US 4,223,644 A · Method and apparatus for controlling operational variables of an internal combustion engine

Abstract

A principal operational variable of an internal combustion engine, for example the fuel-air mixture ratio, is controlled by superposition of three separate control steps. The basic setting of a control variable is obtained with a relatively coarse forward control, for example a carburetor in the case of fuel-air mixture control. Superimposed on this basic control is a refined forward control step which is based on the prevailing magnitudes of at least one operational variable, preferably the engine speed and the throttle valve position, and which applies a multiplicative correction to the basic setting of the fuel-air mixture. The third superimposed control step is a feedback control of the fuel-air mixture within the range of correction applied by the second control steps but based on still another engine variable, in particular the exhaust gas composition as sensed by an oxygen sensor (.lambda.-sensor). After comparison with the reference signal, the .lambda.-sensor signal is multiplied with the sum of the values of the basic air factor setting and the first corrective air factor setting. The data required for applying the first correction are preferably stored in a digital memory.

Claims16

Dependent claims

A method for controlling the magnitude of a first variable quantity associated with the operation of an internal combustion engine, comprising the steps of:

defining the magnitude of said first variable quantity in a first rough approximation (.lambda.O);
data storage means containing data representing a second approximation correcting value;
correcting the magnitude of said first variable quantity in a second approximation, more accurate than said first approximation, on the basis of the magnitude of at least one variable engine operation parameter received by said data storage means containing data (.DELTA..lambda.) being a difference between said first approximation and said second approximation;
providing a closed loop feedback signal based on a third variable quantity associated with the operation of said engine;
and
correcting on a third approximation only said second approximation correcting value by said closed loop feedback signal, said feedback signal being multiplied with other data derived from said data storage means upon receipt of said at least one variable engine operation parameter.

3 more elements

An apparatus for controlling the magnitude of a first variable quantity associated with the operation of an internal combustion engine, comprising:

basic control means for defining the magnitude of said first variable quantity in a first approximation;
first correction means for applying a first correction to the magnitude of said first variable quantity on the basis of the magnitude of at least one other, second variable quantity, said first correction means including sensor means for sensing the magnitude of said at least one other, second variable quantity, data storage means for storing the same, final control means for engaging said basic control means to thereby effect said first correction;
and
feedback control means for applying a second correction to the magnitude of said first variable quantity on the basis of the magnitude of at least one still other, third variable quantity, including sensor means for sensing the magnitude of said third variable quantity, comparator means for comparing the sensed magnitude of said third variable quantity with a reference value, and multiplier means for multiplying the signal from said comparator means with the output from said data storage means to thereby effect said second correction.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for controlling operational variables of an internal combustion engine

Life of this patent

Method and apparatus for controlling operational variables of an internal combustion engine

Life of this patent

Abstract

Claims16