System for optimizing the performance of internal combustion engines

• US 5,168,853 A
• Filed: 04/06/1992
• Issued: 12/08/1992
• Est. Priority Date: 04/06/1992
• Status: Expired due to Fees

• Current Assignee: Optimizer Control Corporation
• Original Assignee: Optimizer Control Corporation
• Inventors: Franklin, Matthew L., Pipho, Michael J., Kittelson, David B.
• Primary Examiner(s): Nelli, Raymond A.
• Application Number:
  US07/864,308
• Time in Patent Office: 246 Days
• Field of Search: 123/419, 123/418, 123/414, 123/422, 123/423, 123/406, 123/416, 364/431.05
• US Class Current: 123/406.23
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/1408 Dithering techniques
• CPC Class Codes: F02D 41/2458 with an additional dither signal
• CPC Class Codes: F02P 5/06 dependent on engine speed
• CPC Class Codes: F02P 5/1455 by using a second control of the closed loop type dependent on pinking F02P5/152
• CPC Class Codes: F02P 5/1502 using one central computing unit
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An engine performance optimizing system is described that requires only a single engine parameter (shaft revolution time) to be measured. By simultaneously dithering spark timing, air/fuel ratio and/or EGR rate in accordance with a predetermined cyclic pattern, and measuring shaft speed during each discrete phase of the dither cycle, correction factors can be computed and used to adjust the spark setting, the air flow and/or the recirculation rate in a way that causes engine performance to be enhanced in terms of fuel economy and lowered emissions.

Claims

1. An adaptive electronic control system for optimizing fuel consumption of an internal combustion engine of the type having an output shaft coupled to a load to be driven, an ignition system with means for varying spark timing about a given spark timing setting during a dither cycle and means for varying the air/fuel ratio of the fuel mixture delivered to the engine about a given air/fuel ratio setting during said dither cycle, said control system comprising:

(a) shaft rotation sensing means coupled to said engine for sensing complete revolutions of said output shaft of said engine with respect to a fixed reference point;

(b) means coupled to said shaft rotation sensing means for symmetrically reciprocally moving the setting of both the spark timing and air/fuel ratio within said dither cycle back and forth about their respective given settings in synchronism with the angular rotation of said output shaft during successive integral engine cycles;

(c) speed determining means coupled to said shaft rotation sensing means for defining the average speed of rotation of said output shaft in plural segments of the period of symmetrical reciprocal movement of said spark timing setting and said air/fuel ratio setting about their respective settings;

(d) means responsive to said speed determining means for computing a spark advance error signal and an air/fuel ratio error signal;

(e) means for periodically adjusting said given settings of said spark timing in accordance with said spark advance error signal; and

(f) means for periodically adjusting said given setting of air/fuel ratio in accordance with said air/fuel ratio error signal.

3. The adaptive control system as in claim 1 wherein the period of symmetrical reciprocal movement of said air/fuel ratio setting is an integral multiple of the period of symmetrical reciprocal movement of said spark timing setting.

5. The adaptive electronic control system as in claim 3 wherein said means for computing comprises a programmed microprocessor.

7. The adaptive electronic control system as in claim 5 wherein said programmed microprocessor computes the revolution time of said output shaft during predetermined phases of said period of reciprocal movement of said spark timing and air/fuel ratio settings.

9. The adaptive electronic control system as in claim 7 or 8 wherein said spark advance error signal is computed by said microprocessor means as the sum of the revolution times of said output shaft during the first quarter and last quarter of one cycle of said period of symmetrical reciprocal movement of said spark timing setting, less the sum of the revolution times of said output shaft during the second and third quarters of one cycle of said period of reciprocal movement of said spark timing setting.

10. The adaptive electronic control system as in claim 7 wherein said air/fuel ratio error signal is computed by said microprocessor means as the sum of the revolution times of said output shaft during the first and fourth quarters of one cycle of said period of symmetrical reciprocal movement of said air/fuel ratio setting less the sum of the revolution times of said output shafts during the second and third quarters of one cycle of said period of symmetrical reciprocal movement of said air/fuel ratio setting.

2. An adaptive electronic control system for optimizing fuel consumption of an internal combustion engine of the type having an output shaft coupled to a load to be driven, an ignition system with means for varying spark timing about a given spark timing setting during a dither cycle and means for varying the EGR flow of the fuel mixture delivered to the engine about a given EGR flow setting during said dither cycle, said control system comprising:

(a) shaft rotation sensing means coupled to said engine for sensing complete revolutions of said output shaft of said engine with respect to a fixed reference point;

(b) means coupled to said shaft rotation sensing means for symmetrically reciprocally moving the setting of both the spark timing and EGR flow within said dither cycle back and forth about their respective given settings in synchronism with the angular rotation of said output shaft during successive integral engine cycles;

(c) speed determining means coupled to said shaft rotation sensing means for defining the average speed of rotation of said output shaft in plural segments of the period of symmetrical reciprocal movement of said spark timing setting and said EGR flow setting about their respective settings;

(d) means responsive to said speed determining means for computing a spark advance error signal and an EGR flow error signal;

(e) means for periodically adjusting said given settings of said spark timing in accordance with said spark advance error signal; and

(f) means for periodically adjusting said given setting of EGR flow in accordance with said EGR flow error signal.

4. The adaptive control system as in claim 2 wherein the period of symmetrical reciprocal movement of said EGR flow setting is an integral multiple of the period of symmetrical reciprocal movement of said spark timing setting.

6. The adaptive electronic control system as in claim 4 wherein said means for computing comprises a programmed microprocessor.

8. The adaptive electronic control system as in claim 6 wherein said programmed microprocessor computes the revolution time of said output shaft during predetermined phases of said period of reciprocal movement of said spark timing and EGR flow settings.

11. The adaptive electronic control system as in claim 8 wherein said EGR flow error signal is computed by said microprocessor means as the sum of the revolution times of said output shaft during the first and fourth quarters of one cycle of said period of symmetrical reciprocal movement of said EGR flow setting less the sum of the revolution times of said output shafts during the second and third quarters of said one cycle of period of symmetrical reciprocal movement of said EGR flow setting.

12. A method for minimizing the fuel consumption of an internal combustion engine of the type having an output shaft coupled to a load to be driven, an ignition system with means for varying spark timing about a given spark timing setting during a dither cycle and means for varying the air/fuel ratio of the fuel mixture delivered to the engine about a given air/fuel ratio setting during said dither cycle comprising the steps of:

(a) sensing integral rotations of said output shaft;

(b) symmetrically reciprocally varying the spark timing and air/fuel ratio about their respective given settings in timed synchronization with the angular rotation of said output shaft;

(c) determining the average speed of rotation of said output shaft in plural segments of said dither cycle of the spark timing and air/fuel ratio settings;

(d) computing from the average speed values in said plural segments a spark timing error and an air/fuel ratio error; and

(e) adjusting the given spark timing setting and given air/fuel ratio setting by an amount proportional to said spark timing error and air/fuel ratio error, respectively.

13. A method for minimizing the fuel consumption of an internal combustion engine of the type having an output shaft coupled to a load to be driven, an ignition system with means for varying spark timing about a given spark timing setting during a dither cycle and means for varying the EGR flow of the air/fuel mixture delivered to the engine about a given EGR flow setting during said dither cycle comprising the steps of:

(a) sensing integral rotations of said output shaft;

(b) symmetrically reciprocally varying the spark timing and EGR flow about their respective given settings in timed synchronization with the angular rotation of said output shaft;

(c) determining the average speed of rotation of said output shaft in plural segments of said dither cycle of the spark timing and EGR flow settings;

(d) computing from the average speed values in said plural segments a spark timing error and an EGR flow error; and

(e) adjusting the given spark timing setting and given EGR flow setting by an amount proportional to said spark timing error and EGR flow error, respectively.

14. An adaptive electronic control system for optimizing fuel consumption of an internal combustion engine, said engine being of the type having an output shaft coupled to a load to be driven, an adjustable spark timing module and means for adjusting the air/fuel ratio or EGR flow delivered to the cylinders of said engine, said control system comprising:

(a) microcontroller means having a first memory means for storing a program of instructions at addressable locations therein and second memory means for storing operands including time per revolution values corresponding to the speed of said output shaft;

(b) means including said microcontroller means coupled to said adjustable spark timing module and to said air/fuel ratio or said EGR flow adjusting means for introducing cyclic bidirectional incremental changes in both the spark timing and the air/fuel ratio or EGR flow of said engine in synchronism with integral rotations of said output shaft;

(c) shaft rotation sensing means coupled to said output shaft and to said microcontroller means for defining integral rotations of said output shaft, said microcontroller means programmed to compute and store in said second memory means the time required for each integral revolution of said output shaft during predetermined phases of the cyclic incremental changes in spark timing and air/fuel ratio or EGR flow;

(d) said microcontroller means being further programmed to compute first and second error signals based upon the stored time values; and

(e) means for periodically modifying the spark timing setting and air/fuel ratio or EGR flow setting in accordance with said first and second error signals, respectively.