System for cleaning exhaust gases from an internal combustion engine

Claim 1

System for cleaning exhaust gases from an internal combustion engine, having a valve device for introducing the flow of air into the exhaust manifold in order to burn the unburnt components in said exhaust gases or for releasing said flow of air into the atmosphere by action of negative pressure within the intake manifold, said valve device including: a casing defining therein first and second chambers separated by a valve seat having a first valve port at the center thereof, and having second valve ports at the outer periphery thereof, said first chamber being in communication with an air supply operated by said engine, said second chamber being in communication with the atmosphere, a third chamber defined in one part of said casing, said third chamber being in communication with said intake manifold, a passageway defined in another part of said casing, said passageway communicating said first chamber with the exhaust manifold, a first valve plate connected to a diaphragm arranged in said third chamber by a rod; in its first position said firSt valve plate closing said first valve port and releasing said passageway so that the air from said air supply is introduced into said exhaust manifold to burn said unburnt components within the exhaust manifold, whereas in its second position said first valve plate releases said first valve port and closes said passageway so that the air from said air supply is released into the atmosphere, and a second valve plate for controlling the pressure in said system, said second valve plate being resiliently urged toward said second valve ports, wherein said valve device comprises: a stop means secured to the inner wall of the casing, said means holding said second valve at a distance from said second valve ports when said first valve is in its second position.