disposed in an exhaust system of the engine, a fuel is injected to at least one selected cylinder selected from the plurality of cylinders to be operated, and subsequently the fuel is injected to all cylinders to be operated. At this time, a warm-up controlled variable for the at least one selected cylinder is smaller than the warm-up controlled variable used when all cylinders are operated. In the in-cylinder injection spark-ignition internal combustion engine, the all cylinder operation is started and the warm-up control is started for all cylinders to warm up the catalyst device disposed in the exhaust system of the engine preferably when a fuel injection pressure exceeds a target value.

Abstract: In an in-cylinder injection spark-ignition internal combustion engine including a plurality of cylinders and a catalyst device disposed in an exhaust system of the engine, a fuel is injected to at least one selected cylinder selected from the plurality of cylinders to be operated, and subsequently the fuel is injected to all cylinders to be operated. At this time, a warm-up controlled variable for the at least one selected cylinder is smaller than the warm-up controlled variable used when all cylinders are operated. In the in-cylinder injection spark-ignition internal combustion engine, the all cylinder operation is started and the warm-up control is started for all cylinders to warm up the catalyst device disposed in the exhaust system of the engine preferably when a fuel injection pressure exceeds a target value.

Abstract: An in-cylinder-injection internal combustion engine of spark ignition type has a plurality of cylinders, a fuel accumulator for storing a pressurized fuel; a fuel injector system that injects the pressurized fuel into each of the cylinders; a spark ignition system that ignites the fuel injected into each of the cylinders; and is controlled such that the engine is started by a partial operation of a selected at least one of the cylinders with a fuel injected into the selected at least one of the cylinders in at least its intake stroke. Then, a full operation of all of the cylinders with the fuel injected into all of the cylinders is started. The full operation is initiated not before a pressure of the fuel in the fuel accumulator has been raised to a level high enough to permit injection of the fuel into each of the cylinders in its compression stroke, as a result of the partial operation of the selected at least one of the cylinders.

Abstract: An in-cylinder-injection internal combustion engine of spark ignition type has a plurality of cylinders, a fuel accumulator for storing a pressurized fuel; a fuel injector system that injects the pressurized fuel into each of the cylinders; a spark ignition system that ignites the fuel injected into each of the cylinders; and is controlled such that the engine is started by a partial operation of a selected at least one of the cylinders with a fuel injected into the selected at least one of the cylinders in at least its intake stroke. Then, a full operation of all of the cylinders with the fuel injected into all of the cylinders is started. The full operation is initiated not before a pressure of the fuel in the fuel accumulator has been raised to a level high enough to permit injection of the fuel into each of the cylinders in its compression stroke, as a result of the partial operation of the selected at least one of the cylinders.

Abstract: In an in-cylinder injection spark-ignition internal combustion engine including a plurality of cylinders and a catalyst device disposed in an exhaust system of the engine, a fuel is injected to at least one selected cylinder selected from the plurality of cylinders to be operated, and subsequently the fuel is injected to all cylinders to be operated. At this time, a warm-up controlled variable for the at least one selected cylinder is smaller than the warm-up controlled variable used when all cylinders are operated. In the in-cylinder injection spark-ignition internal combustion engine, the all cylinder operation is started and the warm-up control is started for all cylinders to warm up the catalyst device disposed in the exhaust system of the engine preferably when a fuel injection pressure exceeds a target value.

Abstract: An exhaust gas purifying apparatus of an internal combustion engine containing: an absorption-reduction catalyst which absorbs nitrogen oxides NOx included in exhaust when an air/fuel ratio of the exhaust is lean and reduces the absorbed NOx when the air/fuel ratio of the exhaust is a stoichiometric ratio or rich; and NOx amount estimating apparatus for estimating an amount of NOx absorbed in the NOx absorption-reduction catalyst; a rich spike executing apparatus for executing a rich spike while switching the air/fuel ratio to the stoichiometric ratio or to a rich air/fuel ratio when the amount of NOx estimated by the NOx amount estimating apparatus exceeds a permissible reference value; an atmospheric pressure detector for detecting atmospheric pressure; and an amount correcting apparatus for correcting the amount of NOx estimated by the NOx amount estimating apparatus, based on the atmospheric pressure detected by the atmospheric pressure detector, such that the amount of correction increases as atmospheric

Abstract: A control device for an internal combustion engine comprises a fuel injector provided for each cylinder, an ignition plug starting ignition in each cylinder simultaneously with a start of the engine cranking, and a detection unit for detecting combustion in each cylinder when the engine is started which determines that the fuel injector of a cylinder in which ignition is carried out before fuel injection has a fuel leak when combustion is detected in the cylinder.