Method and apparatus for controlling the onset of fuel injection in diesel engines

US4265200A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Wolf Wessel · Oberriexingen, DE
• Gerhard Engel · Stuttgart, DE

Key dates

• Filing date: Nov 21, 1977
• Grant date: May 5, 1981
• Expiry date: Nov 21, 1997

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

There is described a method and apparatus for use in association with the fuel injection pumps of Diesel engines to time the moment of injection. The method and apparatus described relate to a closed-loop control system which engages a final control element in the fuel injection pump that changes the injection timing, i.e. the onset of fuel delivery and, hence, the onset of fuel injection. The controlled variable is the moment of fuel injection, detected by suitable means placed near the injection valves. A set-point value for this instant is derived on the basis of stored data which correlate the correct moment of injection as a function of engine speed with various optimum conditions, for example, low fuel consumption, low smoke generation, low noise, etc. The selection of the proper characteristic curve from the stored data set is made automatically or manually. The time of occurrence of the actual value pulse and the time of the set-point pulse are compared, for example, by converting the former to analog form, and the resulting control deviation is obtained as a preferably digital counter content which is used to engage the final control element to reduce the deviation.