To improve adjusting accuracy for amount of exhaust gas to be feedbacked by complementing first and second measured values when an adjusting member is located at a first location (open location) and a second location (close location) and setting an actual value or a correction value based on a difference between both of these measured values.
An adjusting member 120 is controlled in timing so as to be alternately opened or completely closed. When the adjusting member 120 is opened and exhaust gas feedback is performed, a first measured value is complemented. When the adjusting member 120 is closed and exhaust gas feedback is not performed, a second measured value is complemented. A difference between these two measured values are led as an actual value to a controller. An output signal of the controller is coupled with a signal of a modulation setting step. A signal having a fixed frequency and amplitude depending on a comparison result of the actual value and a target value is supplied to the adjusting member 120. As a result, adjusting accuracy of an exhaust gas feedback rate can be improved.
BERGER JOACHIM
BIRK MANFRED
STROHRMANN MANFRED DR
RUPP PETER
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