Cylinder torque balancing for internal combustion engines
View Patent ↗An engine torque control module comprises a derivative module and a cylinder torque module. The derivative module determines a derivative term for a first cylinder of an internal combustion engine based on rotation of a crankshaft and determines an average derivative term for the first cylinder based upon the derivative term. The cylinder torque module determines an operating condition of the first cylinder based on the average derivative term, adjusts a torque output of the first cylinder based on the operating condition, and adjusts a torque output of a second cylinder based on the operating condition.
1. An engine torque control module comprising:
a derivative module that determines a derivative term for a first cylinder of an internal combustion engine based on rotation of a crankshaft and that determines an average derivative term for said first cylinder based upon said derivative term; and
a cylinder torque module that determines an operating condition of said first cylinder based on said average derivative term, that adjusts a torque output of said first cylinder based on said operating condition, and that adjusts a torque output of a second cylinder based on said operating condition.
2. The engine torque control module of claim 1 wherein said cylinder torque module compares said average derivative term with a minimum threshold and determines that said operating condition of said first cylinder is strong when said average derivative term is less than said minimum threshold.
3. The engine torque control module of claim 2 wherein said cylinder torque module adjusts said torque output of said first cylinder by decreasing said torque output of said first cylinder when said first cylinder is strong.
4. The engine torque control module of claim 3 wherein said cylinder torque module increases said torque output of said second cylinder in correspondence with said torque output decrease of said first cylinder.
5. The engine torque control module of claim 2 wherein said cylinder torque module decreases said torque output of said first cylinder by a decrease torque amount, increases said torque output of said second cylinder by a first increase torque amount, and increases a torque output of a third cylinder by a second increase torque amount,
wherein a total of said first and second increase torque amounts corresponds to said decrease torque amount.
6. The engine torque control module of claim 1 wherein said cylinder torque module compares said average derivative term with a maximum threshold and determines that said operating condition of said first cylinder is weak when said average derivative term is greater than said maximum threshold.
7. The engine torque control module of claim 6 wherein said cylinder torque module adjusts said torque output of said first cylinder by increasing said torque output of said first cylinder when said first cylinder is weak.
8. The engine torque control module of claim 7 wherein said cylinder torque module decreases said torque output of said second cylinder in correspondence with said torque output increase of said first cylinder.
9. The engine torque control module of claim 6 wherein said cylinder torque module increases said torque output of said first cylinder by an increase torque amount, decreases said torque output of said second cylinder by a first decrease torque amount, and decreases a torque output of a third cylinder by a second decrease torque amount,
wherein a total of said first and second decrease torque amounts corresponds to said increase torque amount.
10. The engine torque control module of claim 1 wherein said derivative module comprises:
a first derivative module that determines a first derivative term based on said rotation of said crankshaft; and
a second derivative module that determines a second derivative term based on said first derivative term,
wherein said derivative module determines said average derivative term based on said first and second derivative terms.
11. The engine torque control module of claim 1 wherein said derivative module determines said average derivative term based on a first derivative term that is determined for said first cylinder, a second derivative term that is determined for said first cylinder, and another second derivative term that is determined for a recovery cylinder that is immediately after said first cylinder in a firing order.
12. The engine torque control module of claim 1 wherein said cylinder torque module determines a spark timing based upon said average derivative term and adjusts said torque output of said first cylinder by adjusting said spark timing.
13. The engine torque control module of claim 12 wherein said cylinder torque module determines said spark timing further based on a spark versus thermal efficiency curve of said engine.
14. The engine torque control module of claim 1 wherein said cylinder torque module adjusts said torque output of said first cylinder by adjusting a fueling rate to said first cylinder.
15. A method of controlling torque comprising:
determining a derivative term for a first cylinder of an internal combustion engine based on rotation of a crankshaft;
determining an average derivative term for said first cylinder based upon said derivative term;
determining an operating condition of said first cylinder based on said average derivative term;
adjusting a torque output of said first cylinder based on said operating condition; and
adjusting a torque output of a second cylinder based on said operating condition.
16. The method of claim 15 further comprising:
comparing said average derivative term with a minimum threshold; and
determining that said operating condition of said first cylinder is strong when said average derivative term is less than said minimum threshold.
17. The method of claim 16 further comprising adjusting said torque output of said first cylinder by decreasing said torque output of said first cylinder when said first cylinder is strong.
18. The method of claim 17 further comprising increasing said torque output of said second cylinder in correspondence with said torque output decrease of said first cylinder.
19. The method of claim 16 further comprising:
decreasing said torque output of said first cylinder by a decrease torque amount;
increasing said torque output of said second cylinder by a first increase torque amount; and
increasing a torque output of a third cylinder by a second increase torque amount,
wherein a total of said first and second increase torque amounts corresponds to said decrease torque amount.
20. The method of claim 15 further comprising:
comparing said average derivative term with a maximum threshold; and
determining that said operating condition of said first cylinder is weak when said average derivative term is greater than said maximum threshold.
21. The method of claim 20 further comprising adjusting said torque output of said first cylinder by increasing said torque output of said first cylinder when said first cylinder is weak.
22. The method of claim 21 further comprising decreasing said torque output of said second cylinder in correspondence with said torque output increase of said first cylinder.
23. The method of claim 20 further comprising:
increasing said torque output of said first cylinder by an increase torque amount;
decreasing said torque output of said second cylinder by a first decrease torque amount; and
decreasing a torque output of a third cylinder by a second decrease torque amount,
wherein a total of said first and second decrease torque amounts corresponds to said increase torque amount.
24. The method of claim 15 further comprising:
determining a first derivative term based on said rotation of said crankshaft;
determining a second derivative term based on said first derivative term; and
determining said average derivative term based on said first and second derivative terms.
25. The method of claim 15 further comprising determining said average derivative term based on a first derivative term that is determined for said first cylinder, a second derivative term that is determined for said first cylinder, and another second derivative term that is determined for a recovery cylinder that is immediately after said first cylinder in a firing order.
26. The method of claim 15 further comprising:
determining a spark timing based upon said average derivative term; and
adjusting said torque output of said first cylinder by adjusting said spark timing.
27. The method of claim 26 further comprising determining said spark timing further based on a spark versus thermal efficiency curve of said engine.
28. The method of claim 15 further comprising adjusting said torque output of said first cylinder by adjusting a fueling rate to said first cylinder.