EP0062583A2
Expired / Lapsed
EP
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Fuel injection system with fuel mapping
Assignee: Honeywell International Inc
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Filing: 1982-04-01
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Granted: —
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Expires: 2002-04-01
Abstract
Abstract A digital-analog fuel injection system wherein fuel lean out is controlled by a fuel mapping circuit (36) which provides one of sixteen levels of percent lean out control of the fuel pulse width supplied to an injector. In order to provide an immediate update of the engine demands, a pulse generation circuit (72) operates in real time. The fuel mapping circuit (36) provides corrections to the pulse generating circuit on a sampled update basis. This is accomplished by using a digital word (34) generated by a microprocessor (10) to control a multiplying digital to analog converter whose reference input is an electrical signal (V MAP ) representing the present manifold pressure and an offset voltage (V o ) accounting for the several variable of the system such as the engine, injectors and pressure sensor. The output signal (V B ) from the fuel mapping circuit (34) is then applied to a pulse generating circuit (72) to control the generation of fuel pulse width which is being applied to a fuel injector driver (46).
Inventors
- 👤 Peter Ward Harper
- 👤 Mark Coleman Harvey
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 18:15
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/24; F02D41/2406; F02D41/26
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
268 words
A fuel injection system with fuel mapping for energizing a plurality of fuel injectors for supplying controlled amounts of fuel to an engine, wherein said system comprises a plurality of sensors (14) (16) (18) each sensing an engine operating condition and generating an electrical signal (20) indicating said sensed operating condition, one (14) of said sensors indicating manifold absolute pressure and another of said sensors indicating engine operating speed, a microprocessor (10) adapted to receive each of said signals and operative in response thereto for generating a plurality of output signals including one or more digital words, a digital to analog converter (26) receiving one of said digital words and operative to generate an analog voltage signal (VOC) for generating a current control signal, pulse generating means (40) (46) responsive to the engine operating . condition signals and the current control signal and operative to generate a pulse indicating actuation of an injector and having a pulse width proportional to the amount of fuel to be injected by the injector during the occurrence of said pulse, characterized by: fuel mapping circuit means (36) responsive to another of the output digital words (34) from said microprocessor (10) and the signal (VMAP) indicating manifold pressure for leaning out the fuel to be injected by the injector, said fuel mapping circuit generating an analog signal (V B ) which is electrically connected to the pulse generating means (40) (46) and operative to cause the pulse width signal to be shortened in accordance with said another output digital word (34) from the microprocessor (10) and the manifold pressure at time of injection.
Claim 2
Dependent Claim
268 words
A fuel injection system with fuel mapping for energizing a plurality of fuel injectors for supplying controlled amounts of fuel to an engine, wherein said system comprises a plurality of sensors (14) (16) (18) each sensing an engine operating condition and generating an electrical signal (20) indicating said sensed operating condition, one (14) of said sensors indicating manifold absolute pressure and another of said sensors indicating engine operating speed, a microprocessor (10) adapted to receive each of said signals and operative in response thereto for generating a plurality of output signals including one or more digital words, a digital to analog converter (26) receiving one of said digital words and operative to generate an analog voltage signal (VOC) for generating a current control signal, pulse generating means (40) (46) responsive to the engine operating . condition signals and the current control signal and operative to generate a pulse indicating actuation of an injector and having a pulse width proportional to the amount of fuel to be injected by the injector during the occurrence of said pulse, characterized by: fuel mapping circuit means (36) responsive to another of the output digital words (34) from said microprocessor (10) and the signal (VMAP) indicating manifold pressure for leaning out the fuel to be injected by the injector, said fuel mapping circuit generating an analog signal (V B ) which is electrically connected to the pulse generating means (40) (46) and operative to cause the pulse width signal to be shortened in accordance with said another output digital word (34) from the microprocessor (10) and the manifold pressure at time of injection.
Claim 3
Dependent Claim
82 words
A system according to claim 1, characterized in that the pulse generating means (40) comprises a control capacitor (86) means which is rapidly discharged to a discharge voltage level controlled by the said analog signal (V B ) from said fuel mapping circuit means (36) and is responsive to current control signal for charging at a predetermined rate, and comparator means (78) for comparing the voltage charge on said capacitor means and the voltage indicating manifold-pressure, to generate the pulse width signal.
Claim 4
Dependent Claim
42 words
A system according to claim 1 or 2, characterized in that said fuel mapping circuit means (36) comprises a multiplying digital to analog converter (50) for multiplying the manifold pressure voltage (VMAP) with the another output digital word (34) from the microprocessor.
Claim 5
Dependent Claim
93 words
A system according to claim 3, characterized in that it additionally includes an offset voltage generator (66, 68, 69, 70) electrically connected to the input of said fuel mapping circuit means (36) for electrically moving the transfer function of fuel pulse width versus manifold pressure in accordance with the variables of the system by changing the input voltage to said fuel mapping circuit (36) to be a function of 'the manifold pressure voltage and said offset voltage whereby said multiplying digital to analog converter (50) is a differential multiplying digital to analog converter.
Claim 6
Dependent Claim
43 words
A system according to claim 3 or 4, characterized in that said fuel mapping circuit means (36) provides one of sixteen discharge voltage levels for said capacitor means (86) for each of the manifold pressure voltages inputted to said fuel mapping circuit means.
Claim 7
Independent Claim
35 words
A system according to any of the preceding claims, characterized in that the pulse generating means (46) is a sequential injection pulse generating means generating pulses indicating the actuation sequence for each of the injectors.
References Cited (Backward Citations)
No citation records indexed.
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