Abstract: A method and apparatus for automatically indicating speed change operations for a car having a manual type transmission and an electronic control unit having a CPU, a ROM and a RAM in which the method comprises the steps of preliminarily storing at least a data map corresponding to equal fuel consumption rate curves into the ROM of the microprocessor, calculating engine load Q/N in accordance with the current engine speed N and intake air flow Q, calculating V.sub.D.K-Q.sub.D from absolute values of the car speed variables V.sub.D and the intake air flow variables Q.sub.D (K indicates correlation factor) at predetermined time points respectively, comparing and determining if the V.sub.D.K-Q.sub.D is below 0 (zero), and indicating either a shift-up or a shift-down operation on a display or refraining from carrying out the speed change determination during the running on a slope in accordance with the result of the determination.

Abstract: A shift indication apparatus having an engine rotation sensor, a throttle valve sensor, and a shift position sensor, a microcomputer having a ROM and RAM for storing data corresponding to the engine speed, throttle valve openings, and the shift positions therein, and an indicator for indicating preferable shift positions to be performed by a driver in which a torque data map and a fuel consumption rate data map have stored in the ROM for calculating various torque and fuel consumption rates so as to obtain preferable shift positions relating to optimum fuel consumption rate in accordance with said data detected. With this construction, it becomes possible for a driver to run his car in accordance with the indications of the shift operation on the indicator so as to enable the economical running of the car to be realized.

Abstract: An internal combustion engine provided with a first port of a helical shape and second port of a straight shape opened to the combustion chamber. The first port provides a swirl motion in the cylinder, while the second port is opened to the combustion chamber at a position near the spark electrodes located at the upper portion of the combustion chamber in the center thereof. An intake control valve selectively opens or closes the second intake port in accordance with operating conditions of the engine. A main injector is arranged in the second port downstream of the intake control valve. The injector is so controlled that it opens substantially during the intake stroke when the intake control valve is closed. The injector is controlled to inject at the period substantially not located in the intake stroke.

Abstract: A method for indicating gear shifting operation to be performed which comprises the steps of calculating current engine load from the intake air flow Q and the number of engine rotations (i.e. engine speed), comparing the current engine load thus calculated with a predetermined engine load constant, calculating current shift position from the result of the comparison, seeking a first engine load operation function Y=f(N) and a second engine load operation function .beta.=g(N) from known equal fuel consumption rate curves, comparing the first engine load operation function Y thus sought with said current engine load Q/N, and indicating either shift-up or shift-down operation to be performed by a driver in accordance with the result of the comparison. According to the method according to the present invention, preferable shift positions to be performed in the optimum fuel consumption rate can be thereby enabling the maximum engine fuel consumption performance to be carried out during running of a car.

Abstract: An ignition timing control device for an internal combustion engine incorporating exhaust gas recirculation and vacuum advancing of ignition timing, the device including a check valve which holds the largest vacuum which appears in the vacuum port during opening process of the intake throttle valve for the vacuum advancer and a delay means which delays transmission of the largest vacuum to the vacuum advancer.

Abstract: Disclosed is an internal combustion engine comprising a main chamber and an auxiliary chamber which are interconnected with each other via a connecting passage. The connecting passage is tangentially connected to the inner wall of the auxiliary chamber. A raised portion is formed on the inner wall of the auxiliary chamber at a position located opposite to the inner wall to which the connecting passage is tangentially connected with respect to the axis of the auxiliary chamber. A recess is formed on the inner wall beneath the raised portion. The nozzle of a fuel injector is directed to the recess so as to form a rich air-fuel mixture therein. The spark gap of a spark plug is located in the recess for igniting the righ air-fuel mixture therein.

Abstract: Disclosed is an internal combustion engine comprising a main chamber and an auxiliary chamber which are interconnected with each other via a connecting passage. An annular raised portion is formed in the inner wall of the auxiliary chamber so as to divide the auxiliary chamber into a first auxiliary chamber and a second auxiliary chamber. The connecting passage is tangentially connected to the second auxiliary chamber for creating a strong swirl motion in the first auxiliary chamber. This strong swirl motion causes a secondary swirl motion in a portion of the recess, which is located at a position opposite to the inner wall to which the connecting passage is tangentially connected with respect to the axis of the auxiliary chamber. The nozzle of a fuel injector is disposed in the auxiliary chamber so as to be directed to the recess portion for forming a rich air-fuel mixture therein. The spark gap of a spark plug is located in the recess portion.

Abstract: Disclosed is an internal combustion engine comprising a main chamber and an auxiliary chamber which are interconnected with each other via a connecting passage. The connecting passage is tangentially connected to the inner wall of the auxiliary chamber. A raised portion is formed on the inner wall of the auxiliary chamber at a position located opposite to the inner wall to which the connecting passage is tangentially connected with respect to the axis of the auxiliary chamber. A recess is formed on the inner wall beneath the raised portion. The nozzle of a fuel injector is directed to the recess so as to form a rich air-fuel mixture therein and to form a rich air fuel mixture in the auxiliary chamber. The spark plug has an electrode mounting end face on which the central electrode and the earthing electrode are mounted. The mounting end of the central electrode is covered by an insulator and is disposed in the periphery of the electrode mounting face end.

Abstract: A distributor for an internal combustion engine which changes the ignition timing of the engine based on two variables including the rotating speed of the engine and the load imparted to the engine. A sleeve is loosely mounted on a rotary shaft of the distributor, and an ignition changing timing cam is loosely fitted on the sleeve to be rotatable around the axis of the shaft with the sleeve and movable in the axial direction of the shaft relative to the sleeve. A pair of centrifuzed weights urges the cam in the axial direction in response to the speed of the engine. A first link mechanism has at one end a follower of the cam and at the other end is connected to a breaker plate for the distributor contacts to rotate the plate and thereby change the ignition timing in response to engine speed. A second link mechanism is connected at one end to the sleeve and at the other end to a diaphragm actuator which responds to the load on the engine.

Abstract: An internal combustion engine of the type in which the combustion space is divided into a main combustion chamber and an auxiliary combustion chamber connected to each other by a communication passage, and an ignition plug and a fuel injection nozzle are provided for the auxiliary combustion chamber so that the flame produced by the ignition and combustion of a rich fuel-air mixture in the auxiliary combustion chamber spreads into the main combustion chamber to cause effective secondary combustion of the fuel-air mixture in the main combustion chamber; the upper surface of the piston crown is inclined gradually downward and toward the opposite side from the peripheral edge which is brought to a position adjacent to the communication passage when the piston reaches the top dead center, and a stepped portion located remote from the communication passage and a vertical wall having a configuration consisting of a pair of curved surfaces is formed on the surface of the piston crown as the inner wall of the stepped