Denso Corporation

Nippondenso Co., Ltd.

Michio Koshimizu

Kazuto Maeda

Tadashi Komiyama

Shinji Ishida

Katsuhiro Kuroki

Koji Sakurai

Yukio Haniu

The electromagnetic valve has an electromagnetic actuator for operating a valve. The electromagnetic actuator has a movable core that reciprocally moves in an axial direction. A stator core has an attracting portion. The attracting portion has a conical portion that is defined by a uniform diameter inner surface and an outwardly inclined outer surface. The outer surface has a smaller diameter at a position closer to an initial position of the plunger. Therefore outer diameter of the conical portion is increased in an attracting direction of the plunger. Moreover, increasing rate of the outer diameter is decreased in the attracting direction. Therefore the outer surface has a greater inclination angle at a position closer to an initial position of the plunger.

Electromagnetic actuator

A motor-driven air pump operates when an engine is starting so that warming-up of an exhaust gas purifying catalyst may be expedited. The air pump has a low ventilation resistance to pass secondary air therethrough even when the pump is not driven by the motor. A high-response, low pressure-loss check valve is disposed in a passage connecting the catalyst in the exhaust gas passage and the air pump. When the engine is decelerating, the pump is not driven. However, the secondary air is introduced to the catalyst through the high-response, low pressure-loss check valve from the pump under the negative pressure caused by pulsation of the exhaust gas pressure. Thus, a bad smell from the catalyst may be prevented without increasing the size of the air pump and the motor.

Secondary air supplying system having a motor-driven air pump

Growing community of inventors

Toyohashi, Japan

Michio Koshimizu