Apparatus for determining the fuel injection quantity in mixture compressing internal combustion engines

US4048965A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Valerio Bianchi · Biberach an der Riß, DE
• Reinhard Latsch · Leinfelden, DE
• Peter Schmidt · Schwieberdingen, DE

Key dates

• Filing date: Dec 5, 1975
• Grant date: Sep 20, 1977
• Expiry date: Dec 5, 1995

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D2200/1015
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A fuel metering system of an internal combustion engine is controlled by a digital computer circuit which delivers injection pulses to actuate the fuel injection valve of the engine. The duration of these pulses is directly related to the amount of injected fuel and depends on the inherent characteristics of the engine as well as on the engine r.p.m. and the degree of throttle opening. A set of data points each of which correlates a fuel datum with a pair of numbers related to engine speed and throttle valve opening, respectively, is stored in a digital memory and can be addressed by digital signals from transducers associated with engine speed and throttle valve position. An arithmetic unit then performs an interpolation process by weighted addition of nearest neighbor values of the datum stored in the memory. The final, interpolated datum is counted down at constant or variable frequency and represents an output signal related to the fuel injection period.