Toyota Jidosha Kogyo Kabushiki Kaisha

Nippon Soken, Inc.

Eturou Katahira

Shunzo Yamaguchi

Yasuhiko Ishida

Masashi Kida

Hideo Miyagi

In a device for purifying the exhaust gases discharged from an internal combustion engine of the type having a secondary air supply pipe for charging the secondary air from an air source such as an air pump into an exhaust pipe upstream of an exhaust gas reactor or the like, a three-way valve is inserted in the supply pipe in such a manner that the three-way valve may be displaced between a first position at which the air source and the exhaust pipe are communicated with each other and a second position at which the communication between them is interrupted and the secondary air is relieved or returned to the air source bypassing the exhaust pipe; an air-fuel ratio sensor is inserted into the exhaust pipe downstream of the opening of the secondary air supply pipe into the exhaust pipe; and means for controlling the three-way valve is provided so that when the air-fuel ratio detected by the sensor is lower than a reference or optimum ratio at which the best performance of the reactor is expected the three-way valve is caused to move to the first position, whereas when the sensed air-fuel ratio exceeds the reference ratio, the three-way valve is caused to move to the second position, whereby the air-fuel ratio may be controlled with a higher degree of accuracy.

Device for purifying exhaust gases from internal combustion engine

A secondary air supply pipe line is opened in the exhaust pipe of an internal combustion engine on the upstream side of an exhaust gas reactor which is mounted in the exhaust pipe, and an air-fuel ratio sensor for detecting the air-fuel ratio of exhaust gases is mounted in the exhaust pipe on the downstream side of the portion where the secondary air supply pipe line is open. An air flow control valve for on-off controlling the flow of air in the secondary air supply pipe line is operated in accordance with the output signal of the air-fuel ratio sensor. When the air-fuel ratio of the exhaust gases is low the secondary air supply pipe line is fully opened by the air flow control valve in response to the output signal of the air-fuel ratio sensor, whereas when the air-fuel ratio of the exhaust gases is high the secondary air supply pipe line is fully closed by the air flow control valve in response to the output signal of the air-fuel ratio sensor, whereby maintaining the air-fuel ratio of exhaust gases supplied to the exhaust gas reactor at a predetermined value.

Exhaust gas purification apparatus for an internal combustion engine

An engine exhaust gas purification system having an exhaust gas reactor mounted on the engine exhaust pipe, a secondary air supply system having a secondary air supply passage connected to the exhaust pipe upstream of the reactor, and an exhaust gas air-fuel ratio detector mounted on the exhaust pipe to detect air-fuel ratio of exhaust gases in the exhaust pipe. A secondary air supply control valve is provided in the secondary air supply passage and controlled by a valve actuator having a diaphragm to which positive pressure of the secondary air and the engine intake vacuum pressure can be applied. The application of the positive and vacuum pressures to the diaphragm is controlled by solenoid valves which are controlled in accordance with the air-fuel detector output voltage which represents the detected exhaust gas air-fuel ratio, whereby the secondary air supply control valve is controlled such that the secondary air is supplied to the engine exhaust gases at a continuously controlled, variable rate.

Growing community of inventors

Okazaki, Japan

Eturou Katahira