Piston pump

Patent metadata

Field	Value
Publication number	US-11352995-B2
Application number	US-202017097411-A
Country	US
Kind code	B2
Filing date	Nov 13, 2020
Priority date	Nov 14, 2019
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A piston pump as a high-pressure fuel pump of a common rail system includes: a pump cylinder; a pump piston moveably mounted in a recess of the pump cylinder, the pump piston being moveable up and down in the recess; and a leakage groove arranged in the pump cylinder in a region of the recess, the leakage groove being coupled with a leakage line configured to discharge a fuel leakage. Between the pump cylinder and the pump piston a different size pairing clearance is formed in first and second portions of the pump cylinder.

First claim

What is claimed is:

1. A piston pump ( 20 ) as a high-pressure fuel pump of a common rail system, comprising:
a pump cylinder ( 21 );
a pump piston ( 22 ) moveably mounted in a recess ( 23 ) of the pump cylinder ( 21 ), the pump piston ( 22 ) being moveable up and down in the recess ( 23 ); and
a leakage groove ( 24 ) arranged in the pump cylinder ( 21 ) in a region of the recess ( 23 ), the leakage groove ( 24 ) being coupled with a leakage line ( 25 ) configured to discharge a fuel leakage,
wherein between the pump cylinder ( 21 ) and the pump piston ( 22 ) a different size pairing clearance is formed in first and second portions ( 28 , 29 ) of the pump piston,
wherein in the first portion ( 28 ) of the pump piston, in which the pump piston ( 22 ) during its up-and-down movement passes over the leakage groove ( 24 ), a larger pairing clearance is formed than in the second portion ( 29 ) of the pump piston, in which the pump piston ( 22 ) during its up-and-down movement does not pass over the leakage groove ( 24 ),
wherein the pump piston ( 22 ), in the first portion ( 28 ), has a smaller outer diameter than in the second portion ( 29 ), and
wherein portions of the pump piston ( 22 ) having different size outer diameters are separated from one another by a circumferential groove ( 30 ) in the pump piston ( 22 ).

2. The pump piston according to claim 1 , wherein in the first portion ( 28 ), the pairing clearance is formed 25% to 125% larger than in the second portion ( 29 ).

3. The pump piston according to claim 1 , wherein in the first portion ( 28 ), the pairing clearance is formed larger by 30% to 100% than in the second portion ( 29 ).

4. The pump piston according to claim 1 , wherein the leakage line ( 25 ) discharges the fuel leakage in a low-pressure region of the common rail fuel system.

Assignees

• Man Energy Solutions Se

Inventors

• Wagner Wolfgang
• Kovalev Denis
• Meixner Markus
• Hamann Thomas

Classifications

• F02M59/02 Primary

  of reciprocating-piston {or reciprocating-cylinder} type · CPC title

• F02M59/102

  Mechanical drive, e.g. tappets or cams (F02M45/063 takes precedence) · CPC title

• F04B1/0421

  Cylinders · CPC title

• F02M59/442 Primary

  means preventing fuel leakage around pump plunger, e.g. fluid barriers · CPC title

• F04B53/14

  Pistons, piston-rods or piston-rod connections · CPC title