Abstract: The air pressure in the intake valve undergoes a sudden decrease upon closure of the throttle valve. This decrease is sensed and opens a bypass which furnishes some air to the air intake means when the throttle is fully closed. The quantity of air so furnished is sufficient to allow combustion in all cylinders of the engine, thereby preventing excessive cooling.

Abstract: A conduit with inlet and discharge ends respectively for receiving a supply of air under pressure and for delivering the air at a lower pressure has a cylindrical configuration and an eliptical butterfly type damper is disposed diagonally therein. The damper turns about an axis intermediate its diagonally opposite ends and the oncoming air stream thus impinges on the upstream face of the damper on opposite sides of the axis and creates a differential force, the said differential force tending to close the damper and constituting a first closing force. A second closing force for the damper is provided by a small bellows supplied with air through a small conduit from the downstream side of an orifice member disposed in the main conduit upstream of the damper. A second and substantially larger bellows serves to open the damper and a small conduit connects the said bellows with a controller supplied with air from an upstream side of the orifice member in the main conduit.

Abstract: Method and installation for the predetermined addition of secondary air used in effecting optimum combustion of internal combustion engine exhaust gases, including a control arrangement including one or more measuring devices sensing engine operating or exhaust gas contents and, in response to the sensed conditions, regulating the addition of secondary air in order to obtain optimum exhaust gas combustion.