Firing fraction management in skip fire engine control
First Claim
Patent Images
1. A skip fire engine controller comprising:
- a firing fraction determining unit arranged to determine and output a commanded firing fraction;
a filter arranged to receive the commanded firing fraction and output an operational firing fraction, the filter being arranged to spread changes in the commanded firing fraction over multiple firing opportunities;
a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction; and
a filter bypass that causes the filter to be bypassed such that the commanded firing fraction is passed directly to the firing controller as the operational firing fraction in response to at least one predetermined type of circumstances.
1 Assignment
0 Petitions
Accused Products
Abstract
In various described embodiments skip fire control is used to deliver a desired engine output. A controller determines a skip fire firing fraction and (as appropriate) associated engine settings that are suitable for delivering a requested output. In one aspect, the skip fire controller is arranged to select a base firing fraction that has a repeating firing cycle length that will repeat at least a designated number of times per second at the current engine speed. Such an arrangement can be helpful in reducing the occurrence of undesirable vibrations.
132 Citations
16 Claims
-
1. A skip fire engine controller comprising:
-
a firing fraction determining unit arranged to determine and output a commanded firing fraction; a filter arranged to receive the commanded firing fraction and output an operational firing fraction, the filter being arranged to spread changes in the commanded firing fraction over multiple firing opportunities; a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction; and a filter bypass that causes the filter to be bypassed such that the commanded firing fraction is passed directly to the firing controller as the operational firing fraction in response to at least one predetermined type of circumstances. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A skip fire engine controller comprising:
-
a firing fraction determining unit arranged to determine a commanded firing fraction; a firing controller arranged to direct firings in a skip fire manner that delivers an operational firing fraction; a transition management unit arranged to manage transitions between different commanded firing fractions, the transition management unit being configured to receive the commanded firing fraction and output the operational firing fraction based on the commanded firing fraction, and to spread commanded firing fraction changes over multiple firing opportunities in a first set of circumstances, the transition management unit being further configured to cause the commanded operation firing fraction to be passed directly to the firing controller in response to at least one predetermined additional circumstance. - View Dependent Claims (8, 9)
-
-
10. A skip fire engine controller comprising:
-
a firing fraction determining unit arranged to determine and output a commanded firing fraction, the commanded firing fraction being selected from a set of available firing fractions; a filter arranged to receive the commanded firing fraction and output an operational firing fraction, the filter being arranged to spread changes in the commanded firing fraction over multiple firing opportunities; and a firing controller arranged to direct firings in a skip fire manner that delivers the operational firing fraction. - View Dependent Claims (11, 12, 13)
-
-
14. A skip fire engine controller for determining which working cycles to skip and which working cycles to fire during skip fire operation of an internal combustion engine having a plurality of working chambers, the skip fire engine controller comprising:
-
a firing fraction determining unit arranged to determine a firing fraction suitable for delivering a desired engine output, wherein the firing fraction determining unit is arranged and constrained to determine an operational firing fraction that does not have a repeating firing sequence that has a frequency in the range of 2-8 Hz at the current engine speed; and a firing controller arranged to direct firings in a most evenly spaced skip fire manner that delivers the operational firing fraction, the firing controller being arranged to make firing decisions on a firing opportunity by firing opportunity basis. - View Dependent Claims (15, 16)
-
Specification