Method and apparatus for detecting the angular position of a variable position camshaft
First Claim
1. A variable cam timing system for an internal combustion engine comprising,a variable position camshaft comprising a plurality of cams rotating in a variable angular relationship to a crankshaft,means for altering the angular position of said camshaft in relation to said crankshaft, andmeans responsive to a first signal indicative of the rotational speed of the crankshaft and to a second signal indicative of the angular position of said camshaft for determining the angular position of said camshaft in relation to said crankshaft.
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Accused Products
Abstract
A VRS sensor detects the angular rotation of a variable position camshaft which rotates in a variable relationship to a crankshaft, and transmits a Variable Cam Timing/Cylinder IDentification signal, representative of the position of the angular rotation of the camshaft, to an electronic engine controller (EEC). A profile ignition pickup (PIP) sensor detects the rotation of the crankshaft and transmits a PIP signal, representative of the rotation of the crankshaft to the EEC. The EEC receives the VCT/CID signal and the PIP signal and identifies the position of a first firing cylinder in a predetermined sequence of cylinder firing and determines the angular position of the camshaft in relation to the crankshaft by detecting the varying time duration between VCT/CID signals and PIP signals.
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Citations
19 Claims
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1. A variable cam timing system for an internal combustion engine comprising,
a variable position camshaft comprising a plurality of cams rotating in a variable angular relationship to a crankshaft, means for altering the angular position of said camshaft in relation to said crankshaft, and means responsive to a first signal indicative of the rotational speed of the crankshaft and to a second signal indicative of the angular position of said camshaft for determining the angular position of said camshaft in relation to said crankshaft.
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11. In combination,
an internal combustion engine comprising a plurality of cylinders, each firing in a predetermined sequence, a variable position cam shaft comprising a plurality of cam lobes, said camshaft rotating in a variable angular relationship to an engine crankshaft, a pulsewheel positioned on said cam shaft comprising a plurality of teeth, a cam position sensor, responsive to the angular rotation of said pulsewheel, for generating a first pulsetrain comprising a series of pulses indicative of the angular positions of said camshaft; -
an engine position sensor generating a second pulsetrain comprising a series of pulses indicative of the rotational speed of said engine; and a variable cam sensing system comprising, means, responsive to exactly said first and said second pulsetrains, for identifying a first firing cylinder in a predetermined firing sequence, means, responsive to said first and said second pulsetrains, for determining the time duration between certain pulses of said first and said second pulsetrains, and means, responsive to said time duration, to the rotational speed of the engine and to a value indicative of the number of cylinders in the engine, for determining the angular position of said camshaft in relation to the crankshaft. - View Dependent Claims (12, 13, 14)
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15. In an internal combustion engine comprising a variable position camshaft which is movable in a variable angular position in relation to an engine crankshaft, a method for determining the angular position of the camshaft in relation to the crankshaft, comprising the steps of:
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generating an engine position signal comprising a first series of pulses indicative of the rotational speed of said engine crankshaft; generating a cam sensor signal comprising a second series of pulses indicative of the rotation of said camshaft by a predetermined angle; and calculating the angular position of said camshaft in relation to the crankshaft as a function of the relationship between certain pulses of said first series of pulses and certain pulses of said second series of pulses, and as a function of the rotational speed of the engine and as a function of a value indicative of the number of cylinders in the engine. - View Dependent Claims (16, 17, 18, 19)
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Specification