Method and system for particulate matter control
First Claim
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1. A method comprising:
- operating an engine in a first mode that includes cylinder deactivation conditions being met;
in response to operating the engine in the first mode, deactivating individual cylinder valve mechanisms according to a cylinder pattern selected based on engine coolant temperature, including when engine coolant temperature is lower than a threshold, deactivating individual cylinder valve mechanisms according to a first cylinder pattern, and, when engine coolant temperature is higher than the threshold, deactivating individual cylinder valve mechanisms according to a second, different cylinder pattern;
operating the engine in a second mode that includes cylinder reactivation conditions being met;
in response to operating the engine in the second mode, reactivating the deactivated individual cylinder valve mechanisms and injecting fuel to cylinders according to a fuel injection pattern selected based on engine coolant temperature, including injecting fuel as multiple injections per engine cycle to reactivated cylinders while injecting fuel as a single fuel injection per engine cycle to remaining active cylinders when engine coolant temperature is below the threshold, and injecting fuel as a single fuel injection per engine cycle to all cylinders when engine coolant temperature is above the threshold.
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Abstract
Methods and systems are provided for particulate matter control in an engine configured for skip-fire operation. A cylinder pattern selected for selective cylinder deactivation, including a total number of deactivated/active cylinders as well as individual deactivated cylinder identities, may be adjusted based on an engine soot load, or a parameter indicative of engine soot load such as engine coolant temperature. In addition, reactivated engine cylinders may be transiently operated with split fuel injection to raise combustion surface temperatures.
26 Citations
10 Claims
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1. A method comprising:
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operating an engine in a first mode that includes cylinder deactivation conditions being met; in response to operating the engine in the first mode, deactivating individual cylinder valve mechanisms according to a cylinder pattern selected based on engine coolant temperature, including when engine coolant temperature is lower than a threshold, deactivating individual cylinder valve mechanisms according to a first cylinder pattern, and, when engine coolant temperature is higher than the threshold, deactivating individual cylinder valve mechanisms according to a second, different cylinder pattern; operating the engine in a second mode that includes cylinder reactivation conditions being met; in response to operating the engine in the second mode, reactivating the deactivated individual cylinder valve mechanisms and injecting fuel to cylinders according to a fuel injection pattern selected based on engine coolant temperature, including injecting fuel as multiple injections per engine cycle to reactivated cylinders while injecting fuel as a single fuel injection per engine cycle to remaining active cylinders when engine coolant temperature is below the threshold, and injecting fuel as a single fuel injection per engine cycle to all cylinders when engine coolant temperature is above the threshold. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method, comprising:
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responsive to cylinder deactivation conditions being met and engine coolant temperature being lower than a threshold, deactivating a first set of cylinders of an engine according to a first cylinder deactivation pattern that includes a first number of deactivated cylinders and a first duration of deactivation; and injecting fuel as multiple injections per engine cycle when the first set of cylinders is reactivated, a number of injections in the multiple injections per engine cycle based on the first number of deactivated cylinders and further based on the first duration of deactivation, the number of injections increased as the first number of deactivated cylinders increases and as the first duration of deactivation increases; responsive to cylinder deactivation conditions being met and engine coolant temperature being higher than the threshold, deactivating a second set of cylinders according to a second cylinder deactivation pattern that includes a second number of deactivated cylinders and a second duration of deactivation; and injecting fuel as a single injection per engine cycle when the second set of cylinders is reactivated. - View Dependent Claims (8, 9, 10)
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Specification