Lean burn internal combustion engine exhaust gas temperature control
AssigneeTula Technology, Inc.
InventorsMatthew A. Younkins, Shikui Kevin Chen, Mark A. Wilcutts
Life of this patent
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Abstract
A variety of methods and arrangements for controlling the exhaust gas temperature of a lean burn, skip fire controlled internal combustion engine are described. In one aspect, an engine controller includes an aftertreatment system monitor and a firing timing determination unit. The aftertreatment monitor obtains data relating to a temperature of one or more aftertreatment elements, such as a catalytic converter. Based at least partly on this data, the firing timing determination unit generates a firing sequence for operating the engine in a skip fire manner such that the temperature of the aftertreatment element is controlled within its effective operating range.
Claims24
A method of reducing accumulated soot in a particulate filter utilized in an exhaust path of a lean burn internal combustion engine having a plurality of working chambers, each working chamber being configured to operate in a series of successive working cycles, the method comprising:
- during operation of the lean burn internal combustion engine, transitioning to a particulate filter cleaning mode, in which the lean burn internal combustion engine is operated in a skip fire mode to increase the temperature of exhaust gases sufficiently to raise the temperature of the particulate filter sufficiently to oxidize and thereby remove soot accumulated on the particulate filter;
- and
- operating the lean burn internal combustion engine in the skip fire mode by:
- (a) operating the lean burn internal combustion engine at a reduced effective displacement that is less than the full displacement of the lean burn internal combustion engine;
- (b) for a select effective reduced displacement, directing at least one of the plurality of working chambers over a number of working cycles to be (i) fired causing a combustion event in some working cycles and (ii) skipped resulting in no combustion event in other working cycles;
- and
- (c) at the select effective reduced displacement, preventing air from pumping through the at least one working chamber during one or more of the skipped working cycles.
A vehicle, comprising:
- a lean burn internal combustion engine having a plurality of working chambers, each working chamber configured to operate in a series of successive working cycles;
- a particulate filter included in an exhaust path that is fluidly coupled to the lean burn internal combustion engine;
- and
- an engine controller arranged to selectively operate the lean burn internal combustion engine in both:
- (a) a skip fire mode where for an effective reduced displacement that is less than full displacement of the internal combustion engine, at least one working chamber over a number of working cycles is (i) fired causing a combustion event in some working cycles and (ii) skipped resulting in no combustion event in other working cycles;
- and
- (b) a particulate filter cleaning mode in which the lean burn internal combustion engine is operated so that air is prevented from passing through one or more of the skipped working cycles in the skip fire mode, causing gases exhausted from the lean burn internal combustion engine to sufficiently rise in temperature in the exhaust pathway, oxidizing and thereby removing soot accumulation on the particulate filter.
Dependencies are inferred from the claim text.