FIRING FRACTION MANAGEMENT IN SKIP FIRE ENGINE CONTROL
First Claim
1. A skip fire engine controller comprising:
- a lookup table embodied in a computer readable media;
a firing fraction determining unit arranged to determine a firing fraction suitable for delivering a requested engine output, wherein the firing fraction determining unit utilizes the lookup table to determine a desired firing fraction, wherein the firing fraction determining unit utilizes at least (i) the requested engine output, and (ii) a current engine speed as indices to select a desired firing fraction; and
a firing controller arranged to direct firings in a skip fire manner that delivers the desired firing fraction.
0 Assignments
0 Petitions
Accused Products
Abstract
The described embodiments relate generally to skip fire control of internal combustion engines and particularly to mechanisms for determining a desired operational firing fraction. In some embodiments, a firing fraction determining unit is arranged to determine a firing fraction suitable for delivering a requested engine output. The firing fraction determining unit may utilize data structures such as lookup tables in the determination of the desired firing fraction. In one aspect the desired engine output and one or more operational power train parameters such as current engine speed, are used as indices to a lookup table used to select a desired firing fraction. In other embodiments, additional indices to the data structure may include any one of: transmission gear; manifold absolute pressure (MAP); manifold air temperature; a parameter indicative of mass air charge (MAC); cam position; cylinder torque output; maximum permissible manifold pressure; vehicle speed; and barometric pressure.
111 Citations
24 Claims
-
1. A skip fire engine controller comprising:
-
a lookup table embodied in a computer readable media; a firing fraction determining unit arranged to determine a firing fraction suitable for delivering a requested engine output, wherein the firing fraction determining unit utilizes the lookup table to determine a desired firing fraction, wherein the firing fraction determining unit utilizes at least (i) the requested engine output, and (ii) a current engine speed as indices to select a desired firing fraction; and a firing controller arranged to direct firings in a skip fire manner that delivers the desired firing fraction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 22)
-
-
12. A skip fire controller comprising a lookup table embodied in a computer readable media, the lookup table having a multiplicity of entries, each entry including a firing fraction field arranged to store an associated firing fraction indicator indicative of a desired firing fraction, wherein indices for the lookup table include:
-
(i) a desired engine output; and (ii) a first operational power train parameter. - View Dependent Claims (13, 14)
-
-
15. A method of operating an engine comprising:
-
determining a desired engine output in terms of a desired torque fraction, wherein the desired torque fraction is indicative of the desired engine output relative to a reference maximum available engine output; determining a desired operational firing fraction based at least in part on the desired torque fraction; and directing skip fire operation of the engine at the desired operational firing fraction in a manner that delivers the desired engine output. - View Dependent Claims (16)
-
-
17. A skip fire engine controller comprising:
-
a firing fraction determining unit arranged to dynamically determine a desired firing fraction based at least in part upon, i) a desired engine output; ii) a current engine speed; and iii) a current transmission gear; and a firing controller arranged to direct firings in a skip fire manner that delivers the desired firing fraction. - View Dependent Claims (18, 19, 20, 21)
-
-
23. A method of controlling skip fire operation of an engine comprising:
-
determining a desired operational firing fraction by accessing a lookup table having a multiplicity of entries, each entry including a firing fraction field arranged to store an associated firing fraction indicator indicative of a desired firing fraction, wherein indices for the lookup table include; (i) a desired engine output; (ii) engine speed; and (ii) a first operational power train parameter. directing skip fire operation of the engine at the desired operational firing fraction in a manner that delivers the desired engine output. - View Dependent Claims (24)
-
Specification