Methods and systems for variable displacement engine control
First Claim
1. A method of operating a boosted engine with selectively deactivatable cylinders, the method carried out by a processor communicating with the engine, comprising:
- determining a number of deactivated cylinders;
adjusting a crank angle window range and a threshold based on the number of deactivated cylinders; and
indicating cylinder pre-ignition based on a sensed signal only in the crank angle window range relative to the threshold.
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Accused Products
Abstract
Methods and systems are provided for selecting a group of cylinders for selective deactivation, in a variable displacement engine system, based at least on a regeneration state of an exhaust catalyst. The position of one or more valves and throttles may be adjusted based on the selective deactivation to reduce back-flow through the disabled cylinders while also maintaining conditions of a downstream exhaust catalyst. Pre-ignition and knock detection windows and thresholds may also be adjusted based on the deactivation to improve the efficiency of knock and pre-ignition detection.
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Citations
19 Claims
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1. A method of operating a boosted engine with selectively deactivatable cylinders, the method carried out by a processor communicating with the engine, comprising:
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determining a number of deactivated cylinders; adjusting a crank angle window range and a threshold based on the number of deactivated cylinders; and indicating cylinder pre-ignition based on a sensed signal only in the crank angle window range relative to the threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating a boosted engine, the method carried out by a processor communicating with the engine, comprising:
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selecting one of a first and a second group of cylinders for deactivation based on a regeneration state of a first catalyst relative to a second catalyst; deactivating one or more cylinders of the selected group of cylinders; determining a number of deactivated cylinders; adjusting a first crank angle window range, a second crank angle window range, a first threshold, and a second threshold based on the number of deactivated cylinders; and indicating cylinder pre-ignition based on sensed information only in the first crank angle window range relative to the first threshold, and knock based on sensed information only in the second crank angle window range relative to the second threshold. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An engine system, comprising,
an engine; -
a turbocharger configured to provide a boosted intake aircharge to the engine; a first group of cylinders coupled to a first catalyst; a second group of cylinders coupled to a second catalyst; one or more knock sensors; and a control system with computer readable instructions for, selecting one of the first or the second group of cylinders for deactivation based on an operating condition of the first catalyst relative to the second catalyst; estimating an output of the one or more knock sensors relative to a first knock threshold in a first knock window, and relative to a second pre-ignition threshold in a second pre-ignition window, the first and second windows and the first and second thresholds adjusted based on the deactivation; and indicating cylinder knock and/or pre-ignition based on the estimation. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification