Nippondenso Co., Ltd.

Toyota Jidosha Kogyo Kabushiki Kaisha

Katsushi Kato

Toshio Kondo

Shigenori Isomura

Akio Kobayashi

Hiroshi Tamura

Toshiaki Mizuno

Motoharu Sueishi

Yoshifumi Ina

Hirotada Yamada

Yasutaka Yamauchi

Yoshiaki Sato

Ichiro Kowada

Sachio Nishii

Kazuyoshi Nishibori

In a fuel pump driving apparatus for a vehicle engine including a fuel injection system, the selection of a plurality of energizing circuits each formed by the combination of two or all of three brushes of a fuel pump drive motor is effected in accordance with the load conditions of the engine, thereby changing the rotational speed of the motor and hence the fuel quantity delivered from the fuel pump. When the occurrence of a fault in one of the energizing circuits is detected, the driver is informed of the occurrence of the fault and in addition a faulty-condition controller controls switching means in such a manner that the drive motor is energized through another one of the energizing circuits.

Fuel pump driving apparatus

In a fuel injection system for an internal combustion engine, the voltage of a vehicle-mounted battery is monitored to see if the voltage is below a predetermined voltage at which a microcomputer used in an electronic control unit is disabled or malfunctions on engine start where large current is consumed by a starter motor. During engine start, asynchronous fuel injection is performed using the result of the voltage monitoring in place of normal or main fuel injection. The amount of fuel to be injected by the asynchronous fuel injection may be limited and/or the number of times of asynchronous fuel injection may be limited so as to prevent excessive fuel supply. In monitoring the battery voltage, hysteresis characteristic may be given to a reference voltage so as to avoid undesirable chattering.

Apparatus for injecting fuel into internal combustion engine

In an internal combustion engine equipped with exhaust gas recirculation system, air/fuel ratio control is effected using various engine parameters including atmospheric pressure. To this end, basic fuel injection duration is first computed, and this basic fuel injection duration is corrected using a correction factor so that a desired air/fuel ratio is obtained irrespective of the change in atmospheric pressure. When EGR is performed a first correction factor is derived or calculated using engine speed data, intake pressure data and atmospheric pressure data. When EGR is not performed, a second correction factor is derived or calculated using atmospheric pressure data. When obtaining the first correction factor, interpolation is used to obtain the value thereof suitable for detected engine speed, intake pressure and atmospheric pressure.

Apparatus for controlling air/fuel ratio for internal combustion engine

An electronic control type fuel injection system in which, at the time of engine deceleration the fuel injection is stopped, and when resuming to a normal fuel injection from the fuel injection stopped condition, if the reducing rate of the engine speed is smaller than a preset value, a smaller amount of fuel than the amount of fuel injection during normal operation as if fuel injection had not been stopped is first injected and subsequently the amount of fuel to be injected is gradually increased, while when the reducing rate of the engine speed is larger than the preset value, a larger amount of fuel than the fuel injection amount during normal operation is injected.

Electronic control type fuel injection system

An electronically controlled fuel injection system including an air flow sensor disposed in the intake pipe of an internal combustion engine upstream of its throttle valve to detect the amount of air flow to the engine and a control unit responsive to the output signal of the air flow sensor to adjust the amount of fuel to be supplied to the engine, is further provided with a fuel enrichment circuit responsive to the output signal of the air flow sensor whereby when the amount of air flow changes in a direction to decrease, a signal commanding an increase in fuel amount which is proportional to the rate of the change is fed to the control unit. The fuel enrichment circuit has an upper limit value such that the increase in fuel amount is prevented from exceeding an amount corresponding to the upper limit value. The fuel enrichment circuit is adapted so that the amount of fuel is not increased when the rate of change of the air flow in the decreasing direction is smaller than a predetermined lower limit value.

Electronically controlled fuel injection system

The combination of a fuel supply system for an internal combustion engine, an exhaust gas oxygen concentration sensor and a feedback control system including an integration circuit connected to the fuel supply system and a correction control circuit connected to the exhaust gas oxygen concentration sensor and the integration circuit. The combination controls the air-fuel mixture to be supplied to an engine in accordance with an integration output signal, which in turn is generated from the output signal generated by the exhaust gas oxygen concentration sensor. The correction control circuit serves to disconnect the exhaust gas oxygen concentration sensor from the integration circuit when a predetermined operating condition of the engine is reached, thereby holding the output from the integration circuit constant.

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Kariya, Japan

Katsushi Kato