System and method for selective cylinder deactivation
First Claim
Patent Images
1. A method, comprising:
- during a non-skip fire mode where all engine cylinders are fired,port injecting all fuel for combustion into each engine cylinder and not direct injecting fuel; and
during a transition into a skip fire mode from the non-skip fire mode,port injecting a first fuel quantity of a fuel to a first engine cylinder, the first fuel quantity based on a first, predicted air charge amount for the first engine cylinder and lean of a desired air-fuel ratio;
direct injecting a second fuel quantity of the fuel to the first engine cylinder, the second fuel quantity based on the first fuel quantity and a second air charge amount for the first engine cylinder; and
after port injecting the first fuel quantity, during firing the first engine cylinder, skipping firing of a second engine cylinder.
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Abstract
Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.
20 Citations
23 Claims
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1. A method, comprising:
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during a non-skip fire mode where all engine cylinders are fired, port injecting all fuel for combustion into each engine cylinder and not direct injecting fuel; and during a transition into a skip fire mode from the non-skip fire mode, port injecting a first fuel quantity of a fuel to a first engine cylinder, the first fuel quantity based on a first, predicted air charge amount for the first engine cylinder and lean of a desired air-fuel ratio; direct injecting a second fuel quantity of the fuel to the first engine cylinder, the second fuel quantity based on the first fuel quantity and a second air charge amount for the first engine cylinder; and after port injecting the first fuel quantity, during firing the first engine cylinder, skipping firing of a second engine cylinder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising:
during a transition into a skip fire mode from a non-skip fire mode, determining a first air charge amount for a first engine cylinder and a desired air-fuel ratio based on engine operating conditions prior to opening of an intake valve of the first engine cylinder; injecting a first fuel quantity of a fuel to the first engine cylinder, the first fuel quantity based on the determined first air charge amount for the first engine cylinder and the desired air-fuel ratio; after injecting the first fuel quantity of the fuel, during firing the first engine cylinder, skipping firing of a second engine cylinder; determining a second air charge amount for the first engine cylinder based on engine operating conditions following the injection of the first fuel quantity and following opening of the intake valve of the first engine cylinder; and injecting a second fuel quantity of the fuel to a third engine cylinder, the second fuel quantity based on the first fuel quantity and the determined second air charge amount for the first engine cylinder. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A system, comprising:
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an engine having a plurality of cylinders; a port fuel injection system to port inject fuel to each cylinder of the plurality of cylinders; a direct fuel injection system to direct inject fuel to each cylinder of the plurality of cylinders; a spark ignition system to initiate combustion in each cylinder of the plurality of cylinders, including one or more ionization sensors to detect occurrence of combustion events in the plurality of cylinders; and a controller including non-transitory instructions to; determine a commanded firing order of the engine during a skip fire mode, where at least a first cylinder of the plurality of cylinders is scheduled to be fired and at least a second cylinder of the plurality of cylinders is scheduled to be skipped; during a non-skip fire mode, only activating the port fuel injection system to port inject all fuel into each of the plurality of cylinders; during a transition into the skip fire mode from the non-skip fire mode, activate the port fuel injection system to port inject a first fuel quantity of a fuel to the first cylinder during a first, earlier portion of an engine cycle, activate the direct fuel injection system to direct inject a second fuel quantity of the fuel to the first cylinder during a second, later portion of the engine cycle, activate the spark ignition system to initiate combustion in the first cylinder, where the first fuel quantity is lean of a first desired air-fuel ratio for the first cylinder that is based on an estimated air charge amount for the first cylinder at a time prior to the port injection of the first fuel quantity, and the second fuel quantity brings an overall air-fuel ratio for the first cylinder to a second, desired air-fuel ratio for the first cylinder that is based on an updated air charge amount for the first cylinder, and not activate the spark ignition system to not initiate combustion in the second cylinder, in order to skip firing the second cylinder, between port injecting the first fuel quantity and direct injecting the second fuel quantity to the first cylinder; and after transitioning out of the skip fire mode to the non-skip fire mode, which includes firing all of the plurality of cylinders for an entire engine cycle, and during firing of the first cylinder, activating the port fuel injection system to port inject a third fuel quantity of the fuel to the first cylinder, where the third fuel quantity includes all fuel injected into the first cylinder. - View Dependent Claims (22, 23)
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Specification