Method and apparatus for adjusting fuel injection control

US4278061A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Peter Werner · Wiernsheim, DE
• Ulrich Drews · Schwieberdingen, DE

Key dates

• Filing date: Dec 12, 1977
• Grant date: Jul 14, 1981
• Expiry date: Dec 12, 1997

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D2200/503
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A fuel injection system of an internal combustion engine generates valve-actuating pulses for actuating electromagnetic fuel injection valves. The length, or duration, of these valve actuating pulses is a function of various engine conditions and they are generated by a pulse-length multiplying circuit from preliminary control pulses derived from two basic engine variables, e.g. engine speed and air flow rate. In order to compensate for the decreasing pressure drop across the injection valve orifice at high engine load due to increasing manifold pressure, the invention describes methods for lengthening the fuel valve-actuating pulses by engaging the pulse-length multiplying circuit, in order to change the charging or discharging times of the timing capacitor therein. Another method proposed is to engage the battery-voltage compensation circuit in the system to lengthen the valve-actuating pulses. Electronic circuitry to perform these corrections is also described.