FIELD: engines and pumps.
SUBSTANCE: control device of exit gas recirculation (EGR) for control of diesel engine includes EGR valve by means of which the engine EGR flow is controlled, suction air throttle valve by means of which the engine suction air flow is controlled, and the mechanism in which EGR valve opening is enabled in conjunction with the opening of air throttle valve. Each of the determining opening lines (characteristic curves) and with regard to opening of EGR valve and air throttle valve has dead zone section, where the flow rate remains unchanged, even when the valve opening increases above some opening limit. EGR control device is equipped with dead zone evaluation device that estimates excess air design factor λ considering the oxygen residue in EGR gas. The conclusion is made that at least one of EGR valves and air throttle valve is engaged in dead zone, on the basis of the rate of change of the estimated design factor λ of excess air when the rate of change of excess air design factor λ is less than the preset level. EGR control device is equipped with dead zone compensation device that makes the corrections concerning command signals of opening in relation to EGR valve and suction air throttle valve so that dead zones do not interfere with the mechanism concerning joint opening operation when evaluation device of dead zone makes a conclusion that at least one of EGR valves and air throttle valve is engaged in dead zone and the engine is in the condition of transient process.
EFFECT: simpler control of the valve opening.
7 cl, 12 dwg
