US 4,357,922 A · Method and apparatus for operating a fuel-supply system with lambda control

Abstract

A method for operating a fuel-supply system using a lambda-control apparatus for an internal-combustion engine wherein the amount of fuel to be supplied to the internal combustion engine is a function of signals representing the speed (RPM), the engine load, the exhaust-composition, and the temperature of the exhaust-gas sensor together with the attainment of a given temperature of the engine as an additional control criteria for the lambda-control apparatus. The method further includes deriving a temperature signal from the internal combustion engine to operate a threshold element with a hystereses whose switching values lie at about 10.degree. C. and 50.degree. C. to 85.degree. C. for optimum fuel mixture in the combustion chamber. The output signal of the threshold element can be further utilized for a supplementary warm-up fuel enrichment for better ignition characteristics, engine smoothness, and exhaust gas composition. The apparatus according to the invention has transducers for sensing speed, load, exhaust gas composition and temperature together with a threshold element and a logic element for signals from a sensor in the internal combustion engine so that the lambda-control apparatus can be regulated as a function of the output signal from said logic element.

Claims14

Dependent claims

In a method of operation of an internal combustion engine with a fuel supply apparatus and a lambda-control apparatus for the control of the fuel-air mixture based on a certain lambda value, wherein the fuel quantity to be supplied to the engine by the fuel supply apparatus is regulated in accordance with signals representing the engine RPM, intake manifold air-flow rate, and exhaust gas composition, and wherein the lambda-control apparatus operates in accordance with the temperature of an exhaust-gas sensor, the improvement comprising the steps of:

determining an engine temperature by an engine temperature sensor;
enriching the fuel-air mixture in accordance with the engine temperature determined by the engine temperature sensor so that the fuel-air mixture is heavily enriched when the engine is cold and this enrichment is reduced to zero as the engine temperature rises;
supplying the engine temperature determined by the engine temperature sensor to a threshold switching element having a hysteresis characteristic, for generating an output signal which is switched in accordance with the engine temperature between one value corresponding to a low engine temperature and another value corresponding to a high engine temperature;
controlling the actuation of the lambda-control apparatus in accordance with the output signal of the threshold element so that the lambda-control apparatus is only switched on when the value of the threshold element output signal corresponds to a high engine temperature;
and
supplementarily enriching the fuel-air mixture in accordance with the output signal of the threshold element.

3 more elements

In an apparatus for the operation of an internal combustion engine including an intake manifold for supplying air to the engine, a transducer for sensing the air flow rate in the intake manifold, a transducer for sensing the RPM of the engine, a fuel supply apparatus for supplying fuel to the engine in accordance with the sensed engine RPM and intake manifold air flow rate, an exhaust-gas sensor for generating an output signal in accordance with the composition of the engine exhaust gas, and a lambda-control apparatus for controlling the fuel-air mixture supplied to the engine in accordance with the output signal of the exhaust-gas sensor, the improvement which comprises:

a temperature transducer, arranged to sense an engine temperature, for generating an engine temperature signal corresponding to the sensed engine temperature;
fuel enrichment means for enriching the fuel-air mixture in accordance with the engine temperature signal, so that the fuel-air mixture is heavily enriched when the engine is cold and this enrichment is reduced to zero as the engine temperature rises to a normal operating value;
a threshold switch element, having a hysteresis characteristic and connected to receive the engine temperature signal, for generating an output signal which is switched in accordance with the engine temperature signal between one value corresponding to a low engine temperature and another value corresponding to a high engine temperature;
a logic element connected to receive the sensor readiness signal and the threshold element output signal, for controlling the activation of the lambda-control apparatus so that the lambda-control apparatus is switched on only if the exhaust-gas sensor is operationally ready and if the value of the threshold element output signal corresponds to a high engine temperature;
supplementary fuel enrichment means for enriching the fuel-air mixture in accordance with the threshold element output signal;
and
starting control means, associated with the threshold element, for maintaining the threshold element output signal at a constant value during engine starting, to thus obtain a constant starting condition depending upon the engine temperature.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for operating a fuel-supply system with lambda control

Life of this patent

Method and apparatus for operating a fuel-supply system with lambda control

Life of this patent

Abstract

Claims14