Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1997-01-22
1998-02-24
Moulis, Thomas N.
Internal-combustion engines
Charge forming device
Fuel injection system
F02M 4100
Patent
active
057202621
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a dynamic electronic control system for controlling the injection pressure of a rail injection system.
BACKGROUND ART
Control systems are known which provide for controlling the injection pressure of fuel supply systems wherein a pump supplies the fuel at high pressure (1000-1300 bar) to a rail presenting a number of outlets communicating with respective injectors.
Such supply systems also comprise a pressure regulator interposed between the pump outlet and the rail inlet, and communicating with a fuel return conduit.
Known control systems comprise an electronic control unit supplied with a first signal generated by a pressure sensor on the rail, and a second signal representing an optimum reference pressure, and which processes the input signals to generate a pressure regulator drive signal.
More specifically, known control systems comprise a proportional integral regulator P.I. which is supplied with an error signal e(t) representing the difference between the first and second signal, and generates the drive signal u(t) according to an expression of the type: proportional constant and integral constant respectively of the P.I. regulator.
Injection pressure control systems of the above type provide for only approximate control, which is ineffective under certain operating conditions of the fuel supply system.
Moreover, such known known systems are also subject to instability.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a system designed to overcome the aforementioned drawbacks typically associated with known systems.
According to the present invention, there is provided a dynamic control system for controlling the injection pressure of an internal combustion engine fuel injection system; number of outlets communicating with respective injectors of said engine; and and the inlet of said rail; conduit;
said pressure control system comprising: (Pmis) correlated to the fuel pressure in the rail; pressure; and generating an output signal (U(z)) for driving the pressure regulator; means supplied with a digital error signal (Err(z)) and generating said drive signal (u(z)); between said first and second signal; R(z)=U(z)/Err(z) of the type: ##EQU1## where:
z=a digital variable;
a=a numeric coefficient;
Kc=a proportional numeric coefficient.
BRIEF DESCRIPTION OF DRAWINGS
A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:
FIG. 1 shows a dynamic electronic injection pressure control system in accordance with the teachings of the present invention;
FIG. 2 shows a logic block diagram illustrating physical-mathematical operation of the control system according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Number 1 in FIG. 1 indicates a dynamic electronic injection pressure control system applied to the injection system 4 of an internal combustion engine 6 (shown schematically), in particular a diesel engine.
Injection system 4 comprises an electric supply pump 8, the inlet of which is connected by a supply conduit 10 to a fuel tank 12, and the outlet 8a of which is connected by a high-pressure (1000-1300 bar) supply line 15 to the inlet 17a of a known rail 17.
Rail 17 presents a number of outlets 19a, 19b, 19c, 19d communicating with respective injectors 21a, 21b, 21c, 21d of engine 6 (common rail).
Injection system 4 also comprises a pressure regulator 24 located along high-pressure line 15 and preferably consisting of a two-way solenoid valve controlled by an electronic control unit 27. More specifically, solenoid valve 24 comprises an electric winding 30 (shown schematically) for axially displacing a shutter 26 (also shown schematically).
Pressure regulator 24 also communicates with a first fuel return conduit (bypass) 28 terminating in tank 12.
Injection system 4 also comprises a second fuel return conduit 29 presenting inlets communicating with recirculating outlets of injectors 21a-21d, and an outlet
REFERENCES:
patent: 5058553 (1991-10-01), Kondo et al.
patent: 5085193 (1992-02-01), Morikawa
patent: 5094216 (1992-03-01), Miyaki et al.
patent: 5197438 (1993-03-01), Yamamoto
"Application of H Optimal Design to Automative Fuel Control," Kuraoka et al., 1989 American Control Conference, vol. 3, 23 Jun. 1989, pp. 1957-1962.
"Generalized Gain Control of a Diesel Engine Based on H2 Optimization," Jiang, 1993 American Control Conference, vol. 1, 2 Jun. 1993, pp. 306-309.
"Sampled-data theory appliced to the modelling and control of compression-ignition engins-part II," Flower et al., International Journal of Control, vol. 13, No. 4, Apr. 1971, pp. 609-623.
Antonioli Pierpaolo
Pisoni Alberto
C.R.F. Societa Consortile per Azioni
Moulis Thomas N.
LandOfFree
Dynamic electronic control system for controlling the injection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dynamic electronic control system for controlling the injection , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamic electronic control system for controlling the injection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1869377