Exhaust gas recirculation control system for internal combustion engine

Claim 1

An exhaust gas recirculation control system of an internal combustion engine comprising: a core formed therein with a hollow passage opened at its end; a plunger made of a magnetic material and being movable in the axial direction of said core, said plunger having a valve seat opposing the open end of said core; a spring biasing said plunger to bring a valve portion comprised of said open end and said valve seat into an open state; a first exciting coil applying a force to said plunger to move said plunger in the closing direction in opposition to the bias of said spring; a second exciting coil applying to said plunger a force substantially opposite to the force which said first exciting coil applies to said plunger; a housing defining a chamber which incorporates said valve portion; at least one opening formed in said housing and being in communication with a portion at a pressure substantially equal to external atmospheric pressure; a flow-electricity transducer generating an electric signal depending on the amount of inlet air of the internal combustion engine and applying said electric signal to said first exciting coil; means for communicating the hollow passage of said core to the downstream of a throttle valve; an exhaust gas recirculation passage passing recirculation of partial exhaust gas of the internal combustion engine into a mixture introduced into said internal combustion engine; a control valve disposed in said exhaust gas recirculation passage, for controlling the amount of exhaust gas recirculation in response to a negative pressure in the hollow passage of said core; an orifice disposed in said exhaust gas recirculation passage, for generating a negative pressure at the upstream of said control valve; and a pressure-electricity transducer generating an electric signal in inverse proportion to the pressure downstream of said orifice and applying said electric signal to said second exciting coil.