On-off valve in a fuel injection system for internal combustion engines

US6422212B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Erhard Faix · Schrobenhausen, DE
• Helmut Clauss · Tamm, DE
• Rainer Lorenz · Nettetal, DE
• Gerd Loesch · Stuttgart, DE
• Markus Rueckle · Stuttgart, DE

Key dates

• Filing date: Mar 12, 2001
• Grant date: Jul 23, 2002
• Expiry date: Mar 12, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/7927
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A fuel injection system has a low-pressure pump for withdrawing fuel from a tank and a high-pressure pump, which is supplied by the low-pressure pump and has camshaft-actuated pump elements. An on-off valve is connected on the inlet side to the pressure side of the low-pressure pump and on the outlet side, is connected on the one hand to a camshaft chamber of the high-pressure pump and on the other hand, is connected to the suction side of the low-pressure pump. At a first pressure threshold, a spring-loaded valve piston of the on-off valve opens a connection between the low-pressure pump and the camshaft chamber and at a relatively higher second pressure threshold, opens a connection between the pressure side and the suction side of the low-pressure pump. A throttle bore in the bottom of the valve piston serves to ventilate the low-pressure system.