WO2009130153A1

WO2009130153A1 - Device and method for allocating fuel and internal combustion engine equipped with the same

Info

Publication number: WO2009130153A1
Application number: PCT/EP2009/054497
Authority: WO
Inventors: Reinhard Barth; Sebastian Gast
Original assignee: Continental Automotive Gmbh
Priority date: 2008-04-23
Filing date: 2009-04-16
Publication date: 2009-10-29
Also published as: DE102008020329A1

Abstract

The invention relates to a device for allocating fuel, comprising at least one storage device (10), at least one delivery pump (17), at least one injector (10), and a multi-way valve (24). Fuel having a prescribable pressure can be stored in the storage unit (10), wherein the delivery pump (17) is set up to deliver the fuel to the storage device (10). Said fuel can be removed from the storage device (10) in prescribable amounts at prescribable times by means of an injector, and can be fed into at least one combustion chamber of an internal combustion engine. The pressure in the storage device (10) can be controlled by the multi-way valve (24), in that the amount of fuel to be added or removed is affected. The invention further relates to a method for fuel allocation and an internal combustion engine equipped with the device according to the invention.

Description

description

Device and method for fuel allocation and thus equipped internal combustion engine

The invention relates to an apparatus and a method for fuel allocation, in which the fuel is stored under increased pressure in at least one storage device and taken there by at least one injector and at least one combustion chamber of an internal combustion engine is supplied. Such devices are equally used for fuel allocation to self-igniting and spark-ignited internal combustion engines.

In a device for fuel allocation of the type mentioned above, the process for generating pressure is separated from the control of the injection process. Therefore, the injection process can be completely controlled by an electronic control unit, which controls an electrically operated valve by means of electrical signals. In this case, a valve is provided for each cylinder of a multi-cylinder engine. The injection process is influenced by the injection timing, the injection quantity, the number of individual injections and the injection pressure.

In order to control the injection pressure to a predefinable setpoint, the storage device must also have an opening for the removal of excess fuel in addition to a connected to a feed pump inlet, in order to reduce pressure within the storage device can. The removal opening is connected by means of an electrically controllable valve with a fuel return line. To increase the pressure to a predefinable setpoint can thus be controlled by the engine control a certain amount of fuel supplied to the storage device. To reduce the pressure to a predefinable set value, the motor control can control a controlled agreed amount of fuel to be removed from the storage device.

A disadvantage of this prior art, however, that separate components must be present for the allocation of fuel and the removal of excess fuel. These components require space, have additional weight and are susceptible to interference during operation of the internal combustion engine, since even the failure of a single component can lead to failure of the entire internal combustion engine.

Based on this prior art, the invention has the object to increase the reliability of a device for fuel allocation. Furthermore, the space required for an internal combustion engine and its weight should be reduced.

The object is achieved by a device for fuel allocation, which contains at least one storage device, at least one feed pump, at least one injector and a multi-way valve. In the storage device, fuel can be stored with a predeterminable pressure, wherein the delivery pump is adapted to convey the fuel into the storage device. This can be removed by means of an injector in a predeterminable amount at predetermined times from the storage device and can be supplied to the combustion chamber of an internal combustion engine. By the multi-way valve, the amount of fuel supplied can be influenced, whereby the pressure in the storage device can be regulated.

Furthermore, the object is achieved in a fuel allocation method in which the fuel is stored under increased pressure in at least one storage device and removed there by at least one injector and fed to at least one combustion chamber of an internal combustion engine, the pressure in the engine being increased by a multiway valve Storage device is regulated. In addition, the cancellation solution of the problem in an internal combustion engine, which is equipped with a device for fuel allocation of the type mentioned.

According to the invention, it has been recognized that a single multiway valve is adapted to both supply fuel to a storage device to increase the pressure prevailing in the storage device and to withdraw fuel from the storage device to reduce the pressure prevailing in the storage device. The multi-way valve used according to the invention can be controlled particularly advantageously by a single electrical signal from the engine control. In addition, the single multi-way valve saves weight and space.

Since both functions are controlled with only one actuator and one electrical signal, the reliability of the device according to the invention increases. An actuator should be an active element, such as an actuator. a servomotor, a piezo actuator, a solenoid or a similar element to be understood. In some cases, in addition to the actuator, a passive element such as. a spring are provided to bring the multi-way valve in case of failure of the actuator in a predetermined position.

The storage device used according to the invention in the device for fuel allocation can be, for example, a pressure vessel or a connecting line which is shared by all the cylinders of an internal combustion engine. The removed from the storage device and the

Combustion chambers of the internal combustion engine supplied fuel is replaced via a supply line by means of a feed pump. The pressure prevailing in the storage device can be the limit pressure which the delivery pump is able to provide. In a preferred embodiment of the invention, the desired value of the pressure in the storage device is predetermined by a control device, the actual value of the pressure is measured and regulated to this desired value. The setpoint can be adapted to the respective operating condition of the internal combustion engine.

According to the invention it is proposed to connect the storage device by means of the multi-way valve both with a supply line which supplies fuel from a reservoir of the storage device and with a return line, via which fuel from the storage device can be removed. To build up pressure in a first position of the multi-way valve fuel is removed via at least one feed pump from the reservoir and fed to the storage device. For pressure reduction, the multi-way valve is brought into a second position in which fuel is removed from the storage device via a return line. The extracted fuel can be returned, for example, in the reservoir. In a further embodiment of the invention, the withdrawn fuel can be passed back to the feed pump directly or via a heat exchanger.

Both positions of the inventively proposed multi-way valve can be approached sequentially via a single actuator, such as a solenoid, a piezo actuator or a servo motor. A single actuator requires only a single control signal. It can therefore be saved with the inventive device for fuel allocation an actuator and a connecting line to the control unit.

In a further development of the invention, the multi-way valve can be brought in case of failure of the actuator in a position which allows emergency operation. This can be done for example by means of an elastic element which acts on the operating element of the multiway valve. As a result, the multi-way valve can, for example, be brought into a position in which an average pressure is established in the storage device, with which in emergency operation a great deal of number of operating states of the internal combustion engine can be realized.

In order to reduce the amount of fuel fed back via the return line into the storage container, the invention proposes that the multiway valve has a blocking position in which neither the supply line nor the return line from or to the storage container are connected to the storage device. If this blocking position is provided as the center position of the multi-way valve, the supply line from the storage container to the storage device and the return line from the storage device to the storage container are never connected at the same time. It is therefore reliably avoided that subsidized fuel is immediately returned through the return line in the reservoir. In this way, the amount of fuel delivered by the feed pump as well as the drive energy required to drive the feed pump is minimized.

In a further preferred embodiment of the device according to the invention, the multi-way valve is designed as a proportional valve. This allows, as a function of the control signal generated by the control unit, an almost stepless influencing of both the supplied and the discharged fuel quantity and thus a particularly sensitive regulation of the pressure prevailing in the storage device.

A further reduction of the installation space as well as a further increase in the reliability in operation results, in particular, when the delivery pump and the multi-way valve are combined in one assembly. As a result, the line length between the components is effectively reduced.

The fuel allocation device according to the invention can be universally used for self-igniting and spark-ignited

Use internal combustion engines. However, particularly preferred is the use of a self-igniting internal combustion engine, since in these the pressure in the storage device in a especially wide range is adapted to different operating conditions, for example between about 30 bar and about 2500 bar.

Preferably, the inventively proposed is

Multi-way valve on the inlet side of the feed pump. As a result, the amount of fuel sucked in and compressed by the delivery pump can be optimized and the required drive energy is reduced as desired.

The invention will be explained in more detail with reference to figures and embodiments without limitation of the general inventive concept. It shows

1 shows a device for fuel allocation of the generic type according to the prior art.

Figure 2 shows an embodiment of the device according to the invention, in which a 4/3-way valve is used, in a first position of the valve

Figure 3 shows an embodiment of the device according to the invention, in which a 4/3-way valve is used, in a second position of the valve

Figure 4 shows an embodiment of the device according to the invention, in which a 4/3-way valve is used, in a third position of the valve

Figure 5 shows the valve position of a 4/3-way valve in response to a control signal which can be generated by an engine control unit.

FIG. 1 shows a device for allocating fuel to an internal combustion engine of the type mentioned in the introduction according to FIG

State of the art. The fuel is removed from a storage device 10 and supplied to the combustion chamber of an internal combustion engine. There is one for each cylinder Multi-cylinder engine an injector 19a, 19b, 19c and 19d available. Each injector is connected to the storage device 10 by means of a supply line. Each injector has a shut-off valve, not shown in detail, which can be influenced by an electrical control signal of an engine control unit 11. If the controller gives the command to open, the fuel exits at a predetermined time in a predetermined amount at the combustion chamber end of the injector 19. If the injector has leaks, leaking fuel is collected via a return line 22 and fed back to the reservoir 12.

The fuel taken out of the storage device 10 via the injectors 19 is replenished via a supply line 21. For this purpose, the supply line 21 is connected to a reservoir 12. The fuel is taken from a low pressure pump 14 via a fuel filter 13. At the output of the low-pressure pump 14, the fuel temperature is measured by means of a temperature sensor 15. This value is available to the control unit 11 for calculating the injection quantity. The output of the low pressure pump 14 is connected to an input of the high pressure pump 17 via a control valve 16. Via the control valve 16, the amount of fuel precalculated by the control unit 11 is allocated to the high-pressure pump 17. The high pressure pump 17 then conveys the

Fuel in the storage device 10 and puts them under pressure. In a further embodiment, both pumps 14, 17 can be combined to form a single delivery pump.

The pressure prevailing in the storage device 10 is measured by means of a pressure sensor 18. This can be arranged in the supply line 21, the storage device 10 or an injector 19. The actual value measured with the pressure sensor 18 is also available to the control unit 11. Depending on the operating state of the internal combustion engine, the control unit 11 presets a desired value for the accumulator pressure 10. For example, it can be provided in part-load operation lower pressure to the storage device 10 to create. The determination of the desired pressure value can take place, for example, by means of numerical maps, with a neural network or by a fuzzy logic. For this purpose, the control device 11, case by case, further input signals 23 are available. The input signals 23 may detect, for example, an accelerator pedal position, a boost pressure, a coolant temperature, an air temperature, an engine speed, or a crankshaft position.

If the pressure measured via pressure sensor 18 is lower than the desired value, the quantity valve 16 is opened and additional fuel is introduced into the storage device 10 by the high-pressure pump 17, in order to increase the pressure prevailing in storage device 10. If the pressure prevailing in the storage device 10 is higher than the desired value, fuel is discharged from the storage device 10. This is preferably done by means of the injectors 19a, 19b, 19c or 19d fuel from the storage device 10 is passed into the combustion chamber of at least one cylinder of the internal combustion engine. However, if no additional fuel is needed in the combustion chamber in the currently present operating state, for example in overrun, a drain valve 20 is available. This can also be opened by an electrical signal from the controller 11 and returns fuel from the storage device 10 via the return line 22 into the reservoir 12.

Figure 2 shows an embodiment of the present invention düng. Here, the same reference numerals designate the same components as in Figure 1. For clarity, not all existing components are shown.

The device according to the invention also has a storage device 10. Fuel from the storage device 10 is distributed via injectors 19 to at least one cylinder of an internal combustion engine. As already described above, so many injectors are provided as the Internal combustion engine cylinder has. The injectors 19 are controlled as well as the multi-way valve 24 by a control device, not shown.

The fuel passes from a reservoir 12 by means of a low pressure pump 14 via the multiway valve 24 to the input of the high pressure pump 17. Case, further components may be provided, such as sensors for measuring the fuel temperature, fuel filters or sensors for measuring the fuel pressure on the low pressure side.

In some cases, the low-pressure pump 14 can also be dispensed with or combined with the high-pressure pump 17 to form a single delivery pump.

In the switching position of the multi-way valve 24 shown in Figure 2, the input A is connected to the output D. Thus, the fuel flows from the output of the low pressure pump 14 to the input of the high pressure pump 17. The amount thereby conveyed can be influenced by the control unit, for example by the proportion of the opening time to the closing time of the multiway valve 24 is influenced by the control unit. If the multi-way valve 24 is a proportional valve, the flow rate can also be controlled via the opening degree of the multi-way valve.

Subsequently, the fuel is conveyed by the high-pressure pump 17 and the supply line 21 into the storage device 10 until the measured fuel pressure corresponds to the desired value.

To avoid that subsidized fuel via the return line 22 runs back into the reservoir 12, the input C and the output B of the 4/3-way valve 24 is disconnected.

FIG. 3 shows the same mechanical structure as FIGS. 2 and 4. Preferably, but not necessarily, the multiway valve 24 has a blocking means position, which is shown in FIG. In the blocking center position are all Inputs of the multi-way valve 24 separated from all outputs. As a result, overlapping of the opening areas of the paths AD and CB is avoided. The pumped by pump 17 amount of fuel and thus the energy required for pump 17 can be minimized.

Of course, however, a multi-way valve 24 may be used without such blocking means position. In the implementation of the invention, the person skilled in the art will offset in particular the saved effort for the multiway valve 24 against the saved primary energy.

Figure 4 shows the same mechanical structure as Figures 2 and 3. However, another switching position of the 4/3-way valve is shown. The switching position shown in Figure 4 is always set by the engine control unit 11 when the measured actual value of the fuel pressure in the storage device 10 is greater than the desired target value and due to the operating condition, a pressure reduction via an injector 19 is not an option.

In the illustrated switching position, the input A and the output D of the multi-way valve 24 is blocked. Thus, no additional fuel from the reservoir 12 via the feed pumps 14 and 17 in the storage device 10 is promoted. To fuel from the storage device 10 in the

Outlet reservoir 12, the input C of the multi-way valve is connected to the output B. As a result, fuel flows into the return line 22. This leads, as desired, to the pressure reduction in the storage device 10.

In the illustrated embodiment, the return line opens into the reservoir 12. In another embodiment of the invention, the line may end at the input A of the multi-way valve 24.

The discharged via the multi-way valve 24 amount of fuel can in turn be controlled by the control of the engine control 11 via the control of the multi-way valve. This can be For example, about the opening time of the connection from input C to output B done. If the multi-way valve 24 is designed as a proportional valve, the discharged fuel quantity can also be controlled via the opening degree.

FIG. 5 shows by way of example the degree of opening of the two fluid paths of the multi-way valve according to the invention as a function of the control signal. As an example, an analog voltage signal can be used as a control signal, wherein the valve opening curve is successively passed through with an increasing or decreasing voltage value of the control signal. In another embodiment, the control signal may also be a pulse width modulated signal. In this case, a valve position of the multi-way valve is specified by the duty cycle of a rectangular signal. Furthermore, the control signal may also be a digitally coded signal, by means of which a position on the X axis is specified directly as a digital datum. Various implementations of the control signal are considered to be equally effective and can be arbitrarily selected by the person skilled in the art.

As can be seen from FIG. 5, below a threshold ThI of the control signal, one path of the multi-way valve is closed and the other path is opened. For example, the closed path shown in dash-dotted line in FIG. 5 may be the path C-B, through which fuel is returned from the storage device 10 into the storage container 12. The second, shown as a solid line liquid path A-D is fully open. In the exemplary embodiment, a maximum fuel quantity would thus be conducted from the high-pressure pump 17 into the storage device 10 in the case of a control signal below the limit ThI.

With increasing control signal, the fluid path between the high-pressure pump 17 and the storage device 10 is increasingly closed. This means that the pumped from the reservoir 12 and the storage device 10 to guided fuel quantity steadily drops. The illustrated in Figure 5, non-linear waveform is only to be seen as an example. In some cases, the person skilled in the art will provide other linear or non-linear characteristics of the degree of opening as a function of the control signal. In any case, the liquid path from the memory device 10 to the return line 22 remains closed regardless of the value of the control signal, as long as the control signal is smaller than a limit Th3.

Upon reaching the limit Th2, which is greater than the limit ThI but smaller than the limit Th3, the path between the high-pressure pump 17 and the storage device 10 is completely closed. The limits Th2 and Th3 define the blocking means position in which all paths on the multiway valve are closed.

When the control signal exceeds the limit Th3, the path between the memory device 10 and the return line 22 opens. The degree of opening increases as the control signal increases. At the limit Th4, the opening degree reaches its maximum. Therefore, with a control signal between the limits Th3 and Th4, fuel can be drained from the storage device. Regardless of the value of the applied control signal, the path between pump 17 and storage device 10 remains closed.

Also, the course of the opening degree shown as a dash-dot line is merely an example. In some cases, the person skilled in the art will here too adapt the multi-way valve and the associated actuator in such a way that a desired course of the curve results.

The curves of the opening degrees shown in FIG. 5 as a function of the control signal have the result that a value below the threshold ThI is approached in the absence of a control signal. As a result, the connection between the high pressure pump and the storage device is fully opened while the connection between the storage device 10 and return line 22 remains closed. In the absence of a control signal, this results in a maximum value of the pressure in the storage device given by the delivery rate of the high-pressure pump. With this maximum value, an emergency operation of the internal combustion engine can be maintained even in the absence of a control signal.

This realization of an emergency operation shown in FIG. 5 can also be seen by way of example only. In some cases, the person skilled in the art will adapt the multi-way valve and the associated actuator so that a predefinable valve position results for both paths A-D and C-B, by means of which a multiplicity of possible operating states of the internal combustion engine can be realized.

Claims

claims

1. Device for fuel allocation, which contains the following elements: • at least one storage device (10), in which fuel can be stored with a predefinable pressure,

At least one feed pump (17), which is designed to convey the fuel into the storage device,

• At least one injector (19), which is adapted to the fuel in a predeterminable amount at predetermined times from the storage device

(10) and to be supplied to the combustion chamber of an internal combustion engine,

• A multi-way valve (24) which is adapted to influence the amount of fuel which is supplied to or removed from the storage device (10).

2. Device according to claim 1, characterized in that the multi-way valve (24) has at least a first position in which a fuel flow from a reservoir (12) to the storage device (10) is enabled and a second position in which fuel from the Storage device (10) is discharged.

3. Apparatus according to claim 1 or 2, characterized in that the multi-way valve (24) comprises a 4/3-way valve.

4. Apparatus according to claim 3, characterized in that the multi-way valve (24) has two inputs (A, C) and two outputs (D, B) and at least in a first

Position can be brought, in which the first input (A) to the first output (D) is connectable while the second input (C) is locked and the multi-way valve can be brought at least in a second position, in which rather the second input (C ) with the second output (B) is connectable while the first input (A) is disabled.

5. Device according to one of claims 1 to 4, characterized in that an input (A) of the multi-way valve (24) with one of a reservoir (12) coming fuel line is connected and an output (D) of the multi-way valve (24) with a Input of a feed pump (17) is connected.

6. Device according to one of claims 1 to 5, characterized in that the multi-way valve (24) is designed as a proportional valve.

7. Device according to one of claims 1 to 6, characterized in that the multi-way valve (24) is designed as a ball seat valve.

8. Device according to one of claims 1 to 7, characterized in that the multi-way valve (24) has a blocking means position.

9. Device according to one of claims 1 to 8, characterized in that the multi-way valve (24) and the delivery pump (17) are combined in one module.

10. Device according to one of claims 1 to 9, characterized in that the multi-way valve (24) by means of a single actuator by a single electrical control signal is operable.

11. The device according to claim 10, characterized in that a pulse width modulated signal is provided as the control signal.

12. Use of a device according to one of claims 1 to 11 for fuel allocation of a self-igniting internal combustion engine.

13. Internal combustion engine with a device for fuel allocation according to one of claims 1 to 11.

14. Method for fuel allocation, in which the fuel is stored under increased pressure in at least one storage device (10) and removed there by at least one injector (19) and at least one combustion chamber of an internal combustion engine is supplied, wherein by a multi-way valve (24) Pressure in the storage device (10) is controlled by the amount of fuel is affected, which is the storage device (10) added or removed.

15. The method according to claim 14, characterized in that the multi-way valve (24) is temporarily brought into a first position to allow fuel flow from a reservoir (12) to the storage device (10) and temporarily in a second position, in wel - Fuel is rather discharged from the storage device (10).

16. The method according to any one of claims 14 or 15, characterized in that the multi-way valve (24) is temporarily brought into a blocking means position in which no fuel flows from the storage device (10) out or into this.

17. The method according to any one of claims 14 to 16, characterized in that the multi-way valve (24) is driven by a single control signal.

18. The method according to claim 17, characterized in that the control signal includes a pulse width modulated signal.

19. Computer program for carrying out a method according to one of claims 14 to 18, when the computer program is executed on a computer.