US 4,040,408 A · System for reducing toxic components in the exhaust gas of an internal combustion engine

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.

Claims8

Dependent claims

In an apparatus for reducing the concentration of toxic components in the exhaust gas of an internal combustion engine, which engine includes a fuel supply system, a fuel metering system, and a control pressure circuit for controlling said fuel metering system, said control pressure circuit including an electromagnetic valve, said apparatus including a regulating device for cyclic actuation of said electromagnetic valve, and an oxygen sensor located in the exhaust system of the engine and electrically connected to said regulating device, the improvement comprising:

a timing circuit, connected to said regulating device, for supplying a time-dependent control signal to said regulator device, said timing circuit including:
i. a threshold switch for receiving input signals and for generating an output signal;
ii. a logic gate, one of whose inputs is connected to the output of said threshold switch;
and
iii. a timer element, whose trigger input is connected to the output of said logic gate.

2 more elements

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims8