Abstract: Emission control apparatus for an internal combustion engine includes a sensor for detecting the concentration of an exhaust composition to generate an error correction signal for controlling the air-fuel mixture ratio at a predetermined value to minimize noxious exhaust emissions and a transient compensation circuit to provide a step function voltage to compensate for transient engine operating condition in response to a sensed change of engine load.

Abstract: Emission control apparatus for internal combustion engines is provided with a sensor for detecting the concentration of a particular exhaust composition in the emissions from the engine. A signal indicating the deviation of the mixture ratio from a controlled point is generated by comparing the output from the sensor with a reference level, the signal being modified in amplitude according to a predetermined control characteristic and used to regulate the air-fuel mixture ratio at the desired control point. The varying magnitude of the sensed concentration is smoothed into a signal of slowly varying magnitude which is used to control the reference level so that error introduced into the deviation indicating signal due to the change with time in the output performance of the exhaust composition sensor is self-compensated. A level sensor is provided to detect when the reference level reaches an end of the control range to change the operating mode of the engine from closed-loop to open-loop mode.

Abstract: The spark advance control apparatus of the invention comprises a vacuum advance control mechanism and a speed advance control circuit. The vacuum advance control mechanism senses the vacuum pressure in the intake manifold of an internal combustion engine and generates an electrical pulse in advanced timing in relation to the sensed vacuum. The speed advance control circuit receives the pulse from the vacuum advance control mechanism, converts it into a voltage signal representative of the revolution of the engine crankshaft and generates an output voltage which varies nonlinearly as a function of the voltage signal. A pulse-width generator is provided having a first input connected to receive the pulse from the vacuum advance control mechanism and a second input connected to receive the nonlinear speed related voltage signal to generate a pulse which commences in response to the vacuum advance pulse and ends at a time determined by the speed related voltage signal.

Abstract: A closed-loop emission control apparatus for internal combustion engines includes exhaust composition sensor for feedback control of the air-fuel mixture. When the temperature in the exhaust passage is lower than the operating temperature of the sensor, control is switched to an open-loop mode. The feedback control signal is fluctuated above and below a predetermined DC bias at periodic intervals during the open-loop mode to switch the control to the closed-loop mode in a minimum transition time as soon as the sensor's temperature condition warrants feedback control.

Abstract: A reference voltage, which is compared with an output voltage of an exhaust gas sensor in a differential signal generator of an electronic closed loop air-fuel ratio control system, changes depending upon a mean value of an output of the exhaust gas sensor provided in an exhaust pipe extending from an internal combustion engine. Furthermore, the magnitude of the reference voltage is limited in such a manner as to be within a predetermined range, or in other words, the magnitude of the reference voltage is limited at at least one of an upper and a lower values thereof.

Abstract: Operational amplifier circuitry is provided which comprises an operational amplifier having a first input port and a second input port, and a compensating circuit for making a voltage difference between the first and the second input ports of the operational amplifier substantially equal to the offset voltage of the amplifier, compensating the bias currents of the operational amplifier. The compensating circuit may include a series of a first resistor and a second resistor connected between the first and the second input ports of the amplifier. The node connecting the first and the second resistors is coupled to a predetermined voltage, the resistances of the first and the second resistors being selected so that a voltage difference between the first and the second input ports of the amplifier is substantially equal to the offset voltage of the operational amplifier.

Abstract: An ignition spark timing control system for an internal combustion engine, which comprises a reference angle signal generator to generate reference angle signals corresponding to the reference angles of each cylinder of the engine, a divider for dividing the reference angle signals to produce divided signals, and voltage-advance converters substantially operated in an alternative manner in response to said divided signals to control ignition spark timing in dependence on an advance control signal.

Abstract: For a gas turbine engine provided with a fuel feed control system that includes an engine speed sensor and provides a fuel feed rate control signal based on the deviation of the sensed engine speed from an intended speed, the invention provides a system for detecting the presence of an abnormality possibly leading to an overrun of the engine shortly after starting of the engine. This system comprises a timer circuit which produces a signal such as logic "1" signal after the lapse of a preset period of time from starting of the engine, a comparison circuit which produces a signal such as logic "1" signal if the amplitude of the actual engine speed signal is below a normally expected level after the lapse of the preset period of time, and a logical operation circuit which provides a warning signal only when, for example, the outputs of the timer and comparison circuits are both "1" signals.

Abstract: The temperature and pressure of the vapor generated in a vapor generating unit are so controlled that a fuel supply valve is opened for fuel delivery when the temperature or pressure drops below a predetermined lower limit and is closed when the temperature or pressure exceeds a predetermined upper limit, provided that a vehicle operator manipulable throttle valve is substantially in a fixed position. As the throttle valve is abruptly moved, an acceleration or deceleration signal opens or closes the fuel supply valve independently of the actual vapor temperature and pressure.

Abstract: An operation recorder to record a malfunction of a safety device or to record a proper function of the safety device comprises an AND-output gate. The AND-output gate is connected at its input side with the outputs of first and second monostable-multivibrators and at its output side to a memory. The first monostable-multivibrator normally generates a logical one output and a logical zero output signal, when it is triggered by the output of a collision sensor, for 10 to 100 milliseconds. The second monostable-multivibrator normally generates a logical zero output signal and a logical one output signal, when a safety device is actuated, for relatively shorter time than 10 to 100 milliseconds. The AND-output gate supplies a logical one output to the memory to generate the same when it receives logical one input signals.