Multi-level firing engine control
First Claim
1. A method of controlling operation of an internal combustion engine having a plurality of working chambers to deliver a desired output, wherein each working chamber has at least one cam-actuated intake valve and at least one exhaust valve, the plurality of working chambers including first and second sets of the working chambers, each set of working chambers including at least one working chamber, wherein working chambers in the first set are deactivatable and working chambers in the second set are not capable of being deactivated during operation of the engine, the method comprising:
- operating the engine to deliver a desired engine output by causing each of the working chambers in the second set to be fired during every engine cycle and causing the working chambers in the first set to sometimes be fired and sometimes be skipped; and
setting an air charge for each fired working cycle based on whether a high or low torque output was selected for the fired working cycle, whereby within a selected engine cycle, at least one fired working chamber has the high torque output and at least one other fired working chamber has the low torque output.
1 Assignment
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Accused Products
Abstract
In various aspects, internal combustion engines, engine controllers and methods of controlling engines are described. The engine includes a camshaft and a two cylinder sets. Cylinders in the first are deactivatable and cylinders in the second set may be fired at high or low output levels. The air charge for each fired working cycle is set based on whether a high or low torque output is selected. In some implementations, the camshaft is axially shiftable between first and second positions. First cam lobes are configured to cause their associated cylinders to intake a large air charge during intake strokes that occur when the camshaft is in the first position. Second cam lobes for cylinders in the second set cause their associated cylinders to intake a smaller air charge when the camshaft is in the second position. Second cam lobes for cylinders in the first set deactivate their associated cylinders.
162 Citations
26 Claims
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1. A method of controlling operation of an internal combustion engine having a plurality of working chambers to deliver a desired output, wherein each working chamber has at least one cam-actuated intake valve and at least one exhaust valve, the plurality of working chambers including first and second sets of the working chambers, each set of working chambers including at least one working chamber, wherein working chambers in the first set are deactivatable and working chambers in the second set are not capable of being deactivated during operation of the engine, the method comprising:
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operating the engine to deliver a desired engine output by causing each of the working chambers in the second set to be fired during every engine cycle and causing the working chambers in the first set to sometimes be fired and sometimes be skipped; and setting an air charge for each fired working cycle based on whether a high or low torque output was selected for the fired working cycle, whereby within a selected engine cycle, at least one fired working chamber has the high torque output and at least one other fired working chamber has the low torque output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling operation of an internal combustion engine having a plurality of working chambers to deliver a desired output, wherein each working chamber has at least one cam-actuated intake valve and at least one exhaust valve, the method comprising:
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operating the engine in a skip fire manner that skips selected skipped working cycles and fires selected working cycles to deliver a desired engine output; and adjusting an air charge for each fired working cycle based on whether a high or low torque output was selected for the fired working cycle, wherein; the engine includes a first set of one or more working chambers and a second set of one or more working chambers; each working chamber in the first set is arranged to be selectively fired or deactivated; and each working chamber in the second set is arranged to be fired during every engine cycle and is not capable of being deactivated during operation of the engine; and whereby within selected engine cycles, at least one fired working chamber has the high torque output and at least one other fired working chamber has the low torque output. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. An engine controller for an engine including a plurality of working chambers, each working chamber including one or more cam-actuated intake valves, the working chambers arranged in a first set and a second set, wherein working chambers in the first set are capable of deactivation such that air is not pumped through the deactivated working chamber during skipped working cycles and working chambers in the second set are not capable of deactivation, wherein the engine controller is configured to:
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direct each working chamber in the first set to selectively be fired at a high torque output, fired at a low torque output or deactivated; and direct each working chamber in the second set selectively be fired at either the high or low torque output, wherein the working chambers in the second set are not deactivated during operation of the engine; wherein the high torque output firings and low torque output firings have a different air charges and the air charge is adjusted by axially shifting a camshaft to engage different cam lobes with an intake valve stem of the one or more cam-actuated intake valves. - View Dependent Claims (19, 20, 21)
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22. An internal combustion engine comprising:
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a plurality of working chambers arranged in first and second working chamber sets, each working chamber having at least one associated intake valve and at least one associated exhaust valve; and a camshaft having a multiplicity of cam lobes, each of the cam lobes being associated with an associated working chamber and an associated intake valve and each working chamber having first and second associated cam lobes of the multiplicity of cam lobes, the camshaft being axially shiftable between a first axial position in which the first cam lobes engage their associated intake valves and a second axial position in which the second cam lobes engage their associated intake valves; and wherein (a) the first cam lobes are configured to cause all of the working chambers to intake a first air charge during intake strokes that occur when the camshaft is in the first axial position, (b) the second cam lobes associated with working chambers in the second working chamber set cause the associated working chambers to intake a second air charge that is smaller than the first air charge during intake strokes that occur when the camshaft is in the second axial position, and (c) the second cam lobes associated with working chambers in the first working chamber set cause the associated working chambers to not intake an air charge during intake strokes that occur when the camshaft is in the second axial position to thereby deactivate the associated working chambers. - View Dependent Claims (23, 24, 25, 26)
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Specification