US 6,957,642 B2 · Exhaust gas recirculation control system

Abstract

An engine exhaust gas cleaning apparatus is provided to suppress EGR ratio fluctuations when the excess air ratio is adjusted and thereby stabilize the engine operating performance. The engine exhaust gas cleaning apparatus comprises an exhaust gas recirculation control valve configured to recirculate a portion of the exhaust gas from the exhaust system to the air intake system and feedback control the quantity of the recirculated exhaust; an intake air throttle valve arranged in the air intake system at a position upstream of the position where an exhaust gas recirculation passage connects to the air intake system; an excess air ratio control section configured to change the intake air quantity by using the intake air throttle valve in response to a request to adjust the excess air ratio; and a feedback control restricting section configured to temporarily prohibit feedback control of the exhaust gas recirculation quantity delivered by the exhaust gas recirculation control valve, or to temporarily lower the gain of the feedback control, when the excess air ratio is being adjusted.

Claims19

Dependent claims

An exhaust gas recirculation control system comprising:

exhaust gas recirculation control means for recirculating a portion of exhaust gas from an exhaust system of an engine to an air intake system of the engine;
intake air regulating means for regulating air intake at a position upstream of a position where the exhaust gas recirculation control device connects to the air intake system;
feedback control section means for feedback controlling an exhaust gas recirculation quantity of the exhaust gas to be recirculated to the air intake system;
excess air ratio control means for adjusting an excess air ratio in response to a request to change the excess air ratio by using the intake air regulating device to change an intake air quantity;
and
feedback control restricting means for temporarily restricting feedback control of the exhaust gas recirculation quantity delivered by the exhaust gas recirculation control device when the excess air ratio is being adjusted.

3 more elements

An exhaust gas recirculation control system comprising:

an exhaust gas recirculation control device configured to recirculate a portion of exhaust gas from an exhaust system of an engine to an air intake system of the engine;
an intake air regulating device arranged in the air intake system at a position upstream of a position where the exhaust gas recirculation control device connects to the air intake system;
and
a control unit configured to control the exhaust gas recirculation control device and the intake air regulating device, the control unit including
a feedback control section configured to feedback control an exhaust gas recirculation quantity of the exhaust gas to be recirculated to the air intake system;
an excess air ratio control section configured to adjust an excess air ratio in response to a request to change the excess air ratio by using the intake air regulating device to change an intake air quantity;
and
a feedback control restricting section configured to temporarily restrict feedback control of the exhaust gas recirculation quantity delivered by the exhaust gas recirculation control device when the excess air ratio is being adjusted.

5 more elements

Dependencies are inferred from the claim text.

Exhaust gas recirculation control system

Life of this patent

Exhaust gas recirculation control system

Life of this patent

Abstract

Claims19