Firing fraction transition control
First Claim
Patent Images
1. A method of controlling the transition of an engine between different effective firing fractions, the method comprising:
- while the engine is operating at a first effective firing fraction using a first value for an operating parameter that affects working chamber air charge, determining a target value for the operating parameter that is different than the first value, and a target effective firing fraction selected to deliver a requested engine output;
transitioning from the first firing effective fraction to the target effective firing fraction;
during the transition, determining a feed forward adjusted effective firing fraction that at least partially compensates for engine dynamics that occur during the change from the initial value for the operating parameter to the target value for the operating parameter, wherein the feed forward adjusted effective firing fraction changes over the course of the transition;
during the transition, determining an effective firing fraction correction factor indicative of a difference between an actual engine output and the requested engine output, wherein the effective firing fraction correction factor potentially varies over the course of the transition;
determining a commanded effective firing fraction during the transition that combines the effective firing fraction correction factor with the feed forward adjusted effective firing fraction; and
directing dynamic firing level modulation operation of the engine utilizing the commanded effective firing fraction during the transition, whereby the commanded effective firing fraction changes over the course of the transition.
2 Assignments
0 Petitions
Accused Products
Abstract
A variety of methods and arrangements are described for controlling transitions between effective firing fractions during dynamic firing level modulation operation of an engine in order to help reduce undesirable NVH consequences and otherwise smooth the transitions. In general, both feed forward and feedback control are utilized in the determination of the effective firing fractions during transitions such that the resulting changes in the effective firing fraction better track cylinder air charge changing dynamics associated with the transition.
110 Citations
29 Claims
-
1. A method of controlling the transition of an engine between different effective firing fractions, the method comprising:
-
while the engine is operating at a first effective firing fraction using a first value for an operating parameter that affects working chamber air charge, determining a target value for the operating parameter that is different than the first value, and a target effective firing fraction selected to deliver a requested engine output; transitioning from the first firing effective fraction to the target effective firing fraction; during the transition, determining a feed forward adjusted effective firing fraction that at least partially compensates for engine dynamics that occur during the change from the initial value for the operating parameter to the target value for the operating parameter, wherein the feed forward adjusted effective firing fraction changes over the course of the transition; during the transition, determining an effective firing fraction correction factor indicative of a difference between an actual engine output and the requested engine output, wherein the effective firing fraction correction factor potentially varies over the course of the transition; determining a commanded effective firing fraction during the transition that combines the effective firing fraction correction factor with the feed forward adjusted effective firing fraction; and directing dynamic firing level modulation operation of the engine utilizing the commanded effective firing fraction during the transition, whereby the commanded effective firing fraction changes over the course of the transition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method of controlling the transition of an engine between different effective firing fractions, the method comprising:
-
while the engine is operating at a first effective firing fraction using a first value for an operating parameter that affects working chamber air charge, determining a target value for the operating parameter that is different than the first value, and a target effective firing fraction selected to deliver a requested engine output, the target effective firing fraction being different than the first effective firing fraction; transitioning from the first effective firing fraction to the target effective firing fraction, wherein during the transition, the method further includes, (i) determining an effective firing fraction correction factor indicative of a difference between an actual engine output and the requested engine output, wherein the effective firing fraction correction factor potentially varies over the course of the transition; (ii) determining a commanded effective firing fraction that combines the effective firing fraction correction factor with the target effective firing fraction; and (iii) directing dynamic firing level modulation operation of the engine during the transition utilizing the commanded effective firing fraction. - View Dependent Claims (17, 18, 19, 20)
-
-
21. An engine controller arranged to direct dynamic firing level modulation operation of an engine, the engine controller comprising:
-
a firing fraction determining unit arranged to determine a desired operational effective firing fraction suitable for delivering a desired engine output, wherein the desired operational effective firing fraction changes based at least in part on changes in the desired engine output; a transition adjustment unit arranged to adjust the desired effective operational firing fraction during transitions from a first operational effective firing fraction to a target operational effective firing fraction; and a firing timing determining unit arranged to determine a firing sequence that delivers a commanded effective firing fraction; and wherein the transition adjustment unit includes, a feed forward effective firing fraction determining unit that determines a feed forward adjusted effective firing fraction that at least partially compensates for engine dynamics that occur during the change from the first operational effective firing fraction to the target operational effective firing fraction, wherein the feed forward adjusted effective firing fraction changes over the course of the transition, and an error determining unit that determines an effective firing fraction correction factor based at least in part upon a difference between an estimated or actual engine output and the requested engine output, wherein the effective firing fraction correction factor potentially varies over the course of the transition, and wherein the transition adjustment unit is configured to determine the commanded effective firing fraction during transitions based at least in part on the feed forward adjusted effective firing fraction and the effective firing fraction correction factor. - View Dependent Claims (22, 23, 24, 25)
-
-
26. An engine controller arranged to direct firing level modulation operation of an engine, the engine controller comprising:
-
a firing fraction determining unit arranged to determine a desired operational effective firing fraction suitable for delivering a desired engine output, wherein the desired operational effective firing fraction changes based at least in part on changes in the desired engine output; a transition adjustment unit arranged to adjust the desired operational effective firing fraction during transitions from a first operational effective firing fraction to a target operational effective firing fraction; a mode switching unit arranged to cause the desired operational effective firing fraction to be used as a commanded effective firing fraction during steady state engine operation and an output of the transition adjustment unit to be used as the commanded effective firing fractions during effective firing fraction transitions; and a firing timing determining unit arranged to determine a firing sequence that delivers a commanded effective firing fraction. - View Dependent Claims (27, 28, 29)
-
Specification