EP0277826A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electronic control system for an IC engine
Assignee: ZF International UK Ltd
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Filing: 1988-02-03
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Granted: —
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Expires: 2008-02-03
Abstract
Abstract In an engine management system which stores a control value (FBPOS) and increments or decrements this according to whether an oxygen sensor (20) in the exhaust system (18) indicates that the engine (10) is running lean or rich and which controls the duration of pulses (32) applied to fuel injectors (26) of the engine according to the stored control value (FBPOS), a compensating adjustment is determined and applied to the pulse length duration in order to maintain the mark/space ratio of the indicating signal from the oxygen sensor at an optimum value. This avoids unacceptable exhaust emissions which might otherwise occur under some conditions.
Inventors
- 👤 James John Samuel
- 👤 Albert Robert Tingey
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:19
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1473; F02D41/1474; F02D41/1477; F02D41/1483
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
An electronic control system for an internal combustion engine, comprising a sensor (20) for disposing in the engine exhaust stream (18) and arranged to provide an indicating signal as to whether the engine is running rich or lean, a central control unit (30) storing a control value (FBPOS) and responsive to said indicating signal to increment or decrement said stored control value according to whether that signal indicates the engine is running lean or rich, and an output (32) from said control unit for providing an actuating signal for controlling the amount of fuel delivered to the engine, the control unit being arranged to control said actuating signal in accordance with 10 control unit (30) is further arranged to monitor the relative durations for which said indicating signal indicates that the engine is alternately under its rich and lean running conditions, and to exercise a compensating control over said stored control value (FBPOS) so as to tend to maintain said relative durations at an optimum.
Claim 2
Dependent Claim
165 words
An electronic control system for an internal combustion engine, comprising a sensor (20) for disposing in the engine exhaust stream (18) and arranged to provide an indicating signal as to whether the engine is running rich or lean, a central control unit (30) storing a control value (FBPOS) and responsive to said indicating signal to increment or decrement said stored control value according to whether that signal indicates the engine is running lean or rich, and an output (32) from said control unit for providing an actuating signal for controlling the amount of fuel delivered to the engine, the control unit being arranged to control said actuating signal in accordance with 10 control unit (30) is further arranged to monitor the relative durations for which said indicating signal indicates that the engine is alternately under its rich and lean running conditions, and to exercise a compensating control over said stored control value (FBPOS) so as to tend to maintain said relative durations at an optimum.
Claim 3
Dependent Claim
69 words
An electronic control system as claimed in claim 1, characterised in that said central control unit (30) responds to said indicating signal indicating a change of the engine between rich and lean running conditions to effect a step-change in the stored control value (FBPOS), and said control unit 30 exercises its said compensating control over said stored control value by varying the magnitude of said step-change (e.g. A LUMP).
Claim 4
Dependent Claim
64 words
An electronic control system as claimed in claim 1 or 2, characterised in that said control unit (30) comprises a memory (M2) storing a fixed value of of the optimum mark/space ratio for said indicating signal and said control unit controls said stored control value (FBPOS) so as to tend to maintain the mark/space ratio of said indicating signal at said stored fixed value.
Claim 5
Dependent Claim
47 words
An electronic control system as claimed in claim 3, characterised in that said control unit (30) is arranged to deduce an up-dated value for the optimum mark/space ratio of said indicating signal from engine performance, and to replace the value in said memory with the updated value.
Claim 6
Dependent Claim
65 words
An electronic control system as claimed in any preceding claim, characterised in that a device (12) for sensing engine load is provided, in that the control unit (30) determines which of a plurality of ranges the sensed engine load lies within, and the control unit selects a different optimum mark/space ratio for said indicating signal according to the range in which the engine load lies.
References Cited (Backward Citations)
No citation records indexed.
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