Internal combustion engine with exhaust-gas aftertreatment arrangement and method for operating an internal combustion engine of said type
AssigneeFord Global Technologies, LLC
InventorYasser Mohamed sayed Yacoub
Life of this patent
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Abstract
A system and method for controlling temperature of a urea reductant to form ammonia for NOx reduction in a selective catalytic reducer coupled to a turbocharged engine exhaust by portioning a flow across the reductant between compressed air and ambient air.
Claims19
An internal combustion engine comprising:
- an intake system for the supply of charge air;
- an exhaust-gas discharge system for the discharge of the exhaust gases;
- at least one selective catalytic converter arranged in the exhaust-gas discharge system for the reduction of nitrogen oxides;
- an oxidation catalytic converter being arranged, as a further exhaust-gas aftertreatment system, in the exhaust-gas discharge system upstream of the at least one selective catalytic converter;
- wherein
- a bypass line branches off from the intake system and issues into the exhaust-gas discharge system between the oxidation catalytic converter and the at least one selective catalytic converter;
- and
- a dosing device being provided for introducing liquid urea as a reducing agent for the at least one selective catalytic converter into the bypass line.
A method for controlling and engine having a selective catalytic reducer (SCR) coupled to an engine exhaust comprising:
- supplying compressed air to the engine to achieve a desired torque;
- injecting a reductant into the SCR;
- controlling temperature of said reductant within a predetermined range by portioning an air flow into said reductant between a portion of said compressed air and ambient air;
- and
- adjusting engine torque to compensate for said portioning of said compressed air.
A method for controlling an engine having a turbocharger with a turbine positioned in the engine exhaust, a selective catalytic reducer (SCR) positioned downstream of the turbine, and a compressor driven by the turbine comprising:
- supplying compressed air from the compressor to the engine;
- injecting a urea reductant into the SCR through a dosing device to reduce NOx;
- controlling temperature of said dosing device to be within a predetermined range for conversion of said urea to ammonia by portioning an air flow across said dosing device between a portion of said compressed air and another portion of ambient air;
- and
- adjusting engine torque to compensate for said portioning of said compressed air.
Dependencies are inferred from the claim text.