Exhaust gas recirculation system

摘要

Past exhaust emission control systems fail to utilize exhaust gas recirculation during all operating parameters of an engine. The present exhaust gas recirculation system reduces the emissions emitted from an engine during all operating parameters of the engine. The engine has a cylinder, a rotatable crankshaft and a turbocharger defining a compressor section compressing a flow of intake air to a first preestablished pressure and being driven by a flow of exhaust gas having a first preestablished pressure. The exhaust gas recirculation system is comprised of a portion of the flow of exhaust gas being recirculated back to the cylinder and forming a flow of exhaust gas recirculation. The flow of exhaust gas recirculation is cooled. The flow of exhaust gas recirculation is mixed with exhaust gas and compressed to a second preestablished pressure by the positive displacement pump. The second preestablished pressure of the flow of exhaust gas recirculation is at least as great as the first preestablished pressure of the intake air. And, a quantity of the flow of exhaust gas recirculation is controlled by a mixing valve. The mixing valve has an open position in which a portion of the flow of intake air is mixed with the flow of exhaust gas recirculation and a closed position in which the flow of intake air is blocked.