The invention is based on an apparatus as generally described hereinafter. In order to reduce the proportion of toxic substances in the exhaust gases of internal combustion engines, it is known to perform a recirculation of controlled quantities of the exhaust gas back to the intake tube of the engine. Conventionally, an exhaust gas recirculation line is carried from the exhaust gas side of the engine back to the intake tube, and the quantity of recirculated gas is adjusted by means of a throttle valve. In German Offenlegungsschrift No. 2658052, an apparatus is described for the load-dependent actuation of a throttle valve of an exhaust gas recirculation apparatus, in which the throttle valve determining the quantity of recirculated exhaust gas is actuated by a hydraulic servomotor, which obtains its operating medium from the suction chamber of the injection pump. The quantity of the fuel supplied in this manner to the hydraulic servomotor is controlled by means of a throttle, which is adjustable in accordance with the position of a governor sleeve in the governor of the injection pump. It is true that precise load-dependent control of the exhaust gas recirculation rate is attained in this manner; however, the use of the fuel existing in the interior of the injection pump as a hydraulic operating medium may result in inaccuracies, because the pressure in the suction chamber of the injection pump is dependent upon its rpm.
USPTO Backgrounds
USPTO Backgrounds