Reference position learning apparatus and method of a variable valve-timing controlling system
AssigneeNissan Motor Co., Ltd.
InventorHirotada Muraki
Life of this patent
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Abstract
A reference position of a camshaft used in detection of a rotational phase of the camshaft relative to an engine crankshaft during the feedback control operation of a variable valve-timing controlling system adjustably changing the valve-timing of the engine, is learned in such a manner that result of detection of the rotational phase is smoothed more effectively than when the feedback control operation of the variable valve-timing controlling system is carried out, so as absorb unequal spaces among detection subjects of the cam sensor arranged around the camshaft.
Claims20
A reference position learning apparatus of a variable valve-timing controlling system, which changes a rotational phase of a camshaft relative to a crankshaft of an engine to control valve timing of the engine, comprising:
- a crank angle sensor that generates a rotation-detection signal of the crankshaft;
- a cam sensor that detects a plurality of detection subjects provided for the camshaft so as to be arranged in a rotating direction of the camshaft, to generate a rotation-detection signal for each of the plurality of detection subjects;
- and
- a control unit for determining a rotational phase for use during learning of said camshaft reference position based on a detected current rotational phase and at least a detected previous rotational phase, wherein a degree of smoothening of said current rotational phase applied during determination of said rotational phase being dependent on at least one of the number of previous rotational phases taken into account and a weighing factor assigned to said previous rotational phase and wherein the degree of smoothening of said current rotational phase being larger during learning of said camshaft reference position compared to a smoothening degree applied to a current rotational phase in determining a camshaft rotational phase during a valve timing control.
A reference position learning apparatus of a variable valve-timing controlling system, which learns a camshaft reference position used as a reference position in detection of a rotational phase of the camshaft relative to a crankshaft of an internal combustion engine during the controlling of a valve timing of the engine via adjustably changing the rotational phase, comprising:
- a crank rotation detecting means for generating a rotation-detection signal upon detection of rotation of the crankshaft;
- a cam rotation detecting means for generating rotation-detection signal upon detection of each of a plurality of detection subjects provided in a rotating direction of the camshaft;
- a control means for determining a rotational phase for use during learning of said camshaft reference position based on a detected current rotational phase and at least a detected previous rotational phase, wherein a degree of smoothening of said current rotational phase applied during determination of said rotational phase being dependent on at least one of the number of previous rotational phases taken into account and a weighing factor assigned to said previous rotational phase and wherein the degree of smoothening of said current rotational phase being larger during learning of said camshaft reference position compared to a smoothening degree applied to a current rotational phase in determining a camshaft rotational phase during a valve timing control.
A reference position learning method of a variable valve-timing controlling system, which changes a rotational phase of a camshaft relative to a crankshaft of an engine to control valve timing of the engine, comprising:
- inputting a rotation-detection signal of the crankshaft;
- inputting a rotation-detection signal to be output by detecting a plurality of detection subjects;
- detecting the rotational phase of the camshaft relative to the crankshaft on the basis of the rotation-detection signals of the crank angle sensor and the cam sensor;
- determining a rotational phase for use during learning of said camshaft reference position based on a detected current rotational phase and at least a detected previous rotational phase, wherein a degree of smoothening of said current rotational phase applied during determination of said rotational phase being dependent on at least one of the number of previous rotational phases taken into account and a weighing factor assigned to said previous rotational phase and wherein the degree of smoothening of said current rotational phase being larger during learning of said camshaft reference position compared to a smoothening degree applied to a current rotational phase in determining a camshaft rotational phase during a valve timing control.
Dependencies are inferred from the claim text.