Coordinated Control of EGR Valve and Intake Throttle for Better Fuel Economy in Diesel Engines

Modern diesel engines are frequently equipped with an exhaust gas recirculation (EGR) valve and intake throttle (ITH). The intake throttle serves to depress intake manifold pressure, create a greater pressure differential across the EGR valve, and enhance the ability to flow EGR at low speed and load conditions. A conventional approach to controlling the intake throttle is to schedule its desired position as a function of engine speed and load. In this paper we present a coordinated approach to the control of EGR valve and intake throttle.