System for detoxicating exhaust gases

In a system for detoxicating exhaust gases in an internal combustion engine, having air intake pipe means and conduit means for recycling a part of the exhaust gases of said engine into said air intake pipe means, the improvement comprising, in combination, valve means for controlling the flow of said part of the exhaust gases being thus recycled, throttle means comprising a flap and being associated with said air intake pipe means, and means for controlling said valve means in dependence on the adjustment of said throttle flap, wherein

• i. said means for controlling said valve means are so connected to said air intake pipe means that said valve means are controlled by the pressure prevailing in the adjacent zone of said air intake pipe means;
• ii. said flap of said throttle means is turnably disposed in said air intake pipe means whereby during turning of said flap to admit air to the engine a portion of said flap moves against the direction of flow of intake air through said air intake pipe means;
• iii. said valve means comprise pneumatically operating valve means being closed in non-actuated position, and a control conduit from said air intake pipe means to said valve means for having the air pressure in the former act on the latter, which conduit opens into said air intake means upstream of the flap of said throttle means and upstream of that portion of said flap which moves against the direction of intake air flow, but still within the immediate vicinity of the latter flap portion, whereby, at almost closed flap during idling of the engine, and also during wide open flap position during full load operation of the engine, said pneumatically operating valve means remain closed;
• and
• iv. said pneumatically operating valve means comprise two valves controllable independently of one another and interposed in parallel in said exhaust gas recycling conduit means and two control conduits, one of said control conduits leading from one of said valves to said air intake pipe means and opening in the latter upstream of said throttle means, and the other control conduit leading from the other valve to said air intake pipe means and opening in the latter upstream of the opening of the former control conduit thereinto.