ATTENUATION OF ENGINE HARSHNESS DURING LEAN-TO-RICH TRANSITIONS

• US 20070129876A1
• Filed: 02/08/2007
• Published: 06/07/2007
• Est. Priority Date: 11/06/2003
• Status: Active Grant

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Zhang, Guoqing, Gui, Xinqun, Miller, Michael, O'Connor, Justin
• Granted Patent: US 7,292,930 B2
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F01N 2430/06 by varying fuel-air ratio, e.g. by enriching fuel-air mixture
• CPC Class Codes: F01N 3/0871 Regulation of absorbents or adsorbents, e.g. purging by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 2250/28 Control for reducing torsional vibrations, e.g. at acceleration
• CPC Class Codes: F02D 41/0275 the exhaust gas treating apparatus being a NOx trap or adsorbent
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02D 41/403 with pilot injections
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Engine systems and methods for accomplishing regeneration of a NOx adsorber (28) using in-cylinder post-injection in a way that creates a lean-rich transition (FIG. 3) for regenerating the NOx adsorber while attenuating engine torque output fluctuations during the transition without the necessity of using torque sensing to attenuate the fluctuations.

Claims

1. A method for control of output torque developed by an internal combustion engine during lean-rich modulation of engine operation, the method comprising:

a) with the engine running lean, processing data values of certain parameters to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque at a given engine speed;

b) causing the engine to transition from running lean to running rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed by processing i) the data value for desired engine fueling resulting from the processing of step a), ii) a data value for engine speed, and iii) a data value for actual air-fuel ratio at which the engine is operating, to thereby develop a data value for desired engine fueling that causes the engine to run rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed when the engine was running lean.

2. A method as set forth in claim 1 in which step b) comprises:

with the engine running rich, processing a data value for actual air-fuel ratio through a function that correlates data values of air-fuel ratio to data values of engine fueling for causing the engine to run rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed when the engine was running lean, and causing the data value of desired engine fueling to be the data value of engine fueling correlated by the function to the data value of actual air-fuel ratio.

3. A method as set forth in claim 1 wherein step a) comprises:

with the engine running lean, processing data values of engine speed and accelerator pedal position to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque at a given engine speed.

4. An internal combustion engine comprising:

a fueling system for fueling the engine in accordance with a data value for desired engine fueling; and

a control system for processing various data to develop data for control of various engine functions including data values for desired engine fueling, wherein the control system comprises a control strategy

a) for causing the engine to run lean, and with the engine running lean, for processing data values of certain parameters to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque at a given engine speed; and

b) for causing the engine to transition from running lean to running rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed by processing i) the data value for desired engine fueling resulting from the processing of a), ii) a data value for engine speed, and iii) a data value for actual air-fuel ratio at which the engine is operating, to thereby develop a data value for desired engine fueling that causes the engine to run rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed when the engine was running lean.

5. An engine as set forth in claim 4 in which the portion of the control strategy for causing the engine to transition from running lean to running rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed by processing i) the data value for desired engine fueling resulting from the processing of a), ii) a data value for engine speed, and iii) a data value for actual air-fuel ratio at which the engine is operating, to thereby develop a data value for desired engine fueling that causes the engine to run rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed when the engine was running lean, comprises:

with the engine running rich, processing a data value for actual air-fuel ratio through a function that correlates data values of air-fuel ratio to data values of engine fueling for causing the engine to run rich while striving to maintain engine output torque at the corresponding desired output torque at the given engine speed when the engine was running lean, and causing the data value of desired engine fueling to be the data value of engine fueling correlated by the function to the data value of actual air-fuel ratio.

6. An engine as set forth in claim 4 in which the portion of the control strategy for causing the engine to run lean, and with the engine running lean, for processing data values of certain parameters to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque at a given engine speed, comprises:

with the engine running lean, processing data values of engine speed and accelerator pedal position to develop a data value for desired engine fueling for causing the engine to develop a corresponding desired output torque at a given engine speed.

7-18. -18. (canceled)