Abstract: In order to ensure that idling control is assuredly provided when the engine is subject to cold starts and the like, a solenoid which controls the modulation of a pressure signal via which a vacuum operated servo unit is controlled, is arranged to be fed an energization signal having a maximum energizing effect when a parameter indicative of the engine being started or having just been started is detected.

Abstract: A spacer, which is interposed between a cylinder head and an intake manifold in order to facilitate installation of a swirl control valve or valves, is made of thermosetting phenol or epoxy resin so as to prevent the transfer of heat from the cylinder head to the intake manifold. The spacer installs thereon a fuel injector or injectors and may be provided with a fuel supply passage, pressure regulator, fuel damper, etc. as an integral unit.

Abstract: A crank angle detecting system for a multicylinder engine includes a disc formed with a large number of slits to detect one-degree crank angular positions and a small number of slits to detect a predetermined piston stroke for each cylinder. Since the widths of a small number of slits are different from each other, it is possible to separately discriminate each cylinder in crank angular position on the basis of the crank angle signals obtained by a large number of slits. In the case where the detecting system is incorporated with a group-ignition system, it is possible to detect a predetermined piston stroke for each cylinder immediately after the engine is started, thus preventing the engine from erroneous ignition.

Abstract: A crank angle detecting system for a multicylinder engine includes a disc formed with a large number of slits to detect one-degree crank angular positions and a small number of slits to detect a predetermined piston stroke for each cylinder. Since the widths of a small number of slits are different from each other, it is possible to separately discriminate each cylinder in crank angular position on the basis of the crank angle signals obtained by a large number of slits. In the case where the detecting system is incorporated with a group-ignition system, it is possible to detect a predetermined piston stroke for each cylinder immediately after the engine is started, thus preventing the engine from erroneous ignition.

Abstract: A structure for use in an internal combustion engine including a cooling passage between an engine block outer wall and cylinder walls each defining therein a cylinder. The engine block outer wall has a thickened portion with connection arms extending to the respective cylinder walls to provide a rigid connection between the cylinder wall and the position at which a knock sensor is attached. The rigid connection is effective to transmit vibrations due to internal combustion in the cylinders to the knock sensor with minimized attenuation and minimized distortion.

Abstract: In an internal combustion engine provided with a hot-wire air flowmeter and a canister for supplying fuel evaporated from a fuel tank into an intake passage, there exists a state where an excessively-rich mixture is supplied from the canister to the intake passage because of trouble of the canister and therefore engine stops. If the hot wire is heated in such a state as described above for removal of contaminations sticked onto the hot wire after an ignition switch has been turned off, there exists a problem such that rich mixture may be fired by the heated hot wire. To overcome this problem, an engine stop detecting means is additionally provided in order to inhibit the hot-wire from being heated up when the ignition switch is turned off after engine stop. That is, the hot wire is heated only when the engine is running before the ignition switch is turned off.

Abstract: A structure for use in an internal combustion engine for providing shortened vibration channels through which vibratory forces within engine cylinders are transmitted to a knock sensor attached to the engine on its engine block outer wall. The structure includes a plurality of ribs each extending through a cooling passage between the engine block outer wall and corresponding one of cylinder walls.

Abstract: An exhaust gas recirculation system for an internal combustion engine for automotive use, wherein a diaphragm-operated recirculation rate control valve adapted to control the exhaust gas recirculation rate depending upon the relationship between the pressure of the exhaust gases passed through an orifice and a vacuum developed in the mixture supply system of the engine is used in combination with a solenoid and diaphragm operated vacuum compensating valve which is not only responsive to the pressure of the exhaust gases passed through the orifice but is controlled by a microcomputer responsive to various operational parameters of the engine so that the vacuum to be developed in the recirculation rate control valve is compensated to be optimum for operating conditions of the engine.

Abstract: Exhaust gas recirculation system controlled by a microcomputer for an internal combustion engine comprises a pressure sensor for measuring the pressure of the exhaust gas downstream of an orifice disposed in the exhaust gas recirculation passage, a microcomputer for electrically controlling an electromagnetic valve which fluidly controls an exhaust gas recirculation control valve arranged in the exhaust gas recirculation passage, in view of the comparison of an optimal pressure of the exhaust gases, derived from the engine parameters, and the actual pressure measured by the sensor. The gear position of the transmission, engine temperature, engine speed, and the intake airflow rate are used in the microcomputer to produce an output signal with which the electromagnetic valve is controlled.

Abstract: An auxiliary air delivery system for an internal combustion engine includes an intake vacuum sensor for generating an intake vacuum signal, a deceleration sensor and a microcomputer in which is stored a set of data representing different values of reference intake vacuum and programmed to retrieve a datum as a function of the length of time from the occurrence of engine deceleration. The retrieved information is used a reference signal with which the intake vacuum signal is compared to provide a control signal. A servo mechanism is provided to allow auxiliary air to be admitted into the manifold at a point downstream of the nearly closed throttle in response to the control signal to reduce the difference between the actual intake vacuum and the reference intake vacuum.

Abstract: An altitude correction device is constructed to manually open and close a supplementary air bleed to the atmosphere which bleed communicates with a fuel passage of a carburetor, in accordance with changes in the altitude.

Abstract: An auxiliary air delivery system for an internal combustion engine includes an intake vacuum sensor for generating an intake vacuum signal, a deceleration sensor and a microcomputer in which is stored a set of data representing different values of reference intake vacuum and programmed to retrieve a datum as a function of the length of time from the occurrence of engine deceleration. The retrieved information is used a reference signal with which the intake vacuum signal is compared to provide a control signal. A servo mechanism is provided to allow auxiliary air to be admitted into the manifold at a point downstream of the nearly closed throttle in response to the control signal to reduce the difference between the actual intake vacuum and the reference intake vacuum.

Abstract: A crank angle detecting system for a multicylinder engine includes a disc formed with a large number of slits to detect one-degree crank angular positions and a small number of slits to detect a predetermined piston stroke for each cylinder. Since the widths of a small number of slits are different from each other, it is possible to separately discriminate each cylinder in crank angular position on the basis of the crank angle signals obtained by a large number of slits. In the case where the detecting system is incorporated with a group-ignition system, it is possible to detect a predetermined piston stroke for each cylinder immediately after the engine is started, thus preventing the engine from erroneous ignition.