A regulating unit senses the pressures in two zones of a recirculation passage to create a control pressure, and a transducer regulates an operating pressure which positions a control valve to provide exhaust gas recirculation at rates which establish the pressures in the zones necessary to maintain the control pressure equal to a reference pressure. Exhaust gas recirculation thus varies with engine exhaust backpressure and accordingly is a proportion of induction air flow with the proportion being ruled by the regulating unit.

Exhaust gas recirculation control

An exhaust gas recirculation system (EGR system) with an EGR valve means for controlling the amount of the exhaust gas to be recirculated into an intake system in an internal combustion engine, said EGR valve means comprising an intake system vacuum operated valve means for controlling the amount of the recirculated exhaust gas and a vacuum pump operated valve means for additionally controlling the amount of the recirculated exhaust gas. The EGR system preferably further comprises means for stopping EGR operations when not required and means for adjusting a required ignition timing.

Exhaust gas recirculation system

An orifice and a valve to maintain the ratio of recirculated exhaust gas to engine intake air at an optimum level.

Exhaust gas recirculation control device

A preferred embodiment EGR valve permits exhaust gas to be induced into the intake line downstream of the compressor, while minimizing the need to reduce the size of the turbocharger The preferred embodiment EGR valve exploits variations around the mean pressure in the EGR passage created by the engine cycle by selectively opening when the pressure in the EGR valve exceeds the pressure in the intake line Thus, exhaust gas is recirculated even when the engine is running near torque peak The preferred embodiment EGR valve also exploits the higher mean pressure in the exhaust line relative to the intake line at higher engine speeds by remaining open, in order to minimize the energy consumed in opening and closing the EGR valve

Dual mode EGR valve

A vacuum actuated valve uses a specially designed spring having a spring rate as a function of valve position. The spring rate function is determined using physical relationships between flow, pressure, and valve s position. The result is that the relationship between the control input to the valve (either a vacuum signal, or an electrical signal to a vacuum source) and the flow through the valve are linearly related through the entire operating region of the valve.

Valve and valve control method

An apparatus is provided for the recirculation of exhaust gases from an automobile''s engine at a constant volume comprising a flow control valve in a passage for recirculating part of the engine exhaust gases into the engine''s intake system

K Goto

Papers

Engine exhaust recirculation apparatus