System and method for operating an engine
System and methods for an internal combustion engine are described. In one example, the internal combustion engine includes one or more engine cylinders having igniters that include a pre-chamber. One or more of the engine cylinders may be operated in a skip-fire mode if a cylinder misfires or if the internal combustion engine is cold started.
1 . An engine system, comprising:
an internal combustion engine;
a plurality of cylinders, each of the plurality of cylinders including a first igniter having a pre-chamber; and
a controller including executable instructions stored in non-transitory memory that cause the controller to operate the plurality of cylinders of the internal combustion engine in skip-fire mode in response to a cold start of the internal combustion engine,
where the skip-fire mode includes, for each of the plurality of cylinders, alternating between not combusting fuel and combusting fuel every sequential engine cycle, and
where the plurality of cylinders are all operated in the skip-fire mode at a same time for multiple engine cycles.
2 . The engine system of claim 1 , wherein, during the skip-fire mode, each cylinder is operated without two consecutive engine cycles of fuel combustion being carried out.
3 . The engine system of claim 1 , wherein half of the plurality of cylinders combust fuel each engine cycle during the skip-fire mode, and wherein half of the plurality of cylinders do not combust fuel each engine cycle during the skip-fire mode.
4 . The engine system of claim 1 , where the plurality of cylinders includes a first set of cylinders and a second set of cylinders, and where operating all of the plurality of cylinders in the skip-fire mode for multiple engine cycles includes operating both the first set of cylinders and the second set of cylinders in the skip-fire mode,
where the first set of cylinders and the second set of cylinders are operated in skip-fire mode such that the first set of cylinders fires during a different engine cycle than an engine cycle when the second set of cylinders fires.
5 . The engine system of claim 1 , further comprising additional executable instructions that cause the controller to change from skip-fire mode to fire each cycle mode in response to a catalyst temperature.
6 . The engine system of claim 1 , further comprising additional executable instructions that cause the controller to enter skip-fire mode a predetermined actual total number of engine cycles after exiting engine cranking, wherein the engine cranking comprises cranking the internal combustion engine during the cold start as part of a process to initiate combustion.
7 . An engine operating method, comprising:
operating a plurality of engine cylinders each with an igniter that includes a pre-chamber in skip-fire mode in response to cold starting an engine,
where the plurality of engine cylinders are simultaneously operated in the skip-fire mode, and
where the skip-fire mode includes, for each of the plurality of engine cylinders, alternating between not combusting fuel and combusting fuel every sequential engine cycle, and
where the plurality of engine cylinders are all operated in the skip-fire mode at a same time for multiple engine cycles.
8 . The engine operating method of claim 7 , wherein none of the plurality of engine cylinders are operated with two consecutive engine cycles of fuel combustion during the skip-fire mode.
9 . The engine operating method of claim 7 , further comprising, for each of the plurality of engine cylinders, injecting fuel during an engine cycle in which the plurality of engine cylinders operates in the skip-fire mode.
10 . The engine operating method of claim 9 , further comprising igniting the fuel in an exhaust system of the engine via a second igniter.
11 . The engine operating method of claim 7 , where skip-fire mode includes not igniting an air-fuel mixture in the plurality of engine cylinders.
12 . An engine system, comprising:
an internal combustion engine;
a plurality of cylinders of the internal combustion engine, the plurality of cylinders including a cylinder with a first igniter and having a pre-chamber; and
a controller including executable instructions stored in non-transitory memory that cause the controller to:
detect one or more misfires in the cylinder of the plurality of cylinders, and
operate only the cylinder in which the one or more misfires were detected of the plurality of cylinders of the internal combustion engine in skip-fire mode in response to detecting the one or more misfires in the cylinder; and
detect a cold start of the internal combustion engine, and
responsive to the cold start, operate the plurality of cylinders of the internal combustion engine in skip-fire mode,
where the skip-fire mode includes, for each of the plurality of cylinders, alternating between not combusting fuel and combusting fuel every sequential engine cycle, and
where the plurality of cylinders are all operated in the skip-fire mode at a same time for multiple engine cycles.
13 . The engine system of claim 12 , wherein half of the plurality of cylinders combust fuel during the skip-fire mode each engine cycle, and wherein half of the plurality of cylinders do not combust fuel each engine cycle during the skip-fire mode, and
wherein none of the plurality of cylinders are operated with two consecutive engine cycles of fuel combustion during the skip-fire mode.
14 . The engine system of claim 12 , where the cylinder is operated in skip-fire mode for one or more engine cycles following the one or more misfires.
15 . The engine system of claim 12 , further comprising additional executable instructions that cause the controller to not inject fuel to the cylinder while operating the cylinder in the skip-fire mode.
16 . The engine system of claim 12 , further comprising additional executable instructions that cause the controller to operate a second cylinder of the internal combustion engine in the skip-fire mode in response to one or more misfires in the second cylinder.
17 . The engine system of claim 12 , further comprising additional executable instructions that cause the controller to recognize the one or more misfires.
18 . The engine system of claim 12 , where, for multiple engine cycles, a remainder of the plurality of cylinders of the internal combustion engine are operated in a fire each cycle mode while only the cylinder is operated in the skip-fire mode.