Abstract: A method of controlling an intake air passage of an internal combustion engine is provided. The intake air passage cyclically communicates to a combustion chamber of the internal combustion engine, thereby inducting fresh air into said combustion chamber. The cyclic communication of the intake air passage to the combustion chamber generates a pressure wave in the intake air passage. The method comprises reducing an effective length of a transmission path of the pressure wave in an upstream direction of the intake air passage as a desired air flow to the combustion chamber decreases. In accordance with the method, the effective length of the pressure wave transmission path is reduced as desired air flow decreases. With the reduced effective length, the pressure wave bounces back and forth between ends of the transmission path more often before the next cyclic communication. The more bouncing attenuates the pressure wave at the next cyclic communication.

Abstract: A method of controlling an intake air passage of an internal combustion engine is provided. The intake air passage cyclically communicates to a combustion chamber of the internal combustion engine, thereby inducting fresh air into said combustion chamber. The cyclic communication of the intake air passage to the combustion chamber generates a pressure wave in the intake air passage. The method comprises reducing an effective length of a transmission path of the pressure wave in an upstream direction of the intake air passage as a desired air flow to the combustion chamber decreases. In accordance with the method, the effective length of the pressure wave transmission path is reduced as desired air flow decreases. With the reduced effective length, the pressure wave bounces back and forth between ends of the transmission path more often before the next cyclic communication. The more bouncing attenuates the pressure wave at the next cyclic communication.

Abstract: A control apparatus for a direct-injection, spark-ignition engine including a temperature-condition detector for detecting a temperature condition of the engine catalyst, and a controller for controlling a fuel-injection operation.

Abstract: A fuel spray and a tumble collide with each other from approximately opposite directions in a cavity formed in a piston head so that a combustible mixture stays around a spark plug for an extended period of time. An upper opening of the cavity is elongated to both the left and right sides of a cylinder axis. The distance between a ceiling of the combustion chamber and a bottom surface of the cavity is smaller on the right side of the cylinder axis than on the left side thereof and largest at least at a point where the cylinder axis crosses the bottom surface of the cavity, and a portion of the cavity to the left of the cylinder axis has a larger volumetric capacity than a portion of the cavity to the right of the cylinder axis, whereby a strong tumble is maintained up to a fuel injection point.

Abstract: A control apparatus for a direct-injection, spark-ignition engine including a temperature-condition detector for detecting a temperature condition of the engine catalyst, and a controller for controlling a fuel-injection operation of the engine fuel injector for the engine.

Abstract: A fuel spray and a tumble collide with each other from approximately opposite directions in a cavity formed in a piston head so that a combustible mixture stays around a spark plug provided at an upper central part of a combustion chamber for an extended period of time. An upper opening of the cavity is elongated to both the left and right sides of a cylinder axis. The distance between a ceiling of the combustion chamber and a bottom surface of the cavity as measured parallel to the cylinder axis is smaller on the right side of the cylinder axis than on the left side thereof and largest at least at a point where the cylinder axis crosses the bottom surface of the cavity, and a portion of the cavity to the left of the cylinder axis has a larger volumetric capacity than a portion of the cavity to the right of the cylinder axis, whereby a strong tumble is maintained up to a fuel injection point, allowing satisfactory mixture strification.

Abstract: A direct fuel injection ignition engine includes combustion chambers with a pent roof type ceiling. Each piston has a top surface with a configuration complementary to the combustion chamber ceiling. A fuel injector is disposed at a peripheral portion of the combustion chamber and injects fuel toward the center portion of the top surface of the piston. A cavity is formed on the top surface of the piston. The cavity has a configuration of an elongated circle with a substantially flat bottom surface. The surrounding side wall of the cavity is substantially upright in relation to the bottom surface. A cavity centerline drawn through the longitudinal axis of the cavity is perpendicular to the injection axis line and offset from the center of the piston toward the injector.

Abstract: A direct injection engine including an injector disposed in an upper portion of a combustion chamber defined above a piston disposed in a cylinder of the engine with a fuel injecting direction of the injector being provided so that a fuel being injected toward a top portion of the piston, an ignition plug disposed at an upper portion of the combustion chamber, an engine operating condition detector for detecting an engine operating condition. The fuel is injected in a compression stroke from the injector when it is detected by the engine operating condition detector that the engine is in a low engine load and speed zone so as to stratify an injected air fuel mixture around the ignition plug to accomplish a stratified combustion.

Abstract: A direct injection ignition engine includes a piston with a cavity on a top surface thereof, an injector arranged at a peripheral portion of a combustion chamber to be faced to the combustion chamber for injecting a fuel directly into the combustion chamber, an ignition plug arranged to be projected to the combustion chamber for igniting the fuel introduced into the combustion chamber, an intake passage connected to the combustion chamber for introducing an intake air to the combustion chamber, intake air flow control valve arranged in the intake passage for controlling an intake air flow of an inclined vortex including a tumble component and swirl component produced in the combustion chamber, an actuator for driving the control valve, engine load detecting sensor for detecting an engine load, engine speed detecting sensor for detecting an engine speed, fuel supply controller, based on the output signals from the engine load detecting sensor and the engine speed detecting sensor, for producing control signals

Abstract: An intake system for a vehicle for delivering intake air through separate or discrete intake passages of the intake system into engine cylinders through discrete intake passages. A collector chamber and a resonator chamber connect with an upstream main intake passage and the discrete intake passages. The collector chamber communicates at one end with upstream ends of the discrete intake passages and at its another end, opposite to the one end, with the resonator chamber. The discrete intake passages are clustered or grouped together at their upstream ends and connected as a cluster to the collector chamber.

Abstract: Discrete intake passages communicating with respective cylinders of a multiple-cylinder in-line engine are merged into an integrated chamber at their upstream ends. The integrated chamber is disposed above the engine and extends substantially horizontally. Each discrete intake passage extends from the engine body, bends upward toward the integrated chamber and is connected to the downstream side end face of the integrated chamber. The discrete intake passages for the cylinders which are positioned relatively near to the integrated chamber are connected to the downstream side end face of the integrated chamber at an upper portion of the end face and the discrete intake passages for the cylinders which are positioned relatively far from the integrated chamber are connected to the downstream side end face of the integrated chamber at a lower portion of the end face.

Abstract: Plural cylinders are grouped, for example, into two cylinder groups composed of plural cylinders having each inspiration stroke in an equal distance, and each of the grouped cylinder groups is communicated with a volume chamber. To this volume chamber is connected each of the independent air intake passages extending independently or separately from each of the corresponding cylinder. A first connecting portion is disposed to communicate the individual air intake passages for each of the cylinder groups with each other in a position spaced apart in an equal distance from an intake port. Further, a second connecting portion as a resonant passage is disposed to communicate one first connecting portion with the other connecting portion for each cylinder group.

Abstract: An intake system for a multiple-cylinder engine has a plurality of discrete intake passages which are substantially equal to each other in length and are connected to the respective cylinders at their downstream ends. The upstream ends of the discrete intake passages are merged into an integrated chamber, and an upstream side intake passage communicates the integrated chamber with the atmosphere. The integrated chamber has an upstream side end face and a downstream side end face, and the cross-sectional area of the integrated chamber increases from the upstream side end face to the downstream side end face, the upstream side intake passage having opening into the integrated portion in the upstream side end face, and the discrete intake passages respectively having openings into the integrated chamber in the downstream side end face. The area of the upstream side and downstream side end faces of the integrated chamber S.sub.0 S.sub.

Abstract: The air-fuel ratio of an air-fuel mixture supplied to an internal combustion engine is determined on the basis of a smoothed amount of intake air and a smoothed throttle opening. The smoothed amount of intake air is reflected by a predetermined ratio of a former amount of intake air to the newest amount of intake air. The smoothed throttle opening is reflected by a ratio of a former throttle opening to the newest throttle opening substantially identical to said predetermined ratio.