Abstract: An auxiliary mechanism mounting structure for mounting an auxiliary mechanism on an engine has an auxiliary mechanism mounting portion whose bearing rigidity is high in the longitudinal direction of the engine and is low in the vertical direction of the engine so that the auxiliary mechanism is easy to vibrate in the vertical direction of the engine.

Abstract: An internal combustion engine is provided with a fuel injection valve. The fuel injection valve is actuated so that fuel injected therefrom reaches the combustion chamber in the latter half of the intake stroke, thereby accomplishing stratified charge. The timing at which blow-back of intake gas occurs is detected and the timing for terminating fuel injection is advanced as the timing at which blow-back of intake gas occurs becomes earlier.

Abstract: An engine control system having an engine vibration sensor which detects engine vibrations. A control circuit is provided for discriminating engine roughness wherein the engine vibration level is above a predetermined level and for decreasing the fuel supply continuously when engine roughness is not detected, in order to make the mixture leaner, but increasing the fuel supply when engine roughness is detected to make the mixture richer. A detector is provided for detecting a specific engine condition wherein the mixture is enriched for specific purposes. The control circuit is responsive to the output of the engine condition detector and discontinues the roughness control when the specific engine condition is detected.

Abstract: An intake system for a rotary piston engine having a plurality of engine sections, each engine section being separated by an intermediate housing. In the intake system, there are provided communicating passages for communicating the engine sections so that intake air can be transferred between working chambers formed in the engine sections in accordance with a difference in rotor phase between the engine sections. The communicating passage is located so as to be closed after an intake port is closed in each engine section and positioned so that there remains a larger amount of intake air in each of the working chambers than the minimum amount of intake air required for ensuring idling rotation speed under idling engine operating condition when the communicating passage is closed. This intake system makes it possible to obtain a rotary piston engine which can remarkably reduce pumping loss and desirably control the amount of intake air in accordance with an engine operating condition.

Abstract: An engine intake system including a supercharger of a type wherein the intake air drawn from the intake air inlet port is compressed by the pressure of the exhaust gas before it is discharged through the intake air outlet port. An exhaust gas recirculation passage is provided between the exhaust passage upstream of the supercharger and the intake passage downstream of the supercharger. The recirculation passage can be used for decreasing the pressure difference between the exhaust gas and the intake air to thereby minimize the engine pumping loss. Further, the recirculation passage can be used for recirculating the exhaust gas to the intake passage to thereby decrease nitrogen oxides in the exhaust gas.

Abstract: A control system for a vehicle engine in which fuel supply quantity is controlled in accordance with the engine roughness level. An engine roughness sensor is provided for detecting engine vibrations and producing a roughness signal which is compared with a reference signal. When the roughness signal is greater than the reference signal, the fuel supply is increased to enrich the air-fuel mixture but, when the roughness signal is smaller than the reference signal, the fuel supply is decreased to make the mixture leaner. The reference signal is smallest in idling operation and stepwisely increased depending on an increase in the load on the engine.

Abstract: An internal combustion engine is provided with a separately formed intake passage for each cylinder. Each intake passage is provided with a fuel injection valve. The fuel injection valve is controlled to inject fuel in the latter half of the intake stroke of the corresponding cylinder. The amount of fuel injected from the fuel injection valve is increased upon acceleration of the engine by an amount which is separately determined for each cylinder and is generally reduced in the order of the firing order.

Abstract: The idling speed of an internal combustion engine is controlled by controlling the position of a control valve disposed in the intake system of the engine to control the amount of intake air fed to the engine. A desired idling speed is determined according to the operating condition of the engine and the control valve is moved to a temporary target position which is expected to be suitable to obtain the desired idling speed. Then feedback control is carried out to converge the actual idling speed to the desired idling speed. When the actual idling speed is finally equalized to the desired idling speed, the actual position of the control valve at that moment is detected and memorized to be adopted as the temporary target position for the same operating condition in later control of the idling speed.

Abstract: An internal combustion engine is provided with an exhaust gas recirculating passage for communicating the intake passage and the exhaust passage thereof. The recirculating passage is provided with a valve for controlling the amount of recirculated exhaust gas. A fundamental air-fuel ratio control value for regulating the air-fuel ratio of the intake gas to a predetermined value is corrected by an operating condition correction value according to the operating condition of the engine. The operating condition correction value is successively changed to an optimal value by comparing the actually obtained air-fuel ratio with a predetermined value. The operating condition correction value for correcting the fundamental air-fuel ratio control value when the exhaust gas recirculation is carried out is changed independently from the same for correcting the fundamental air-fuel ratio correction value when the exhaust gas recirculation is not carried out.

Abstract: A fuel intake system for a multi-cylinder internal combustion engine includes at least two intake passages leading to respective engine cylinders, and a shutter valve positioned within one of the intake passages for, when closed, allowing the entire amount of a combustible air-fuel mixture to be introduced into one of the engine cylinders communicated with the other of the intake passages. For operating the shutter valve, a composite negative pressure which is made up of a negative pressure, developed within the one of the intake passages at a position downstream of the shutter valve with respect to the direction of flow of the combustible air-fuel mixture towards the engine cylinders, and that developed within the other of the intake passages at a position downstream of a throttle valve, is utilized.