Abstract: An engine control system comprises a circuit for selecting a first engine controlled variable or a second engine controlled variable according to engine condition, changeover value for introducing to a pressure sensor the atmospheric pressure when the circuit selects the first engine controlled variable and the negative suction pressure when the circuit selects the second engine controlled variable, an engine control circuit for controlling the engine on the basis of a selected engine controlled variable and the atmospheric pressure and a delay circuit for making the selecting circuit to select the second engine controlled variable after a predetermined time period from the time when the pressure to be introduced to the pressure sensor is changed over from the atmospheric pressure to the negative suction pressure.

Abstract: In an engine control system which determines the amount of fuel to be injected on the basis of an intake pipe pressure detected downstream of a throttle valve and engine speed (D-EFI), fail-safe action is provided when a failure of an intake pipe on the downstream side of the throttle valve is detected. The fail-safe apparatus of the present invention is designed to signal the occurrence of an abnormality with the intake system when the throttle valve is not being opened, that is, the throttle valve is stationary or is closing, a vehicle speed variation exceeds its specific value and the engine speed exceeds its specific value. When these conditions are detected, engine power is controlled lower, thereby assuring vehicle driving safety.

Abstract: An engine throttle valve position detector has a throttle switch formed by a rotary detector member rotatable with the engine throttle valve, a single stationary contact and a single movable contact movable by a guide groove in the rotary detector member into and out of electrical contact with the stationary contact. The stationary and movable contacts are contacted together when the throttle valve is in both fully-closed and fully-open positions, to thereby emit electric signals to an electric control unit in which the signals are processed on the basis of engine intake air flow and engine oil temperature to judge one of the throttle valve fully closed and fully-open positions.

Abstract: In an electronic fuel injection control system for an internal combustion engine having an odd number of cylinders wherein the fuel injection is performed by supplying fuel injection valves with a fuel injection pulse signal having a duration indicative of the quantity of fuel to be injected into the engine and two injection pulse signals are generated in each engine cycle on the basis of ignition signals, the first injection pulse signal is generated in response to the first ignition signal in each engine cycle and the second injection pulse signal is generated after the elapse of an additional period of time from the generation of (m+1)/2.sup.th ignition signal where m represents the number of cylinders. The additional period of time is basically established to the half of an ignition interval and is trimmed in accordance with the variation of engine speed.

Abstract: A method of controlling an internal combustion engine in which the pressure in a cylinder or working chamber of the engine is detected by reading the output signal which is delivered from a pressure sensor when a predetermined time has elapsed from a point of time when the pressure should be detected. Based on this pressure detection, the fuel supply amount or ignition spark timing is controlled.

Abstract: An engine throttle valve position detector has a throttle switch formed by a rotary detector member rotatable with the engine throttle valve, a single stationary contact and a single movable contact movable by a guide groove in the rotary detector member into and out of electrical contact with the stationary contact. The stationary and movable contacts are contacted together when the throttle valve is in both fully-closed and fully-open positions, to thereby emit electric signals to an electric control unit which compares the signals with another signal representative of the engine operating condition, such as engine intake air per engine revolution or manifold vacuum, to judge one of the throttle valve fully closed and fully-open positions.

Abstract: A magnetic type fuel injection valve comprises a stationary core magnetized upon energization of a magnetic coil, a movable core arranged in an axially opposed relation with the stationary core to be movable toward and away from the stationary core in response to the magnetization and demagnetization of the stationary core, and a needle valve connected to the movable core for controlling a fuel injection through a fuel injection port. The movable core is formed with a bottomed axial bore open to that end of the movable core which is remote from the stationary core. Into the bottomed axial bore is tightly fitted an end portion of the needle valve which is defined between one end face of the needle valve and a stepped portion thereof which is formed at a location spaced from the one end face and having a surface facing in an opposite direction from the one end face.

Abstract: A magnetic type fuel injection valve comprises a stationary core magnetized upon energization of a magnetic coil, and a movable core juxtaposed at one end to the stationary core to be normally urged away therefrom by a spring and formed at the other end with an axial bore for receiving one end of a needle valve normally closing a fuel injection nozzle. The movable core is movable as being attracted toward the stationary core together with the needle valve upon magnetization of the stationary core to thereby open the fuel injection nozzle. Through the wall portion of the movable core surrounding the axial bore is formed a transverse hole extending perpendicularly to the axial bore, and another transverse hole is formed through the one end of the needle valve in a manner to align with the first-mentioned transverse hole. A securing pin is snugly fitted in the transverse holes to securely connect the needle valve to the movable core.