Exhaust gas recirculation adjuster for vehicle IC engine - uses resistive element having negative temp. coefft. in circuit supplying pulse-width-modulated current to coil of pressure controller

摘要

The recirculation valve (2) in the branch (1) from the exhaust pipe is controlled by a device (3) composed conventionally of an excitation coil (4) with an NTC resistance (7) compensator. The excitation circuit (5) is supplied with PWM current from a controller (6) responsive to sensors of e.g. engine speed and/or load. With a constant duty ratio of control signals throughout the temp. range, the average value of excitation current flowing through the coil and compensator in series is likewise constant and independent of temp. ADVANTAGE - Sufficient precision of control in all circumstances is achieved without the expense of a flow regulator.