System for reducing toxic components in the exhaust gas of an internal combustion engine

US4040408A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Bernd Kraus · Gerlingen, DE
• Otto Glockler · Renningen, DE

Key dates

• Filing date: Aug 5, 1975
• Grant date: Aug 9, 1977
• Expiry date: Aug 5, 1995

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02M69/26
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A fuel supply and metering valve assembly used for fuel injection to an internal combustion engine includes a control pressure circuit which determines the restoring force on the movable valve member of the metering valve. The magnitude of the control pressure, and hence the fuel quantity metered out by the valve assembly, can be altered by intermittent actuation of a pressure relief valve whose duty cycle is controlled by an oxygen sensor located in the exhaust line of the engine. The oxygen sensor voltage is superimposed on a sawtooth voltage at the input of a control circuit which varies the duty cycle of the bypass valve. When the oxygen sensor is too cold to generate an output signal, the control circuit is provided with a temporary control signal supplied by a timing circuit until the oxygen sensor has reached its normal temperature and generates an output signal.