Vehicle fuel consumption indicator - measures induction system pressure and produces acoustic warning when transducer output exceeds threshold voltage

摘要

The device displaying instantaneous fuel consumption, esp. for vehicles, measures the consumption from the underpressure in the engine induction system. A transducer converts reduced pressure variations into electrical voltage variations. It is used to generate an unambiguous accoustic signal when a given consumption rate is exceeded and, if required, when consumption falls below this rate. The transducer is connected to the induction manifold via a mechanical choke which excludes higher frequency pressure variations. The transducer output is compared with an adjustable threshold voltage by a comparator producing a voltage when the threshold is exceeded. The comparator output drives an accoustic signal generator. The transducer has an associated damping circuit which suppresses the higher frequency components of its output signal.