US 5,345,912 AGranted

Method and device for controlling a carburetor

AssigneeAktiebolaget Electrolux

InventorsUlf Svensson, Hans Strom

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a method and device for controlling a carburetor (1) of an i. c. engine, the A/F ratio thereof is automatically adjusted to a preferred level during varying operating conditions. An adjusting means (5) is continuously actuated by a first control unit (4) of a first control circuit (3) to provide a A/F ratio having a modified dependency on the speed of rotation. An adjusting means (9) is periodically actuated for a short period by a second control unit (7) of a second control circuit (6), said second control unit receiving speed information (8) from the engine (2), to provide a short-term change of the mixture ratio, and the change of speed of rotation caused thereby is measured. With regard to the obtained result and stored information the second control unit (7) performs an adjustment of the mixture ratio by a predetermined step towards leaner or richer mixture by actuating an adjusting means (5). This procedure is repeated in the second control circuit (6) until the change of speed of rotation indicates that the mixture ratio is at a preferred level, and this adjustment is maintained for a period of time.

Claims8

Dependent claims

A method of controlling a carburetor of an internal combustion engine to automatically adjust an A/F ratio thereof to a preferred value, said method comprising the steps of:

(a) adjusting said A/F ratio to provide a modified relation of said A/F ratio to a speed of rotation of said engine with regard to a predetermined relation of said A/F ratio to said speed of rotation, said A/F ratio being generally continuously adjusted by an adjusting means, said adjusting means being actuated by a first control unit in response to a signal output of a first control circuit;
(b) periodically changing said A/F ratio to a different level for a short period of time, said A/F ratio being changed by said adjusting means, said adjusting means being actuated by a second control unit in response to a signal output of a second control circuit, wherein said second control unit receives a signal corresponding to said speed of rotation;
(c) measuring a change in said speed of rotation when said A/F ratio is changed to said different level;
(d) determining whether said A/F ratio is a leaner mixture or a richer mixture compared to said preferred value;
(e) adjusting said A/F ratio a predetermined step toward said preferred value by said adjusting means, said adjusting means being actuated by said second control unit in response to a signal output of said second control circuit;
(f) repeating steps (b) through (e) until said A/F ratio is substantially equal to said preferred value;
and
(g) repeating steps (b) through (f) after a predetermined period of time.

5 more elements

Dependencies are inferred from the claim text.