Toyota Jidosha Kogyo Kabushiki Kaisha

Aisan Industry Co., Ltd.

Yoshiki Fukumori

Takeru Yasuda

Tadao Mitsuda

Yoshio Yamakawa

Disclosed is an exhaust gas cleaning apparatus of an internal combustion engine, provided with a three-way catalytic converter, an air-fuel ratio sensor and a secondary air injection system. The secondary air injection system has a diaphragm-operated flow control valve for increasing or decreasing the amount of secondary air introduced into the exhaust manifold of the engine in accordance with electrical signals transmitted from the air-fuel ratio sensor. Means are provided for rapidly increasing or decreasing the air-fuel ratio to a stoichiometric value at the moment when the amount of secondary air passed through the flow control valve is increased or decreased. Therefore, the air-fuel ratio is maintained quite near the stoichiometric value at which the three-way catalytic converter can effectively operate to clean the three major toxic components in the exhaust gas.

Exhaust gas cleaning apparatus for an internal combustion engine

Disclosed is an exhaust gas cleaning apparatus of an internal combustion engine, provided with a three-way catalytic converter and a vacuum-operated flow control valve. The flow control valve has a diaphragm for controlling the amount of secondary air directed into an exhaust manifold of the engine for the effective operation of the three-way catalytic converter. In order to move the diaphragm to increase or decrease the amount of secondary air, a vacuum chamber is formed on one side of the diaphragm. This vacuum chamber is opened to a vacuum port formed in the intake system of the engine for transmitting the vacuum signal from the port to the vacuum chamber. Further, in order to maintain a constant rate of movement of the diaphragm irrespective of the vacuum level at the port, means are provided for transmitting a vacuum signal from the port to another vacuum chamber formed on the other side of the diaphragm.

Exhaust gas cleaning apparatus of an internal combustion engine

Disclosed is an exhaust gas cleaning apparatus of an internal combustion engine, provided with a three-way catalytic converter, an air-fuel ratio sensor in the form of an oxygen concentration-cell which detects an air-fuel ratio higher than a stoichiometric air-fuel ratio at which the converter effectively operates, and a secondary air injection system adapted for increasing or decreasing the amount of secondary air introduced into the exhaust pipe of the engine in accordance with electrical signals transmitted from the air-fuel ratio sensor. Means are provided for controlling the speed of introduction of secondary air so that the speed of decreasing the amount of secondary air is higher than the speed of increasing the amount of secondary air. Therefore, the air-fuel ratio of the exhaust gas is effectively controlled by signals transmitted from the sensor to approximate the stoichiometric ratio.

Growing community of inventors

Obu, Japan

Yoshiki Fukumori