Patent ID: 7032375
Filing Date: 2006-04-25
Classification: F01N,F04D,Y02T,Y10T

Abstract:
1. 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, 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, wherein said valve element is arranged in the neighborhood of said diaphragm, and the internal path leading from said outlet of said blower to said on-off valve has a small volume, and wherein a pressure sensor for detecting the pressure of said internal path is arranged in said internal path, and the operating conditions of said air pump are detected by said pressure sensor.