Secondary air supply system
AssigneeDenso Corporation
InventorsKunihiro Tsuzuki, Shinichi Yokoyama
Life of this patent
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Abstract
In the disclosed secondary air supply system, an on-off valve (13) is driven by the discharge pressure of an air pump (12). A diaphragm chamber (44) is arranged in the neighborhood of a discharge outlet (54), and a part of the discharge air flows directly into the diaphragm chamber (44). Thus, the on-off valve (13) is positively operated even at high places with low atmospheric pressure and has a fast open/close response. As an electromagnetic actuator is not used to drive the on-off valve (13), the voltage supplied to the air pump (12) (DC motor (29)) does not drop inconveniently, and at the same time, the cost is reduced. Further, the number of the lead wires (65) is reduced.
Claims6
A secondary air supply system comprising:
- an air pump including an electric motor and a blower;
- a secondary air path for leading the secondary air discharged from said blower to an exhaust pipe upstream of a catalyst for purifying the exhaust gas;
- an on-off valve operated to open/close said secondary air path;
- and
- a driving means for opening/closing the valve element of said on-off valve,
- wherein said driving means for opening/closing the valve element of said on-off valve includes a diaphragm unit having a diaphragm adapted to be displaced by the pressure difference between a diaphragm chamber with the discharge pressure of said blower led thereinto and an atmospheric chamber communicating with the atmosphere, and a transmission means for transmitting the displacement of said diaphragm to said valve element, and
- wherein said diaphragm chamber is arranged in the neighborhood of the outlet of said blower, and part of the air discharged from said blower flows directly into said diaphragm chamber.
Dependencies are inferred from the claim text.