Diesel engine exhaust gas recirculation (EGR) system and method
AssigneeSiemens Canada Limited
InventorJohn Edward Cook
Life of this patent
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Abstract
Apparatus for and method of exhaust gas recirculation in an internal combustion engine that operates with charge air boost. An EGR valve has an inlet port communicated to the engine exhaust system upstream of a throttle valve in the tailpipe and an outlet port communicated to the engine intake system. The throttle valve is controlled to selectively restrict exhaust gas flow through the tailpipe so as to maintain the difference between pressure at the EGR valve inlet and pressure at the EGR valve outlet substantially unaffected by changes in pressure in the intake system and in the exhaust system. The invention is particularly suited for a turbocharged diesel engine.
Claims11
An internal combustion engine that operates with charge air boost and comprises:
- an intake system;
- an exhaust system comprising a tailpipe;
- a throttle valve for selectively restricting exhaust gas flow to the tailpipe;
- an exhaust gas recirculation (EGR) system for controlled recirculation of exhaust gas from the exhaust system to the intake system comprising an EGR valve having an inlet port communicated to the exhaust system upstream of the throttle valve and an outlet port communicated to the intake system;
- and
- a control for operating the EGR valve and the throttle valve, including a regulator for operating the throttle valve to partially restrict exhaust gas flow to the tailpipe to regulate the difference between pressure at the EGR valve inlet and pressure at the EGR valve outlet to a desired differential that is substantially unaffected by pressure change in the intake system and in the exhaust system.
A method of exhaust gas recirculation in an internal combustion engine that operates with charge air boost and comprises:
- an intake system;
- an exhaust system comprising a tailpipe;
- a throttle valve for selectively restricting exhaust gas flow to the tailpipe;
- an exhaust gas recirculation (EGR) system for controlled recirculation of exhaust gas from the exhaust system to the intake system comprising an EGR valve having an inlet port communicated to the exhaust system upstream of the throttle valve and an outlet port communicated to the intake system;
- the method comprising:
- controlling the EGR valve and the throttle valve, including operating the throttle valve to partially restrict exhaust flow to the tailpipe in a manner that regulates the difference between pressure at the EGR valve inlet and pressure at the EGR valve outlet to a desired differential that is substantially unaffected by pressure change in the intake system and in the exhaust system.
Dependencies are inferred from the claim text.