Internal combustion engine with intake and exhaust camshaft phase shifting for cylinder deactivation
First Claim
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1. A four-stroke cycle, multi-cylinder reciprocating internal combustion engine having a crankshaft and a plurality of pistons reciprocably contained within a plurality of cylinders, said engine comprising:
- at least one intake poppet valve and at least one exhaust poppet valve for each engine cylinder;
a camshaft for operating said intake valves and said exhaust valves;
a camshaft phaser coupled to said camshaft for adjusting the timing of the camshaft with respect to the rotational position of the crankshaft; and
,a controller, connected to said camshaft phaser, for deactivating at least some of the cylinders by operating said camshaft phaser such that for the cylinders which are to be deactivated, the camshaft timing is adjusted such that said intake valve and said exhaust valve open and close at points which are approximately symmetrical about a rotational position of the crankshaft at which the direction of motion of the cylinder'"'"'s piston changes.
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Abstract
A four-stroke cycle, multi-cylinder reciprocating internal combustion engine has a camshaft phaser or phasers for adjusting the timing of the intake and exhaust camshafts with respect to the rotational position of the crankshaft so that some of the cylinders of the engine may be deactivated such that the intake and exhaust valves for each deactivated cylinder open and close at points which are approximately symmetrical about a rotational position of the crankshaft at which the direction of motion of the pistons change.
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Citations
20 Claims
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1. A four-stroke cycle, multi-cylinder reciprocating internal combustion engine having a crankshaft and a plurality of pistons reciprocably contained within a plurality of cylinders, said engine comprising:
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at least one intake poppet valve and at least one exhaust poppet valve for each engine cylinder; a camshaft for operating said intake valves and said exhaust valves; a camshaft phaser coupled to said camshaft for adjusting the timing of the camshaft with respect to the rotational position of the crankshaft; and
,a controller, connected to said camshaft phaser, for deactivating at least some of the cylinders by operating said camshaft phaser such that for the cylinders which are to be deactivated, the camshaft timing is adjusted such that said intake valve and said exhaust valve open and close at points which are approximately symmetrical about a rotational position of the crankshaft at which the direction of motion of the cylinder'"'"'s piston changes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for operating a multi-cylinder, four-stroke cycle reciprocating internal combustion engine on fewer than the maximum number of cylinders, comprising the steps of:
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sensing a plurality of engine and vehicle operating parameters, including at least engine load and engine speed; comparing the sensed operating parameters with predetermined threshold values; issuing a fractional engine cylinder operation command in the event that the sensed parameters exceed said threshold values so as to deactivate at least one cylinder of said engine; and
,adjusting the timing of at least one camshaft which operates poppet intake and exhaust valves of the cylinders to be deactivated so that valve lift events for both intake and exhaust valves are shifted out of phase of standard timing. - View Dependent Claims (17, 18, 19)
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20. A four-stroke cycle, multi-cylinder reciprocating internal combustion engine having a crankshaft and a plurality of pistons reciprocably contained within a plurality of cylinders, said engine comprising:
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at least one intake popper valve and at least one exhaust poppet valve for each engine cylinder; at least one camshaft for operating said intake valves and said exhaust valves; a camshaft phaser for adjusting camshaft timing with respect to the rotational position of the crankshaft; and
,a controller for deactivating at least some of the cylinders by operating said camshaft phaser such that for each cylinder which is to be deactivated, the camshaft is adjusted such that valve lift events for both intake and exhaust valves are shifted approximately 90°
out of phase of standard timing.
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Specification