TORQUE CONTROL STRATEGY FOR A DIESEL ENGINE DURING LEAN-RICH MODULATION USING INDEPENDENT FUEL INJECTION MAPS
First Claim
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1. A control strategy for lean-to-rich modulation of an internal combustion engine comprising:
- with the engine running lean at a particular speed, causing the engine to transition from running lean to running rich while striving to maintain a desired engine torque at that particular speed by a) processing data values for engine speed and desired engine torque to develop a data value for desired mass airflow into the engine and a data value for desired air-fuel ratio for rich running, b) processing the data value for desired mass airflow into the engine, a data value for actual mass airflow into the engine, and a data value for actual air-fuel ratio to develop a data value for quantity of engine fueling, c) processing the data value for quantity of engine fueling and other data relevant to a determination of the timing of introduction of that quantity of engine fueling into the engine during an engine cycle that will cause the engine to run rich while striving to maintain desired engine torque at the particular engine speed, to develop a data value for that timing, d) forcing intake mass airflow toward that desired mass airflow, and e) fueling the engine with that quantity of engine fueling at that timing.
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Abstract
An engine (20) and an engine control strategy (FIGS. 2 and 3) for lean-to-rich transitions, such transitions being useful for various purposes, one of which is purging, or regenerating, a NOx adsorber (36) in the engine exhaust system.
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Citations
22 Claims
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1. A control strategy for lean-to-rich modulation of an internal combustion engine comprising:
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with the engine running lean at a particular speed, causing the engine to transition from running lean to running rich while striving to maintain a desired engine torque at that particular speed by a) processing data values for engine speed and desired engine torque to develop a data value for desired mass airflow into the engine and a data value for desired air-fuel ratio for rich running, b) processing the data value for desired mass airflow into the engine, a data value for actual mass airflow into the engine, and a data value for actual air-fuel ratio to develop a data value for quantity of engine fueling, c) processing the data value for quantity of engine fueling and other data relevant to a determination of the timing of introduction of that quantity of engine fueling into the engine during an engine cycle that will cause the engine to run rich while striving to maintain desired engine torque at the particular engine speed, to develop a data value for that timing, d) forcing intake mass airflow toward that desired mass airflow, and e) fueling the engine with that quantity of engine fueling at that timing. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A strategy for regenerating a NOx adsorber in an exhaust system of an internal combustion engine by conditioning engine operation to generate excess CO for inducing regeneration, the strategy comprising:
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with the engine running lean at a particular speed, generating excess CO by causing the engine to transition from running lean to running rich while striving to maintain a desired engine torque at that particular speed by a) processing data values for engine speed and desired engine torque to develop a data value for desired mass airflow into the engine and a data value for desired air-fuel ratio for rich running, b) processing the data value for desired mass airflow into the engine, a data value for actual mass airflow into the engine, and a data value for actual air-fuel ratio to develop a data value for quantity of engine fueling, c) processing the data value for quantity of engine fueling and other data relevant to a determination of the timing of introduction of that quantity of engine fueling into the engine during an engine cycle that will cause the engine to run rich while striving to maintain desired engine torque at the particular engine speed, to develop a data value for that timing, d) forcing intake mass airflow toward that desired mass airflow, and e) fueling the engine with that quantity of engine fueling at that timing. - View Dependent Claims (9, 10)
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11. A strategy for regenerating a NOx adsorber in an exhaust system of an internal combustion engine by conditioning engine operation to generate excess CO for inducing regeneration, the strategy comprising:
with the engine running lean and delivering a certain torque at a certain speed, controlling at least one of airflow entering the engine through an intake system of the engine and fueling of the engine to substantially maintain that torque and speed while significantly decreasing the air-fuel ratio in the process to generate excess CO for regenerating the NOx adsorber. - View Dependent Claims (12)
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13. An internal combustion engine comprising:
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a) a fueling system for fueling the engine in accordance with a data value for desired engine fueling;
b) an intake system through which airflow enters the engine, and c) a control system for processing various data to develop data for control of various engine functions including data values for desired engine fueling, for desired mass airflow into the engine, and for desired air-fuel ratio, wherein the control system comprises a control strategy i) for causing the engine to transition from running lean to running rich while striving to maintain engine torque at a particular engine speed by ii) processing data values for engine speed and desired engine torque to develop a data value for desired mass airflow into the engine and a data value for desired air-fuel ratio for rich running, iii) processing the data value for desired mass airflow into the engine, a data value for actual mass airflow into the engine, and a data value for actual air-fuel ratio to develop a data value for quantity of engine fueling, iv) processing the data value for quantity of engine fueling and other data relevant to a determination of the timing of introduction of that quantity of engine fueling into the engine during an engine cycle that will cause the engine to run rich while striving to maintain desired engine torque at the particular engine speed, to develop a data value for that timing, v) forcing intake mass airflow toward that desired mass airflow, and vi) fueling the engine with that quantity of engine fueling at that timing. - View Dependent Claims (14, 15, 16, 17)
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18. An internal combustion engine comprising:
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a) a fueling system for fueling the engine in accordance with a data value for desired engine fueling;
b) an intake system through which airflow enters the engine;
c) a NOx adsorber in an exhaust system of the engine; and
d) an engine control system that at times conditions engine operation to generate excess CO for inducing regeneration of the NOx absorber and that comprises a strategy for generating excess CO by causing the engine to transition from running lean at a particular speed to running rich while striving to maintain a desired engine torque at that particular speed by i) processing data values for engine speed and desired engine torque to develop a data value for desired mass airflow into the engine and a data value for desired air-fuel ratio for rich running, ii) processing the data value for desired mass airflow into the engine, a data value for actual mass airflow into the engine, and a data value for actual air-fuel ratio to develop a data value for quantity of engine fueling, ii) processing the data value for quantity of engine fueling and other data relevant to a determination of the timing of introduction of that quantity of engine fueling into the engine during an engine cycle that will cause the engine to run rich while striving to maintain desired engine torque at the particular engine speed, to develop a data value for that timing, iv) forcing intake mass airflow toward that desired mass airflow, and v) fueling the engine with that quantity of engine fueling at that timing. - View Dependent Claims (19, 20)
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- 21. An internal combustion engine comprising a control system endowed with a strategy for regenerating a NOx adsorber in an exhaust system of the engine by conditioning engine operation to generate excess CO for inducing regeneration, the control system comprising a processor that develops data for controlling at least one of airflow entering the engine through an intake system of the engine and fueling of the engine by a fueling system of the engine to substantially maintain a particular torque and speed while significantly decreasing the air-fuel ratio in the process to generate excess CO for regenerating the NOx adsorber.
Specification