Abstract: A heat generating element having a thermal characteristic such that its resistance varies in response to changes in temperature is provided in the intake pipe of an engine. A heating power, the voltage of which is set by a reference voltage source, is supplied to the heat generating element via a transistor. The supply of this heating power is controlled by a start pulse signal periodically generated by a set flip-flop circuit when the ignition switch is on. When the heat generating element reaches a predetermined temperature, the supply is cut off by the flip-flop circuit. A measurement signal having a pulse width corresponding to the time period of heating power supply is generated from the flip-flop circuit. The opening of the ignition switch is detected and a one-shot multivibrator is driven to produce a burn-off signal having a pulse width to which the burn-off period corresponds.

Abstract: An air flowrate measuring apparatus with a heat wire measures the flow rate of the air flowing through the intake pipe of an engine. The apparatus has a temperature sensitive element which has a specific temperature-resistance characteristic and is disposed in the intake pipe. Constant heating voltage is applied to this element in response to a start signal, thus heating the element. When the temperature of the element rises to a specified value, the application of the voltage is stopped. At the same time, a pulse signal whose width corresponds to the period of applying the voltage is generated. The signal is supplied to an interface circuit through a drive circuit driven by a reference voltage which has been also used to control the heating voltage. The interface circuit comprises two wave-shaping circuits. The first wave-shaping circuit has a filter means of a small integration time constant.

Abstract: An engine control system has a heater and a temperature measuring element with a temperature-resistance characteristic. The heater and element are provided in the intake pipe of an engine. Heating, which initiated by a start pulse signal generated by an engine control unit in synchronism with engine rotation is supplied to the heater through a transistor. When the heater temperature has reached a reference temperature preset in accordance with the intake air temperature measured by the element, a comparator generates an output to deenergize the heater. The period of supplying the heating power is represented by a pulse signal from a flip-flop. This pulse signal is supplied as an airflow measurement signal to the engine control unit. The engine control unit calculates the basic fuel injection quantity and determines if the starting of the pulse signal received by the control unit falls within a predetermined period from the starting of the start pulse signal.

Abstract: This apparatus measures and detects the air-flow taken into an intake pipe of an internal combustion engine, and includes an air-flow detecting sensor. The air-flow detecting sensor comprises a support frame made of heat-resistant insulation material, a heating line supported by the support frame on the upper side when viewed from the direction in which the air-flows, a heat-controlled heating current, and a resistance line also supported by the support frame on the lower side when viewed from the direction in which the air-flows which has a temperature characteristic. Air-flow detecting signals which represent the condition under which heat is transmitted to the resistance line through the air-flow are picked up from the sensor for every specified timing to set and calculate the transmitting coefficients of heat transmitted from the heating line to the resistance line, which is specified by the sensor and which is set corresponding to the amount of the signal detected by the sensor.

Abstract: An air flow detecting element is located in the air flow to be measured. This air flow detecting element comprises a heater made of resistant material having a positive temperature coefficient and wound around a first heat resistant frame, a first heat sensitive element wound around the first frame together with the heater and made of resistant material having a positive temperature coefficient and receiving heat from the heater, and a second heat sensitive element wound around a second heat resistant frame and made of resistant material having a positive temperature coefficient, and serving to measure the temperature of the air. A bridge circuit comprises a series circuit consisting of the heater and fixed resistances connected in series with each other, and a series circuit consisting of the first and second heat sensitive elements connected in series with each other. Potential differences at the output terminal of this bridge circuit are compared by an OP amplifier.

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: Fuel injection modes including an independent injection mode, group injection mode and simultaneous injection mode are changed over in accordance with an engine operating condition, for example, a load condition. The independent injection mode is selected when the engine is operating in a low load condition, and the fuel injection timing for each cylinder is controlled independently. When the low load condition of the engine changes to an intermediate load condition, the group injection mode is selected and the fuel injection timing is controlled for each group of cylinders formed by grouping the cylinders into at least two groups. The simultaneous injection mode is selected when the intermediate load condition changes to a high load condition, and the fuel injection timing for all the cylinders is controlled to be simultaneous.

Abstract: In a method for correcting the controlled variable of an engine according to the present invention, the quantity of suction air is measured by means of a thermal type flowmeter. The magnitude of pulsation of the suction air is obtained on the basis of the differential or variation of the measured section air quantity. At the same time, a coefficient representing the susceptibility to the pulsation which depends on the layout of the thermal type flowmeter and the like and the engine speed is calculated. A final correction for correcting the controlled variable is obtained on the basis of the magnitude of the pulsation and the coefficient representing the susceptibility.

Abstract: In an electronic digital control system for engine, a throttle position is sensed at predetermined time intervals to detect a variation thereof from the previous time to the present time, and, after modifying the detected variation by a correction coefficient related to a cooling water temperature to obtain the modified variation, the previous value of a fuel injection amount correction factor computed at the time of previous computation is added to the value of the modified variation to compute the sum. Then, a predetermined subtraction constant is subtracted from the sum to compute the difference therebetween, thereby obtaining the new data of the fuel injection amount correction factor, and this new factor is used to correct the basic fuel amount computed separately on the basis of the operating condition of the engine.

Abstract: The sectional area of an air bypass passage which is bypassing a throttle valve in an intake passage of an internal combustion engine is increased or decreased depending upon the difference between the actual rotational speed of the engine and the variable desired rotational speed. The variable desired rotational speed is slowly changed with respect to time according to an increment rate or to a decrement rate, when the operating condition of the engine and/or the load condition of the engine changes.

Abstract: A method and apparatus for controlling the rotation speed of an engine by the steps of calculating a desired value of the idling rotation speed of the engine, sensing the actual idling rotation speed of the engine, calculating the deviation of the sensed actual idling rotation speed from the desired value, calculating a data of a rotation speed control factor on the basis of the deviation, limiting the control factor to within a control range between an upper limit and a lower limit, storing a correction factor related to a value of the control factor used under a specific operating condition of the engine, calculating the upper limit and the lower limit of the control factor using the value of the correction factor, and controlling the amount of intake air or the amount of the air-fuel mixture supplied to the engine on the basis of the value of the control factor thus calculated.

Abstract: A method for controlling the rotational speed of a combustion engine which drives an automotive vehicle by computing the actual and desired values of the idle rotational speed of the engine, computing a control amount corresponding to the difference between the actual and desired values and controlling the amount of air or the amount of mixture supplied to the engine in accordance with the control amount. The desired value and the upper and lower limit values of the control amount are changed in accordance with a plurality of operating parameters including the condition of a brake switch.

Abstract: The amount of secondary air flowing through a bypass air passage bypassing the throttle valve of an engine, which is connected to an automatic transmission of a vehicle having an air-conditioner, is controlled by an air control valve disposed in the bypass air passage. The air control valve is controlled on the basis of the result of comparison between a signal indicative of the actual idling rotation speed of the engine detected by the distributor of the engine and a reference signal indicative of a desired idling rotation speed of the engine. The level of this reference signal indicative of the desired idling rotation speed of the engine varies depending on the on-off of the air-conditioner in the vehicle or on the position of the shift lever of the automatic transmission.

Abstract: An engine control system which controls the engine fuel injection amount and the ignition timing by being supplied with and processing the rotational speed signal produced on the basis of the output of a rotational speed sensor producing the rotational speed signal at every predetermined engine crank shaft angle and an intake air amount signal from an air amount sensor for detecting the intake air amount of the engine. At certain predetermined engine rotational angles, the rotational speed signal and the intake air amount signal are read and compared with the previously-read rotational speed signal and intake air amount signal respectively, thus detecting changes therein respectively. These changes and signal values are used to correct control signals for ignition timing and fuel injection amount.

Abstract: A system for controlling the amount of air taken in by an engine comprises an air duct tube bypassing a throttle valve of an intake tube for taking in air supplied to an automobile engine, a plurality of valves for regulating the amount of air passing through the air duct tube, and control device therefor. The amount of air in the bypass is controlled in accordance with the temperature and number of revolutions of the engine and the air intake pressure downstream of the throttle valve. During the idling of the engine, the air intake control system generates a signal representing the standard engine idling revolutions in accordance with the engine temperature, compares the actual engine revolutions with a reference, and regulates the amount of air flowing in the bypass by use of the results of a comparison, thus rendering the actual engine revolutions identical to the reference.

Abstract: An air-flow metering device for a fuel injection system of an internal combustion engine comprises a blade means installed in an intake pipe of the engine and turned by the air flowing therethrough, a blade turn detecting means and an air passing means for changing the air passing area thereof in combination with the blade means in accordance with the turning of the blade means, thereby to supply optimum air flow into the engine.