Denso Corporation

Akira Ando

Shigeru Takeuchi

Makoto Ito

Makoto Miwa

Kiyotoshi Oi

Satoshi Yoshimura

Kazuji Minagawa

Naoki Yoshiume

Masatoshi Yokai

An inverter apparatus includes an inverter circuit, a temperature sensor, and a control circuit. The inverter circuit is driven by a PWM signal and includes switching elements that are divided in first and second groups. The temperature sensor detects a temperature of at least one of the switching elements of the first group. The control circuit controls a duty cycle of the PWM signal such that a first value of heat generated in the first group is equal to or greater than a second value of heat generated in the second group. The control circuit performs an overheat protection for protecting the inverter circuit from overheating when the detected temperature is equal to or greater than a threshold temperature.

Apparatus and method for driving inverter circuit

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

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

Growing community of inventors

Nagoya, Japan

Akira Ando