ITMI20000470A1 - PROCEDURE FOR THE OPERATION OF A FUEL ADDITIONAL DEVICE FOR A ENGINE, ESPECIALLY ENDOTHERMAL AND ESPECIALLY OF - Google Patents

Description

State of the art

The invention relates to a method for the operation of a device for feeding the fuel of an internal combustion engine, especially of a motor vehicle, in which the quantity of fuel supplied to the internal combustion engine is controlled and / or regulated by means of a control valve of the internal combustion engine. amount of fuel and a subsequent high-pressure pump. The invention also relates to a control apparatus for a fuel supply device for an internal combustion engine, especially of a motor vehicle, where the fuel supply device is equipped with a quantity control valve and a high-pressure pump, furthermore, the control apparatus is provided for controlling and / or regulating the quantity of fuel supplied to the internal combustion engine. Likewise, the invention relates to a fuel supply device for an internal combustion engine, especially of a motor vehicle, with a quantity control valve, a high pressure pump and a control apparatus for controlling and / or regulating the quantity of fuel. adduced to the internal combustion engine.

A method of this type, as well as a control apparatus of this type and a fuel supply device of this type are known from EP 481 964 A2. There the quantity control valve is open in the de-energized state. If the quantity control valve is controlled then it is closed and the high-pressure pump pumps fuel for the subsequent injection of this into the combustion chambers of the internal combustion engine.

The object of the invention is to further develop a method of the mentioned type, as well as a control apparatus and a fuel supply device of the type respectively mentioned at the beginning, in such a way that the most precise possible metering of the fuel is possible. desired quantity of fuel in the combustion chamber of the internal combustion engine.

For a method of the kind mentioned at the outset this problem is solved by the invention in that the quantity control valve is influenced as a function of a battery voltage with which the quantity control valve is energized, and, or depending on a coil resistance of the quantity control valve. For a control device or a fuel supply device of the kind mentioned at the beginning, the object is solved by means of the invention, in that the quantity control valve can be controlled by the control device depending on a voltage of the battery with which the quantity control valve is energized, and / or as a function of the coil resistance of the quantity control valve.

The instant of closure of the quantity control valve essentially represents the instant from which fuel from the high-pressure pump is pumped to the injection nozzles and therefore to the combustion chambers of the internal combustion engine. When the quantity control valve is closed, the quantity of fuel supplied to the combustion chambers and therefore to the internal combustion engine is also influenced. The closing instant of the quantity control valve depends on a plurality of quantities. Thus the closing instant is reached first when the voltage of the battery to which the quantity control valve is applied is large. There are likewise dependencies of the closing instant on the coil resistance of the quantity control valve, since this defines the current through the quantity control valve. According to the invention, these dependencies are taken into consideration for the control of the quantity control valve. Thus for the invention the dependence of the quantity control valve on the battery voltage and / or on the coil resistance for the determination and resulting control of the quantity control valve is taken as a basis. Consequently, the advantage is obtained which consists in the fact that the quantity of fuel influenced by the quantity control valve and supplied to the internal combustion engine, even in the case of different battery voltages and, or different coil resistances, always corresponds to the desired value. In this way, the precision of the fuel metering is improved, which is equivalent to a reduction in fuel consumption as well as a reduction of harmful substances emitted.

In a further advantageous development of the invention the coil resistance is determined by a temperature of the quantity control valve coil. Thus according to the invention it is not necessary to directly measure the coil resistance. Instead of this it is sufficient to measure the coil temperature. From this coil temperature it is possible to determine the resistance of the coil. The temperature of the coil of the quantity control valve can in turn be determined in a particularly advantageous way by the temperature of the cooling water of the internal combustion engine and / or by the temperature of the intake air of the internal combustion engine.

In an advantageous embodiment of the invention, the quantity control valve is influenced as a function of the actual pressure produced by the high-pressure pump. In this way, with the invention it is taken into account that the closure of the quantity control valve and therefore the instant of closure of the quantity control valve depend on the actual pressure produced by the high-pressure pump. This actual pressure acts on the quantity control valve so that it aids the closing process of the quantity control valve. Taking this effective pressure into account, the accuracy of the fuel metering is further improved with the advantages already illustrated.

In a further advantageous embodiment of the invention, the quantity control valve is influenced as a function of the number of revolutions of the internal combustion engine. Especially when using a mechanical high pressure pump, coupled with the internal combustion engine, the number of revolutions of the internal combustion engine has a direct influence on the high pressure pump. This is taken into account according to the invention by the fact that the number of revolutions of the internal combustion engine or of the high-pressure pump enters the control of the quantity control valve. Also with this expedient the precision of the fuel metering towards the combustion chambers of the internal combustion engine is further improved.

The implementation of the method according to the invention in the form of a control element provided for a control apparatus of an internal combustion engine, especially of a motor vehicle, is particularly important. In this connection, a program is stored on the control element which can run on a computer device and especially on a microprocessor and is suitable for carrying out the method according to the invention. In this case, therefore, the invention is implemented by means of a program stored on the control element, so that this control element equipped with the program represents the invention in the same way as the method for which the program is suitable. An electrical memory medium, for example a read-only memory, can especially be used as the operating element.

Further characteristics, possibilities of use and advantages of the invention result from the following description of embodiments shown in the figures of the drawing. In this regard, the characteristics described or represented per se or in any combination as desired constitute the object of the invention, regardless of their summary in the claims or their consequence as well as regardless of their formulation, respectively representation in the description or respectively in the drawing.

In particular:

Figure 1 shows a block diagram of an example of embodiment of a fuel supply device according to the invention for an internal combustion engine,

Figure 2 shows a schematic representation of a high-pressure pump of the fuel supply device of Figure 1 in three different operating states with a relative time diagram;

Figure 3 shows a block diagram of an embodiment example of a method for operating the fuel supply device of Figure 2;

Figure 4 shows schematic time diagrams of signal patterns of the fuel delivery device of Figure 1, and Figure 5 shows a diagram of an integrative process with respect to the method of Figure 3.

Figure 1 shows a fuel supply device 10 provided for the operation of an internal combustion engine. In particular, the fuel supply device 10 is suitable for use in an internal combustion engine with direct petrol injection. For an internal combustion engine of this type, petrol in a so-called homogeneous operation during the intake phase and in a so-called stratified charge operation during the compression phase is injected directly into the combustion chambers of the internal combustion engine.

The fuel supply device 10 has an electric fuel pump 11, with which the fuel is sucked from a fuel tank 12 and passed further through a fuel filter 13. the fuel pump 11 is adapted to produce a low pressure. To control and / or regulate the low pressure, a low pressure regulator 14 is provided which is connected to the outlet of the fuel filter 13 and through which fuel can be returned to the fuel tank 12.

The series circuit formed by a quantity control valve 15 and a high pressure mechanical pump 16 is also connected to the outlet of the fuel filter 13. The outlet of the high-pressure pump 16 through a pressure limiting valve 17 is returned to the inlet of the quantity control valve 15.

The high pressure pump 16 is designed to produce a high pressure substantially higher than the low pressure produced by the electric fuel pump 11. The pressure limiting valve 17 is provided to discharge any overpressure produced. As will again be illustrated, the quantity control valve 15 is suitable for setting that quantity of fuel to be pumped with the high pressure pump 16.

The outlet of the high-pressure pump 16 is connected to a pressure accumulator 18, to which a plurality of injection valves 19 is connected. The pressure accumulator 18 is also often referred to as Rail or Common Rail. Furthermore, a pressure gauge 20 is connected to the pressure accumulator 18. With the injection valves 19 they are associated with the combustion chambers of the endothermic engine. The fuel supply device 10 is shown in Figure 1 and is therefore provided for a four-cylinder internal combustion engine. By means of the injection valves 19 the fuel is injected into the combustion chambers. The quantity of fuel which is injected into the relevant fuel chambers via the individual injection valves is set via the quantity control valve 15.

In FIG. 2 the quantity control valve 15 and the high pressure pump 16 are shown in more detail. The control valve 15 has an electromagnet 21, with which it is possible to open and close a valve 22. The high-pressure pump 16 has a piston 23, which is actuated by a cam 24 of the internal combustion engine. Furthermore, the high-pressure pump 16 is equipped with a valve 25.

Between the valve 22 and the piston 23 and the valve 25 there is a delivery space 26 of the high-pressure pump 16.

With the valve 22 it is possible to separate the delivery space 26 from a fuel supply by means of the electric fuel pump 11 and therefore from the pressure passage with the valve 25 the delivery space 26 can be separated from the pressure accumulator 18 and therefore from the 'high pressure. In the starting state, as shown in Figure 2 on the left, the valve 22 is open and the valve 25 is closed.

The open valve 22 corresponds to the de-energized state of the electromagnet 21. The closed valve 25 is obtained by means of a corresponding spring or the like.

The left-hand representation of Figure 2 shows the suction stroke of the high-pressure pump 16. In the event of a rotation of the cam 24 in the direction of the arrow 27, the piston 23 moves in the direction of the arrow 28. The valve then opens 22 then the fuel, which has been pumped by the electric fuel pump 11 is sucked into the delivery space 26.

The central representation of Figure 2 shows the delivery stroke of the high-pressure pump 16, where however the electromagnet 21 is still de-energized and therefore the valve 22 is still open. Upon rotation of the cam 24, the piston 23 moves in the direction of the arrow 29. Thereafter, the open valve 22 and thus the fuel from the delivery space 26 is pumped backwards in the direction of the electric fuel pump 11. This fuel then returns to the fuel tank 12 via the low pressure regulator 14.

In the right representation of Figure 2 - as in the central representation - the discharge stroke of the high-pressure pump 16 is also shown. Unlike the central representation, however, at this point in the right representation the electromagnet 21 is mentioned and therefore the valve is closed 22. It follows from this that at this point the piston 23, moved by the cam 24 in the direction of the arrow 29, forms a pressure in the delivery space 26. With this pressure, the valve 25 is opened in opposition to the spring load mentioned. In this way, fuel from the piston 23 from the delivery space 26 is pumped towards the pressure accumulator 18 and then towards the injection valves 19.

The amount of fuel pumped to the pressure accumulator 18 depends on when the valve 22 goes into its closed state. The sooner the valve 22 is closed, the more fuel is pumped through the valve 25 into the pressure accumulator 18. This is represented in Figure 2 by a zone B characterized by an arrow.

As soon as the piston 23 has reached its maximum stroke with the right-hand representation of Figure 2, no further fuel can be pumped from the piston 23 via the valve 25 into the pressure accumulator 18. As a result of the aforementioned spring, the valve 25 is closed again. Furthermore, the electromagnet 22 is de-energized again, so that the valve 22 opens again. The piston 23, which moves in the direction of the arrow 28 in the left-hand representation of Figure 2, can then draw fuel from the electric pump 11 into the delivery space 26 again.

Figure 3 shows a method for operating the fuel supply device of Figure 1. In particular, the method of Figure 3 is provided for influencing the quantity control valve 15.

The method of Figure 3 is carried out by a control unit not shown in more detail. The control apparatus has in particular a microprocessor suitable for processing programs. The blocks represented in figure 3 are realized as programs of this type program modules. Programs can be manualized on an electronic memory, especially on a Read-Only-Memory.

Figure 3 shows a range of characteristics 30, to which the number of revolutions of the internal combustion engine N and the load L applied to the internal combustion engine are given as input signals. Depending on the speed N and the load L, the characteristic range 30 produces an output signal corresponding to a desired set pressure Psoll in the pressure accumulator 18. This set pressure Psoll is compared with an actual pressure Pist at a comparison point 31. The actual Pist pressure in particular is measured by the pressure gauge 20.

The difference between the Psoll prescribed pressure and the actual Pist pressure is adopted by a regulation system 32 of the start of delivery. As regards the regulation 32 of the start of the delivery, it can be a usual regulator, for example a PI regulator or a PID regulator.

The output signal of the regulation 32 of the start of delivery is sent to a command 33, with which the electromagnet 21 of the quantity control valve 15 is controlled and therefore the valve 22 of the high-pressure pump 16 is influenced. The command 33 is provided to determine the passage from the electromagnet 21 from its de-energized state to its energized state and therefore to determine the instant of closure of the valve 22. With the aid of the command 33 it is therefore possible to realize the zone B illustrated in relation to figure 2. With the control 33 it is therefore possible to vary the instant of closure and therefore the quantity of fuel, convex towards the pressure accumulator 18, in the direction of zone B.

Command 33 is dependent on a plurality of input signals. Thus the closing instant of the valve 22 is varied as a function of the battery voltage UBatt, whereas this battery voltage UBatt is used to supply energy, inter alia, to the electromagnet 21 of the quantity control valve 15 as well as the injection valves. electromagnetic 19. Likewise, the instant of closure of the valve 22 depends on the temperature TK of the cooling water of the internal combustion engine as well as on the temperature TA of the intake air of the internal combustion engine. From these temperatures the command 33 can obtain the temperature of the coil and therefore the resistance of the coil of the electromagnet 21. This resistance of the coil is taken into consideration by the command 33 for determining the instant of closing of the valve 22 and therefore in the passage of the electromagnet 21 from its de-energized state to its energized state. Likewise, the command 33 and therefore the instant of closure 22 of the valve depend on the number of revolutions N of the internal combustion engine. This number of revolutions N corresponds directly or indirectly to the number of revolutions of the high-pressure pump 16. Furthermore, the instant of closure of the valve 22 is determined by the command 33 as a function of the effective pressure Pist. A further dependence on the instant of closure of the valve 22 and therefore on the quantity of fuel supplied to the pressure accumulator 18 is taken into consideration by the control 33 in relation to the position of the cam 24. From the position of the cam 24 the control 33 obtains a measurement for the speed of the piston 23, which enters into the determination of the instant for the command of the magnetic valve 21 and therefore in the determination of the instant of closure of the valve 22. As an output signal, the command 33 produces a signal ta of the instant of closing with which the electromagnet 21 of the quantity control valve 15 is controlled and this is brought from its de-energized state to its energized state and vice versa. Consequently, the closing instant signal ta defines the closing instant of the valve 22.

Figure 4 shows the signal ta of the closing instant in the upper diagram. During the time interval in which the closing instant signal t has a voltage, the electromagnet 21 is energized and the valve 22 is closed. This time interval ta goes from the instant t1 to the instant t2. After closing therefore fuel from the delivery space 26 and the high pressure pump 16 is pumped into the pressure accumulator 19.

If the closing instant signal ta has a voltage then - as already illustrated - it follows from this that the valve 22 is closed. This is represented in the second diagram of Figure 4. In this case the valve reaches its closed state at an instant t3, which precedes the instant t2.

The third diagram of Figure 4 shows the current through the electromagnet 21. From this diagram it can be seen that the current, starting from the instant t1 up to the instant t3 substantially increases uniformly. Following the stop of the valve 22 in its closed state, the current between states t3 and t2 increases once again steeply. After the instant t2, i.e. after the signal ta of the closing instant no longer has voltage, the current drops back to 0.

The lower diagram of Figure 4 shows the trend of the pressure in the delivery space 26 of the high-pressure pump 16. Initially, the low pressure ND produced by the electric fuel pump 11 exists in the delivery space 26. As a result of the valve 22 which closes as a result of the movement of the piston 23 in the direction of the arrow 29 corresponding to the representation on the right of Figure 2, the pressure in the discharge space 26 slowly increases. From this it follows - as has already been illustrated, that valve 25 opens. In this way, at the instant t3, ie the valve 22 being closed, the high pressure HD produced by the high pressure pump 16 exists in the delivery space 26 of the high pressure pump 16. This high pressure HD falls again at the end of the discharge stroke at the instant t4.

It is possible that the valve 22 following a fouling or for another reason is difficult to operate and therefore does not perform any normal movement from its open state to its closed state. This can lead as a consequence to the fact that the valve 22 is not closed at the instant t3. In this way, the closing instant, determined by the command 33, for the valve 22 and the quantity of fuel resulting therefrom and fed to the pressure accumulator 18 is no longer correct.

Such an incorrect operation of the valve 22 can for example be detected by the control 33 based on the actual pressure Pist, measured by the pressure gauge 20, in the pressure accumulator 18. By itself this actual pressure Pist in the pressure accumulator 18 despite the injections should remain approximately constant due to the amount of fuel supplied by the high pressure pump 16. However, if this does not happen and therefore the pressure drops substantially in the pressure accumulator 18, especially after an injection, then this can be traced back to to incorrect operation of the valve 22.

In this case, for example, from the control 33 it is possible to additionally implement the method shown in Figure 5. With the method shown in Figure 5, the instant of closure of the valve 22, that is, the instant t2 in Figure 4, is shifted in the direction of " delay". In this way the current acting on the magnetic valve 21 is increased. From this it follows that under certain circumstances it is possible to overcome the present difficulty of movement in the valve 22 by means of the high current. At the same time, an overcurrent shutdown is integrated for the method according to FIG. 5.

The method according to Fig. 5 starts with a signal of the closing instant with the command duration ta = ta0, which is determined, for example, in the manner described by the command 33. With this command duration ta, it is also possible to take into account a pre-assigned safety supplement. As far as the operating time ta is concerned, this is a pre-assigned start value. According to Figure 5, the command duration ta is defined in a block 34.

In a subsequent block 35 it is checked whether the current through the electromagnet 21 exceeds a predetermined maximum value. If this is the case, then an F diagnostic bit is set to "1". If this is not the case, then the diagnostic bit F remains at "O".

If the current through the electromagnet 21 has not exceeded the predetermined maximum value, ie F = 0, then the command duration Td in a block 36 is increased and therefore the instant t2 is shifted towards "delays". This is done with the help of the equation ta = ta + At. The procedure is then continued with block 35.

However, if it is detected in block 35 that the current through the magnetic valve 21 has exceeded the pre-assigned maximum value, ie if the diagnostic bit F is set to "1", then the procedure is continued with block 37. In block 37 it is reduced the command duration and therefore the instant t2 is shifted towards "advance". This is done with the help of the equation ta: = ta - Δt.

In a block 38 following block 37 it is checked whether the command duration ta has fallen below a predetermined minimum value. This is done with the help of the query ta ≤ tamin. The aforementioned minimum value tamin corresponds to a minimum operating time which cannot be constructively exceeded downwards.

If the query of block 38 is answered with "no", i.e. the command duration ta is not less than the minimum value tamin, then the procedure of Figure 5 is continued again with block 35. However, if the command duration ta is dropped below the minimum value, ie the interrogation of block 38 is positive, then an error is recorded and possibly signaled by means of a block 39. As far as this error is concerned, it is therefore a short circuit on valve 22.

With block 35 the aforementioned overcurrent disconnection is realized. The block 35 prevents the current through the electromagnet 31 from exceeding the predetermined maximum value. At the same time, by means of the block 38 it is ensured that the electromagnet 21 is always controlled with the signal of the closing instant with the command duration ta which from the constructive point of view represents a suitable value.

With the method in Figure 5, the electromagnet 21 is always controlled with the maximum current that the control apparatus can make available. If even with this current the valve 22 cannot be closed due to a movement difficulty, then the error is detected by the pressure drop in the pressure accumulator 18.

Legend

10 Fuel supply device 11 Electric fuel pump

12 Fuel tank

13 Fuel filter

14 Low pressure regulator

15 Quantity control valve

16 High pressure mechanical pump

17 Pressure limiting valve

18 Pressure accumulator

19 Injection valve

20 Pressure gauge

21 Electromagnet

22 Valve

23 Piston

24 Cam

25 Valve

26 Delivery space

27 Arrow, cam 24

Arrow, piston 23

Arrow, piston 23

Characteristic range

Comparison point Start of delivery adjustment Commanded

Closing instant definition Current comparison by means of 21 Increase in ta

Reduction of ta

Comparison with minimum

Mistake

Claims (13)

CLAIMS 1. Process for the operation of a fuel injection device (10) of an internal combustion engine, especially of a motor vehicle, in which the quantity of fuel supplied to the internal combustion engine is controlled and / or regulated by means of a control valve (15) , of the quantity and a following high-pressure pump (16), characterized in that the quantity control valve (15) is influenced depending on a battery voltage (UBatt), with which the control valve (15 ) of the quantity, and / or depending on a resistance of the coil of the quantity control valve (15). Method according to claim 1, characterized in that the coil resistance is determined by a temperature of the coil of the control valve (15) of the quantity. Method according to one of claims 1 or 2 / characterized in that the quantity control valve (15) is influenced as a function of the actual pressure (Pist) produced by the high-pressure pump (16). Method according to one of claims 1 to 3, characterized in that the quantity control valve (15) is influenced as a function of the speed (N) of the internal combustion engine. Method according to one of the preceding claims, characterized in that the quantity of fuel supplied to the internal combustion engine is influenced by a passage of the quantity control valve (15) from its de-energized state to its energized state. Method according to claim 5, characterized in that with the passage of the quantity control valve (15) from its de-energized state to its energized state, a valve (22) is closed. Method according to one of the preceding claims, characterized in that the actual pressure (Pist) produced by the high-pressure pump (16) is controlled and / or adjusted to a prescribed pressure (Psoll). 8. Method according to one of the preceding claims, characterized in that the current is limited to a maximum value via the quantity control valve (15). 9. Control element, especially Read-Only-Memory, for a control unit of a fuel supply device (10) of an internal combustion engine, especially of a motor vehicle, on which a program is stored, which can run on an apparatus calculation, especially on a microprocessor and is suitable for carrying out a method according to one of claims 1 to 8. 10. Control apparatus for a fuel supply device (10) for an internal combustion engine, especially of a motor vehicle, where the fuel supply device (10) is equipped with a quantity control valve (15) and a high-pressure pump (16), where the control apparatus is also provided to control and / or regulate the quantity of fuel supplied to the internal combustion engine, characterized in that the quantity control valve (15) can be influenced by the apparatus control depending on a battery adhesion (UBatt), with which the quantity control valve (15) is urged and / or depending on a coil resistance of the quantity control valve (15). 11. Fuel supply device (10) for an internal combustion engine, especially of a motor vehicle, with a quantity control valve (15), with a high-pressure pump (16) and with a control apparatus for controlling and, or adjust the quantity of fuel supplied to the internal combustion engine, characterized in that the quantity control valve (15) can be influenced by the control unit depending on a battery voltage (UBatt), with which the valve (15) is stressed. ) for quantity control and / or depending on a coil resistance of the quantity control valve (15). Control device or fuel supply device (10) according to claim 10 or 11, characterized in that the quantity control valve (15) can be influenced by the control device as a function of the actual pressure (Pist) produced by the high pressure pump (16). Control unit, fuel supply device (10) according to claims 10 or II, characterized in that the quantity control valve (15) can be influenced as a function of the number of revolutions (N) of the internal combustion engine.