Abstract: A vane type pump having a rotor with slots through which vanes extend and engage the inside of a cylindrical casing to pump upon rotation of the rotor. The slots have a longitudinal groove on each inner side facing each other and elongated carbon sealing elements are positioned in the grooves to sealably engage the vane extending therebetween. A leaf spring is positioned behind one sealing element in compression and its amplitude of movement, as a result of the dimensions of all the components, is limited to 0.6 mm or less.

Abstract: A closed-loop air-fuel control system for an internal combustion engine comprising a control circuit having an open-loop mode of operation in which an air-fuel ratio control signal is fixed to a predetermined value determined by a sensed value of the atmospheric pressure and the temperature of the intake air of the engine. In order to shorten the time period for calculating the air-fuel ratio and to simplifying the circuit construction, an output signal of an atmospheric pressure sensor is supplied to an intake air temperature sensor so as to produce an output signal which represents both the temperature of the intake air and the atmospheric pressure at the same time.

Abstract: An electronic circuit for use in a vehicle equipped with an internal combustion engine. The electronic circuit comprises a constant-voltage regulated power-supply circuit, a control circuit having a central processing unit for controlling electrical apparatus installed in the vehicle, and a detecting circuit for detecting variations in supply voltage supplied from the power-supply circuit. The detecting circuit is adapted to generate an output signal when the supply voltage of the power-supply circuit is out of a predetermined range. The electronic circuit further includes circuitry responsive to the output signal of the detecting circuit to render the central processing unit inoperative and an alarm responsive to the same output signal to give warnings.

Abstract: A method of controlling the recirculation of exhaust gases in an internal combustion engine provided with an exhaust-gas recirculation system by which the exhaust gases emitted from the exhaust manifold are partially recirculated into the intake manifold of the engine, comprising cutting off the recirculation of exhaust gases to the intake manifold of the engine when the engine is being warmed up, recirculating exhaust gases to the intake manifold of the engine at a rate variable in a predetermined required exhaust-gas recirculation ratio to the rate at which air is circulated to the intake manifold of the engine after the engine is warmed up, and recirculating exhaust gases to the intake manifold of the engine with a reduced exhaust-gas recirculation ratio lower than said required exhaust-gas recirculation ratio during a transient period of time intervening the conditions in which the engine is being warmed up and the conditions in which the engine has been warmed up.

Abstract: An air/fuel ratio control system for use with an internal combustion engine, which includes a three-way catalyst arranged in the exhaust system of the engine, an electrical circuit operatively connecting an O.sub.2 sensor with fuel quantity adjusting means in a manner effecting feedback control of the air/fuel ratio of a mixture produced by the fuel quantity adjusting means and being supplied to the engine, in response to an output signal produced by the O.sub.2 sensor, and secondary air supply means for supplying atmospheric air into the exhaust system at a zone upstream of the O.sub.2 sensor. The secondary air supply means is adapted to operate only during open loop control of the air/fuel ratio.

Abstract: An electric control system for controlling an internal combustion engine, which comprises sensor means for detecting at least one of operating condition of the engine and ambient condition in the vicinity of the engine to generate an output continuously variable with a change in the above at least one condition, comparator means for comparing the output of the sensor means with upper and lower limits which are set at values lying slightly beyond a normal range of values indicative of the at least one condition which can exist during normal operation of the engine, and generating a first signal when the output of the sensor means lies beyond the upper limit or the lower limit; and a timer arranged to generate a second signal is continuously generated over a predetermined period of time. The electric control system includes an air/fuel ratio control system for internal combustion engines.

Abstract: An air/fuel ratio feedback control system for internal combustion engines, which includes: a fail safe device comprising at least one of a first failure detecting means for detecting whether no inversion occurs in the output level of the O.sub.2 sensor over a predetermined period of time during air/fuel ratio feedback control dependent upon the O.sub.2 sensor output when the O.sub.2 sensor is activated, and a second failure detecting means for detecting whether no activation of the O.sub.2 sensor occurs over a second predetermined period of time after the engine temperature has risen above a predetermined value during the above feedback control; and means for rendering the fail safe device inoperative when a detected value of ambient atmospheric pressure is lower than a predetermined value.

Abstract: A fail safe device comprising means for detecting a failure in an air/fuel ratio feedback control system and generating a fault signal when such failure is detected, and means responsive to the fault signal to drive an actuator for driving an air/fuel ratio control valve and also responsive to a reference position signal supplied thereto during the above driving, which is generated when the actuator passes its reference position, to stop the actuator at the reference position.

Abstract: An air/fuel ratio control system for performing feedback control of the air/fuel ratio of an air/fuel mixture being supplied to an internal combustion engine in response to the concentration of an exhaust gas ingredient. The air/fuel ratio control system includes a device for controlling a shot air valve for supplying secondary air into the intake pipe of the engine. The control device is connected to a solenoid valve for controlling the shot air valve and operable to open the solenoid valve to hold the shot air valve inoperative for a predetermined period of time after the engine rpm has increased across a predetermined value which is higher than the engine cranking rpm but lower than the engine idling rpm, to thereby prevent misfire within engine cylinders at the start of the engine.

Abstract: An air/fuel ratio control system for use with an internal combustion engine, in which an acceleration detecting circuit produces a signal indicative of engine acceleration when the engine rpm increases across a predetermined value which is slightly higher than an idle rpm to which the engine is adjusted, and driving pulse supply means is responsive to this acceleration signal to supply driving pulses to a pulse motor to cause it to move the valve position of an air/fuel ratio control valve to a preset position whereby improved exhaust gas emission characteristics of the engine can be obtained at the standing start of the engine and during subsequent normal operation thereof.

Abstract: An air/fuel ratio control system for use in an internal combustion engine, which is adapted to initiate air/fuel ratio control upon concurrent fulfillment of a first condition that a first predetermined period of time which is provided as a period of time from the start of the engine to the warming-up of the engine is determined in dependence on the engine temperature available at the start of the engine by means of a first timer circuit and the first timer circuit finishes counting the first predetermined period of time, and a second condition that a second timer circuit finishes counting a second predetermined period of time after the internal resistance of an O.sub.2 sensor for detecting the oxygen concentration in the engine exhaust gases has dropped below a predetermined value.

Abstract: An air/fuel ratio control system for use with an internal combustion engine. The system is provided with an electrical circuit which operatively connects an O.sub.2 sensor with fuel quantity adjusting means in a manner effecting feedback control of the air/fuel ratio of a mixture produced by the fuel adjusting means and being supplied to the engine in response to the output signal of the O.sub.2 sensor. The electrical circuit includes means operable during open loop control of the air/fuel ratio under a particular engine operating condition, for controlling the fuel quantity adjusting means so as to obtain a mixture having a predetermined air/fuel ratio appropriate for the particular engine operating condition, irrespective of the O.sub.2 sensor output signal, and means for correcting the above predetermined ratio in response to atmospheric pressure. The electrical circuit further comprises fail safe means for detecting a malfunction in the atmospheric pressure sensor.

Abstract: An air/fuel ratio feedback control system for internal combustion engines, which is arranged such that when a pulse motor for driving an air/fuel ratio control valve passes the switching point of position detecting means during feedback control operation, a value indicative of the number of steps corresponding to the reference position of the pulse motor, stored in a memory in an electrical circuit for driving the pulse motor is simultaneously shifted to an actual position counter. Air/fuel ratio control can be achieved with accuracy on the basis of a count in the above actual position counter which thus exactly corresponds to the actual position of the pulse motor.

Abstract: An air/fuel ratio control system for use with an internal combustion engine, which comprises O.sub.2 sensor activation determining means having a comparator and a timer and adapted to determine the activation of an O.sub.2 sensor for detecting oxygen concentration in engine exhaust gases, to produce an output upon determining the activation, engine temperature determining means adapted to produce an output when an engine temperature detected by an engine temperature sensor exceeds a predetermined value, and signal generating means adapted to produce a feedback control initiating signal when supplied with both of the above outputs, whereby air/fuel ratio control operation can be initiated at an appropriate time. Further provided is means for supplying secondary air to the exhaust system of the engine, which is arranged to be rendered inoperative by the above feedback control initiating signal.

Abstract: A system for control of the flow rate of a fluid being supplied to an internal combustion engine. The system includes a flow rate control valve for controlling the flow rate of a fluid being supplied to the engine, a pulse motor for driving the flow rate control valve, position detecting means for detecting the position of the flow rate control valve with respect to a reference position to produce two different levels of output, depending upon a detected valve position, and an electrical circuit responsive to the output of the position detecting means to drive the pulse motor. At the start of the engine, the electrical circuit is operable to drive the pulse motor in directions as a function of the output of the position detecting means, stopping same upon a certain change in the level of the above output, which corresponds to the reference position and hence setting it to a predetermined position preset as a function of parameters of the operating condition of the engine.

Abstract: An air/fuel ratio control system for performing feedback control of the air/fuel ratio of an air/fuel mixture being supplied to an internal combustion engine. The air/fuel ratio control system is provided with an exhaust gas recirculation system which is adapted to use a pressure sensor and a temperature sensor for detection of conditions of interruption of the exhaust gas recirculation at low engine load and at low engine temperature. At the same time, the above sensors are used for detection of various engine operating conditions for control of the air/fuel ratio of the mixture, and are adapted to produce outputs continuously variable with wide ranges of changes in the absolute pressure in the intake system of the engine and in the engine temperature. The exhaust gas recirculation system thus precludes the use of special sensors and therefore has a simple exhaust gas recirculation control section.

Abstract: An air/fuel ratio control system for performing feedback control of the air/fuel ratio of an air/fuel mixture being supplied to an internal combustion engine. The air/fuel ratio control system is provided with an evaporated fuel purging control arrangement which is adapted to use an engine cooling water temperature sensor as an engine temperature sensor for control of purging of evaporated fuel from a canister to a venturi of the engine. At the same time, the above sensor is used for detection of various engine operating conditions for control of the air/fuel ratio of the mixture and adapted to produce an output continuously variable with a change in the temperature of engine coolant. The preclusion of the use of a special temperature sensor simplifies the structure of the evaporated fuel purging arrangement.

Abstract: An air/fuel ratio control system which is adapted to perform feedback control of the air/fuel ratio of a mixture being supplied to an internal combustion engine, selectively by porportional term control or by integral term control in response to changes in the output of an O.sub.2 sensor. Immediately after changeover from open loop control to closed loop control, the position of an actuator for driving an air/fuel ratio control valve is controlled initially with integral term correction for feedback control of the air/fuel ratio, to thereby keep small the deviation of the actuator position from its proper position immediately after the changeover to the closed loop control.

Abstract: A control system for internal combustion engines, which comprises: a power transistor connected to the solenoid of a solenoid valve forming an EGR control valve for energization of the same; an abnormality detecting circuit arranged for comparing the input and output levels of the power transistor to generate an output signal when the two levels are out of an inverted relationship; a timer arranged for generating an output signal when the output signal of the abnormality detecting circuit is continuously generated over a predetermined period of time; and emergency means actuatable by the output signal of the timer. The emergency means may include an alarm device and a safety circuit, both responsive to the output of the timer to give the alarm and render the power transistor inoperative, respectively.

Abstract: A control device for a pulse motor having a plurality of polyphase stator coils, which includes a driving circuit having a plurality of power transistors arranged for sequentially energizing the stator coils, an abnormality detecting circuit arranged for comparing the input and output levels of the transistors to produce an output when the two levels are out of an inverted relationship, and a timer circuit arranged for producing a fault signal when the output of the abnormality detecting circuit is continuously produced over a predetermined period of time. The pulse motor control device may also include an alarm device and a safety device, both responsive to the output of the timer circuit to give the alarm and render the power transistors inoperative, respectively.