Reductant Injection Control System
First Claim
1. A control system for reducing nitrogen oxides in an engine exhaust of an engine, the control system comprising:
- an emissions catalyst having an inlet adapted to receive an exhaust from the engine;
a reductant tank that stores a reductant;
an injector in fluid communication with the reductant tank and operable to inject the reductant into the exhaust upstream of the catalyst;
a reductant pump that pumps the reductant from the reductant tank to the injector; and
a controller that determines a target pressure of the reductant based on an engine operating condition and operates the reductant pump to supply the target pressure.
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Accused Products
Abstract
A control system for reducing nitrogen oxides in an engine exhaust of an engine includes an emissions catalyst having an inlet adapted to receive an exhaust from the engine. A reductant tank stores a reductant. An injector is in fluid communication with the reductant tank and is operable to inject the reductant into the exhaust upstream of the catalyst. A reductant pump pumps the reductant from the reductant tank to the injector. A controller determines a target pressure of the reductant based on an engine operating condition and operates the reductant pump based on the target pressure.
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Citations
21 Claims
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1. A control system for reducing nitrogen oxides in an engine exhaust of an engine, the control system comprising:
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an emissions catalyst having an inlet adapted to receive an exhaust from the engine; a reductant tank that stores a reductant; an injector in fluid communication with the reductant tank and operable to inject the reductant into the exhaust upstream of the catalyst; a reductant pump that pumps the reductant from the reductant tank to the injector; and a controller that determines a target pressure of the reductant based on an engine operating condition and operates the reductant pump to supply the target pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for reducing nitrogen oxides in an exhaust stream of an engine with a reductant, the method comprising:
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determining an operating condition of the engine including one of “
off” and
“
on”
;setting a target pressure of the reductant to one of a first pressure and a second pressure based on the operating condition of the engine, the second pressure being less than the first pressure; determining a temperature of the exhaust stream; setting a cool down mode based on the temperature being greater than a predetermined threshold temperature; and operating the reductant pump to supply the second pressure based on the operating condition of the engine being “
off” and
the cool down mode being set. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for reducing nitrogen oxides in an exhaust stream of an engine with a reductant, the method comprising:
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determining a first temperature of the exhaust stream; setting a target pressure of the reductant to one of a first pressure and a second lower pressure based on a comparison of the first temperature to a predetermined injector enabling threshold temperature; determining an operating condition of the engine including one of “
off” and
“
on”
;operating a reductant pump to supply one of the first pressure and the second pressure to an injector when the operating condition is “
on”
;setting the target pressure of the reductant to the second pressure when the operating condition of the engine is “
off”
;determining a second temperature of the exhaust system; determining a cool down time based on the second temperature; and operating the reductant pump for the cool down time based on the second temperature being greater than a threshold and the operating condition being “
off”
. - View Dependent Claims (21)
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20. The method of claim 20, further including adjusting the cool down time based on at least one of an ambient temperature, an ambient humidity and an ambient pressure.
Specification