Method of controlling a positive-ignition internal combustion engine by means of a knock estimator

Patent metadata

Field	Value
Publication number	US-10830659-B2
Application number	US-201816211796-A
Country	US
Kind code	B2
Filing date	Dec 6, 2018
Priority date	Dec 6, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

The present invention relates to a method of controlling a positive-ignition internal combustion engine, in which the ignition advance is controlled (CON) by means of an estimation (EST) of the distribution of the knock measurements (MEAS). This estimation (EST) makes it possible to determine, for these measurements (MEAS), a confidence interval (q min , q max ) of a predetermined quantile of the distribution of the knock measurements (MEAS).

First claim

The invention claimed is:

1. A control method of a positive-ignition internal combustion engine, including a knock sensor located on the internal combustion engine which measures knock and a knock threshold, comprising:
a) carrying out N measurements of knock by use of the knock sensor;
b) constructing an estimator of a distribution of the N measurements of knock which determines a confidence interval of a predetermined quantile from the N measurements of knock;
c) controlling an ignition advance within the internal combustion engine as a function of a comparison with the confidence interval by:
i) decreasing the ignition advance if the knock threshold is less than a minimum value of the confidence interval of the predetermined quantile;
ii) increasing the ignition advance if the knock threshold is greater than a maximum value of the confidence interval of the predetermined quantile; and
iii) making no change to the ignition advance if the knock threshold is determined to be within the confidence interval.

2. The control method according to claim 1 , wherein the estimator is a Bayesian estimator.

3. The control method according to claim 1 , wherein the distribution is mathematically related to a normal distribution.

4. The control method according to claim 3 wherein the distribution is a log-normal distribution.

5. The control method according to claim 1 , wherein the estimator also determines an expected value of the predetermined quantile.

6. The control method according to claim 2 , wherein the estimator also determines an expected value of the predetermined quantile.

7. The control method according to claim 3 , wherein the estimator also determines an expected value of the predetermined quantile.

8. The control method according to claim 4 , wherein the estimator also determines an expected value of the predetermined quantile.

9. The control method according to claim 5 , wherein when the ignition advance is changed to either decrease or increase, the change in ignition advance is proportional to a difference between an expected value for the predetermined quantile and the knock threshold.

10. The control method according to claim 6 , wherein when the ignition advance is changed to either decrease or increase, the change in ignition advance is proportional to a difference between an expected value for the predetermined quantile and the knock threshold.

11. The control method according to claim 7 , wherein when the ignition advance is changed to either decrease or increase, the change in ignition advance is proportional to a difference between an expected value for the predetermined quantile and the knock threshold.

12. The control method according to claim 8 , wherein the ignition advance is either decreased or increased proportionally to a difference between the expected value for the predetermined quantile and the knock threshold.

13. The control method according to claim 1 , wherein N is between 5 and 20.

14. The control method in accordance with claim 13 wherein N is between 7 and 15.

15. The control method according to claim 1 , wherein the confidence interval contains a value of a real quantile in 98% of cases.

16. The control method according to claim 1 , wherein the knock sensor is an accelerometer located on the cylinder head of the internal combustion engine.

17. The control method according to claim 16 , wherein the knock measurement is a maximum amplitude of a filtered signal provided from the accelerometer.

18. A control method according to claim 1 , wherein the knock threshold is obtained from engine bench tests during calibration of the engine.

19. A control method according to claim 18 , wherein the predetermined quantile of the distribution is greater than 80%.

20. A control system for a positive-ignition internal combustion engine comprising implementing the method according to claim 1 .

21. A computer program product recorded on a tangible computer-readable medium and which is executed by a processor, comprising program code instructions for implementing the method according to claim 1 .

Assignees

• Ifp Energies Now

Inventors

• Jean Maxime
• Leroy Thomas
• Vidal-Naquet Fabien

Classifications

• F02P2017/128

  for knock detection · CPC title

• F02P5/1523

  with particular laws of return to advance, e.g. step by step, differing from the laws of retard · CPC title

• F02D2041/1433

  using a model or simulation of the system · CPC title

• F02D35/023

  by determining the cylinder pressure · CPC title

• G01L23/227 Primary

  using numerical analyses · CPC title