JP2003097390A - Method, computer program and control/adjustment device for operating internal combustion engine, in particular with direct injection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and reliably remove impurities in an injector, or to prevent any impurities from the beginning. SOLUTION: At least one area 44 adjacent to at least one flow-out opening 50 of a fuel injector 30 is subjected to the high frequency vibration 84 at least on a temporal basis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to operating an internal combustion engine, in particular with direct injection, by pumping fuel into at least one fuel injection device and from the fuel injection device into at least one combustion chamber. Regarding the method.

[0002]

2. Description of the Prior Art Such a method is known from DE-A 199445813. This German Federal Patent Application Publication No. 19945
No. 813 describes an internal combustion engine in which fuel is directly injected by an injection valve into the combustion chamber of the internal combustion engine.
Deposits in the combustion chamber or injection valves are inferred via misfire recognition. Such deposits can impair the fuel jet, which can lead to combustion loss and combustion misfires, especially in stratified combustion operation of internal combustion engines. In order to remove the perceived deposits in the injection valve, it is proposed to generate knocking combustion and / or to introduce a cleaning liquid into the combustion chamber of the internal combustion engine.

[0003]

The object of the present invention is to improve a method of the type mentioned at the beginning such that impurities in the injector can be removed more easily and reliably or from the beginning. To be able to even do it. In this case, it is desirable that the operation of the internal combustion engine is not impaired.

[0004]

In order to solve this problem, the method of the present invention is characterized in that at least one region adjacent to at least one outflow opening of the fuel injector is subjected to high frequency vibration at least in time.

[0005]

The method according to the invention has the advantage that deposits, for example coke, which may be present in the region of the outlet opening of the injector can be reliably dissociated. This ensures that the outflow opening always has a maximum and defined cross section. In this case, the operation of the internal combustion engine remains largely unaffected. This is because knocking combustion does not occur and the additive is not introduced into the combustion chamber. by this,
For example, the characteristics of the internal combustion engine emission and quietness of operation are improved.

Since the operation of the internal combustion engine remains largely unaffected, the measures according to the invention can also be implemented as a preventive measure, whereby deposits in the injector are formed from the beginning. I don't get it.

Advantageous variants of the invention are described in the dependent claims.

In a first variant, it is proposed to oscillate the valve element of the fuel injector at least in time. The vibration of the valve element is transmitted to the fuel located between the valve element and the outlet opening and from there to the area surrounding the outlet opening. This facilitates the dissociation of deposits in the area of the outflow opening. That is, this variant of the method according to the invention works with high efficiency.
Moreover, this efficiency can be easily achieved. This is because the valve element is a member that can be moved in a highly dynamic manner. This member is technically relatively easy to oscillate at high frequencies.

It is proposed to oscillate the valve element during at least one range of at least one opening phase. Therefore, the outflow opening can be cleaned during normal operation of the internal combustion engine. This allows the outflow opening to be frequently cleaned.

It is also advantageous to operate the valve element by means of a piezoactuator and to generate high-frequency oscillations by superposition of high-frequency control voltages or control currents of the piezoactuator. Piezo actuators are highly dynamic drive elements used in valve elements. High frequency vibrations can be generated very reliably and inexpensively by this drive element.

In another variant, in a multi-cylinder internal combustion engine, torque and / or lambda values of the individual cylinders are measured in order to recognize possible contaminants in at least one outflow opening of the fuel injector and Compare at least 1
At least one outflow opening of the fuel injector when a maximum permissible deviation of torque and / or lambda value between one cylinder and at least one other cylinder is reached and / or exceeded A high frequency vibration of at least one adjacent region is performed at least temporally.

In other words, this variant of the method according to the invention makes it possible to recognize when it is necessary to clean the outlet opening of the injection valve or the area of the injection valve adjacent the outlet opening. This is generally based on the idea that not all outlet openings of all injection valves are likewise changed, narrowed or blocked. However, if the outlet openings of the injectors of one cylinder have a generally different cross section than the outlet openings of the injectors of another cylinder, different air / fuel mixture ratios and / or individual cylinders are possible. Different fuels are produced. This is manifested in the torque and / or lambda deviation between one cylinder and another. That is, the method according to the invention simply monitors the condition of the outlet opening of the injector without the need for additional components and, in some cases, introduces a cleaning sequence. That is, an appropriately operated internal combustion engine can always be optimally operated without user's involvement.

In a variant to this, after the end of the period of high-frequency oscillating of at least one region of the fuel injection device adjacent to the outflow opening, is the possible removal of possible contaminants in the outflow opening of the injection valve? In order to recognize whether
The torque and / or lambda values of the individual cylinders are measured again and compared, and the maximum permissible deviation of the torque and / or lambda value of at least one cylinder and at least one other cylinder is reached and And / or at least one of the fuel injection devices if the deviation is exceeded.
It is proposed to oscillate at least one region adjacent to one outflow opening at least in time.

In this variant of the method according to the invention, after one cleaning sequence it is checked whether cleaning is necessary. If the period during which the high frequency vibration is generated is still insufficient to sufficiently release the outflow opening, the residue cleaning sequence is automatically started again without user intervention. This variant of the method according to the invention therefore better ensures that the outlet opening of the injection valve always has an optimum and free cross section.

In a variant to this, it is proposed to output an error notification and / or file it in memory when the maximum number of implementations of a method of the type described above has been reached and / or exceeded. It After a specified number of runs, if the cleaning sequence is found to not improve the mixture quality in the combustion chamber sufficiently, the cause for the incorrect mixture composition in the combustion chamber is the cause of the fuel injector outlet opening. You have to start from nothing in the filth. This is signaled to the user of the internal combustion engine and / or
Or a corresponding error notification is filed in memory for subsequent maintenance. In other words, this variant of the method according to the invention ensures that the cleaning sequence is not unnecessarily carried out. This information can also be filed in the error memory if the mixture quality is improved after one cleaning sequence. Thus, factories often have information on how fuel injectors are coked.

The method according to the invention works particularly well if the high frequency vibrations have a frequency in the ultrasonic range. As a result, relatively large energy can be transmitted. This energy also enables stubborn decontamination of contaminants. In this case, no audible noise is generated.

The invention also relates to a computer program, of the type which is suitable for carrying out the method described above, when the computer program is executed on a computer. In this case, it is particularly advantageous if the computer program is stored in a memory, in particular a flash memory.

Furthermore, the present invention provides a control / control for controlling and / or regulating at least one function of an internal combustion engine.
Regarding the adjusting device. In such a control / adjustment device, it is particularly advantageous if the control / adjustment device has a memory, and the memory stores a computer program of the above-mentioned type.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, the internal combustion engine is indicated by a dash-dotted line and is generally designated by 10. This internal combustion engine 10
The fuel system belonging to the company has the general reference number 12.

The fuel system 12 has a fuel container 14. From this fuel container 14 to the electric fuel pump 1
6 pumps fuel through a filter 18. The fuel reaches the high-pressure fuel pump 22 via the low-pressure fuel line 20.
The pressure in the low pressure fuel line 20 is adjusted by the pressure adjusting valve 24.

The high-pressure fuel pump 22 pumps the fuel into the fuel collecting line 26 under an extremely high pressure. This fuel collecting line 26 is generally called a "rail". Fuel is stored here under extremely high pressure. Quantity control valve 28
Controls the amount of fuel that is pumped to the fuel collecting line 26.

A plurality of fuel injection valves 3 are provided in the fuel collecting line 26.
0a, 30b, 30c are connected. Regarding the detailed structure of these fuel injection valves 30a, 30b, 30c,
Further details will be given below. Fuel injection valve 3
Reference numerals 0a, 30b, 30c denote fuel for combustion chambers 32a, 32b, 32 of cylinders 33a, 33b, 33c of the internal combustion engine 10.
Inject directly into c. Fuel injection valves 30a, 30b, 30
c is controlled by the control / adjustment device 34.

The detailed structure of the fuel injection valves 30a, 30b, 30c can be obtained from FIG. In FIG. 2, for example, the fuel injection valve 30 is shown. Further details of possible fuel injectors are described in DE-A-19844837, which is explicitly related to the subject matter of the present invention.

Each fuel injection valve 30 has a valve element 36. The valve body 36 is axially fastened to the valve holding body 40 by a tension nut 38. Disc 36
Is an internal combustion engine 1 with a reduced free end as seen in cross section.
It has entered the combustion chamber 32 of 0. In the bore 42 of the valve element 36, a piston-shaped valve element 44 is axially movably guided in a known manner. This valve element 44
The conical end surface on the combustion chamber side forms a valve sealing surface 46. This valve sealing surface 46 cooperates with a corresponding valve seat surface 48, which is formed in the form of a hollow cone at the end of the bore 42 on the closed combustion chamber side. The valve seat surface 48 is followed by a plurality of outflow openings 50 distributed around the wall of the valve element 36 downstream of the fuel to be injected.

The valve body 36 has a pressure chamber 52 formed by expanding the cross section of the hole 42. The pressure chamber 52 has an inflow passage 54 penetrating the valve body 36 and the valve holding body 40.
Is open. The inflow passage 54 is connected to the fuel collecting conduit 26 via a high-pressure connecting portion 56.

A piezo actuator 58 is provided in the valve carrier 40 for operating the valve element 44, which is pressure-compensated by the cross-sectional geometry. The piezo actuator 58 is formed of a large number of plates that overlap each other in the axial direction. Piezo actuator 5
The axial length of 8 is reduced when the operating voltage is applied.

The piezo actuator 58 is rigidly connected to the valve element 44 at its end facing the valve body 36. A compensating piston 60 is provided at the other end of the piezo actuator 58. The cross section of this compensating piston 60 is dimensioned smaller than the piezo actuator 58. One end of the compensating piston 60 contacts the end face 62 of the piezo actuator 58 with an axial extension, and the free end of the compensating piston 60 is the compensating chamber 64.
Plunge inside. The end of the piezo actuator 58 opposite the valve element 44 partitions a spring chamber 66 which is penetrated by a compensating piston 60. A valve spring 68 that functions as a compression spring is provided in the spring chamber 66. This valve spring 68 is sandwiched between the end face 62 of the piezo actuator 58 and the wall of the spring chamber 66 and loads the valve element 44 via the piezo actuator 58 in the closing direction.

The operation of the piezo actuator 58 is performed via the power supply line 70. The power supply line 70 is connected to the control / adjustment device 34.

For a precisely defined axial adjustment movement of the piezo actuator 58 and thus an exact opening stroke movement of the valve element 44, the piezo actuator 5
A clamping device 72 is arranged at the upper end of 8, opposite the valve element 44. This clamping device 72 allows the upper end of the piezo actuator 58 to be fixed in position with respect to the valve holder 40 during the injection phase. In this case, the clamping device 72 is formed by a ring 74 arranged coaxially with the piezo actuator 58. The inner diameter of the ring 74 is reduced so that the ring 74 comes into friction-resistant contact with the peripheral surface of the piezo actuator 58 when an operating voltage is applied.

Power is supplied through the power supply line 76 and is also controlled by the control / regulation device 34. Since the clamp device 72 is energized during normal operation, the position of the piezo actuator 58 is fixed. However, during the injection phase, the clamping device 72 is released in order to compensate for temperature and pressure-based length changes of the piezo actuator 58 and to avoid a violation of the correct opening stroke movement caused by the length changes. obtain.

The internal combustion engine 10 and the fuel injection valve 30 formed as shown in FIG. 2 are operated by the method stored in the control / regulation device 34 as a computer program. Now, this method will be described with reference to FIGS.

When it is desired to start the internal combustion engine 10, the clamp device 72 is controlled by the control / adjustment device 34, and the clamp device 72 causes the piezo actuator 5 to operate.
8 is fixed in position with respect to the valve holder 40. Therefore, first the valve spring 68, which acts to load the valve sealing surface 46 towards the valve seat surface 48, becomes ineffective.

Now, in order to start the opening stroke movement of the valve element 44, the piezo actuator 58 controls and
It is energized by the adjusting device 44. In this case, a significantly excessively increased current is first applied to the piezo actuator 58. This is characterized by the reference numeral 78 in FIG. This excessive increase in current helps to achieve a very short switching time of the piezo actuator 58. The realization is made by capacitive electronic circuits with connection voltages up to 90 Volts.

By energizing the piezo actuator 58, the piezo actuator 58 is shortened.
Since the valve element 44 is fixedly fixed to the lower end of the piezo actuator 58, the valve element 44 is pulled upwards as seen in FIG. 2, which causes the valve sealing surface 46 to lift from the valve seat surface 48. . This operation is indicated by reference numeral 80 in FIG.

As soon as the valve element 44 reaches its open end position, the energization of the piezo actuator 58 is interrupted in a pulsed and repeated manner. This is indicated by reference numeral 82 in FIG. Piezo actuator 58
Due to this high-frequency and pulsed interruption of the control current of the piezo actuator 58, a high-frequency oscillation is performed. This is indicated by reference numeral 84 in FIG.
In this case, the energizing pulse frequency 82 is selected so that the vibration frequency produced by the piezo actuator 58 and the valve element 44 connected to the piezo actuator 58 is in the ultrasonic range.

The stroke of the valve element 44 can be optimized by the vibration frequency of the valve element 44 being in the range of the resonance frequency of the system consisting of the valve element 44 and the piezo actuator 58. As is apparent from FIG. 3, the valve element 44 does not close due to the inertia of the piezo actuator 58, despite the fact that the energization of the piezo actuator 58 is zero between individual current pulses, and the valve element 44 as a whole does not close. Only the oscillatory movement in the open position of 44 is carried out.

However, due to the oscillatory movement of the valve element 44 during the opening period of the valve element 44, the valve sealing surface 4
Since the cross section provided between 6 and the valve seat surface 48 is slightly smaller than without oscillating motion, the valve opening time is to allow the same fuel quantity to be injected by the fuel injector 30. It must be slightly extended. The end of the injection period without vibration of the valve element 44 is indicated by the dashed line in FIGS. This dashed line has the reference numeral 86. The end of the injection period with high frequency oscillation of the valve element 44 is indicated by the solid line 88. The amount of fuel injected is indicated by the horizontal line 90 in FIG. As is clear from FIG. 5, the course of the amount of fuel injected into the combustion chamber 32 by the fuel injection valve 30 is linear. In the presence of vibration superposition in the valve element 44, the course is slightly lower (89) than in all cases where high frequency vibrations are not imposed on the valve element 44 (91).

The average current intensity required for opening the valve element 44 is indicated by the dash-dotted line in FIG. As is apparent from FIG. 3, this current strength is about half as high as the current strength required without oscillation of the valve element 44. Therefore, a small amount of current is generally required to maintain the fuel injection valve 30 open.

When the desired amount of fuel is being injected,
The energization of the piezo actuator 58 controls the control / adjustment device 34.
Terminated by. This is indicated by reference numeral 94 in FIG.
Characterized by. The corresponding closing movement of the valve element 44, in which the valve sealing surface 46 again comes into close contact with the valve seat surface 48, has the reference numeral 96 in FIG. The maximum period provided to generate the vibration of the valve element 44 has the reference numeral 98 in FIG. This maximum period is valve element 4
It is set shorter than the open period of 4. because,
At the beginning of opening the valve element 44, the valve element 4
4 must wait until it is in the open end position. This prevents a prolonged opening of the valve element 44.

By generating high frequency vibration in the valve element 44, the vibration is also excited in the liquid column existing between the valve sealing surface 46 and the valve seat surface 48. by this,
This vibration is transmitted to the area of the outflow opening 50. In this case, the generation of vibrations in the valve element 44 of the fuel injection valve 30 can be used in two basically different ways: Such vibrations can be generated regularly during the injection of the fuel injection valve 30. Thus, it is prevented that deposits can generally form in the area of the outflow opening 50 or in the outflow opening 50 itself. However, as an alternative to this, the vibrations may occur at greater time intervals in the valve element 44.
It is also possible to dissociate existing deposits that are generated in the outflow opening 50 and that surround the outflow opening 50. In this case, it is possible to detect the presence of deposits in the following manner:
So-called "cylinder equalization (Zylinderglei
chstellung) ”is standard. This means that the individual cylinders 33a of the internal combustion engine 10;
b; combustion chambers 32a; 32b; 3 arranged corresponding to 33c;
Cylinders 33a; 3 based on different combustion in 2c;
This means that a torque difference of 3b; 33c can be perceived. Therefore, if it is now confirmed that the torque of the cylinder 33a differs from the torque of the cylinder 33b by more than the allowable deviation, this means that the outflow opening 50 of the fuel injection valve 30a of the cylinder 33a.
The cross-section of each is narrowed due to deposits, which may mean that a small amount of fuel has reached the corresponding combustion chamber 32a.

Therefore, in this case, the valve element 44 of the corresponding fuel injection valve 30a is loaded by the control and regulating device 34 with the above-mentioned high-frequency vibration. This loading is performed over a period having a plurality of injections of the fuel injection valves 30a and 30b. After the end of this period, the load on the valve element 44 due to the high frequency vibration is terminated, and the torques of the cylinders 33a and 33b are compared again.

Now, when the deviation is within the allowable range,
This means that the deposits present in the area of the outflow opening 50 have been stripped. Otherwise, it may be possible that not all deposits have been removed yet. Therefore, thereafter, the valve element 4 of the fuel injection valve 30a, 30b for a defined period, which also has a plurality of injections.
4 is again loaded with high-frequency vibrations (this loading is naturally only during the opening phase of the fuel injection valve, respectively). Next, the torques of both cylinders 33a and 33b are compared again, and it is confirmed whether the deviation of the torque is within the allowable range now. This process is repeated multiple times.

However, the number of implementations is limited to the maximum value. When this maximum value is reached and / or exceeded, the deposit cannot be dissociated by the high-frequency vibration of the valve element 44 or both cylinders 33.
It can be started that the torque difference between a and 33b has another cause. In this case, the control and adjustment device 34
Outputs an error notification. This causes a warning light to be emitted, for example, in the instrument panel of a motor vehicle in which the internal combustion engine 10 is incorporated. further,
An entry is made in the error memory provided in the control / adjustment device 34. This entry can be read during maintenance, for example by a diagnostic device.

[Brief description of drawings]

FIG. 1 is a principle diagram of an internal combustion engine including a fuel system and a plurality of fuel injection devices.

2 is a partial cross-sectional view of one of the fuel injectors shown in FIG.

3 is a diagram showing a control current of an actuator of the fuel injection device shown in FIG. 2 with respect to time.

4 is a diagram showing the stroke of the valve element of the fuel injection device shown in FIG. 2 as a function of time.

5 is a diagram showing the amount of fuel injected during the opening phase of the fuel injection device shown in FIG. 2 with respect to time.

[Explanation of symbols]

10 internal combustion engine, 12 fuel system, 14 fuel container, 16 fuel pump, 18 filter, 20
Low-pressure fuel line, 22 high-pressure fuel pump, 24 pressure regulating valve, 26 fuel collecting line, 28 quantity control valve,
30a, 30b, 30c Fuel injection valve, 32a, 32
b, 32c combustion chamber, 33a, 33b, 33c cylinder, 34 control and adjustment device, 36 valve body, 38
Tension nut, 40 valve holder, 42 holes,
44 valve element, 46 valve sealing surface, 48 valve seat surface, 50 outlet opening, 52 pressure chamber, 54 inflow passage, 56 high pressure connection, 58 piezo actuator, 60 compensating piston, 62 end surface, 64
Compensation chamber, 66 spring chamber, 68 valve spring, 70 power supply line, 72 clamp device, 74 ring, 76
Feed line, 78 Over-enhanced current, 80
Opening motion of valve element, 82 pulse frequency, 84
High frequency vibration, 86 end of injection period without vibration,
88 end of injection period accompanied by high frequency vibration, 89 progress of injected fuel amount, 90 progress of injected fuel amount, 91 progress of injected fuel amount, 92 average current intensity, 94 end of energization , 96 Closing motion of valve element, 98 Maximum vibration period

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 51/00 F02M 51/00 A 51/06 51/06 KM N P 61/10 61/10 Z 61/16 61 / 16 T 63/00 63/00 B (72) Inventor Klaus Ries-Muller Federal Republic of Germany Bad Rappenau Heinsheimer Strasse 47 F term (reference) 3G066 AB02 BA32 BA46 CC05U CE27 CE28 DB15 DC01 DC24 3G084 BA11 BA33 CA05 DA14 DA19 DA22 DA27 DA33 EB12 EB22 FA26 FA32

Claims (11)

[Claims] 1. An internal combustion engine, in which fuel is pumped to at least one fuel injector (30) and made to reach from the fuel injector (30) into at least one combustion chamber (32), in particular with direct injection. 10) A method for operating a fuel injection device (30), characterized in that at least one region (44) adjacent to at least one outflow opening (50) of a fuel injector (30) is subjected to a high frequency vibration (84) at least in time. A method for operating an internal combustion engine. 2. A method as claimed in claim 1, characterized in that the valve element (44) of the fuel injector (30) is subjected to a high frequency vibration (84) at least in time. 3. The method according to claim 2, wherein the valve element (44) is subjected to high frequency oscillation during at least one range (98) of at least one opening stage. 4. The valve element (44) is operated by a piezo actuator (58) and the high frequency vibration (84) is generated by superposition of a high frequency control voltage or control current (82) of the piezo actuator (58). The method according to 2 or 3. 5. In a multi-cylinder internal combustion engine (10), at least one outflow opening (5) of a fuel injector (30).
0) the torque and / or lambda values of the individual cylinders (33) are measured and compared in order to recognize possible contaminants of at least one cylinder (33a) and at least one other cylinder (33b). Torque with and /
Or if the maximum allowable deviation of the lambda value is reached and / or exceeded, the fuel injector (3
Method according to any one of the preceding claims, wherein the at least one region (44) adjacent to the at least one outflow opening (50) of 0) is subjected to a high frequency vibration (84) at least in time. 6. The outflow opening (5) of the fuel injector (30).
0) to recognize if possible contaminants in the outlet opening (50) of the injection valve (30) have been removed after the end of the period of high frequency oscillating of the at least one region (44). And again measuring and comparing the torque and / or lambda values of the individual cylinders (33), of the torque and / or lambda values of at least one cylinder (33a) and at least one further cylinder (33b), At least one region (44) adjacent to at least one outflow opening (50) of the fuel injector (30) is at least temporally if a maximum acceptable deviation is reached and / or exceeded. High frequency vibration (84)
The method according to claim 5, wherein 7. A method according to claim 6, wherein an error notification is output and / or filed in memory if the maximum number of implementations of the method according to claim 6 has been reached and / or exceeded. . 8. A method according to claim 1, wherein the high frequency vibrations (84) have a frequency in the ultrasonic range. 9. The computer program according to any one of claims 1 to 8, when the computer program is executed by a computer.
Computer program, characterized in that it is suitable for carrying out the method according to any one of the above. 10. The computer program is stored in a memory, in particular a flash memory.
The described computer program. 11. A control and regulation device (34) for controlling and / or regulating at least one function of an internal combustion engine (10), the control and regulation device (34) comprising:
A memory is provided, and the memory has a memory.
A control / adjustment device, characterized in that the computer program described is stored therein.