Control Strategy For A Diesel Engine During Lean-Rich Modulation
First Claim
1. A method of operating a compression ignition engine to accomplish lean-rich modulation of fueling, the method comprising:
- processing certain engine specific data to modulate fueling between lean modulation and rich modulation;
during lean modulation, processing data representing a particular set of operating conditions to select a particular set of lean modulation maps that comprise data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and
during rich modulation, processing data representing substantially the same particular set of operating conditions to select a particular set of rich modulation maps that comprises data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run rich and develop substantially the same corresponding torque as during lean modulation.
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Abstract
The control system controls lean-rich modulation of fueling using a set of engine specific fueling parameter maps. One set of maps is a set of lean fueling maps, and another set is a set of rich fueling maps. The two map sets each comprise a fuel injection pressure map, an EGR valve opening map, and a VGT valve opening map, established for the particular diesel engine, with neither form of modulation requiring post injection. The strategy is represented by a flow diagram and is useful in regenerating an NOx adsorber catalyst in the engine exhaust system in a manner that controls torque so that the regeneration process is transparent to the operator of the vehicle, while producing significant fuel savings.
36 Citations
21 Claims
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1. A method of operating a compression ignition engine to accomplish lean-rich modulation of fueling, the method comprising:
- processing certain engine specific data to modulate fueling between lean modulation and rich modulation;
during lean modulation, processing data representing a particular set of operating conditions to select a particular set of lean modulation maps that comprise data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and
during rich modulation, processing data representing substantially the same particular set of operating conditions to select a particular set of rich modulation maps that comprises data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run rich and develop substantially the same corresponding torque as during lean modulation. - View Dependent Claims (2, 3, 4, 5, 6)
- processing certain engine specific data to modulate fueling between lean modulation and rich modulation;
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7. A compression ignition engine comprising:
- an engine specific control system for processing data including a set of lean fueling maps and a set of rich fueling maps;
one or more combustion chambers; and
a fueling system for injecting fuel into the one or more combustion chambers;
wherein the control system at times modulates fueling between lean modulation and rich modulation, and for lean modulation, processes data representing a particular set of operating conditions to select a particular set of lean fueling maps that comprise fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and
for rich modulation, processes data representing substantially the same particular set of operating conditions to select a particular set of rich fueling maps that comprise fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run rich and develop substantially the same corresponding torque as during lean modulation, both rich and lean modulation causing the engine to be fueled by at least a main fuel injection without post-injection. - View Dependent Claims (8, 9, 10, 11)
- an engine specific control system for processing data including a set of lean fueling maps and a set of rich fueling maps;
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12. A method of operating a specific compression ignition engine to accomplish lean-rich modulation of fueling for regeneration of a NOx adsorber catalyst in an exhaust system of the engine, the method comprising:
- processing certain engine specific data to modulate fueling between lean modulation and rich modulation;
during lean modulation, processing data representing a particular set of operating conditions to select a particular set of lean fueling maps that comprise fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and
during rich modulation, processing data representing substantially the same particular set of operating conditions to select a particular set of rich fueling maps that comprise fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run sufficiently rich to create sufficient carbon monoxide for regenerating the NOx adsorber catalyst while developing substantially the same corresponding torque as during lean modulation. - View Dependent Claims (13, 14, 15, 16)
- processing certain engine specific data to modulate fueling between lean modulation and rich modulation;
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17. A compression ignition engine comprising:
- a control system for processing engine specific data including a set of lean fueling maps and a set of rich fueling maps;
one or more combustion chambers;
a fueling system for injecting fuel into the one or more combustion chambers; and
an exhaust system having a NOx adsorber catalyst through which exhaust from the combustion chambers is constrained to pass;
wherein the control system at times modulates fueling between lean modulation and rich modulation for regenerating the NOx adsorber catalyst, and for lean modulation, processes data representing a particular set of operating conditions to select a particular set of lean fueling maps that comprise fueling data appropriate to the particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run lean and develop a corresponding torque; and
for rich modulation, processes data representing substantially the same particular set of operating conditions to select a particular set of rich fueling maps that comprise fueling data appropriate to that substantially same particular set of operating conditions for causing the engine to be fueled in a manner that causes the engine to run sufficiently rich to create sufficient carbon monoxide for regenerating the NOx adsorber catalyst while developing substantially the same corresponding torque as during lean modulation. - View Dependent Claims (18, 19, 20, 21)
- a control system for processing engine specific data including a set of lean fueling maps and a set of rich fueling maps;
Specification