Control device for regulating the compositions of the inlet and exhaust gases of an internal combustion engine

Claim 1

A control device useful in an internal combustion engine having a carburetor, an engine inlet, and an exhaust outlet, for regulating the composition of the inlet gases and hence the exhaust gases, said control device having first passage means bypassing said carburettor for supplying extra air to said engine inlet, a control valve in said first passage means, second passage means for recirculating exhaust gases to said engine inlet, an electrically operated valve in said second passage means, an exhaust gas composition sensor installed in said exhaust outlet of said engine for providing signals dependent on the composition of the engine exhaust gases, and a controller responsive to said signals from said exhaust gas composition sensor to control said electrically operated valve and thereby the flow of exhaust gases through said second passage means, the improvement wherein said control device further comprises a pressure-sensitive device communicating with said second passage means upstream of said electrically operated valve, and means connecting said pressure-sensitive device to said control valve in said first passage means whereby said control valve is operated to regulate the supply of extra air to said engine inlet in response to the pressure in said second passage means.