Thermal flow meter and control system

摘要

The invention relates to a control system comprising a thermal flow meter. In regard to an output of the intake flow meter for an internal combustion engine or the like, a pulsation error can be reduced and dispersion in correction at the time of correction of response delay (a recovering of response delay) is reduced. As a digital device for a pre-processing of a control unit (5) for inputting a flow rate measuring signal, there are provided means (41) for converting an output voltage of the flow sensor into a digital value, conversion means (42) (linear forming means) for converting this digital value into a flow rate, means (43) for smoothening the flow rate value (for example, a low-pass filter; an element for adding a response delay), and means (44) for converting the smoothened flow rate value into a voltage value and the like. In addition, there is provided a selection means (49) for changing over an output signal after pre-processing and a clock signal of the device by a selection signal. The control unit (5) detects a degree of response delay in reference to dispersion in clock signal so as to perform a response delay recovering and corrects to reduce dispersion of the response delay.