摘要:
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. The second wave-shaping circuit has a filter means whose integration time constant is large enough to remove noise from the input signal.
摘要:
A control system for an engine has a temperature sensitive element as part of a device for measuring the air flow in an air intake manifold to the engine. Further, a first pulse signal is generated, corresponding to the rotation of the engine, for controlling the setting of a flip-flop. A transistor is conducted in the set state of the flip-flop to supply a heating electric current to the element. The element supplied with the current is raised to the temperature that corresponds to the air flow in the manifold. When the temperature of the element is raised until the specified temperature difference to the air temperature (measured by a sub temperature sensitive element) is set, the temperature difference is detected by a comparator, and the flip-flop is reset by the detection signal. A pulse-shaped signal corresponding to the set state of the flip-flop is produced as a measurement output signal, supplied as one detection signal of the operating state of the engine to an engine control unit, and the current to the element is controlled to be supplied by the pulse-shaped signal.
摘要:
In an apparatus for controlling an engine, as an air flow sensor for measuring intake air flow quantity, a heater resistor having temperature-resistance characteristic and a temperature sensitive resistor for sensing air temperature are provided in an intake passage, and heating electric power is supplied to the heater resistor in response to a start signal generated periodically. The heating electric power is cut off when the temperature of the heater resistor is raised to a specified reference temperature predetermined in accordance with the air temperature, so that an output signal indicative of the time width in which the heating electric power is supplied is applied to an electronic control unit to measure air flow quantity therefrom. Further, compensation coefficient stored in a memory is derived in correspondence to the intake air temperature sensed by the temperature sensitive resistor, and the output signal is compensated for by the compensation coefficient to compensate the measured air flow quantity. Based on the compensated air flow quantity, fuel injection quantity, ignition timing or the like is computed in the electronic control unit.
摘要:
A heater, which comprises an element whose resistance varies with changes in temperature, and a temperature element are provided in the air intake pipe of an engine. This heater and temperature element together with resistors form a bridge circuit to which heating power is supplied via a transistor. An engine control unit generates start signals Tin simultaneously with the rotation of the engine. A flip-flop circuit is set by these start signals and, when set, the transistor is turned on and the heating power rises. The output signal from the bridge circuit is supplied to a comparator and the output signal of the comparator resets the flip-flop circuit, which outputs a pulse-shaped signal representing the airflow quantity as a length of time. This pulse-shaped time signal is sent via a constant current circuit to another comparator, where it is compared with a reference voltage and the output signal from the comparator is supplied together with the above time signal to an exclusive OR circuit. This exclusive OR circuit outputs a first and second pulse signal as the measurement output signal Tout synchronously with the rise and fall of the time signal and this signal is supplied to the engine control unit.
摘要:
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. This burn-off control signal turns the transistor on and heating power is supplied to the heat generating element and the voltage of the reference power source is reduced so that the voltage of the heating power is switched to a low level.
摘要:
Disposed in an intake pipe of an engine is a temperature-sensitive element formed of a resistance element whose resistance value varies with temperature. A heating current is supplied to the temperature-sensitive element through a transistor. The voltage of the heating current is set by a constant-voltage circuit. The temperature of the temperature-sensitive element is compared with a reference temperature of an auxiliary temperature-sensitive element. When the temperature of the temperature-sensitive element is increased to a predetermined level, an output signal is delivered from a comparator. A flip-flop circuit is reset by the output signal from the comparator, and is set by a start pulse signal. When the flip-flop circuit is set, the transistor is turned on, allowing the heating current to be supplied to the temperature-sensitive element. A burning-off instruction signal is supplied to a monostable multivibrator, and a signal with a duration suited for the burning-off operation is delivered from an AND circuit. In response to the output signal from the AND circuit, the flip-flop circuit is held set, and a reference voltage supplied to the differential amplifier is changed to a low level.
摘要:
The intake airflow rate supplied to an internal combustion engine is measured and an obtained airflow rate measurement signal is used for detecting the operating state of the internal combustion engine. The internal combustion engine is electronically controlled, and an airflow rate measuring unit includes a heat-generating element having a temperature-resistance characteristic. A heating current which rises in correspondence with a signal synchronous with rotation of the engine is supplied to the heat-generating element. The heating current is controlled to rise when the heat-generating element is heated to a predetermined temperature, and the heating current duration indicates the airflow rate measurement signal. A burn-off command signal is generated so as to burn off dust attached to the heat-generating element. The command signal is used to generate a periodic signal having a preset effective duration. The pulse signal sets a continuous supply of the heating current to the element for the pulse duration, so that the heat-generating element is heated to a temperature for burning off dust attached thereto.
摘要:
A system for controlling the operating condition of an engine in which a temperature sensing element constitutes an airflow measuring device disposed in an intake air passage of the engine. The temperature sensing element is supplied with a heating current in response to a start pulse signal produced with every one-half period of each combustion cycle of the engine. A comparator delivers an output signal when a reference temperature set on the basis of the air temperature measured by an auxiliary temperature sensing element is reached by the temperature of the temperature sensing element. A pulse signal indicative of the time interval between the generation of the start pulse signal and a rise in the output signal of the comparator is delivered as an airflow measurement signal. The average airflow quantity responsive to one combustion cycle of the engine is detected, and a correction factor K is calculated from the difference between two airflow rate data measured in each combustion cycle and the average airflow quantity. Based on the correction factor K, the injection quantity, injection timing and the like are calculated.
摘要:
A plurality of control units are connected via a common signal line through which they communicate. Each control unit is operative to control an apparatus according to certain information the control unit normally receives directly through an exclusive signal line by operation of a directly-inputting device. A check is made to determine whether the directly-inputting device is operating normally. If not, then the required information is inputted from its source indirectly through another control unit by way of the common signal line.
摘要:
A communication control unit for controlling communication between an electronic control unit and other equipment or other electronic control units, the communication control unit functioning to judge whether or not the operation of the electronic control unit is normal and, if it is judged that the electronic control unit is operating abnormally, the communication control unit acts to reset the electronic control unit to an initial operating status in order to attempt recovery from the abnormal condition, while halting transmission by the electronic control unit until it is judged that the electronic control unit has commenced to operate normally.