An exhaust gas recirculation system for a compression ignition engine and a method of controlling exhaust gas recirculation in a compression ignition engine

摘要

An exhaust gas recirculation system for a compression ignition engine and a method of controlling exhaust gas recirculation in compression ignition engines are disclosed. The method and apparatus are adapted to the control of exhaust gas recirculation in diesel and/or multifuel (e.g. diesel and natural gas) engines. The apparatus includes a first pressure sensor for sensing an absolute gas pressure in the intake manifold of the engine, a second pressure sensor for sensing an absolute gas pressure in the exhaust manifold of the engine, an engine speed sensor for detecting engine RPM, a fuelling rate sensor for detecting the commanded fuelling rate for the engine, a temperature sensor for detecting the temperature of intake air in the intake manifold, a conduit for directing exhaust gas from the exhaust manifold to the intake manifold, an electronically actuated mechanical valve in the conduit for controlling the flow of exhaust gas and an electronic controller for analyzing signals from the sensors and outputting control signals to an electric stepper motor which controls the position of the valve. The advantages include accurate control of exhaust gas recirculation in real time, rapid response to changing combustion conditions which result in reduced pollution emission and higher fuel efficiency. A further advantage is a system which is readily retrofit to an existing compression ignition engine or included as a part of original equipment in new engines without engine redesign.