JP2002106400A - Fuel feed system for internal combustion engine for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve the energy saving of the whole automobile by the control (demand control) fitted to the demand of a second pump without restricting the function of an internal combustion engine. SOLUTION: The second pump is controlled in an open loop and/or a closed loop within its rotation speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of operating a fuel supply system for an internal combustion engine of a motor vehicle, wherein the fuel is supplied to a first pressure zone by at least one first pump, Fuel is supplied by a second electric pump from the first pressure region to the second pressure region by at least one pressure accumulator, and fuel is injected directly from the second pressure region into the combustion chamber by an injection valve;
The pressure in the second pressure area is detected by the pressure sensor,
The pressure in the second pressure range is closed-loop controlled by the pressure control means disposed in the second pressure range, and an open-loop control signal for open-loop control of the pressure control means is generated. Type of operation. The invention also relates to a fuel supply system for an internal combustion engine of a motor vehicle, comprising at least one first pump, by means of which the first pump can supply fuel into a first pressure zone. And having at least one second electric pump, which can supply fuel from the first pressure zone to a second pressure zone with at least one pressure accumulator. , An injection valve, the fuel can be directly injected from the second pressure region into the combustion chamber using the injection valve, and a pressure sensor is provided. The pressure in the area is detected, and the apparatus has pressure control means. The pressure control means is disposed in the second pressure area, and the pressure in the second pressure area is controlled by the pressure control means. Closed loop control is possible. That relates to a fuel supply system of the type having an open-loop control signal generating means. Furthermore, the invention relates to a control device for an internal combustion engine of a motor vehicle and a storage medium for the control device of an internal combustion engine of a motor vehicle.

[0002]

2. Description of the Related Art For example, in an internal combustion engine of an automobile or the like,
There is an increasing demand for reducing fuel consumption and for suppressing exhaust gas generated simultaneously with desired high output. To this end, modern internal combustion engines have a fuel supply system in which the supply of fuel into the combustion chamber of the internal combustion engine is controlled electronically, in particular in a computer-assisted manner, by open-loop control and / or closed-loop control. Have been.

A so-called direct fuel injection system (BDE)
Thus, fuel needs to be injected under pressure into the combustion chamber. For this purpose, a pressure accumulator is provided which places the fuel under high pressure by actuation of the pump. From this pressure accumulator, fuel is injected directly into the combustion chamber of the internal combustion engine via an injection valve.

German patent application DE 195 48 278
A1 discloses a method and a device for controlling an internal combustion engine with a high-pressure injection system for a self-igniting internal combustion engine. Here, fuel is supplied by a discharge pump into a low pressure region, and further supplied by a high pressure pump into a high pressure region, a so-called common rail. This discharge pump is configured as an electric fuel pump,
Fuel is supplied from a fuel storage container or fuel tank into the low pressure region. A pressure limiting valve is provided in parallel with the electric fuel pump, and the pressure limiting valve returns fuel from a low pressure region into a fuel tank of the vehicle when a predetermined pressure is exceeded. A pressure sensor is provided in the high pressure area, and detects a pressure in the common rail. Further, a pressure control valve is provided between the high pressure region and the fuel tank of the vehicle, and the pressure control valve depends on an open loop control current to transfer fuel from a high pressure region to the fuel tank from a predetermined settable pressure. return. Here, the number of revolutions of the electric fuel pump is controlled in a closed loop according to the control signal in order to adapt the discharge amount to the current demand of the engine. In the event of a system error, this pressure control valve can be used as an emergency actuation valve for rapidly reducing the pressure in the common rail.

German patent application DE 198 53 823
From the A1 specification, a motor vehicle in which fuel is supplied to a pressure accumulator of an internal combustion engine by a first fuel pump, usually driven by an electric motor, and a second, high-pressure pump, usually mechanical. A method of operating an internal combustion engine is disclosed. The amount of fuel supplied in this case can be changed by a corresponding control of the fuel pump driven by the electric motor. The respective required fuel quantity is thus supplied to the pressure accumulator. The output of the first fuel pump is controlled via a characteristic map as a function of the amount of fuel to be injected and / or the speed of the internal combustion engine and / or the intake air temperature and / or the operating voltage. Means for compensating and adjusting a characteristic map for each start-up process of an internal combustion engine is disclosed in order to compensate for fluctuation errors caused by, for example, aging of various fuel pumps. For this compensation, for example, the actual value of the pressure in the pressure accumulator is measured and compared with the desired value of the pressure in the pressure accumulator depending on the required fuel quantity. Depending on the result of the comparison between the detected actual value of the pressure in the pressure accumulator and the desired value, the characteristic map is compensated. The pressure in the pressure accumulator is detected using a pressure sensor located in the high pressure path.
For controlling the pressure in the high-pressure accumulator, a pressure control valve is arranged in this high-pressure accumulator. This valve returns excess fuel to the vehicle's fuel tank. This pressure control valve can be opened and closed via an input signal. Furthermore, an electronic control unit is provided, which is supplied with the output signal of the pressure sensor, which generates input signals for the first fuel pump and the pressure control valve. By such means, the control of the discharge amount of the first fuel pump is performed by the electronic control device, and the control of the pressure in the high-pressure region is performed by the pressure control valve.

German patent application D not yet published
E 199 03 272.6-13 discloses a fuel supply system for an internal combustion engine of a motor vehicle, in which fuel is pumped into a pressure accumulator using a pump and injected directly into the internal combustion engine by an injection valve. . Means for driving the pump mechanically, that is to say by means of a rigid connection with the internal combustion engine, and for configuring the pump as an electric pump are known. The integrated system according to this unpublished German patent application DE 199 03 272.6-13 has an electric pump for supplying fuel from a tank to a low-pressure area. From this low pressure region, fuel is supplied to the high pressure region or common rail using a high pressure pump. From this pressure region, fuel is injected directly into the combustion chamber of the internal combustion engine using an injection valve. In the high pressure region of the system, a pressure sensor and a pressure control valve are further provided. Electric high pressure pumps, pressure sensors, injection valves,
A pressure control valve is also connected to the control device, and the control device performs open-loop control of at least the electric high-pressure pump, the injection valve, and the pressure control valve based on data supplied from the pressure sensor. For controlling the amount of fuel supplied,
Means for controlling the number of revolutions of the electric pump in a closed loop according to the required discharge force are known. The open-loop control of the pressure control valve is performed using a respective constant clock ratio, which is selected according to the operating state, for example the starting mode or the normal mode. This unpublished German patent application D
E 199 03 272.6-13 The specificity of the description is considered as follows. In other words, the pump is designed and designed in such a way that in a short period of time, in particular during a slight revolution of the internal combustion engine, there is already sufficient pressure in the pressure accumulator to inject fuel into the combustion chamber of the internal combustion engine. Is a point.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improvement in view of the above-mentioned drawbacks of the prior art.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided, in accordance with the present invention, a method for controlling a second pump within its rotational speed by open loop control and
And / or closed loop control to resolve.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Fuel is supplied to a first pressure zone by at least one first pump and fuel is transferred from a first pressure zone to a second pressure zone by at least one second electric pump. The fuel is supplied by at least one pressure accumulator, fuel is injected directly from a second pressure zone into the combustion chamber by an injection valve, and a pressure in the second pressure zone is detected by a pressure sensor. For controlling the pressure in the second pressure range in a closed loop by means of a pressure control means arranged in the internal combustion engine and generating an open loop control signal for the open loop control of the pressure control means. The method of operation of the fuel supply system is improved over the prior art in that the second pump is controlled in open-loop and / or closed-loop manner within its rotational speed. The advantage of the method according to the invention is that the control of the demand of the second pump (demand control) without constraining the functioning of the internal combustion engine makes it possible to save energy for the entire system, that is, for the entire vehicle. .
This lies in particular in that the electrically driven second pump (high-pressure pump) has a very high energy demand. Overall, it has been found that the method according to the invention leads to an energy saving of 1-2%.

[0010] Advantageously, the fuel quantity required for the engine is determined, and the target rotational speed of the second pump is determined at least from the fuel quantity required for the engine. In addition, under open-loop control of the second pump with a predetermined target speed, the following must also be taken into account: That is, it must also be taken into account that the pressure control means actually requires an excess flow which is fed back to the first pressure zone via the pressure control means. In other words, the target speed for the second pump must be chosen as follows. That is, it is selected so that at least the fuel necessary for combustion in the combustion chamber of the vehicle and the fuel for the excess flow of the pressure control means in the second pressure region are supplied. Specifically, the target rotation speed determined in this way is a safety coefficient and / or a correction coefficient,
And / or apply a safety offset and / or a correction offset.

According to another advantageous embodiment of the method according to the invention, the first pump is controlled by an open-loop control and / or a closed-loop control so that at least the fuel quantity required for the engine is supplied to the first pressure range. Is done. It has been shown that the control of the first pump according to the invention further contributes to the energy saving of the whole system, that is, the fuel consumption of the motor vehicle.

According to another advantageous embodiment of the method according to the invention, the open-loop control signal for the open-loop control of the pressure control means is formed from the sum of two independent partial signals.
In this case, advantageously, the first partial signal comprises at least a second
Is formed as a function of the actual pressure value in the pressure range and the desired pressure value which depends on the operating point. The second partial signal is determined at least as a function of the fuel mass flowing into or out of the pressure accumulator.
In this case, the second partial signal is taken from the applicable characteristic map. Determination of an open-loop control signal for open-loop control of the pressure control means from a first partial signal (which represents a closed-loop control component) and a second partial signal (which represents a pre-control component) according to the invention In this way, the pressure in the pressure accumulator is controlled in a closed-loop manner, so that the pressure required for the injection is obtained under all operating conditions.

[0013] There is at least one first pump, by which fuel can be supplied into the first pressure zone, and at least one second electric pump. Wherein the second pump is capable of supplying fuel from the first pressure region to a second pressure region having at least one pressure accumulator, and having an injection valve. Is capable of directly injecting fuel from the second pressure region into the combustion chamber, has a pressure sensor, detects the pressure in the second pressure region using the pressure sensor, and has pressure control means. , The pressure control means is disposed in a second pressure region, and the pressure control means
The fuel supply system for an internal combustion engine of a motor vehicle, in which the pressure in the pressure region is closed-loop controllable and has an open-loop control signal generating means (3) for said pressure control means, compared to the prior art It has been improved in the following points. That is, open-loop control of the second pump within its rotational speed and
It is improved in that means for enabling closed-loop control are provided.

According to an advantageous embodiment of the fuel supply system according to the invention, the pressure control means in the second pressure zone is a pressure control valve.

The advantages of the fuel supply system according to the invention are:
As mentioned above under the method according to the invention, the stability of the pressure in the second pressure zone and the existing reliable supply as well as the energy savings of the entire system.

According to another embodiment of the fuel supply system,
The pressure control means and the second pump form one structural unit, or the pressure control means is integrated in the second pump. The advantage of such a structural unit lies in the flexible unit arrangement in the engine compartment. Here, advantages are also obtained when dividing the space in the engine room.

According to another advantageous embodiment of the fuel supply system, at least one ignition device is assigned to the combustion chamber, with which the fuel in the combustion chamber can be ignited. More preferably, the internal combustion engine is designed as follows. That is, fuel can be injected into the combustion chamber at least in the first operating mode during the compression phase, and in the second operating mode during the intake phase. In particular, the application of direct injection and injection in two different modes of operation are combined with the fuel supply system according to the invention, in particular a fuel-saving and space-saving and low-cost internal combustion engine design is achieved.

It is particularly important that the implementation of the method according to the invention takes place in the form of a control device for the internal combustion engine of a motor vehicle. In this case, the steps of the method of operating the fuel supply system for a motor vehicle internal combustion engine are continuously implemented, in particular on a storage medium for the control device of the motor vehicle internal combustion engine, on a computer, especially on a microprocessor in the control device. A program is stored. In this case, the invention is realized by a program stored on a storage medium, so that this storage medium with the program represents the invention in a manner similar to that which is suitable for implementation in a program. As the storage medium, an electric storage medium, for example, a ROM or an EPROM is particularly applicable.

Further advantageous embodiments and refinements of the invention are described in the dependent claims.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail hereinafter with reference to the drawings.

FIG. 1 shows a first embodiment of the device according to the invention. A first pump 2 is arranged in the area of the fuel storage container or fuel tank 1 of the motor vehicle, which is usually configured as an electric fuel pump. The electric fuel pump 2 is connected to an engine control device 3 via a control line 4. This control line 4
The engine control device is, for example, an electric fuel pump 2
And also affects the discharge rate. The electric fuel pump 2 supplies fuel from the fuel tank 1 to the second pump 6 via the first pressure line 5. The second pump 6 is configured as an electrically driven high-pressure pump, and is connected to the engine control device 3 via a control line 7. The electric high-pressure pump 6 supplies fuel to a pressure accumulator 9, a so-called common rail 9, via a second pressure line 8. From this common rail 9, fuel placed under high pressure is injected via a pressure line 10 into the injection valve 1.
1 (also referred to as an injector). The fuel is directly injected into the combustion chamber 12 using the injection valve 11.
For controlling the injection valves 11, each of these injection valves is connected to the engine control device 3 via a control line 13. For the detection or measurement of the pressure in the common rail 9, a pressure sensor 14 is arranged in the second pressure area, and the pressure sensor 14 transmits a signal representing the pressure in the common rail 9 via a signal line 15. The signal is transmitted to the engine control device 3. Furthermore, in the area of the common rail 9, means 16 for controlling the pressure in a closed loop and / or in an open loop are arranged. In this example,
The means 16 for controlling the pressure in a closed and / or open loop is configured as a pressure control valve. Alternatively, the application of any means for closed-loop and / or open-loop control of the pressure is also conceivable here (pressure regulator, flow control valve, etc.). The fuel flowing out of the pressure control valve 16 is returned via the fuel line 18 to the first pressure area 5, that is, the area before the second pump 6. The pressure control valve 16 is connected to the engine control device 3 via a control line 17. The engine control zone 3 influences the parameters of the pressure control valve 16 via this control line 17. This may be, for example, the setting of a predetermined pressure level in the common rail 9. Once the overpressure on the common rail exceeds this pressure level,
Fuel is returned to the first pressure region via the pressure control valve 16 (overflow).

The core of the fuel supply system according to the present invention is as follows.
A rotation speed control device 19 for controlling the electric high-pressure pump 6. On the other hand, the rotation speed control device 19 controls the control line 2
0 is connected to the engine control device 3. Corresponding control of the electric high-pressure pump 6 is carried out via a line 21 in response to a setting / control signal from the engine control device 3 which is transmitted to a speed control device 19 via a control line 20.

In the case of the electrically driven high pressure pump 6,
For example, an asynchronous motor coupled to a mechanical pump.
Furthermore, within the framework of the fuel supply system according to the invention, the high-pressure pump unit 6 is structurally arranged away from the engine block 23 surrounding the combustion chamber. Such an arrangement offers thermal advantages, in particular in hot starting situations, and flexibility in mounting the system in the engine compartment of a motor vehicle (good packaging). Inside the high-pressure pump unit 6, there is a flow control valve. This can be controlled via a control line 7 connecting the engine control 3 and the high-pressure pump unit 6. The use of a flow control valve in the high-pressure pump unit 6 makes it possible to determine the amount of fuel supplied to the high-pressure pump unit 6 via a control signal.

The control device referred to as the engine control device 3 in the above-described embodiments is, of course, a dedicated control device having a task of exclusively controlling the components of the fuel supply system in a general case. There may be. In this case, the control device 3 together with the speed control device 19 and the high-pressure pump 6 may be integrated into a single structural unit. The integration of these component units into a single open-loop / closed-loop / pump unit is an advantage, especially for packaging in the engine compartment, and makes the actual engine configuration particularly easy for car manufacturers. It is an advantage that a new high-pressure fuel supply system can be equipped with high flexibility and high flexibility.

If the control device 3 is a central engine control device of a motor vehicle, various additional signal lines 22 are suggested which are used to take advantage of the further functions of the engine control device 3. According to the invention, inside the control device 3 is stored a program which realizes the functions described above and which enables the functions of the method according to the invention, which will be further described below with reference to FIGS. There is a storage medium stored.

It is particularly important that the fuel supply system according to the present invention is a gasoline direct injection system (BDE system).
That is for an internal combustion engine that operates according to: In such a system, at least one
One spark plug is arranged, and the gasoline in the combustion chamber 12 can be ignited using the spark plug. These spark plugs (at least one of which is a combustion chamber of an internal combustion engine)
/ Provided for each cylinder 12) is not shown in the drawing of FIG. 1 (and FIG. 2).

Further, such a system provides a means by which fuel can be injected into the combustion chamber during at least the first mode of operation during the compression phase and further in the second mode of operation during the intake phase. I do.
The second mode of operation, in which the injection takes place in the intake phase of the respective combustion chamber 12, corresponds in particular to a homogeneous air-gas mixture. This achieves injection into the combustion chamber within the framework of conventional injection (not direct injection). The first mode of operation, during which the fuel is injected during the compression phase of the combustion chamber, is also referred to as a stratified mode or a stratified charge mode. This stratified mode is provided especially when high power demands are not imposed on the internal combustion engine. The internal combustion engine in this case usually has lower fuel consumption than in the homogeneous mode. The fuel supply system according to the invention is particularly suitable for supplying the internal combustion engine with the required fuel to meet demand, especially during the stratified mode. This means that the number of revolutions of the discharge pump 2 and the number of revolutions of the high-pressure pump 6 can be reduced particularly during the period of the layered mode. This leads to a significant reduction in the energy demand of the pumps 2 and / or 6. A further advantage is that, due to the reduced rotational speed of the pumps 2 and / or 6 during operation, the burden on each pump is not as high as at maximum rotational speed, and thereby the pumps 2 and / or 6 It can have a longer lifespan. The flow control valve integrated in the high-pressure pump 6 is also correspondingly reduced and controlled.

FIG. 2 shows a second embodiment of the device according to the invention. In this case, the same elements have the same reference numbers. This embodiment differs from the embodiment shown in FIG. 1 in the arrangement of the pressure control valve 16 '. This pressure control valve 16 ′ is integrated in the high-pressure pump unit 6 in this second embodiment or is incorporated in the high-pressure pump unit 6. This pressure control valve 16 '
The excess fuel is thereby returned to the first pressure zone 5 before the high-pressure pump 6 via line 18 '. The control of the pressure control valve 16 'is performed via a control line 17'. This control line 17 ′ connects the pressure control valve 16 ′ to the engine control device 3. An advantage of the integration of the pressure control valve 16 'in the high-pressure pump unit 6 is that a flexible high-pressure pump module can be obtained in the actual concept of the internal combustion engine. In other words, it becomes easier for an automobile manufacturer to convert an existing internal combustion engine to an internal combustion engine having a high-pressure injection system.

FIG. 3 shows an embodiment of the method according to the invention, in which FIG.
16 to 16 'are shown. According to the invention, two partial signals are formed inside the two determination units 31 and 32. These two partial signals are applied to block 33
Are added to one total signal. The input signals / input data required for the determination of the two partial signals by the determination units 31 and 32 are supplied from the engine control device 3 either directly or indirectly. This indirect meaning here does not mean that data is not supplied, for example, between the engine control unit 3 and the determination units 31, 32 via direct connection lines, but rather that the transmission of the data takes place in the vehicle bus system ( CAN bus)
Is meant to be done via For example, in the chart of FIG. 3, three input amounts are shown for the determination units 31 and 32, respectively. However, this display is merely an example, and does not represent a limitation of the present invention. That is, more or less input signals may be processed. In the determination unit 31, a partial signal called a closed-loop control component is refined. In the determination unit 32, on the other hand, a partial signal called a pre-control component is generated. In this case, the closed-loop control component of the determination unit 31 is formed as a function of the actual pressure value predominantly occupied in the common rail 9 and the pressure setpoint of the common rail 9 depending on the operating point. The actual pressure value of the common rail 9 is detected by the pressure sensor 14 and transmitted to the determination unit 31 via the control device 3 as described with reference to FIG. The pressure setpoint for the common rail 9 depending on the operating point is taken, for example, from an applicable characteristic map stored in the control device 3. The pre-control component formed in the determination unit 32 is determined at least as a function of the fuel mass flowing into or out of the pressure accumulator. The specific determination of the amount of fuel flowing into or out of the common rail 9 will be described in the frame of the embodiment based on FIG.

After forming the sum of the closed-loop control component and the pre-control component in step 33, this sum signal is used in step 3
At 4, the corresponding control signals for the pressure control valves 16 to 16 'are converted. The resulting control signal (which is formed in step 34) may use, for example, a duty ratio (on / off ratio), pulse width modulation, or in the case of a magnet valve, for example, from 0 °. A 180 degree angle control may be used.

FIG. 4 shows the details of the formation of the first partial signal for the pressure control valves 16 to 16 '. The blocks of the method steps corresponding to the determination unit 31 of FIG. 3 are surrounded by a dashed line labeled 31. The method steps 41, 42 shown in FIG. 4 represent the actual value detection of the pressure in the common rail 9. Method step 44, on the other hand, represents the formation of the desired value of the common rail 9. In step 43, a target value-actual value control difference is formed from the difference between the target value and the actual value of the pressure of the common rail 9. In step 45, this step 43
Are converted by the PI controller or the PID controller into corresponding first partial signals for controlling the pressure control valves 16 to 16 ', and the method step 3 of FIG.
3 is transmitted.

The actual value detection in steps 41 and 42 is effected by the transfer of a signal representing the pressure to the method step 41 by means of the pressure sensor 14 for detecting the pressure in the common rail 9. In step 41, the signal characterizing the pressure of the pressure sensor 14 is received and forwarded to step 42 for filtering. Step 42
For example, low-pass filtering is performed to filter high-frequency interference components from a pressure signal. Step 42
Is transferred to step 43 as the actual value of the pressure in the common rail 9.

In a method step 44 according to the invention, a desired value for the pressure of the common rail 9 is derived or formed from an operating point-dependent characteristic map stored in the control device 3 in accordance with the current operating data. , 43.

In step 33 of FIG. 3, a pre-control component for controlling the pressure control valves 16 to 16 'is determined based on the amount of fuel flowing into or out of the common rail 9. The determination of the quantitative balance required for this is described below in the frame of FIG. Here, too, the engine control device 3 is shown, which supplies all the input quantities required for the method steps 51, 53, 55.

In step 51, the amount of fuel flowing into the common rail 9 is determined. This fuel amount is determined by the efficiency of the electric high-pressure pump 6, the number of revolutions of the electric high-pressure pump 6, the duty ratio of the magnet control valve integrated in the high-pressure pump (or the equivalent control of the magnet control valve). Signal).

In step 53, the amount of fuel injected into the combustion chamber of the internal combustion engine via the injector 11 is determined. This fuel amount is proportional to the product of the fuel amount for each injection determined by the engine control device 3 and the rotation speed of the internal combustion engine.

In step 55, the amount of surplus fuel recirculated to the second Au power region before the electric high-pressure pump 6 via the pressure control valves 16 to 16 'is determined. The corresponding surplus fuel quantity of the pressure control valve is determined by at least the control signal or duty ratio of the pressure control valve and the common rail 9 generated at that time.
Depending on the pressure in the engine control device 3, it is taken from an applicable characteristic map.

Hereinafter, the fuel amount determined in step 53 and flowing out of the common rail 9 by injection into the combustion chamber is subtracted from the fuel amount determined in step 51 and supplied to the common rail 9. The difference forming step is denoted by reference numeral 52. The output signal of method step 52 is transmitted to a further differentiator of step 54,
There, the surplus of the pressure control valves 16 to 16 'determined in step 55 is further reduced. The result of the method step 54 is the amount of fuel actually flowing into the common rail 9, specifically the increase in the amount of fuel in the common rail 9. These data are transmitted back to the control device 3. The control device 3 can provide these data to the method step 32 of FIG.

In the general case, the method steps shown in FIGS. 3, 4 and 5 are integrated in the engine control device 3, so that the method steps from the control device 3 shown in FIGS. 31, 32, 41, 44, 51, 53,
The transmission of information / data to 55 represents an internal process in the control device in the general case. The transmission of the determined fuel amount from the step 54 to the control device 3 is the same. However, within the framework of the method according to the invention, FIG.
These method steps corresponding to 4, 5 correspond to the control device 3
It may be implemented by a separate control device that is not integrated therein. In such a case, as already mentioned in the description of the device according to the invention with reference to FIGS.
A separate control device may be integrated in the structural unit of the electrically driven high-pressure pump 6.

A further measure for improving the control of the fuel supply system within the framework of the method according to the invention is to take the rotational speed of the high-pressure pump 6 into account when pre-controlling the electric fuel pump 2. In response to this, the control device 3 determines a correction coefficient and / or a correction offset of a control signal (for controlling the rotation speed) of the electric fuel pump depending on a predetermined target rotation speed of the high-pressure pump 6. Characteristic maps can be filed.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the device according to the invention.

FIG. 2 shows a second embodiment of the device according to the invention.

FIG. 3 shows an embodiment of the method according to the invention.

FIG. 4 shows a first detail of a first embodiment of the method according to the invention.

FIG. 5 shows a second detail of the first embodiment of the method according to the invention.

[Explanation of symbols]

 Reference Signs List 1 fuel tank 2 first pump (electric fuel pump) 3 engine control device 6 second pump (electric high-pressure pump) 9 common rail 11 injection valve 12 combustion chamber 14 pressure sensor 16 pressure control valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 364 F02D 45/00 364K F02M 37/08 F02M 37/08 B 55/02 350 55/02 350E (72) Inventor Jens Wolber Germany Federal Republic of Germany Geringen Pappe Leweg 6 (72) Inventor Thomas Frenz Germany Germany Nördlingen Boe Tenor Strasse 5 (72) Inventor Marx Amraer Germany Leonberg-Gevabausheim am Schlaugengraben 23 (72) Inventor Hansjerk Bochum USA Michigan Novi Palmer Drive 30842 F-term (reference) 3G066 AA02 AB02 AC09 AD12 BA17 BA39 BA41 BA61 BA67 C A01U CB07U CB12 CB15 CC01 CD02 CD03 CD25 CD26 CE21 CE22 DC08 DC18 3G084 BA11 BA14 BA15 BA16 DA02 FA00 FA13 FA33 3G301 HA01 HA04 JA02 LB06 LB07 MA19 PA10Z PB03Z PB08Z PE01Z

Claims (14)

[Claims] 1. A method for operating a fuel supply system for an internal combustion engine of a motor vehicle, the fuel being supplied to a first pump by at least one first pump (2).
At least one pressure accumulator (5) from the first pressure zone (5) to the second pressure zone (8) by at least one second electric pump (6). 9), and fuel is supplied by the injection valve (11) to the second pressure region (8, 8).
9) is directly injected into the combustion chamber (12), the pressure in the second pressure region (8, 9) is detected by the pressure sensor (14), and the pressure in the second pressure region (8, 9) is detected. The pressure in the second pressure region (8, 9) is closed-loop controlled by the pressure control means (16, 16 ') provided, and an open-loop control signal for the open-loop control of the pressure control means is generated. In the operating method of the type (31,32,33,34) to be generated, the second pump (6) is controlled (19,20,21) by open-loop control and / or closed-loop control within its rotational speed. A method for operating a fuel supply system, comprising: 2. The method according to claim 1, further comprising calculating a fuel quantity required for the engine, and determining a target rotational speed for at least the second pump from the fuel quantity required for the engine. 3. The open-loop control and / or the closed-loop control of the first pump (2) such that at least the amount of fuel required for the engine is supplied to the first pressure zone (5). Method. 4. The method according to claim 1, wherein the open-loop control signal for the open-loop control of the pressure control means is formed from the sum of two independent partial signals. 5. The first partial signal (31) comprises an actual pressure value (41, at least) in a second pressure range (8, 9).
42. The method as claimed in claim 4, wherein the pressure value is formed as a function of an operating point. 6. The second partial signal (32) depends at least on the fuel mass flowing into the pressure accumulator (9) and / or the fuel mass flowing out of the pressure accumulator (53, 55). 5. The method of claim 4, wherein the method is defined as: 7. The method according to claim 6, wherein the second partial signal is derived from an applicable characteristic map. 8. A fuel supply system for an internal combustion engine of a motor vehicle, comprising at least one first pump (2) by which fuel is pumped at a first pressure. Area (5)
And having at least one second electric pump (6) by which fuel is supplied from the first pressure zone (5) to at least one pressure accumulator. Supply to a second pressure zone (8) provided with a pressure vessel (9), comprising an injection valve (11);
The fuel can be directly injected from the second pressure zone (8, 9) into the combustion chamber (12) by using the pressure sensor (1), and the pressure sensor (1) has the pressure sensor (14).
The pressure in the second pressure region (8, 9) is detected by using (4), and the pressure control means (16, 16 ') includes a pressure control means (16, 16'). Pressure area of 2 (8, 9)
And the pressure control means (16, 16 ')
The pressure in the second pressure region (8, 9) can be controlled in a closed loop by the above, and the fuel supply of the type having the open loop control signal generation means (3) for the pressure control means (16, 16 ') Means (19, 20,) for enabling the second pump (6) to be open-loop and / or closed-loop controlled within its rotational speed.
21) A fuel supply system provided with: 9. The pressure control means (16, 16 ') and the second pump (6) form one structural unit, or the pressure control means (16, 16') comprises a second unit. 9. The fuel supply system according to claim 8, wherein the fuel supply system is integrated in the pump (6). 10. The pressure control means (16, 16 ').
The fuel supply system according to claim 8, wherein is a pressure control valve. 11. The fuel supply system according to claim 8, wherein at least one igniter is assigned to the combustion chamber, and the igniter can ignite fuel in the combustion chamber. 12. The fuel injection system according to claim 11, wherein fuel can be injected into the combustion chamber during at least a first operating mode during a compression phase and further during a second operating mode during an intake phase. A fuel supply system as described. 13. Control device for an internal combustion engine of a motor vehicle, comprising means for performing the steps of the method according to at least one of claims 1 to 7. 14. A control device for an internal combustion engine of a motor vehicle, wherein a program is stored on a computer, in particular on a microprocessor in the control device, which continuously causes the execution of the method steps according to claims 1 to 7. Storage medium.