Valve means for the recycling of waste gas in internal combustion engines

Claim 1

In a waste gas recycling system for use in internal combustion engines, wherein a portion of the waste gases, determined by control means comprising a throttle flap means, is recycled to the air aspiration system of the engine in order to reduce the content of noxious components in the waste gas, improved waste gas return valve means comprising a. a valve housing having a passageway for waste gas therethrough; b. a first valve seat located in said passageway; c. a valve stem having one end thereof extending into the vicinity of said first valve seat; d. a valve-closing body mounted on said valve stem adjacent said first valve seat and having two sealing surfaces; e. a distancing tube about said valve stem intermediate said valve-closing body and the stem end remote from said valve seat and having an open end portion facing said valve-closing body and forming a second valve seat for the latter; said remote end of said valve stem protruding from the other open end of said distancing tube; f. a resiliently flexible membrane fastened on said valve housing across said other open end of said distancing tube and having a central membrane aperture; g. said valve stem being sealingly mounted in said central membrane aperture near the protruding stem end, the flexibility of said membrane being such as to permit a stroke of said valve stem sufficiently long for displacing said valve-closing body from sealing engagement with one of said first and second valve seats to sealing engagement with the other valve seat; h. spring means biassing said valve stem toward engagement of said valve-closing body with said second valve seat and thereby closing said tube against the penetration of waste gas thereinto; i. cam means the position of which is responsive to the position of said throttle flap means; and j. a resilient force-transmitting means intermediate said cam means and said protruding end of said valve stem and being frictionally engaged by said cam means, said cam means being adapted, depending on their position controlled by said throttle flap means, to urge said valve shaft via said forcetransmitting means and against the force of said spring means into said housing so as to move said valve-closing body away from said second valve seat and toward said first valve seat and, when sealingly engaging the latter, to obturate said passageway.