Fuel injection pump for internal combustion engines

US4535742A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Helmut Laufer · Gerlingen, DE
• Helmut Pfeifle · Stuttgart, DE
• Max Straubel · Stuttgart, DE

Key dates

• Filing date: Mar 30, 1984
• Grant date: Aug 20, 1985
• Expiry date: Mar 30, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A fuel injection pump for internal combustion engines, in which beyond a predetermined remnant stroke during the supply stroke of the pump piston a relief conduit is opened via a first control edge and the remaining fuel pumped by the pump piston is pumped into a reservoir connected there. During the subsequent intake stroke, the diverted fuel is pumped back into the pump work chamber of the pump piston, until the first control edge again closes the relief conduit. During the subsequent intake stroke of the pump piston, in particular at the bottom dead center position of the pump piston, the relief conduit to the reservoir is once again opened by a second control edge, and then a complete relief of the reservoir is attained. It is during this phase that the metering of the fuel to be injected during the next supply stroke of the pump piston also takes place, via a magnetic valve. With an apparatus of this kind, it is advantageous that the fuel quantity per supply stroke of the pump piston that is actually to be injected can be metered exactly by means of a magnetic valve under pressure conditions that remain constant despite variable opening times.