Abstract: A fluid flow regulating or shut-off valve of the kind having a bimetallic element which regulates or opens and closes a flow passage through the valve in dependence upon temperature is provided with at least one electrically heatable PTC-element which is in thermal contact with the bimetallic element. Heating of the PTC-element by control of the supply of electricity to it thus controls the operation of the valve. The bimetallic element is preferably in the form of a snap-acting bending bimetallic plate which is heated by radiation from the PTC-element and which itself forms the valve closure member. With the bimetallic plate snapped in one direction, a passage through the valve is opened, but when the plate snaps in the other direction, it bears against a sealing ring surrounding a valve opening within the valve to close and seal the opening and thus shut the valve.

Abstract: A control installation for the dosing or proportioning of a secondary air quantity for the improvement of combustion in internal combustion engines, or the afterburning of the exhaust gases of internal combustion engines, including an auxiliary arrangement which is responsive to an emergency signal for effecting the prompt shutting-off of the secondary air. The emergency signal may be initiated in response to a failure in the ignition voltage of the internal combustion engine; an increase in the hydrocarbon content of the exhaust gases; a disparity between the position of the mixture dosing element and the engine rotational speed; the exceeding of a limiting temperature in the exhaust gas manifold; or the exceeding of a limiting temperature in the afterburner.

Abstract: A control installation for the proportioning of a secondary air quantity employed for achieving optimum combustion or after-burning in internal combustion engines. The installation provides for stabilization of the measuring receptivity of sensors employed for the measurement of the oxygen content or carbon monoxide content of the exhaust gases, and to reduce the load on a subsequently switched-in after-burner. Upstream of the sensor employed for the measurement of the oxygen content or carbon monoxide content of the exhaust gases, there is located a catalytically operative element for effecting the conversion of the deleterious materials into other harmless materials or compounds. The catalytically operative element may be combined in a unitary structure with a mixing chamber.

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.