Denso Corporation

Nippondenso Co., Ltd.

Shigeru Takeuchi

Taketoshi Sato

Kiyotoshi Oi

Kazuji Minagawa

Akira Ando

Makoto Ito

Makoto Miwa

Takafumi Ito

Naoki Yoshiume

Masao Yamada

Katsunori Michiyama

Takeshi Matsuda

Junji Sugiura

Yasunobu Hirao

Yosuke Matsuo

Takahiko Hasegawa

Takayoshi Yamaguchi

Masatoshi Kuwayama

A load control apparatus outputs a PWM signal to a switching element to control a load. The switching element is connected between a power supply and a grand in series with the load. An abnormal increase detecting unit outputs an abnormal increase detection signal when detecting abnormal increase in applied voltage, which is applied to the load, relative to target voltage. An abnormal decrease detecting unit outputs an abnormal decrease detection signal when detecting abnormal decrease in the applied voltage relative to the target voltage. An operating state monitoring unit outputs a normally operating signal when the load normally operates. A signal combining unit generates a combined signal by combining the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal and outputs the combined signal via a common signal output terminal.

Load control apparatus and method for processing diagnosis signal for the same

In a secondary air injection system, MOSFETs control supply of electric current to an air pump and to a motor for driving an electromagnetic valve and to an electromagnetic coil to introduce secondary air into an exhaust gas passage upstream of a catalyst for purifying the exhaust gas of an internal combustion engine. Gate drive circuits control the MOSFETs based on an instruction from an ECU via input signal processing circuits. Abnormal conditions in the operation for controlling the air pump and the electromagnetic valve are detected, and, when an abnormal condition is detected, forcibly turn the MOSFETs off to interrupt the current to the motor and to the electromagnetic coil. A diagnosing circuit sends to the ECU diagnosis signals representing the state of controlling the load.

Drive device for a secondary air injection system

A cooling apparatus for automotive use wherein speed of an electric cooling fan is controlled solely at a predetermined speed. When a relay switch is switched on, voltage of a battery is applied to a lag circuit. Output of the lag circuit is applied to a gate G of a MOS transistor, but rise of the gate-applied voltage is delayed by the lag circuit according to a time constant thereof, and increases slowly. When the gate-applied voltage reaches the threshold voltage of the MOS transistor, the MOS transistor begins to switch on. However, when the gate-applied voltage is low, the drain current flowing through the MOS transistor is limited and thereby surge current at the motor is minimized.

Motor vehicle cooling apparatus with electric motor surge current

In a fuel pump control, until a rotational speed of an electrically-driven fuel pump rises to a predetermined speed, an electric current supplied to the fuel pump at an engine starting is increased higher than that normally supplied after engine starting thereby causing fast build-up of the fuel pressure. After the fuel pump reaches the predetermined speed, the electric current is decreased to a normal after-start current thereby suppressing a fuel pressure overshoot and resulting overrich mixture. Alternatively, a fuel pump speed is raised by the voltage control first at an engine starting operation, while switching the voltage control to the current control intermittently to detect the voltage applied to the fuel pump. When the detected voltage reaches a first predetermined voltage, the fuel pump speed is controlled exclusively by the current control.

Fuel pump control with control mode switching between before and after

An electric motor has first and second power feed terminals. A power feed line connects a dc power supply and the electric motor. A switching element provided in the power feed line includes a MOS-FET having a gate subjected to a pulse width modulation signal with a controllable duty cycle. The switching element changes between its on state and its off state in response to the pulse width modulation signal. The first power feed terminal of the electric motor is connected to the switching element. A flywheel diode connected in parallel with the electric motor operates to absorb a voltage which appears across the electric motor and returning a current when the switching element changes to its off state. A capacitor connected between the gate of the switching element and the second power feed terminal of the electric motor operates to suppress radio-frequency noise occurring upon every change of the switching element between its on state and its off state.

Control apparatus for electric motor

A fuel supply system for an engine having no fuel return pipe is disclosed. In steps target fuel is set according to an engine operating state. Thereafter, a target current value to be supplied to the motor of a fuel pump according to the target fuel pressure is obtained. In the succeeding step, an actual motor current is detected and, then, the target current value and the detcted current are compared. Thereafter, the supply current is controlled by feedback based upon the difference obtained by comparison between the target current value and the detected current value to eliminate the difference.

Fuel supply system for internal combustion engine and method of

In a pump control circuit, if a battery voltage declines to a voltage level lower than that required to insure a constant voltage, a low-voltage detection circuit outputs a low voltage detection signal. In the case of the decline in the battery voltage, an NOR circuit outputs the conversion signal from an internal logic section, and a pump control signal bypassing the internal logic section, giving priority to the latter signal. A motor drive circuit turns FET ON and OFF in accordance with the output signal of the NOR circuit. According to ON/OFF of the FET, the intermittent control of the current from the battery to the pump drive motor is performed.

Fuel pump control device for internal combustion engine

A pump control apparatus is disclosed which is of a small size, quietly operates and has a small number of signal output lines without loosing the fuel pump stopping function upon engine stall. This control apparatus of the invention includes a computer 5 which provides a signal output line 9 with an off-signal that is equal to the potential of a body 7 of a vehicle upon engine stop, and which provides the signal output line 9 with a drive signal that is higher in potential than the off-signal upon engine operation. This control apparatus further includes an FET 12 which is connected in series with a power supply line 8 and a fuel pump 4 and which, when receiving the drive signal, changes the terminal voltage of the fuel pump 4 in accordance with the input drive signal, and when receiving a voltage corresponding to the off-signal, stops the fuel pump 4. Thus, according to this invention, even if the power supply line 8 and the signal output line 9 are brought to the ground potential, or grounded, the fuel pump 4 is sure to be stopped, and thus the safety can be achieved.

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Gamagori, Japan

Shigeru Takeuchi