Secondary air supply system for internal combustion engines
The invention discloses a relief pressure control valve for controlling the pressure in a secondary air supply line which has first and second pressure chambers divided by a diaphragm, a spring for biasing the diaphragm towards the second pressure chamber, a relief port connected to the secondary air supply line, a valve head connected to the diaphragm and being biased to close the relief port. The air pumped out from an air pump is supplied to the first pressure chamber and the first pressure chamber is communicated with the second pressure chamber through an orifice. Accordingly, during stable running operations of the engine, the pressures in the first and second pressure chambers are made equal by means of the orifice, while during the accelerations pressure difference is produced between the chambers for a certain time period. The pressure difference urges the diaphragm in the same direction as that of the urging force of the spring, whereby the pressure in the secondary air supply line controlled by the relief pressure control valve is increased during the accelerations so as to supply the increased amount of the secondary air to the exhaust pipe of the engine.
- Assignee:
- Nippondenso Co., Ltd.
- Patent Number(s):
- US 4147033
- OSTI ID:
- 5583527
- Resource Relation:
- Patent Priority Date: Priority date 8 Dec 1976, Japan
- Country of Publication:
- United States
- Language:
- English
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