Device for detecting cam top position of high pressure pump
A device detects the cam top position in an in-line type high pressure pump with a decreased amount of time required to detect the rotation position of the cam top position in an engine starting operation, thereby decreasing the time for starting an engine. A cam for driving a plunger has a plurality of cam lobes, and a plurality of cam top position pointers are attached to the outer periphery of the camshaft or to the outer periphery of a flywheel connected to the camshaft such that each of the pointers corresponds to each of the cam lobes of the cam in number and angle phase, respectively. A cam top position detector is located to face the pointers when the camshaft rotates so that the pointers are detected by the detector.
1. A device for detecting cam top position of an in-line type high pressure pump having a camshaft for driving a plurality of plungers to pressurize fuel to a high pressure to be accumulated in an accumulator, the device comprising:
a plurality of cams formed on the camshaft for driving the plurality of plungers;
a plurality of cam lobes provided to each of the plurality of cams;
a flywheel provided to the camshaft; and
a plurality of cam top position pointers attached to an outer periphery of the camshaft or to an outer periphery of the flywheel, wherein
the plurality of cam top position pointers correspond to the cam lobes of one of the plurality of cams in number and angle phase, and
a cam top position detector is located to face the cam top position pointers when the camshaft rotates so that the cam top position pointers are detected by the cam top position detector.
2. The device as claimed in claim 1 , wherein each of the cam top position pointers is a protrusion protruding from the outer periphery of the camshaft or flywheel.
3. The device as claimed in claim 1 , wherein each of the cam top position pointers is a depression on the outer periphery of the camshaft or flywheel.