Abstract: An apparatus for controlling the operation of an internal combustion engine having a carburetor which, controls the air-fuel ratio of the air-fuel mixture supplied to the engine in the steady operating condition of the engine on the basis of predetermined data determined relative to the engine crankshaft rotation speed and intake vacuum and stored in a memory. A three-way catalyst purifies engine exhaust gases, and an output signal from an O.sub.2 sensor in the exhaust system is fed back for the control of the air-fuel ratio in the engine exhaust gases. A circuit checks whether this feedback control is normally carried or not. The air-fuel ratio supplied to the engine in an unsteady operating condition of the engine is controlled by regulating the fuel and air supplied to the engine while bypassing the carburetor, by the sensed values of the intake vacuum, engine crankshaft rotation speed and engine temperature and also depending on the throttle valve position.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine accurately controls the air-fuel ratio of a mixture by first determining the desired fuel injection quantity in accordance with the engine speed and the amount of depression of the accelerator pedal, then determining the desired amount of intake air flow and finally controlling the opening of the throttle valve in accordance with the desired amount of intake air flow.

Abstract: In an electrical fuel injector which comprises an air flow meter for detecting an amount of air intake to an internal combustion engine, a revolution counter for measuring the rate of rotations of the internal combustion engine, and an electronic circuit adapted to arithmetically control an opening time of an injection valve for injecting fuel into the internal combustion engine based on output signals from both air flow meter and revolution counter, a digital filter is provided which has a coefficient variable in accordance with drive conditions of the internal combustion engine, so that the output signal from the air flow meter is applied to the electronic circuit through the digital filter.

Abstract: An air flow rate measuring apparatus in which an air flow sensor whose electric characteristic varies with the rate of air flowing by the sensor is supported on a heat-insulating support member and located in a bypass tube provided in the vicinity of the main venturi of an internal combustion engine, whereby the air flow sensor is isolated from adverse thermal influences so as to reduce an error in measuring air flow rate.

Abstract: There is disclosed an electronic control system for controlling a carburetor equipped with a slow-main system solenoid valve and an enrichment system solenoid valve of different control ranges whose openings are electromagnetically controlled to control the air-fuel ratio of a mixture supplied to an internal combustion engine. The control system calculates, based on signals representative of the engine operating condition including engine temperature, the duty for control of the slow-main system solenoid valve in accordance with the air-fuel ratio required for various engine operating states. When the value of this duty exceeds a predetermined value, the enrichment system solenoid valve is added to the slow-main system solenoid valve to accurately control the air-fuel ratio over a wide range.

Abstract: An electronic controlled fuel injection system having electromagnetic fuel injection valves each of which injects fuel twice during 4-cycle operation strokes, wherein a reference cylinder is provided to inject fuel at intervals of 360.degree. in crankshaft angle, and the next operating cylinder is made to inject fuel 180.degree. after the fuel injection timing for the reference cylinder.

Abstract: An engine revolution speed control device includes sensors (8, 9, 10) for detecting parameters representing the engine conditions, an actuator (7) for controlling the reset position of the throttle (13), a switch (11) producing a signal when the throttle action returns under the control of the actuator (7) and a device (12) which is cyclically driven under the condition that no signal from the switch (11) exits. The device (12) takes in one of the data from the sensors (8, 9, 10) and operates the actuator (7) by a predetermined amount in such a direction as to close the reset opening of the throttle every time that the amount of variation in the data taken in reaches a predetermined value.

Abstract: In an apparatus for controlling an internal combustion engine in which the quantity of air supplied to the engine is controlled to control the warming-up rotational speed of the engine, a first desired warming-up rotational speed characteritic relative to the temperature of engine cooling water and a second desired warming-up rotational speed characteristic lower in rotational speed level than the former are stored in an ROM of a micro-computer, so that, when the throttle valve is not opened during warming-up of the engine, the actual rotational speed of the engine coincides with the first desired warming-up rotational speed, while, when the throttle valve is opened during warming-up, the actual rotational speed of the engine coincides with the second desired warming-up rotational speed.

Abstract: In a single point electronic fuel injection system for injecting fuel at the upstream side of a throttle valve in synchronism with the sucking stroke of engine, upon low-speed driving, particularly upon idling drive, the total amounts of fuel necessary for a previous sucking stroke and the following sucking stroke are injected at a time in the previous sucking stroke and no fuel is injected in the following sucking stroke.

Abstract: An apparatus for controlling the operation of an internal combustion engine having a carburetor, especially, the air-fuel ratio and the rate of exhaust gas recirculation, controls the air-fuel ratio of the air-fuel mixture supplied to the engine in the steady operating condition of the engine on the basis of predetermined data determined relative to the engine crankshaft rotation speed and intake vacuum and stored previously in a memory. A three-way catalyst is used to purify engine exhaust gases, and an output signal from an O.sub.2 sensor in the exhaust system is fed back for the control of the air-fuel ratio in the engine exhaust gases. A circuit is provided to check whether this feedback control is normally carried or not.

Abstract: An engine rotation speed control system which comprises an actuator for prescribing the recovery position of a throttle valve, a recovery position sensor for detecting that the throttle valve is returned to the recovery position, an idle speed control unit for controlling the engine to a predetermined idling speed, and a negative pressure restricting unit for controlling the throttle actuator such that reduction in intake negative pressure to below a predetermined negative pressure is prevented. When the throttle valve returns to the recovery position with the engine speed in excess of an upper limit of the idling speed, the actuator is controlled by the negative pressure restricting unit. When the engine speed falls below the upper limit, the idle speed control unit is actuated. Upon engine starting, the actuator is set such that the opening degree of the throttle valve suitable for the engine starting is obtained before the starter starts operating.

Abstract: Method of controlling a control system for an air-fuel ratio of air-fuel mixture supplied to an internal combustion engine so that the proper air-fuel ratio is obtained over the whole operation range including a normal operation region and an accelerating operation mode independently of a decrease in oxygen contents at places of high altitudes. When the accelerating operation region is sensed, a proper power duty, corresponding to a negative pressure at that time, is read out from a data table stored in a read-only memory and added to a duty pulse signal which is then utilized for controlling a fuel supply actuator.

Abstract: An engine rotation speed control system which comprises an actuator for prescribing the recovery position of a throttle valve, a recovery position sensor for detecting that the throttle valve is returned to the recovery position, an idle speed control unit for controlling the engine to a predetermined idling speed, and a negative pressure restricting unit for controlling the throttle actuator such that reduction in intake negative pressure to below a predetermined negative pressure is prevented. When the throttle valve returns to the recovery position with the engine speed in excess of an upper limit of the idling speed, the actuator is controlled by the negative pressure restricting unit. When the engine speed falls below the upper limit, the idle speed control unit is actuated. Upon engine starting the actuator is set such that the opening degree of the throttle valve suitable for the engine starting is obtained before the starter starts operating.

Abstract: A fuel supply device for an internal combustion engine having an intake manifold includes a throttle body defining therein an intake passage communicating at one end thereof with the intake manifold. A flow accelerating valve arranged in the intake passage upstream of a throttle valve cooperates with the wall surface of the intake passage to define a flow accelerating passage of a smaller flow area than the intake passage. The flow accelerating valve is angularly movable in response to a change in the intake fluid flow between a fully closed position in which the flow accelerating passage has a minimum flow area and a fully open position in which the flow accelerating passage has a maximum flow area, to thereby control the flow area of the flow accelerating passage. A fuel injector injects liquid fuel into the accelerated intake fluid flow passing through the flow accelerating passage.

Abstract: An air-fuel ratio controller for carburetors in which an auxiliary fuel system opening to the downstream side of a throttle valve of a carburetor is provided separately from the main and slow fuel systems of the carburetor. The air-fuel ratio of the mixture flowing through this auxiliary fuel system is controlled by a solenoid valve adapted to operate in accordance with either one or both of a parameter representing the warming up after cold start and a parameter representing deceleration of the engine.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine comprises a carburetor for controlling the air-fuel ratio of the fuel-air mixture supplied to the engine, a thermal reactor in which the exhaust gas from engine is caused to undergo reaction with secondary air supplied to the reactor, an oxygen sensor disposed in an exhaust gas passage between the reactor and three-way catalyst, a negative pressure generator for producing a negative pressure corresponding to the output from the oxygen sensor, a detector for detecting a low and a high speed operation region of the engine, and means for controlling a low speed fuel system and a main fuel system, respectively, of the carburetor in response to the negative pressure in such a manner that the fuel-air mixture is enriched with the secondary air supply being concurrently increased in the low speed operation region of the engine, while in the high speed operation range the fuel-air mixture having an approximately stoichiometric air-fuel ratio is sup

Abstract: A method of controlling the air-fuel ratio so as to be effectively maintained at a desired air-fuel ratio of .lambda.=1 is composed of a combination of an electronic map control for effecting the air-fuel ratio control on the basis of map data read out from a data map stored in ROM as air-fuel ratio control data in correspondence to various operation parameters of an engine and an O.sub.2 -feedback control for controlling the air-fuel ratio on the basis of oxygen quantity detected from the exhaust gas. Upon the occurrence of changes in the control quantity for a predetermined number of times in the course of the O.sub.2 -control, the latter is changed over to the map control. At that time point, a control quantity for the map control is corrected on the basis of a mean control quantity during the O.sub.2 -feedback control. Unless a significant variation takes place in the engine operating conditions, the map control is continued for a predetermined time and then changed over to the O.sub.2 -control.

Abstract: A secondary air flow rate control device for use in an exhaust gas purifying device of the type in which the secondary air delivered from an air pump is fed through an air passage to an exhaust gas purifying device provided in an exhaust system for purifying the unburnt components contained in exhaust gases from an internal combustion engine, while an aperture for bleeding air to atmosphere is provided in the aforesaid air passage, with a valve being provided in the aforesaid aperture, so that at the time of acceleration of an engine, the aforesaid valve is closed to increase the amount of the secondary air to be fed to the exhaust gas purifying device.

Abstract: A secondary air control device which comprises an air passage communicating an air pump with a recombustion device and having a resistor such as an orifice provided midway of the passage and a control valve for maintaining substantially constant the pressure ratio of the pressure on the upstream side of the aforesaid resistor to that on the downstream side thereof, said control valve being so designed as to be operated in association with the pressure of the secondary air and that of exhaust gas, thereby eliminating fluctuation in pressure in the secondary air due to reduction in the discharging performance of the air pump, and thus the secondary air proportional in quantity to the exhaust gas from an engine may be supplied.