Engine idling duration control
First Claim
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1. A method for controlling an engine in a vehicle, comprising each of:
- after a threshold duration of engine idling, continuing engine idle operation when an exhaust NOx sensor indicates a NOx level below a NOx threshold, and stopping engine idle and shutting down the engine when the exhaust NOx sensor indicates the NOx level is above the NOx threshold, the exhaust NOx sensor positioned in an exhaust passage downstream of an emission control device; and
adjusting engine operation to take mitigating action during idling to reduce NOx emissions below the NOx threshold in response to the exhaust NOx sensor indication that the NOx level is above the threshold.
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Abstract
Systems and methods are described for controlling an engine in a vehicle. One example method includes, after a threshold duration of engine idling, continuing engine idle operation when an exhaust NOx sensor indicates a NOx level below a NOx threshold, and stopping engine idle and shutting down the engine when the exhaust NOx sensor indicates the NOx level is above the NOx threshold. In this way, when the exhaust emissions are below the NOx threshold, it is possible to prolong engine idling operation using the exhaust NOx sensor.
26 Citations
15 Claims
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1. A method for controlling an engine in a vehicle, comprising each of:
after a threshold duration of engine idling, continuing engine idle operation when an exhaust NOx sensor indicates a NOx level below a NOx threshold, and stopping engine idle and shutting down the engine when the exhaust NOx sensor indicates the NOx level is above the NOx threshold, the exhaust NOx sensor positioned in an exhaust passage downstream of an emission control device; and
adjusting engine operation to take mitigating action during idling to reduce NOx emissions below the NOx threshold in response to the exhaust NOx sensor indication that the NOx level is above the threshold.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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during a first operating mode, shutting down a diesel engine from idle after a threshold duration of idling operation when exhaust NOx emissions are above a threshold value; and during a second operating mode, continuing to run the diesel engine in idle after the threshold duration when;
NOx mitigating actions responsive to increased NOx emissions reduce NOx emissions to below the threshold value, and when NOx emissions are below the threshold. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A system in a vehicle comprising:
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a diesel engine having an exhaust; at least an SCR catalyst coupled to said exhaust downstream of said engine; a reductant delivery system coupled to said exhaust and configured to deliver reductant to the SCR catalyst; an exhaust NOx sensor coupled to said exhaust downstream of at least one NOx mitigating device; and a control system configured to deliver reductant to the SCR catalyst at least during non-idling conditions, monitor a duration of continuous engine idling, and during the duration of continuous engine idling, continue engine idle operation when the exhaust NOx sensor indicates a NOx level below a threshold, and shutting down the engine when the exhaust NOx sensor indicates the NOx level is above the threshold and when the monitored duration of continuous idling at NOx levels above the threshold is greater than a threshold duration, the control system further configured to adjust engine operation to take mitigating action to reduce NOx emissions below the threshold in response to the NOx exhaust sensor indication that the NOx level is above the threshold.
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Specification