CONTROL SYSTEM FOR HIGH-PRESSURE FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

Description

TECHNICAL FIELD

[0001] The present invention relates to an injection control system for internal combustion engine high-pressure injection systems.

BACKGROUND ART

[0002] A high-pressure injection system substantially comprises a fuel tank, and a high-pressure injector supply circuit in turn comprising a pump for supplying fuel at high pressure to a manifold in turn supplying a number of injectors. The pump presents a pressure regulating solenoid valve for supplying fuel at a predetermined pressure.

[0003] The EP-A-501 463 discloses a common rail high pressure fuel injection system, which comprises a fuel tank, and a high-pressure injector supply circuit in turn comprising a pump for supplying fuel at high pressure to a manifold in turn supplying a number of injectors. The pump presents a pressure regulating solenoid valve for supplying fuel at a predetermined pressure. The fuel pressure is PID feed-back controlled using the input from a pressure sensor by controlling the on time of a solenoid valve. One table is used for determining the fuel injection quantity as a function of engine parameters.

[0004] For best vehicle performance in terms of power, consumption, smoke level, exhaust and drivability, operation of the engine must be controlled to ensure the right quantity of fuel is injected at each injection with the right timing and pressure. Injection pressure in particular affects several injection parameters, such as fuel injection quantity for a given injection time; the fuel injection plan (volume per unit of time); fuel atomization; jet penetration; actual injection time; and duration of the electric signal; which parameters greatly affect engine performance, especially in terms of output, exhaust, noise level and drivability.

DISCLOSURE OF INVENTION

[0005] It is an object of the present invention to provide an injection control system for electronically controlling fuel injection quantity, injection advance (timing) and injection pressure with a high degree of resolution and flexibility, and as a function of the state of the engine (as indicated by speed, temperature, pressure and load values) and of power demand (as indicated by the position of the accelerator pedal).

[0006] According to the present invention, there is provided an injection control system for internal combustion engine high-pressure injection systems, comprising a number of injectors for injecting fuel at high pressure on the basis of injection control quantities; characterized in that it comprises regulation generating means for generating values regulating the injection control quantities on the basis of engine parameters; and control means for controlling the injection control quantities on the basis of said regulating values, according to claim 1.

BRIEF DESCRIPTION OF DRAWINGS

[0007] A preferred non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows an overall diagram of the hydraulic system of an injection system to which the control system according to the present invention is applied;

Figure 2 shows a detail of the pressure regulator of the Figure 1 system;

Figures 3-6 show block diagrams illustrating control of the controlled quantities according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] A general description will now be given, with reference to Figure 1, of a high-pressure injection system for internal combustion engines. The system, indicated by 1, comprises a tank 2 at atmospheric pressure, connected by a delivery line 5 to a radial-piston pump 6 presenting a pressure regulating solenoid valve (or pressure regulator) 7 connected by drain line 8 to tank 2.

[0009] Pump 6 feeds the fuel at high pressure along line 11 to a manifold 10 which provides for distributing the fuel to the injectors and damping any fluctuation in pressure caused by the action of the pump and opening of the injectors. Manifold 10 consists of a steel body in the form of a parallelepipedon and in which is formed a cylindrical cavity extending along the length of the manifold and connected to line 11 by a central hole 12. Manifold 10 also presents four holes 13 spaced along the length of the manifold and connected to four high-pressure (up to 1500 bar) supply conduits 14 of four injectors 15 of an engine 16. Each injector 15 is also connected to a conduit 17 for recirculating the drive valve operating fuel into tank 2.

[0010] Manifold 10 is fitted at one end with a known pressure sensor 18.

[0011] Pressure regulator 7 is conveniently formed as shown in Figure 2, and comprises a body 20 defining a conical seat 21 for a spherical shutter 22. By means of a push rod 23, shutter 22 is subjected to the combined force of a spring 24 and a solenoid 25 which cooperates with a core 26 integral with a rod 27 in turn integral with push rod 23. Varying the current supply to solenoid 25 regulates the force exerted on spherical shutter 22 in the closing direction and, hence, the output pressure of pump 6.

[0012] Pressure is regulated by supplying solenoid 25 with a current whose duty cycle is modulated at a fixed oscillation frequency (PWM - Pulse Width Modulation - technique) and using a closed regulating loop which takes into account the actual pressure measured by pressure sensor 18, as shown in the Figure 3 diagram described below.

[0013] A description will now be given of the control system according to the present invention, which is based on the observation that each instant in the operation of the engine is characterized by a given engine speed and load (torque). As load is in turn related to the quantity of fuel injected at each injection, controlling the fuel injection quantity therefore provides for regulating the power of the engine.

[0014] The relationship between load and the quantity of fuel injected at each point in the operation of the engine may be determined by bench testing the engine and simultaneously measuring load and fuel consumption. Bench testing also provides for determining the best injection pressure, injection advance and injection time adjustments and so obtaining control maps as a function of load and engine speed, i.e. as a function of fuel injection quantity and engine speed.

[0015] According to the present invention, operation of the engine is controlled using such maps. That is, on determining power demand by the user and the fuel quantity required for meeting it, the control system determines, by means of the maps, the adjustments to be made for ensuring correct operation of the engine.

[0016] The fuel injection quantity Q is calculated as shown in Figure 3. More specifically, during startup, a map 40 is used, having as inputs engine speed N and the temperature of the engine (e.g. of the coolant) or of the oil in the case of air-cooled engines. As such, output QO is in no way limited, and is independent of the position of the accelerator pedal.

[0017] At steady speed, a quantity QCARB is first calculated by means of a map 42 called a regulating map (by virtue of performing the same function as a normal mechanical pump regulator) and having as inputs engine speed N and a quantity Va related solely to the position of the accelerator pedal. If the closed-loop idling speed control is activated and engine speed is below a given threshold value, a parallel calculation is made of the fuel quantity QCMIN required to sustain the engine at zero power demand and low engine speed. QCMIN is calculated by means of a proportional-integral closed-loop control algorithm based on the error between a target idling speed and engine speed N; and, as a function of the error, a calculation is made of the fuel quantity QCMIN required to restore the target speed. The control algorithm is represented in Figure 3 by idling speed control block 43. Subsequently, the QCARB value is compared with QCMIN in block 44 to give a value Q1 corresponding to the greater of the two.

[0018] To control the smoke level at the exhaust when accelerating - as required by turbosupercharged diesel engines, due to the delay in adaptation of the supercharge pressure caused by the high degree of inertia of the turbosupercharger - provision is made for limiting the fuel quantity; which limitation is calculated by means of a smoke limiting map 45 having as inputs the air intake QA at each cycle, measured by means of a device at the intake, and engine speed N. The output QCMAX of map 45 is compared with Q1 in block 46 to give a value Q2 corresponding to the lesser of the two.

[0019] The fuel quantity is finally limited by means of a one-dimensional (power limiting) map 47 having engine speed N as the input and in which are stored the maximum acceptable fuel quantities at high power (fully pressed accelerator pedal). The output QCPOW of map 47 is compared with Q2 in block 48 to select the lesser of the two values, which represents the steady-state fuel injection quantity Q3. Quantity Q3 is used during steady-state operation, as shown schematically in Figure 3 by switch 41 which represents, ideally, selection of value QO or Q3 according to the operating condition of the engine (startup or steady state). Figure 3 of course merely illustrates the operating principle of the two processing operations performed respectively in the startup/steady-state condition, in that Q0 and Q3 are never calculated simultaneously, and switch 41 is purely indicative of enabling by the type of processing operation performed.

[0020] As already stated, fuel quantity Q is used for regulating the engine, comprising regulation of injection pressure, injection advance and injection time, which will now be described with reference to Figures 4, 5 and 6 respectively.

[0021] As shown in Figure 4, the injection pressure regulating system, indicated as a whole by 30, is a closed-loop type, and comprises a pair of maps 31, 32 for calculating a reference pressure correlated to the state of the engine. More specifically, map 31 provides for calculating steady-state reference pressure P_R1 on the basis of engine speed N and fuel injection quantity Q (corresponding to steady-state value Q3 calculated as described with reference to Figure 3); while map 32 provides for calculating startup reference pressure P_R2 as a function of engine temperature T and engine speed N, to take into account the requirements of the engine at different startup temperatures.

[0022] Via an ideal switch 33, the outputs of maps 31, 32 are connected selectively to the noninverting input of an error comparator 34, the inverting input of which is connected to the output of a filter 35 supplied with a signal correlated to the actual pressure measured by sensor 18 fitted to manifold 10.

[0023] The output of comparator 34, presenting error signal E, is connected to the input of a regulating element 36 and to a memory 37 whose output is also connected to regulating element 36. On the basis of the error between the reference and actual pressures, and of a proportional-integral control algorithm, regulating element 36 provides for controlling the duty cycle of the supply current to solenoid 25 (Figure 2). In practice, the output of regulating element 36 is connected to memory 37, and also controls an actuator 38 supplying solenoid 25.

[0024] The output of sensor 18 is conveniently read every 5 ms; the read pressure signal is filtered by filter 35 and compared with the reference pressure value from map 32 or 31, depending on whether the engine is in the startup or steady state respectively; the error E between the actual and reference pressure values is supplied to regulator 36 and to memory 37 which stores it for use in the following cycles; and regulator 36 calculates the duty cycle on the basis of a proportional-integral algorithm.

[0025] More specifically, the regulating element determines a new duty cycle percentage value (ranging from 1 to 99%) which in turn affects the force generated by solenoid 25 on spherical shutter 22. In -particular, the sign and value of error E determine the amount by which the duty cycle is varied, which in turn provides for so varying pressure as to achieve the required pressure value (set by the maps). When the duty cycle of the current supply to solenoid 25 is increased, this increases the force exerted on shutter 22 and hence the pressure inside the hydraulic circuit (conduits 11, 14, manifold 10). Similarly, a reduction in the duty cycle provides for a reduction in pressure.

[0026] Injection advance is determined as shown in Figure 5. More specifically, during startup, injection advance is determined by means of a map 50 (startup advance map) having as inputs engine speed N and engine temperature T, and generating an output value ANT0.

[0027] At steady speed, injection advance is calculated by means of two maps: a base map 51 and a correction map 52. Base map 51 presents as inputs fuel injection quantity Q (corresponding to steady-state value Q3 calculated as described with reference to Figure 3) and engine speed N, and generates a base advance value normally used for high-temperature operation of the engine; while correction map 52 presents as inputs engine speed N and engine temperature T, and provides, as a function of the input quantities, for determining an advance correction for low-temperature operation of the engine.

[0028] Outputs ANT1 and ANT2 of maps 51 and 52 are added in adding block 53 to give a value ANT3 which is used during steady-state operation as shown schematically in Figure 5 by switch 54 which represents, ideally, selection of the ANT0 or ANT3 value, depending on the operating condition (startup or steady state) of the engine.

[0029] Injection time ET is determined as shown in Figure 6. More specifically, during startup, injection time is determined as a function of fuel injection quantity Q (corresponding to value Q0 in Figure 3) and pressure P (output of filter 35 in Figure 4) measured just prior to injection, by means of a map 60 (startup ET map) supplying an output value ET0. If ET0 equals zero, no fuel is injected; if ET0 is above a maximum permissible value (e.g. 3000 µs), injection time is limited to the maximum permissible value (in a manner not shown in Figure 6).

[0030] At steady speed, injection time is determined as a function of fuel injection quantity Q (corresponding to value Q3 in Figure 3) and pressure P measured just prior to injection, by means of a map 61 supplying an output value ET1. In this case also, if ET1 equals zero, no fuel is injected (cut-off condition); and the maximum injection time is limited to a maximum permissible value (e.g. 1500 µs) in a manner not shown.

[0031] In this case also, the ET0 and ET1 values are calculated selectively, depending on whether the engine is in startup or the steady state, as shown schematically by switch 62.

[0032] The control system described thus provides for adapting the controlled injection variables to the operating condition of the engine, for ensuring the best values of the various injection parameters, such as atomization, jet penetration and injection plan, for each condition.

[0033] The system described also provides for a high degree of reliability, and may be implemented using easy-to-implement software with no major alterations to the injection system.

[0034] Injection pressure in particular, which is of vital importance for controlling the other quantities, is closed-loop controlled to ensure the best values are achieved at all times.

[0035] Clearly, changes may be made to the system as described and illustrated herein, for example, all the regulations described may be refined to take into account particular operating conditions of the engine.

Claims

1. An injection control system (30) for internal combustion engine high-pressure injection systems (1), comprising a number of injectors (15) for injecting fuel at high pressure (P) on the basis of injection control quantities (Q, P, ANT, ET); and regulation generating means (31, 32, 40-48, 50-53, 60, 61) for generating values regulating the injection control quantities (Q, P, ANT, ET) on the basis of engine parameters (N, Vα, T, QA); and control means (34-38) for controlling the injection control quantities on the basis of said regulating values; and pressure detecting means (18) for detecting an actual injection pressure value; and error detecting means (34) for generating an error signal related to the difference between a reference pressure value and said actual injection pressure value; said error signal being supplied to said regulating means (36-38) to obtain an injection pressure value equal to said reference pressure value; characterized in that it comprises first and second memory means (31, 32) for calculating the reference pressure value, having respective inputs supplied with signals relative to engine parameters; and switching means (33) having an output connected to said regulating means (36-38), and which selectively connect said first and second memory means to said regulating means according to the operating condition of said engine, said first and second memory means (31, 32) respectively relate to a steady-state and a startup condition of the engine; said engine parameters comprising engine speed and fuel injection quantity for said first memory means, and engine speed and engine temperature for said second memory means.

2. A system as claimed in Claim 1, comprising a solenoid valve (7) for regulating the pressure of a high-pressure pump (6) supplying said injectors (15); characterized in that said control means comprise regulating means (36-38) for varying the duty cycle of the supply current of said solenoid valve.

3. A system as claimed in Claim 1 or 2, wherein said injection system comprises a manifold (10) interposed between said pump (6) and said injectors (15); characterized in that said pressure sensor (18) fitted to said manifold (10).

4. A system as claimed in any one of the foregoing Claims from 1 to 3, characterized in that said error detecting means comprise a comparator (34) having a first input connected to the output of said pressure detecting means (18), and a second input connected to said generating means (31, 32); and said regulating means comprise a proportional-integral regulator (36).

5. A system as claimed in Claim 4, characterized in that it comprises third memory means (37) having inputs connected to said error detecting means (34) and said regulator (36), and an output connected to said regulator; said third memory means storing preceding error signals.

6. A system as claimed in Claim 4 or 5, characterized in that it comprises filter means (35) interposed between said pressure detecting means (18) and said comparator (34).

7. A system as claimed in any one of the foregoing Claims from 1 to 6, characterized in that said regulation generating means comprise startup generating means (40) for generating a first fuel injection quantity value as a function of engine speed and engine temperature; regulating generating means (42) for generating a second fuel injection quantity value as a funtion of engine speed and power demand; closed-loop control means (43) for controlling a minimum quantity as a function of engine speed and engine temperature; smoke limiting generating means (45) for generating an acceleration smoke limiting value as a function of air intake and engine speed; power generating means (47) for generating a power limiting value as a function of engine speed; first selecting means (44) for selecting the greater of said second value and said minimum quantity; second selecting means (46) for selecting the lesser of the output of said first selecting means and said acceleration smoke limiting value; and third selecting means (48) for selecting the lesser of the output of said second selecting means and said power limiting value.

8. A system as claimed in Claim 7, characterized in that said regulation generating means comprise startup advance generating means (50) for generating a first advance value as a function of engine temperature and engine speed; base advance generating means (51) for generating a second advance value as a function of fuel injection quantity and engine speed; correction generating means (52) for generating a correction value as a function of engine temperature and engine speed; and correcting means (53) for adding said second advance value and said correction value.

9. A system as claimed in Claim 7, characterized in that said generating means comprise startup injection time generating means (60) for generating a first injection time value as a function of fuel injection quantity and injection pressure; and steady-state injection time generating means (61) for generating a second injection time value as a function of fuel injection quantity and injection pressure.

10. A system as claimed in any one of the foregoing Claims, characterized in that said generating means comprise memorized maps.

Ansprüche

1. Einspritzsteuersystem für ein Hochdruckeinspritzsystem einer Brennkraftmaschine, mit einer Anzahl von Injektoren (15) zum Einspritzen von Kraftstoff mit hohem Druck (P) abhängig von Einspritzsteuergrößen (Q, P, ANT, ET), mit Mitteln (31, 32, 40 - 48, 50 - 53, 60, 61) zur Bildung von Größen zur Regelung der Einspritzsteuergrößen (Q, P, ANT, ET) ausgehend von Betriebsparametern (N, V, T, QA) der Brennkraftmaschinen, mit Regelmitteln (34 - 38) zur Steuerung der Einspritzsteuergrößen abhängig von diesen Größen zur Regelung, mit Druckmeßmitteln (18) zur Messung eines Istwerts des Einspritzdrucks, mit Fehlerermittlungsmitteln (34) zur Bildung eines Fehlersignals abhängig von der Differenz zwischen einem Sollwert und dem Istwert für den Einspritzdruck, wobei das Fehlersignal dem Regelmittel (36 - 38) zugeführt wird, um einen Einspritzdruck entsprechend dem Solldruck zu erhalten, dadurch gekennzeichnet, daß erste und zweite Speichermittel (31, 32) vorgesehen sind, um den Sollwert für den Einspritzdruck zu berechnen, wobei die Speichermittel als Eingangsgrößen die Parameter der Brennkraftmaschine verarbeiten, und mit Schaltmitteln (33), deren Ausgang mit dem Regelmittel (36 - 38) verbunden sind welche wahlweise abhängig vom Betriebszustand der Brennkraftmaschine das erste oder das zweite Speichermittel mit dem Regelmittel verbinden, wobei das erste und das zweite Speichermittel (31, 32) jeweils im Normalbetrieb und beim Start der Brennkraftmaschine verwendet werden, wobei dem ersten Speichermittel die Parameter Drehzahl und Einspritzmenge und dem zweiten Speichermittel die Parameter Drehzahl und Brennkraftmaschinentemperatur zugeführt werden.

2. System nach Anspruch 1 mit einem Magnetventil (7) zur Regelung des Druckes einer Hochdruckpumpe (6), die die Injektoren (15) versorgt, dadurch gekennzeichnet, daß das Steuermittel Regelmittel (36 - 38) zur Veränderung des Tastverhältnisses des Stroms, mit dem das Magnetventil beaufschlagt wird, umfaßt.

3. System nach Anspruch 1 oder 2, wobei das Einspritzsystem ein Druckspeicher (10) umfaßt, der zwischen der Pumpe (6) und den Injektoren (15) angeordnet ist, dadurch gekennzeichnet, daß das Druckmeßmittel (18) an dem Druckspeicher (10) angeordnet ist.

4. System nach einem der vorhergehenden Ansprüche 1 bis 3, dadurch gekennzeichnet, daß das Fehlerermittlungsmittel einen Komparator (34) umfaßt, dessen erster Eingang mit dem Druckmeßmittel (18) und dessen zweiter Eingang mit den Mitteln (31, 32) verbunden ist und daß das Regelmittel einen Proportional-Integralregler (36) umfaßt.

5. System nach Anspruch 4, dadurch gekennzeichnet, daß dritte Speichermittel (37) vorgesehen sind, deren Eingang mit dem Fehlerermittlungsmittel (34) und dem Reglelmittel (36) und dessen Ausgang mit dem Reglelmittel (36) verbunden ist, wobei dieses dritte Speichermittel zurückliegende Fehlersignale speichert.

6. System nach einem der Ansprüche 4 oder 5, dadurch gekennzeichnet, daß Filtermittel (35) vorgesehen sind, die zwischen dem Druckmeßmittel (18) und dem Fehlerermittlungsmittel (34) angeordnet sind.

7. System nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Regelmittel Startregelmittel (40), zur Bildung eines ersten Kraftstoffmengenwertes abhängig von der Drehzahl und der Brennkraftmaschinentemperatur umfaßt, mit Steuermitteln (42) zur Bildung eines zweiten Kraftstoffmengenwerts als Funktion der Drehzahl und der Last, mit Regelmittel (43) zur Bildung eines Minimalwerts als Funktion der Drehzahl und der Brennkraftmaschinentemperatur, mit Begrenzungsmittel (45) zur Bildung eines Rauchbegrenzungswert abhängig der angesaugten Luftmenge und der Drehzahl, mit Leistungsbegrenzungsmittel (47) zur Bildung eines Leistungsbegrenzungswerts abhängig von der Drehzahl, ersten Auswahlmitteln (44) zur Auswahl des größeren Wertes von dem zweiten Kraftstoffmengenwerts und dem Minimalwert, zweiten Auswahlmitteln (46) zur Auswahl des kleineren Ausgangssignals des ersten Auswahlmittels und des Rauchkennfeldes, und dritte Auswahlmittels (48) zur Auswahl des kleineren Werts des Ausgangsgrößen des zweiten Auswahlmittels (46) und des Leistungsbegrenzungswerts.

8. System nach Anspruch 7, dadurch gekennzeichnet, daß das Regelmittel Spritzbeginnregelmittel (50) umfaßt, um einen ersten Spritzbeginnwert abhängig von der Brennkraftmaschinentemperatur und der Drehzahl zu bilden, mit Mitteln (51) zur Bildung zweiten Werts als Grundspritzbeginns abhängig von der Einspritzmenge und der Drehzahl, Mitteln (52) zur Bildung eines Korrekturwerts abhängig von der Brennkraftmaschinentemperatur und der Drehzahl und Korrekturmitteln (53) zur Verknüpfung des zweiten Wertes und des Korrekturwertes.

9. System nach Anspruch 7, dadurch gekennzeichnet, daß ein Mittel (60) zur Bildung eines Einspritzdauerwertes vorgesehen ist, zur Bildung eines ersten Einspritzdauerwertes als Funktion der einzuspritzenden Kraftstoffmenge und des Einspritzdruckes, und ein Mittel (61) zur Bildung eines zweiten Einspritzdauerwertes als Funktion der Kraftstoffmenge und des Einspritzdruckes.

10. System nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Mittel Kennfelder umfassen.

Revendications

1. Système de commande d'injection (30) d'un moteur à combustion interne à système d'injection haute pression (1), comprenant un certain nombre d'injecteurs (15) pour injecter du carburant à haute pression (P) en fonction de quantités de commande d'injection (Q, P, ANT, ET), et des moyens de régulation (31, 32, 40-48, 50-53, 60, 61) générant des valeurs de régulation des grandeurs de commande d'injection (Q, P, ANT, ET) sur la base des paramètres du moteur (N, Vα, T, QA), ainsi que des moyens de commande pour commander des grandeurs de commande d'injection sur la base des valeurs de régulation, ainsi qu'un moyen de détection de pression (18) détectant une valeur de pression d'injection réelle, et un moyen de détection d'erreur (34) générant un signal d'erreur lié à la différence entre une valeur de pression de référence et la valeur de la pression d'injection réelle, ce signal d'erreur étant fourni aux moyens de régulation (36-38) pour donner une valeur de pression d'injection égale à la pression de référence,
caractérisé en ce qu'
il comprend une première et une seconde mémoire (31, 32) pour calculer la valeur de la pression de référence, avec des entrées respectives recevant des signaux liés aux paramètres du moteur, ainsi qu'un moyen de commutation (33) ayant une sortie reliée aux moyens de régulation (36-38) et reliée sélectivement à la première et à la seconde mémoire pour les moyens de régulation, selon les conditions de fonctionnement du moteur, la première et la seconde mémoires (31, 32) concernant respectivement un état permanent et un état de démarrage du moteur, les paramètres du moteur comprenant la vitesse du moteur et la quantité de carburant injectée pour la première mémoire, ainsi que la vitesse du moteur et la température du moteur pour la seconde mémoire.

2. Système selon la revendication 1, comprenant une électrovanne (7) pour réguler à la pression d'une pompe à haute pression (6) alimentant les injecteurs (15),
caractérisé en ce que
le moyen de commande comprend des moyens de régulation (36-38) modifiant le cycle de travail du courant alimentant l'électrovanne.

3. Système selon la revendication 1 ou 2, dans lequel le système d'injection comporte un collecteur (10) interposé entre la pompe (6) et les injecteurs (15),
caractérisé en ce que
le capteur de pression (18) est logé dans le collecteur (10).

4. Système selon l'une quelconque des revendications 1 à 3,
caractérisé en ce que
le moyen de détection d'erreur comprend un comparateur (34) dont la première entrée est reliée à la sortie du détecteur de pression (18), et la seconde entrée est reliée au générateur (31, 32), tandis que le moyen de régulation comprend un régulateur proportionnel-intégral (36).

5. Système selon la revendication 4,
caractérisé en ce qu'
il comporte une troisième mémoire (37) dont les entrées sont reliées au détecteur d'erreur (34) et au régulateur (36), ainsi qu'une sortie reliée au régulateur, la troisième mémoire enregistrant les signaux d'erreur précédents.

6. Système selon la revendication 4 ou 5,
caractérisé en ce qu'
il comporte un filtre (35) placé entre le détecteur de pression (18) et le comparateur (34).

7. Système selon l'une quelconque des revendications 1 à 6,
caractérisé en ce que
le générateur de régulation comporte un générateur de démarrage (40) générant une première quantité de carburant injectée en fonction de la vitesse du moteur et de sa température, un générateur de régulation (42) générant une seconde quantité de carburant injectée en fonction de la vitesse du moteur et de la demande de puissance, un moyen de commande en boucle fermée (43) commandant une quantité minimale en fonction de la vitesse du moteur et de sa température, un générateur de limitation de fumées (45) générant une valeur de limitation de fumées d'accélération en fonction de l'air d'alimentation et de la vitesse du moteur, un générateur de puissance (47) générant une valeur limitant la puissance en fonction de la vitesse du moteur, un premier sélecteur (44) sélectionnant la plus grande des valeurs comprenant la seconde valeur et la quantité minimale, un second sélecteur (46) sélectionnant la plus petite des valeurs composées de la sortie du premier sélecteur et de la valeur de limitation de fumées d'accélération, et un troisième sélecteur (48) pour sélectionner la plus petite des sorties du second sélecteur et de la valeur limitant la puissance.

8. Système selon la revendication 7,
caractérisé en ce que
le générateur de régulation comporte un générateur d'avance de démarrage (50) générant une première valeur d'avance en fonction de la température et de la vitesse du moteur, un générateur d'avance de base (51) générant une seconde valeur d'avance en fonction de la quantité de carburant injectée et de la vitesse du moteur, un générateur de correction (52) générant une valeur de correction en fonction de la température du moteur et de sa vitesse, ainsi qu'un moyen de correction (53) additionnant la seconde valeur d'avance et la valeur de correction.

9. Système selon la revendication 7,
caractérisé en ce que
le générateur comporte un générateur de durée d'injection de démarrage (60) générant une première durée d'injection en fonction de la quantité de carburant injectée et de la pression d'injection, et un générateur de temps d'injection en mode permanent (61) générant un second temps d'injection en fonction de la quantité de carburant injectée et de la pression d'injection.

10. Système selon l'une quelconque des revendications précédentes,
caractérisé en ce que
le générateur comporte des cartes de mémoire.

Drawing