JP2002106446A - Driving method of fuel metering system for direct injection type internal combustion engine, fuel metering system for direct injection type internal combustion engine, direct injection type internal combustion engine, control device for direct injection type internal combustion engine, and control method for direct injection type internal combustion engine Adjusting element of control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a diagnostic function of a fuel metering system so that a defect of a high-pressure pump can be diagnosed as desired. SOLUTION: For each high-pressure pump, an amount representing a pumping characteristic curve of each high-pressure pump is monitored and used for diagnosing a defect of the high-pressure pump. If the difference in the amount monitored by the high-pressure pump exceeds at least one predetermined limit, a fault of the high-pressure pump is concluded. This difference can be related to the last monitored amount or the preceding amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for delivering fuel from a fuel storage tank to a low-pressure area of a fuel metering system, and delivering fuel in the low-pressure area to a high-pressure accumulator by at least one demand-controlled high-pressure pump. A fuel injection control system for a direct injection internal combustion engine in which a dominant injection pressure in a high pressure accumulator is controlled by changing a pumping speed of at least one high pressure pump, and fuel is injected from the high pressure accumulator into a combustion chamber of the internal combustion engine. It relates to a driving method of the quantity system.

The present invention also provides a fuel storage tank, a pre-feed pump for delivering fuel from the fuel storage tank to a low pressure region of the fuel metering system, and a demand controlled at least for delivering fuel from the low pressure region to a high pressure accumulator. One high pressure pump and at least one dominant injection pressure in the high pressure accumulator
Fuel control for a direct injection type internal combustion engine, comprising: a control device for controlling by changing the pumping speeds of two high pressure pumps; and a fuel injection valve for injecting fuel from a high pressure accumulator into a combustion chamber of the internal combustion engine. About the system.

The invention furthermore relates to a direct injection type internal combustion engine of the type mentioned at the outset and to a control device for a direct injection type internal combustion engine.

[0004]

2. Description of the Related Art A direct injection internal combustion engine having a fuel metering system of the type mentioned at the outset is known from the prior art, for example, as a gasoline direct injection internal combustion engine BDE. Such a fuel metering system has a pre-feed pump, which is usually configured as an electronic fuel pump, and delivers the fuel in the fuel storage tank to the low-pressure region of the fuel metering system. At least one high pressure pump of the fuel metering system applies high pressure to the fuel in the low pressure region and delivers it to the high pressure accumulator. The high-pressure accumulator is configured, for example, as a distributor rail of a common-rail fuel metering system (CR fuel metering system). An injection valve exits from the high-pressure accumulator, through which fuel in the high-pressure accumulator is injected into the combustion chamber of the internal combustion engine. The injection valve is driven by a control device of the internal combustion engine. The control device also has the task of controlling the dominant injection pressure in the high-pressure accumulator by changing the pumping speed of the high-pressure pump. The control of the injection pressure is performed, for example, via a closed-loop control circuit provided with a preliminary adjusting unit. The increase in injection pressure is achieved by proper operation of the high-pressure pump, i.e. by increasing the fuel supply to the high-pressure accumulator. The reduction of the injection pressure is achieved by appropriate actuation of the control valve which branches off from the high-pressure accumulator, ie increasing the fuel flow from the high-pressure accumulator or reducing the pumping power of the high-pressure pump. The control valve is configured, for example, as an electromagnetic control valve (one cylinder plunger high pressure pump) or a pressure control valve (three cylinder plunger high pressure pump). A direct-injection internal combustion engine having a fuel metering system with two high-pressure pumps as described above is known, for example, from DE 100 23 033 A1, and is pointed out here.

[0005] In internal combustion engines known from the prior art, the diagnosis is generally limited to errors in the fuel metering system. If the preliminary control by pressure control of the injection pressure must be corrected beyond a predetermined limit value, an error in the fuel metering system is immediately diagnosed. If there is no preliminary control in the control of the injection pressure, a general error in the fuel metering system will not be identified and the target pressure will not be achieved unless the pressure controller is stroked. Diagnostic functions for diagnosing errors in the high-pressure pump of the fuel metering system as desired, in particular diagnostic functions for diagnosing reduced pumping power or high-pressure pump defects, are not yet known.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the diagnostic function of a fuel metering system so that faults in a high-pressure pump can be diagnosed as desired.

[0007]

This object is achieved by a method for monitoring the quantity of each high-pressure pump which represents the pressure-feeding characteristic curve of each high-pressure pump and for utilizing it for diagnosing faults in the high-pressure pump.

If the difference in the amount monitored by the high-pressure pump exceeds at least one predetermined limit, a fault of the high-pressure pump is concluded. This difference can be related to the last monitored amount or the preceding amount.

[0009]

In accordance with the method of the present invention, a fault in a high-pressure pump of a fuel metering system is diagnosed as desired. According to this diagnosis, not only the complete destruction of the high-pressure pump but also a decrease in the pumping output, for example, can be detected by using a plurality of set limit values. The diagnostic function outputs which high pressure pump has failed as a result and what percentage of pumping output has been lost. On the basis of this result from the diagnostic function, the factory can check or replace the defective high-pressure pump for the purpose. Since the diagnostic function can also identify a drop in the pumping output before the high-pressure pump is completely destroyed, the high-pressure pump can be replaced early and a chain fault in the fuel metering system or the internal combustion engine can be avoided.

The pumping characteristic curve of the high-pressure pump is a function of the pumping speed of the high-pressure pump, which function depends on the drive signal which changes the pumping speed. In the case of a defective high-pressure pump, the course of the pumping characteristic curve fluctuates or shifts and a large amount of fuel is delivered despite the application of a drive signal corresponding to a low pumping speed or a high pumping speed. Even though a drive signal is applied, only a small amount of fuel is delivered. If the course of the pumping characteristic curve of the high-pressure pump deviates from the original course of that pump or the course of the pumping characteristic curve of another high-pressure pump by more than a predetermined limit value, it is concluded that the high-pressure pump is defective. You. A plurality of limit values can be provided, whereby the delivery losses of the high-pressure pump can be reported via a plurality of stations and repaired in advance.

According to an advantageous embodiment of the invention, the pumping speed of the high-pressure pump is monitored as a quantity representing a pumping characteristic curve. If the pumping speed of the high-pressure pump deviates beyond at least one set limit, it is concluded that the high-pressure pump is defective. This embodiment specifically considers a fuel metering system that does not adapt the pumping speed of the high pressure pump. Without the adaptation of the pumping speed, all the high-pressure pumps of the fuel metering system are driven by the same drive signal (with the angles offset from one another depending on the pump knocking condition). The pumping speed of the high-pressure pump, that is, the amount of fuel delivered from a predetermined high-pressure pump per unit of time is an amount representing a pumping characteristic curve.

According to another advantageous embodiment of the invention, 1
In connection with the pumping of the two high-pressure pumps, the dominant injection pressure in the high-pressure accumulator is monitored as a quantity representing the pumping characteristic curve. If the current injection pressure deviates beyond at least one set limit, it is concluded that the last delivered high-pressure pump is defective. It is also possible to determine the pumping speed of the high-pressure pump that last sent out from the dominant injection pressure in the high-pressure accumulator. If the relationship between the dominant injection pressure in the high-pressure accumulator and the pumping speed of the high-pressure pump is known, the pumping speed of the high-pressure pump can be easily determined from the injection pressure (at least during steady-state operation of the pressure control unit). be able to.

[0013]

[Outside 1]

Preferably, the injection pressure determined for each high-pressure pump is normalized to the largest average value of all the high-pressure pumps. If the currently determined injection pressure for each high-pressure pump deviates from the normalized injection pressure by at least one set limit, it is concluded that the last delivered high-pressure pump is defective. Due to the averaging, a relatively slow and long-term change of the injection pressure can lead to a conclusion of the fault of the high-pressure pump.

According to another advantageous embodiment of the invention, in a method of the type mentioned at the outset, the pumping speed of the high-pressure pump is adapted by means of a correction factor which is multiplied by a drive signal for the control valve of the high-pressure pump. Alternatively, it is adapted by means of a correction value to which the drive signal is applied, and this correction coefficient or correction value is monitored as a quantity representing the pumping characteristic curve. If the correction factor or correction value of one of the high-pressure pumps deviates beyond at least one set limit, a fault of the high-pressure pump is concluded. In adapting the pumping speed of the high-pressure pump, a drive signal of the high-pressure pump is multiplied by a correction coefficient, or a correction value is applied to the drive signal (that is, the correction value and the drive signal are added or subtracted). In order to avoid pressure fluctuations in the high-pressure accumulator based on different pumping characteristic curves for each high-pressure pump, when adapting the pumping speed, the drive signal of the high-pressure pump is adjusted so that the pumping speed of all high-pressure pumps has the same value. to correct. The pumping speed of the high-pressure pump does not indicate a defect of the high-pressure pump when adapting the pumping speed.
This is because, in this case, the pumping loss of the high-pressure pump is compensated (at least within a predetermined range). For this purpose, in a fuel metering system that adjusts the pumping speed of the high-pressure pump, a correction coefficient or a correction value for the adjustment is monitored and used for error diagnosis.

According to an advantageous embodiment of the invention, the correction factor or the average of the correction values is formed continuously for each high-pressure pump. If, at the point of adapting the high-pressure pump, the currently calculated correction factor or correction value deviates from the average correction factor or correction value by at least one set limit, a fault of the high-pressure pump is concluded.

According to an advantageous embodiment of the invention, the averaging takes place synchronously with the speed of the internal combustion engine.

Preferably, the average correction factor or the average correction value for each high-pressure pump is normalized to the largest average value of all the high-pressure pumps. For the adaptation of the high-pressure pump, the currently calculated normalized correction factor or correction value deviates from the normalized average correction factor or normalized average correction value by at least one set limit value. In the case, a fault of the high-pressure pump is concluded.

Preferably, the quantity representing the pumping characteristic curve of the individual high-pressure pump is monitored only if the target value for controlling the injection pressure is constant. Alternatively, the target value for controlling the injection pressure may be considered when diagnosing the high-pressure pump. For example, when the difference between the average value of the injection pressure of each high-pressure pump and the target pressure is correlated, error diagnosis can be performed even if the target pressure fluctuates.

Preferably, the quantity representing the pumping characteristic curve of the individual high-pressure pump is monitored only if the quantity of fuel injected constantly into the combustion chamber lies within a set limit. Alternatively, the amount of fuel to be injected into the combustion chamber may be considered when diagnosing the high-pressure pump. The quantity of fuel to be injected is known to the control unit and can be calculated without problems during error diagnosis.

As another means for solving the problems of the present invention,
In a fuel metering system of the type mentioned at the outset, means are provided for monitoring the quantities representing the pumping characteristic curves of the individual high-pressure pumps and for diagnosing faults in the high-pressure pump on the basis of characteristic quantities. The fuel metering system has means for diagnosing a fault in the high-pressure pump, for example, from a deviation of a feature of the high-pressure pump beyond at least one set limit.

In order to achieve the object of the invention on the basis of a direct-injection internal combustion engine of the type mentioned at the outset, the fuel metering system further comprises means for monitoring the quantities representing the pumping characteristic curves of the individual high-pressure pumps. And means for diagnosing a defect in the high-pressure pump based on the characteristic amount. The internal combustion engine further comprises means for diagnosing a fault in the high-pressure pump, for example, from a deviation of a characteristic value of the high-pressure pump beyond at least one set limit value.

In order to achieve the object of the invention, a control device of the type mentioned at the outset is provided, in which the control device monitors a quantity representing the pumping characteristic curve of the individual high-pressure pump, and a fault of the high-pressure pump. Means for diagnosing is based on the characteristic amount. The control device further comprises means for diagnosing a fault in the high-pressure pump, for example, from a deviation of a feature of the high-pressure pump beyond at least one set limit value.

Particularly important is the manner in which the method according to the invention is implemented in the form of an adjusting element provided for the control device of the direct injection internal combustion engine. Here, a program is stored on the adjusting element, which runs on a computing device (in particular a microprocessor) and is suitable for implementing the method according to the invention. In this case, the invention is realized by a program stored on the adjusting element, the adjusting element with this program representing the invention as well as a method suitable for implementing the program. In particular, an electric storage medium, for example a read-only memory ROM or a flash memory, is used as the adjusting element.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS Further features, means of application and advantages of the invention will be described hereinafter with reference to the illustrated embodiments of the invention. All features set forth in the specification or figures herein, regardless of whether they are recited in the claims or in the description or figures, may be used by themselves or in any combination in accordance with the present invention. It can be.

FIG. 1 shows how a piston 2 reciprocates in a cylinder 3 in a direct injection type internal combustion engine 1 of a vehicle. The cylinder 3 is provided with a combustion chamber 4, which is limited by a piston 2, an intake valve 5, and an exhaust valve 6. The intake valve 5 is connected to an intake pipe 7, and the exhaust valve 6 is connected to an exhaust pipe 8.

In the region of the intake valve 5 and the exhaust valve 6, the injection valve 9 and the ignition coil 10 project into the combustion chamber 4.
Fuel is injected into the combustion chamber 4 via the injection valve 9. The fuel in the combustion chamber 4 is ignited by the ignition coil 10.

The piston 2 reciprocates due to the combustion of the fuel in the combustion chamber 4, and this movement is transmitted to a crankshaft (not shown), where a rotational torque is generated.

The internal combustion engine 1 has a fuel metering system 11 by which fuel to be injected into the combustion chamber 4 via the injector 9 is metered. The fuel metering system 11 has a fuel storage tank 12 from which fuel is delivered to a low-pressure region ND of the fuel metering system 11 by a prefeed pump 13 configured as an electronic fuel pump. The two high-pressure pumps 14 and 15 deliver the fuel in the low-pressure region ND to the high-pressure accumulator 16. The high-pressure pumps 14 and 15 each have two check valves 1
It is configured as a one-cylinder high-pressure pump provided with a solenoid valve 7 and a solenoid valve 18. An electromagnetic control line 19 is provided by an electromagnetic valve 18.
Is opened or closed. Open electromagnetic control line 19
Then, the sucked fuel is returned to the low-pressure circuit again, and is not pumped to the high-pressure circuit. The fuel amount control valve 18 is driven by a drive signal T. Alternatively, each of the high-pressure pumps 14 and 15 may be configured as a three-cylinder radial plunger pump having one pressure control valve, and driven by a drive signal T.

The high-pressure accumulator 16 is configured as an accumulator rail of a common rail fuel metering system (CR fuel metering system). The high-pressure accumulator 16 is provided with a pressure sensor 24, which detects the prevailing injection pressure in the high-pressure accumulator 16 and forms a corresponding output signal p_r. A plurality of injection valves 9 (four injection valves in this embodiment) emerge from the high-pressure accumulator 16, whereby fuel is injected into the combustion chamber 4 of the cylinder 3 of the internal combustion engine 1. To inject fuel, the injector 9 is driven by a corresponding drive signal ES. The ignition coil 10 is driven by the drive signal ZW.

In order to maintain the pressure in the low pressure region ND of the fuel metering system 11 at a predetermined value, a low pressure controller 20 is arranged in the low pressure region ND.
Is higher than the predetermined pressure value, the fuel flows from the low pressure region ND to the fuel storage tank 12 in the return direction. A filter 21 is arranged between the pre-feed pump 13 and the high-pressure pumps 14 and 15.

An input signal 23 representing the amount of operation of the internal combustion engine 1 measured by the sensor is applied to the control device 22. The control device 22 is connected to, for example, an air flow sensor, a lambda sensor, a rotational speed sensor, or a pressure sensor 24. The control device 22 forms an output signal 25 which is used to control the characteristics of the internal combustion engine 1 via an actuator or a regulating element. The control device 22 is, for example, the injection valve 9
(Drive signal ES), ignition coil 10 (drive signal ZW),
It is connected to an electromagnetic control valve 18 (drive signal T) or a throttle valve arranged in the intake pipe 7, and forms a signal required for drive.

The control device 22 is configured to open and / or close the operation amount of the internal combustion engine 1 as occasion demands. The control device 22 controls the amount of fuel injected from the injection valve 9 into the combustion chamber 4 in an open or closed manner, in particular with respect to low fuel consumption and / or low emissions of interfering substances. For this purpose, the control device 22 is provided with a microprocessor, which stores a program in an adjusting element, in particular a read-only memory or a flash memory, which implements the aforementioned opening or closing control. Suitable to run. A program suitable for carrying out the method according to the invention is also stored in the adjusting element.

The internal combustion engine 1 of FIG. 1 can be driven in a plurality of operation modes. For example, the internal combustion engine can be driven in a uniform operation, a stratified air supply operation, or a uniform lean operation. The aforementioned driving modes of the internal combustion engine 1 can be switched respectively. Such switching is performed by the control device 22.

The fuel metering system 11 shown in FIG.
Is characterized in particular by having only one fuel circuit for metering fuel into the entire combustion chamber 4 of the internal combustion engine 1.
This fuel circuit is provided with two high pressure pumps 14,15. The two high-pressure pumps 14, 15 are driven independently of each other by a control unit 22 via a common pressure control circuit. The increase in the injection pressure p_r is formed by sending the fuel of the high-pressure pumps 14 and 15 to the high-pressure accumulator 16. The pressure drop is characteristic after injection of the fuel into the combustion chamber 4. Such a direct-injection internal combustion engine 1 is known, for example, from DE 100 230 33 A1, and is hereby incorporated by reference.

The injection pressure p provided in the control device 22
During the operation of the internal combustion engine 1, the control unit _r first generates a drive signal T ′ for the same two high-pressure pumps 14, 15 (except for the mutual time lag). Two high pressure pumps 14, 1
5 are therefore driven with the same drive time T. However, in practice, the two high-pressure pumps 14, 15 often have different pumping characteristic curves. The various pumping characteristic curves differ, for example, due to manufacturing tolerances, wear or temperature fluctuations. A high pressure pump 14 having a pumping characteristic curve,
If the 15 are driven with different drive signals T, the pressure level in the high-pressure accumulator after the pumping of the stronger high-pressure pump 14 is higher than the pressure level after the pumping of the weaker high-pressure pump 15. A different amount of fuel is injected into the combustion chamber 4 based on the change in the pressure level, whereby the control unit of the injection pressure p_r can be urged to perform the change control.

FIG. 2 shows a fuel metering system 1 in which the characteristic of the injection pressure p_r does not adapt the pumping speed q with respect to time t.
1, the high-pressure pumps 14, 15 have different pumping characteristic curves. It can be clearly seen in the high-pressure accumulator 16 that there is a higher pressure level after pumping of the high-pressure pump 14 than after pumping of the high-pressure pump 15. These pressure level fluctuations are indicated in FIG. 2 by the dashed line numbered 26.

FIG. 3 shows a time characteristic of the injection pressure p_r for the fuel metering system 11 for adjusting the pumping speed q. Here, the same pressure level is generated in the high-pressure accumulator 16 following the pumping of the high-pressure pumps 14,15.
This ensures that the same fuel quantity is always injected into the combustion chamber 4. In this case, no fluctuation of the pressure control is triggered.

The present invention also relates to a method for diagnosing the fuel metering system 11 shown in FIG. 4, in which a method for diagnosing defects in the high-pressure pumps 14, 15 as desired is proposed. The method starts at function block 30.
For each of the high-pressure pumps 14, 15, a function block 31 monitors the quantity representing the pumping characteristic curve of the high-pressure pump. If the monitored quantity or the quantity derived for one of the high-pressure pumps deviates beyond at least one set limit, a fault of the high-pressure pump is concluded. This deviation is determined in relation to the quantity previously monitored with the same high-pressure pump or with the quantity of the other high-pressure pump.

In the fuel metering system 11 (see FIG. 2) which does not adjust the pumping speed q of the high-pressure pumps 14 and 15 as an amount representing the pumping characteristic curve, for example, the high-pressure pump 1
After the pumping of 4 and 15, the dominant injection pressures p_r1 and p_r2 are recorded and analyzed in the high-pressure accumulator 16. Alternatively, the pumping speeds of the individual high-pressure pumps 14, 15 may be recorded and analyzed.

[0041]

[Outside 2]

In the function block 33, each high-pressure pump 14,
15, the average injection pressure p_r1_m, p_r2_m is the maximum average value p_r of all the high-pressure pumps 14, 15
Normalized according to 1_m. Thereby, relative pumping speeds q_1 and q_2 for the individual high-pressure pumps are obtained.

The function block 34 checks whether a constant target pressure p_r_soll controlling the injection pressure p_r is present in the high-pressure accumulator 16. Individual high pressure pump 1
The quantities representing the pumping characteristic curves of 4, 15 are constant target pressures p_r
_Soll is only monitored if it is present, so that the influence of the setpoint pressure p_r_soll on the diagnostic function and therefore erroneous error diagnosis are avoided.

Alternatively, the target pressure p_r_soll for controlling the injection pressure p_r may be considered when diagnosing the high-pressure pumps 14 and 15. For example, individual high pressure pumps 14,
When the difference values between the 15 injection pressure average values p_r1_m, p_r2_m and the target pressure p_r_soll are correlated, error diagnosis can be performed without any problem even if the target pressure p_r_soll fluctuates.

In the function block 35, it is checked whether or not a certain amount of fuel is injected into the combustion chamber 4 within a predetermined limit range. The quantities representing the pumping characteristic curves of the individual high-pressure pumps 14, 15 are monitored only when the fuel injection quantity is constant, so that errors in error diagnosis are avoided.

Alternatively, the amount of fuel to be injected into the combustion chamber 4 can be taken into account when diagnosing the high-pressure pumps 14, 15. The quantity of fuel to be injected is known to the control unit 22 and does not need to be calculated again when diagnosing an error.

Further, the pumping speeds q_1 and q_2 can be used in the inquiry block 36 for diagnosis.
Here, it is checked whether the relative pumping speeds q_1 and q_2 are within a predetermined range. This range is limited by set limits. If the pumping speeds q_1 and q_2 are outside of this range, that is, if the limit value has been exceeded or exceeded, the checked pumping speeds q_
It is diagnosed that the high-pressure pumps 14, 15 corresponding to 1, q_2 are defective (functional block 37). Block 32
36 have an analysis unit for the quantity (in this case, the injection pressure p_r) representing the pumping characteristic curve.

The features can be analyzed in a plurality of formats in addition to the form described here. For example, the injection pressure p determined at that time for the high-pressure pumps 14 and 15
If the difference between _r1, p_r2 and the normalized injection pressure exceeds at least one predetermined limit value, it is also concluded that the last pumped high-pressure pump 14, 15 is defective.

At the end of the method according to the invention, it is checked in query block 38 whether the internal combustion engine 1 is to be driven further. If so, the method of the invention is started again from function block 30. If not, the method ends at function block 39.

FIG. 5 shows a second preferred embodiment of the invention, in which the pumping speeds q_1, q_2 of the high-pressure pumps 14, 15 are shown.
Are used in the fuel metering system 11 which is adapted to the same value. In order to avoid pressure fluctuations in the high-pressure accumulator 16 based on different pumping characteristic curves of the high-pressure pumps 14, 15, the drive signal T 'of the high-pressure pumps 14, 15 is adjusted when the pumping speeds q_1, q_2 are adjusted. This is corrected so that the pumping speeds p_r1 and p_r2 of all the high-pressure pumps 14 and 15 have the same value. Pumping speed q of high pressure pumps 14, 15
_1 and q_2 cannot indicate a defect in the high-pressure pumps 14 and 15 when adjusting the pumping speeds q_1 and q_2. This is because the pumping loss of the high-pressure pumps 14, 15 is compensated at least within a predetermined range.

Instead of the injection pressure p_r, in this method, the correction coefficients k_1 and k_2 determined in the function block 31 within the range of the adaptation unit are used for diagnosis. The correction coefficients k_1 and k_2 represent the pumping characteristic curves of the high-pressure pumps 14 and 15. Apart from the method of FIG. 4 (see functional blocks 32 and 33), in the method of FIG. 5, the average formation and normalization of the correction coefficients k_1 and k_2 are performed. Correction coefficient k_1,
A correction value obtained in the range of the adaptation unit can be used for diagnosis instead of k_2. The difference between the correction coefficients k_1 and k_2 or the correction values of the high-pressure pumps 14 and 15 is at least 1
If two predetermined limits are exceeded (query block 3
6), a defect of the high-pressure pumps 14, 15 is concluded (see function block 37).

According to the method of the present invention, defects of the high-pressure pumps 14 and 15 of the fuel metering system 11 can be diagnosed as desired. The diagnosis can be performed not only by completely destroying the high-pressure pumps 14 and 15 but also by detecting, for example, a decrease in the pumping output using a plurality of set limit values. As a result, the diagnostic function outputs which of the high-pressure pumps 14, 15 has failed and what percentage of the pumping output has been lost.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an embodiment of an internal combustion engine of the present invention.

FIG. 2 is a characteristic diagram when the dominant injection pressure in the high-pressure accumulator of the internal combustion engine of FIG. 1 is not adapted to the pumping speed of the high-pressure pump.

FIG. 3 is a characteristic diagram in a case where a dominant injection pressure in a high-pressure accumulator of the internal combustion engine of FIG. 1 is adapted to a pumping speed of a high-pressure pump.

FIG. 4 is a flow chart of an advantageous embodiment of the method of the present invention.

FIG. 5 is a flow chart of an advantageous second embodiment of the method of the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Direct injection internal combustion engine 2 Piston 3 Cylinder 4 Combustion chamber 5 Intake valve 6 Exhaust valve 7 Intake pipe 8 Exhaust pipe 9 Injection valve 10 Ignition coil 11 Fuel metering system 12 Fuel storage tank 13 Prefeed pump 14, 15 High pressure pump 16 High pressure accumulator 17 Check valve 18 Electromagnetic control valve 19 Electromagnetic control line 20 Low pressure controller 21 Filter 22 Control device 23 Input signal 24 Pressure sensor 25 Output signal

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hans Jörg Bochum USA Michigan Novi Palmer Drive 30842 F-term (reference) 3G066 AA01 AA02 AB02 AC01 AC09 AD01 AD02 BA01 BA05 BA12 BA13 BA14 BA16 BA29 BA51 BA69 CA05Z CA31 CC06Z CC66 CC68T CD03 CD26 CD29 CE13 DA01 DA06 DC11 DC18 (54) [Title of the Invention] Driving method of fuel metering system for direct injection type internal combustion engine, fuel metering system for direct injection type internal combustion engine, direct injection type internal combustion engine, direct injection Control device for direct-type internal combustion engines, and adjusting element of control device for direct-injection internal combustion engines

Claims (17)

[Claims] At least one high pressure pump (14) for delivering fuel from a fuel storage tank (12) to a low pressure region (ND) of a fuel metering system (11) and demand-controlling the fuel in the low pressure region (ND). , 15) to the high pressure accumulator (16), in which the dominant injection pressure (p_r) is reduced by the pumping speeds (q_1, q_2) of at least one high pressure pump (14, 15). Drive by directing a fuel metering system (11) of a direct-injection internal combustion engine (1), which controls the fuel injection from a high-pressure accumulator (16) into the combustion chamber (4) of the internal combustion engine (1). In the method, for each high pressure pump (14, 15), the high pressure pump (1
4. A method for driving a fuel metering system for a direct injection type internal combustion engine, comprising monitoring a quantity representing a pumping characteristic curve of (4, 15) and utilizing the quantity to diagnose a defect of the high-pressure pump (14, 15). 2. The method according to claim 1, wherein the pumping speeds (q_1, q_2) of the high-pressure pumps (14, 15) are monitored as quantities representing a pumping characteristic curve. 3. The injection pressure (p_r) dominant in the high-pressure accumulator (16) in connection with the pumping to the high-pressure pumps (14, 15).
_1, p_r_2) are monitored as quantities representing the pumping characteristic curve. 4. The method according to claim 3, wherein an average of the continuously determined injection pressures (p_r_1, p_r_2) for each high-pressure pump (14, 15) is formed. 5. The method according to claim 4, wherein the average injection pressure for each high-pressure pump is normalized to the largest average of the averages of all the high-pressure pumps. 6. A correction coefficient (k) that is multiplied by a drive signal (T) for a control valve of the high-pressure pump (14, 15).
_1, k_2) or by a correction value applied to the drive signal (T), the correction factor or the correction value being monitored as a quantity representing the pumping characteristic curve. . 7. The method as claimed in claim 6, wherein a correction factor (k_1, k_2) or an average of the correction values is continuously formed for each high-pressure pump (14, 15). 8. The method according to claim 4, wherein the averaging is performed synchronously with the rotational speed of the internal combustion engine. 9. An average correction coefficient (k_1, k_2) or an average correction value for each of the high-pressure pumps (14, 15) is normalized according to the maximum average value among the average values of all the high-pressure pumps (14, 15). , The normalized correction coefficient (k_
1, k_2) or from the normalized correction values, the relative pumping speeds (q_1_n, q) of the individual high-pressure pumps (14, 15).
_2_n). 10. The method according to claim 1, wherein the quantity representing the pumping characteristic curve of the individual high-pressure pumps is monitored only when the control value of the injection pressure is constant. Or the method of claim 1. 11. The method as claimed in claim 1, wherein the target value of the control of the injection pressure (p_r) is taken into account when diagnosing the high-pressure pump (14, 15). 12. The quantity representing the pumping characteristic curve of the individual high-pressure pumps (14, 15) is monitored only when the quantity of fuel injected constantly into the combustion chamber is within a set limit. A method according to any one of the preceding claims. 13. The method as claimed in claim 1, wherein the amount of fuel to be injected into the combustion chamber is taken into account when diagnosing the high-pressure pump (14, 15). 14. A fuel storage tank (12), and a fuel metering system (1) for supplying fuel from the fuel storage tank (12).
1) at least one pre-feed pump (13) delivering to the low pressure region (ND) and at least one demand controlled high pressure pump (14) delivering the low pressure region (ND) fuel to the high pressure accumulator (16). , 15) and a control device (p_r) for controlling the dominant injection pressure (p_r) in the high-pressure accumulator (16) by changing the pumping speed (q_1, q_2) of at least one high-pressure pump (14, 15). 22) and a fuel injection valve (9) for injecting fuel from the high-pressure accumulator (16) into the combustion chamber (4) of the internal combustion engine (1).
Fuel metering system for direct injection internal combustion engine (1) (11)
Wherein the fuel metering system (11) comprises individual high pressure pumps (1).
Means for monitoring a quantity representing the pumping characteristic curve of 4, 15);
Means for diagnosing defects in the high-pressure pumps (14, 15) based on the characteristic amount. 15. A fuel metering system (1) comprising: a fuel storage tank (12); and a fuel in the fuel storage tank (12).
1) at least one pre-feed pump (13) delivering to the low pressure region (ND) and at least one demand controlled high pressure pump (1) delivering the fuel in the low pressure region (ND) to the high pressure accumulator (16).
4, 15) and a control device for controlling the dominant injection pressure (p_r) in the high-pressure accumulator (16) by changing the pumping speed (q_1, q_2) of at least one high-pressure pump (14, 15) (22) and a fuel metering system (11) having a fuel injection valve (9) for injecting fuel from the high-pressure accumulator (16) into the combustion chamber (4) of the internal combustion engine (1). In the direct injection type internal combustion engine (1), the fuel metering system (11) includes individual high-pressure pumps (14,
15) A direct injection type internal combustion engine, comprising: means for monitoring an amount representing a pumping characteristic curve of 15); and means for diagnosing a defect of the high-pressure pump (14, 15) based on the characteristic amount. 16. A fuel metering system (1) comprising: a fuel storage tank (12); and fuel in the fuel storage tank (12).
1) at least one pre-feed pump (13) delivering to the low pressure region (ND) and at least one demand controlled high pressure pump (1) delivering the fuel in the low pressure region (ND) to the high pressure accumulator (16).
4, 15) and a control device for controlling the dominant injection pressure (p_r) in the high-pressure accumulator (16) by changing the pumping speed (q_1, q_2) of at least one high-pressure pump (14, 15) (22) and a fuel injection valve (9) for injecting fuel from the high-pressure accumulator (16) into the combustion chamber (4) of the internal combustion engine (1).
In a control unit (22) for a direct injection internal combustion engine (1) with a fuel metering system (11), the control unit (22) determines a quantity representing the pumping characteristic curve of the individual high-pressure pumps (14, 15). A control device for a direct injection internal combustion engine, comprising: means for monitoring; and means for diagnosing a defect in a high-pressure pump (14, 15) based on a characteristic amount. 17. An adjusting element of a control device (22) for a direct injection internal combustion engine (1), for example a read-only memory (R).
OM) or a flash memory in which a program operable on a computing device, for example a microprocessor, is stored and is suitable for implementing the method according to any one of claims 1 to 13. The regulating element of a control device for a direct-injection internal combustion engine, characterized by: