Method and apparatus for controlling lean-burn engine based upon predicted performance impact
First Claim
1. A method for controlling the operation of an internal combustion engine in a motor vehicle, wherein the engine operates at a plurality of operating conditions including a near-stoichiometric operating condition, wherein the engine generates exhaust gas including an emissions constituent, and wherein exhaust gas is directed through an emissions control device before being exhausted to the atmosphere, the method comprising:
- determining a measure representing a performance impact of operating the engine at a first operating condition other than the near-stoichiometric operating condition, wherein the measure is based on at least one engine or vehicle operating parameter; and
enabling the first operating condition based on the measure.
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Accused Products
Abstract
A method and apparatus for controlling the operation of a “lean-burn” internal combustion engine in cooperation with an exhaust gas purification system having an emissions control device capable of alternatively storing and releasing NOx when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, determines a performance impact, such as a fuel-economy benefit, of operating the engine at a selected lean or rich operating condition. The method and apparatus then enable the selected operating condition as long as such enabled operation provides further performance benefits.
110 Citations
40 Claims
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1. A method for controlling the operation of an internal combustion engine in a motor vehicle, wherein the engine operates at a plurality of operating conditions including a near-stoichiometric operating condition, wherein the engine generates exhaust gas including an emissions constituent, and wherein exhaust gas is directed through an emissions control device before being exhausted to the atmosphere, the method comprising:
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determining a measure representing a performance impact of operating the engine at a first operating condition other than the near-stoichiometric operating condition, wherein the measure is based on at least one engine or vehicle operating parameter; and
enabling the first operating condition based on the measure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
calculating a first value representing a desired torque output for the engine operating at the first operating condition; and
calculating a second value representing a maximum torque output for the engine operating at a near-stoichiometric operating condition.
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5. The method of claim 1, wherein determining is performed prior to operating the engine at the first operating condition.
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6. The method of claim 1, wherein the first operating condition is characterized by combustion of an air-fuel mixture that is lean of a stoichiometric air-fuel mixture.
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7. The method of claim 1, wherein the first operating condition is characterized by combustion of an air-fuel mixture that is rich of a stoichiometric air-fuel mixture.
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8. The method of claim 1, wherein enabling includes comparing the measure to a predetermined threshold value.
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9. The method of claim 8, wherein enabling further includes inhibiting the first operating condition when the measure is in a first predetermined relationship relative to the predetermined threshold value.
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10. The method of claim 8, wherein enabling further includes operating the engine at the first operating condition when the measure is in a second predetermined relationship relative to the threshold value.
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11. The method of claim 1, wherein the performance impact is a relative efficiency calculated with reference to engine operation at the near-stoichiometric operating condition.
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12. The method of claim 11, wherein the performance impact is a relative fuel efficiency.
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13. The method of claim 11, wherein determining includes calculating a value for relative efficiency at each of a plurality of time intervals, and deriving the measure based on at least two of the values.
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14. The method of claim 13, further including, in each time interval, storing an amount of the emissions constituent in the emissions control device and thereafter releasing substantially all of the stored amount.
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15. The method of claim 13, wherein deriving includes averaging the at least two values.
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16. A system for controlling the operation of an internal combustion engine in a motor vehicle, wherein the engine operates at a plurality of operating conditions including a near-stoichiometric operating condition, wherein the engine generates exhaust gas including an emissions constituent, and wherein exhaust gas is directed through an exhaust gas purification system including an emissions control device before being exhausted to the atmosphere, the system comprising:
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a controller including a microprocessor arranged to determine a first measure representing a first performance impact of operating the engine at a first operating condition other than the near-stoichiometric operating condition, wherein the first measure is based on at least one engine or vehicle operating parameter; and
wherein the controller is further arranged to enable the first operating condition based on the first measure. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for controlling the operation of an internal combustion engine in a motor vehicle, wherein the engine generates exhaust gas including an emissions constituent, and wherein exhaust gas is directed through an exhaust gas purification system including an emissions control device before being exhausted to the atmosphere, the method comprising:
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determining a first and second measure representing an efficiency, relative to a near-stoichiometric operating condition, of a first operating condition and a second operating condition, respectively, wherein the measures are each based on at least one engine or vehicle operating parameter; and
enabling at least one of the first and second operating conditions based on the first and second measures. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
calculating a second torque value representing a maximum torque output for the engine operating at a near-stoichiometric operating condition.
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36. The method of claim 33, wherein determining is performed prior to operating the engine at the first operating condition.
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37. The method of claim 33, wherein enabling includes inhibiting the first operating condition when the first of the two measures is in a first predetermined relationship relative to a predetermined threshold value.
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38. The method of claim 33, wherein determining includes calculating an efficiency value with respect to each of a plurality of time intervals;
- and deriving at least one of the measures based on at least two efficiency values.
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39. The method of claim 38, further including, in each time interval, storing an amount of the emissions constituent in the emissions control device and thereafter releasing substantially all of the stored amount.
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40. The method of claim 38, wherein deriving includes averaging the at least two values.
Specification