METHOD AND APPARATUS FOR DETERMINING A PARAMETER FOR NORMALIZED INSTANTANEOUS HEAT RELEASE IN AN INTERNAL COMBUSTION ENGINE

• US 20080221774A1
• Filed: 03/05/2008
• Published: 09/11/2008
• Est. Priority Date: 03/06/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Kang, Jun-Mo, Dagci, Oguz H., Brown, Alan W.
• Granted Patent: US 7,822,529 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F02B 11/00 Engines characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition, e.g. in different cylinders
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02D 13/0203 Variable control of intake and exhaust valves
• CPC Class Codes: F02D 2041/281 between sensors and control unit
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/028 by determining the combustion timing or phasing
• CPC Class Codes: F02D 41/3035 a mode being the premixed charge compression-ignition mode
• CPC Class Codes: G01M 15/042 by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Operation of an internal combustion engine selectively operative in a controlled auto-ignition combustion mode is monitored. The engine is equipped with a pressure sensing device operative to monitor in-cylinder pressure. An analog signal output from the pressure sensing device is monitored during a combustion cycle. A peak cylinder pressure and a corresponding crank angle are detected and captured during the combustion cycle. A state for a combustion parameter for the cylinder for the combustion cycle is determined based upon the peak cylinder pressure and the corresponding crank angle.

Claims

1. Method for monitoring operation of an internal combustion engine, comprising:

equipping the engine with a pressure sensing device operative to monitor in-cylinder pressure;

operating the engine in a controlled auto-ignition combustion mode;

monitoring an analog signal output from the pressure sensing device during a combustion cycle;

detecting and capturing the analog signal output from the pressure sensing device corresponding to a peak cylinder pressure during the combustion cycle;

identifying a crank angle whereat the peak cylinder pressure occurs during the combustion cycle; and

calculating a state for a combustion parameter indicative of instantaneous heat release due to in-cylinder combustion based upon the peak cylinder pressure and the crank angle whereat the peak cylinder pressure occurs during the combustion cycle.

2. The method of claim 1, wherein detecting the analog signal output from the pressure sensing device corresponding to the peak cylinder pressure during the combustion cycle comprises:

time-delaying the analog signal output from the pressure sensing device;

comparing the analog signal output from the pressure sensing device and the time-delayed analog signal; and

,

identifying when the analog signal output from the pressure sensing device is less than the time-delayed analog signal.

3. The method of claim 2, comprising capturing the analog signal output from a peak detection circuit when the analog signal output from the pressure sensing device is less than the time-delayed analog signal.

4. The method of claim 3, comprising identifying the crank angle corresponding to the analog signal output from the peak detection circuit.

5. The method of claim 4, further comprising calculating a state for the combustion parameter indicative of instantaneous heat release due to in-cylinder combustion for each cylinder for each combustion cycle.

6. The method of claim 1, comprising:

determining a cylinder volume at the crank angle whereat the peak cylinder pressure occurs during the combustion cycle;

determining a cylinder pressure at a closing of an intake valve for the combustion cycle;

determining a cylinder volume at the closing of the intake valve for the combustion cycle; and

calculating the state for the combustion parameter indicative of instantaneous heat release due to in-cylinder combustion based upon the peak cylinder pressure, the cylinder pressure at the closing of the intake valve for the combustion cycle, the cylinder volume at the location of the peak cylinder pressure, and the cylinder volume at the closing of the intake valve for the combustion cycle.

7. The method of claim 6, further comprising calculating the state for the combustion parameter indicative of the instantaneous heat release due to in-cylinder combustion for each cylinder for each combustion cycle.

8. Method for monitoring operation of a multi-cylinder internal combustion engine selectively operative in a controlled auto-ignition combustion mode, comprising:

equipping the engine with a plurality of pressure sensing devices each operative to monitor pressure in one of the cylinders of the engine;

operating the engine in the controlled auto-ignition combustion mode;

monitoring an analog signal output from each pressure sensing device during each combustion cycle;

detecting the analog signal output from each of the pressure sensing devices corresponding to a peak cylinder pressure during each combustion cycle;

capturing the analog signal output from each of the pressure sensing devices corresponding to the peak cylinder pressure during each combustion cycle; and

identifying a crank angle whereat the peak cylinder pressure occurs during each combustion cycle for each of the cylinders.

9. The method of claim 8, wherein detecting the analog signal output from each of the pressure sensing devices corresponding to the peak cylinder pressure during each combustion cycle comprises:

time-delaying the analog signal output from one of the pressure sensing devices;

comparing the analog signal output from the pressure sensing device and the time-delayed analog signal; and

identifying when the analog signal output from the pressure sensing device is less than the time-delayed analog signal.

10. The method of claim 9, comprising capturing the analog signal output from a peak detection circuit when the analog signal output from the pressure sensing device is less than the time-delayed analog signal.

11. The method of claim 10, comprising identifying the crank angle corresponding to the analog signal output from the peak detection circuit for the cylinder.

12. The method of claim 8, further comprising calculating a state for a combustion parameter for each of the cylinders for each combustion cycle based upon the peak cylinder pressure and the crank angle whereat the peak cylinder pressure occurs during the combustion cycle.

13. A system to monitor operation of an internal combustion engine selectively operative in a controlled auto-ignition combustion mode, comprising:

the internal combustion engine including a pressure sensing device operative to monitor in-cylinder pressure and a crank angle sensor;

the pressure sensing device signally connected to an analog peak detector circuit;

the analog peak detector circuit signally connected to and controllably connected to an engine control module;

the crank angle sensor signally connected to the engine control module; and

the engine control module;

commanding the analog peak detector circuit to capture an analog signal output from the pressure sensing device corresponding to a peak cylinder pressure during a combustion cycle for the cylinder;

identifying a crank angle corresponding to the peak cylinder pressure during the combustion cycle for the cylinder;

reading the captured analog signal output from the analog peak detector circuit;

converting the captured analog signal output from the analog peak detector circuit to the corresponding peak cylinder pressure; and

calculating a state for a combustion parameter for the cylinder for the combustion cycle based upon the peak cylinder pressure and the corresponding crank angle.

14. The system of claim 13, comprising:

an electronic circuit operative to execute a time delay in the analog signal output from the peak detection circuit; and

a comparator operative to compare the time-delayed analog signal output and the analog signal output;

wherein an output of the comparator comprises a digital signal input to the control module.

15. The system of claim 14, comprising the comparator operative to identify when the analog signal output from the pressure sensing device is less than the time-delayed analog signal by an amount greater than a predetermined threshold.

16. The system of claim 14, comprising capturing the analog signal output from the peak detection circuit when the analog signal output from the pressure sensing device is less than the time-delayed analog signal.