Fuel pump
AssigneeDenso Corporation
InventorsMichihisa Ishikura, Seiji Kunihiro
Life of this patent
Estimating the term…
Abstract
A fuel pump includes a cylinder that forms a compression chamber which pressurizes a fuel, a plunger that compresses the fuel in the compression chamber, a cam that pushes the plunger, and a driven gear that engages a driving gear to transmit a rotational driving force. A profile of the cam is configured such that a peak arrival range is half or less of a compression range. Cam speed is obtained by differentiating a lift amount of the plunger by a rotation angle of the cam, the compression range is an angle range during which the plunger is pushed in the direction of compressing the fuel, and the peak arrival range is an angle range from a start of the compression range until a most retarded position of a peak of the cam speed.
Claims7
A fuel pump configured to compress and discharge fuel, comprising:
- a cylinder configured to form a compression chamber which pressurizes a fuel;
- a plunger configured to compress the fuel in the compression chamber;
- a cam configured to push the plunger in a direction of compressing the fuel;
- and
- a driven gear configured to engage a driving gear to rotate, the driven gear transmitting a rotational driving force of the driving gear to the cam to rotate the cam, wherein
- the cam pushes the plunger by a lift amount,
- a cam speed includes a value obtained by differentiating the lift amount by a rotation angle of the cam,
- a compression range includes an angle range of the rotation angle during which the plunger is pushed in the direction of compressing the fuel,
- a suction range includes an angle range of the rotation angle during which the plunger is pushed in a direction of sucking in the fuel,
- a peak arrival range includes an angle range from a start of the compression range until a most retarded position of a peak of the cam speed,
- a profile of the cam is configured such that the peak arrival range is less than 40% of the compression range, and such that the compression range is greater than the suction range,
- a cam speed waveform includes a waveform representing changes in the cam speed with respect to changes in the rotation angle,
- a compression end waveform includes a partial angle range of the cam speed waveform, starting from a rotation angle retarded from the peak by a particular angle and until the compression range ends, and
- the profile of the cam is configured such that for an entire angle range of the cam speed waveform from the peak until the end point of the compression range, the cam speed is greater than a straight line that connects a point at the peak with the end point of the compression range.
A fuel pump configured to compress and discharge fuel, comprising:
- a cylinder configured to form a compression chamber which pressurizes a fuel;
- a plunger configured to compress the fuel in the compression chamber;
- a cam configured to push the plunger in a direction of compressing the fuel;
- and
- a driven gear configured to engage a driving gear to rotate, the driven gear transmitting a rotational driving force of the driving gear to the cam to rotate the cam, wherein
- the cam pushes the plunger by a lift amount,
- a cam speed includes a value obtained by differentiating the lift amount by a rotation angle of the cam,
- a compression range includes an angle range of the rotation angle during which the plunger is pushed in the direction of compressing the fuel,
- a suction range includes an angle range of the rotation angle during which the plunger is pushed in a direction of sucking in the fuel,
- a peak arrival range includes an angle range from a start of the compression range until a most retarded position of a peak of the cam speed,
- a profile of the cam is configured such that the peak arrival range is half or less of the compression range, and such that the compression range is greater than the suction range,
- a cam speed waveform includes a waveform representing changes in the cam speed with respect to changes in the rotation angle,
- a compression end waveform includes a partial angle range of the cam speed waveform, starting from a rotation angle retarded from the peak by a particular angle and until the compression range ends at an end point of the compression range, and
- the profile of the cam is configured such that for an entire angle range of the cam speed waveform from the peak until the end point of the compression range, the cam speed is greater than a straight line that connects a point at the peak with the end point of the compression range.
Dependencies are inferred from the claim text.