Cold start gas component retention system in EGR circuit with recirculated gas control
First Claim
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1. An internal combustion engine exhaust system, comprising:
- an EGR line routing a selected amount of exhaust gases from an exhaust passage of an engine toward an intake passage of the engine, the EGR line including a first inlet located downstream of an emission control device and a second inlet located upstream of the emission control device;
a gas component reduction element in the EGR line reducing a quantity of one or more selected components from the selected amount of exhaust gases and located downstream of the second inlet; and
an exhaust line coupled with the EGR line and coupled to route a first portion of the selected amount of the exhaust gases to pass into the intake passage of the engine, and to route a second portion of the selected amount of the exhaust gases from the gas component reduction element to atmosphere while the first portion is routed into the intake passage.
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Abstract
Methods and systems are provided for managing exhaust gases from an internal combustion engine are described. In one example system, hydrocarbons in engine exhaust gases may be stored during an engine cold start and later released into an intake manifold of the engine. The methods and systems may reduce engine hydrocarbon emissions.
18 Citations
20 Claims
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1. An internal combustion engine exhaust system, comprising:
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an EGR line routing a selected amount of exhaust gases from an exhaust passage of an engine toward an intake passage of the engine, the EGR line including a first inlet located downstream of an emission control device and a second inlet located upstream of the emission control device; a gas component reduction element in the EGR line reducing a quantity of one or more selected components from the selected amount of exhaust gases and located downstream of the second inlet; and an exhaust line coupled with the EGR line and coupled to route a first portion of the selected amount of the exhaust gases to pass into the intake passage of the engine, and to route a second portion of the selected amount of the exhaust gases from the gas component reduction element to atmosphere while the first portion is routed into the intake passage. - View Dependent Claims (2, 3, 4, 5)
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6. A method of operating an engine comprising:
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routing exhaust gas from the engine to a hydrocarbon retaining system located on an EGR line before an emission device reaches a threshold temperature; directing a first portion of the exhaust gas from the hydrocarbon retaining system to an engine air intake passage; and directing a second portion of the exhaust gas from the hydrocarbon retaining system to atmosphere. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of operating an engine comprising an emission control device:
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routing a selectively adjustable proportion of exhaust gas from downstream of the emission control device to a hydrocarbon retaining system to store hydrocarbons in the hydrocarbon retaining system before an emission device reaches a threshold temperature, the hydrocarbon retaining system being located on an EGR line; directing a first portion of the exhaust gas from the hydrocarbon retaining system to an engine air intake passage for re-introduction in a combustion chamber of the engine; directing a second portion of the exhaust gas from the hydrocarbon retaining system to atmosphere; adjusting the first portion and the second portion in response to engine operating conditions, including, adjusting the first portion in response to at least temperature and combustion stability, where the first portion is reduced and the second portion increased at least in response to a drop in engine combustion stability; and adjusting a fuel injection amount to the engine in response to temperature of the hydrocarbon retaining system. - View Dependent Claims (20)
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Specification