JP2001349244A - Method for adjusting accumulation pressure existing in pressure accumulator of fuel quantity adjusting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an accumulating pressure adjusting speed, and to enhance adjusting accuracy by reducing a burden of adjusting accumulation pressure existing in an accumulator. SOLUTION: An accumulation pressure adjusting method of the above- mentioned form is provided for advantageously determining an electric control quantity depending on a flow rate and the accumulation pressure passing through a pressure control valve or the accumulation pressure generated in the accumulator 6 by depending on the flow rate passing through the pressure control valve 9 and the electric control quantity of the pressure control valve by using a characteristic map in a frame of previous control by performing the previous control before an adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel metering system for a direct injection type internal combustion engine, in which fuel from an accumulator is guided to a low pressure region of the fuel metering system via a pressure control valve in order to reduce the accumulated pressure. The present invention relates to a method for regulating the accumulated pressure present in an accumulator of a system by using a pressure control valve which can be electrically controlled. The present invention further provides a high pressure pump for delivering fuel from a low pressure region of the fuel metering system at a high pressure to a pressure accumulator, an injection valve capable of injecting fuel from the pressure accumulator into a combustion chamber of an internal combustion engine, and an electric valve. A pressure control valve that can be controlled in a controlled manner, and in order to reduce the accumulated pressure, the fuel from the accumulator is guided to a low pressure region of the fuel metering system via the pressure control valve. The present invention relates to a fuel metering system in which the accumulated pressure in an accumulator is adjusted. The present invention is further directed to a high pressure pump for injecting fuel into a combustion chamber using a fuel metering system, wherein the fuel metering system delivers high pressure fuel from a low pressure region of the fuel fuel metering system to an accumulator. And an injection valve for injecting fuel from the pressure accumulator into the combustion chamber of the internal combustion engine, and an electrically controllable pressure control valve.In order to reduce the pressure, the pressure is controlled via the pressure control valve. The present invention relates to a direct-injection internal combustion engine in which fuel from the accumulator is guided to a low-pressure region of the fuel metering system, whereby the accumulated pressure generated in the accumulator is adjusted via the pressure control valve. Finally, the present invention provides a fuel injection system using a fuel metering system, wherein the fuel metering system comprises:
The fuel-fuel metering system has a high-pressure pump that sends fuel from a low-pressure region to a pressure accumulator at a high pressure, and an injection valve that injects fuel from the pressure accumulator into a combustion chamber of an internal combustion engine. To guide the fuel from the accumulator to a low pressure region of the fuel metering system via a pressure control valve, the control device can electrically control the accumulated pressure existing in the accumulator. The present invention relates to a control device for a direct injection internal combustion engine having a combustion chamber, which is regulated using a pressure control valve.

[0002]

2. Description of the Related Art A direct-injection internal combustion engine of the type described at the outset with the fuel metering system described at the outset is known from the prior art. This fuel metering system has a predischarge pump, usually formed as an electronic fuel pump,
The predischarge pump supplies fuel from the storage container to the low pressure region of the fuel metering system. The high pressure pump delivers fuel from the low pressure region at high pressure to the accumulator. This accumulator is formed, for example, as a distribution rail in a common rail (CR) fuel metering system. The accumulator communicates with the injector, through which fuel from the accumulator can be injected into the combustion chamber of the internal combustion engine. This injection valve is controlled by a control device of the internal combustion engine. Further, an electrically controllable pressure control valve branches off from the pressure accumulator, through which the fuel from the pressure accumulator is fed to the fuel metering system in order to reduce the accumulated pressure applied in the pressure accumulator. To the low pressure region. Therefore, the accumulated pressure applied in the accumulator can be adjusted via the pressure control valve. This pressure control valve is likewise controlled by the control device of the internal combustion engine.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to increase the speed of pressure accumulation adjustment and to increase the accuracy of the adjustment by reducing the burden of adjusting the pressure accumulation existing in the pressure accumulator.

[0004]

In order to solve this problem, according to the present invention, pre-control is performed prior to adjustment, and within this pre-control, the flow rate and the accumulated pressure passing through the pressure control valve are controlled. It is possible to determine the electrical control variable as a function of the flow rate through the pressure control valve and the pressure buildup occurring in the accumulator as a function of the electrical control variable of the pressure control valve, advantageously using a characteristic map, A method for accumulating pressure of the type mentioned at the outset is provided.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure control valve which has a unique proportional relationship between the flow rate passing through the pressure control valve, the electric control amount of the pressure control valve, and the accumulated pressure generated in the accumulator. Based on the perception that they have. This relationship is filed in a property map from which a third quantity can be determined based on the two quantities of data. This characteristic map shows the relation between the three characteristic quantities stored in it, namely the relation between the flow rate through the pressure control valve, the electric control quantity of this pressure control valve and the accumulated pressure applied to the accumulator. It is used by the invention for the pre-control together with the data relating to it, by means of which the adjustment stroke of the subsequent pressure accumulation adjustment is shortened. Therefore, the speed of the adjustment is significantly increased, and the accuracy of the adjustment is increased.

According to an advantageous variant of the invention, the flow through the pressure control valve is determined by the fuel mass delivered to the accumulator by the high-pressure pump of the fuel metering system and the internal combustion engine via the injector of the fuel metering system. From the difference in the mass of fuel injected into the combustion chamber. Using this mass balance, the flow rate through the pressure control valve can be modeled simply and accurately. The fuel mass delivered by the high-pressure pump is obtained from the product of the stroke volume of the high-pressure pump, the speed of the internal combustion engine, the density of the fuel, the speed-dependent efficiency and the temperature-dependent efficiency. The fuel mass flowing out of the accumulator via the injector is determined from the product of the fuel mass required to reach the target torque and the target torque and the calibration factor. The fuel mass required to reach the target torque is a dimensionless variable,
rk is displayed.

According to an advantageous embodiment of the invention, the setpoint pressure is used as the pressure accumulation to determine the electrical control of the pressure control valve. The setpoint pressure is supplied to a characteristic map together with the flow rate through the pressure control valve, from which a corresponding value of the electrical control of the pressure control valve is obtained. The pressure control valve is controlled using the value of the electric control amount obtained within the frame of the preliminary control. Subsequent adjustments need only compensate for small deviations in the value of this pre-controlled electrical control variable.

According to another advantageous embodiment of the invention, the actual control variable which is used together with the regulation of the pressure accumulation is used as the electrical control variable of the pressure control valve in order to determine the pressure build-up that occurs. This control variable occurs within the framework of the accumulation of pressure and is used as an electrical control of the pressure control valve in order to determine the resulting accumulation. When the accumulated pressure applied in the accumulator changes, it is necessary to increase or decrease the control amount of the pressure control valve only for a short time. This control variable does not directly affect the pressure change. Therefore, a predetermined component of this control variable must be subtracted from the duty ratio used for pressure calculation.

According to a particularly advantageous variant of the invention, the temperature of the pressure control valve is determined and is taken into account when determining the electrical control variable of the pressure control valve or the pressure buildup occurring in the accumulator. The pressure control valve is usually controlled via a magnetic coil. The resistance of the magnetic coil depends on the temperature. Therefore, the effective electric control amount also depends on the temperature. The temperature of the pressure control valve is therefore determined and is taken into account when determining the electrical control variable or the pressure accumulation via the correction factor.

According to an advantageous embodiment of the invention, the temperature of the pressure control valve is modeled from the temperature of the internal combustion engine, the temperature of the surrounding air, the control variable of the pressure control valve and / or the speed of the motor vehicle driven by the internal combustion engine. Be transformed into Instead of the temperature of the surrounding air, the temperature of the inhaled air can also be used. This is because it provides a good approximation to the temperature of the surrounding air. As the speed of the vehicle increases, the internal combustion engine cools more. Such a situation is taken into account when modeling the temperature of the pressure control valve, taking into account the speed of the motor vehicle.

What is particularly significant is the realization of the method according to the invention in the form of a control element provided for the control device of the direct-injection internal combustion engine. In this case, a program is stored in the control element. This program is executable on a computing device, in particular on a microprocessor, and is suitable for implementing the method according to the invention. In this case, the present invention is also realized by a program stored in the control device. The control element with this program therefore represents the invention in the same way as the method according to the invention, and the program is suitable for implementing the method according to the invention. This control element can in particular be an electrical storage medium, for example a read-only memory (ROM) or a flash memory.

As a further solution of the object of the invention, a fuel metering system of the type described at the outset is provided, in which a pre-control is pre-connected to the adjusting unit,
Within the pre-control frame, an electrical control variable is generated depending on the flow rate and pressure accumulation through the pressure control valve or the accumulator depending on the flow rate passing through the pressure control valve and the electrical control quantity of the pressure control valve. The pressure build-up can advantageously be determined using a characteristic map.

Further, as means for solving the problems of the present invention,
A direct-injection internal combustion engine of the type mentioned at the outset is provided, in which a pre-control unit is connected upstream of the regulating unit and, in the pre-control frame, depends on the flow rate through the pressure control valve and the accumulator pressure. As a result, the electrical control variable or the pressure build-up occurring in the accumulator as a function of the flow through the pressure control valve and the electrical control variable of the pressure control valve can be determined, preferably using a characteristic map.

Finally, as a further solution to the problem of the invention, there is provided a control device for a direct-injection internal combustion engine of the type mentioned at the outset, which control device is connected to a pre-adjusted control device. It has a control unit, and in the pre-control frame, depends on the electric control amount depending on the flow rate and the pressure accumulation passing through the pressure control valve, or on the flow rate passing through the pressure control valve and the electric control amount of the pressure control valve. The accumulated pressure occurring in the accumulator can then be determined, preferably using a characteristic map.

[0015] Other features, applicability and advantages of the present invention will become apparent in the following description of embodiments of the present invention. In the following description, embodiments are illustrated. All described or displayed features, by themselves or in any combination,
It forms the subject of the present invention. They form the subject of the present invention irrespective of the summary in the claims or in their citations, or their formulation or presentation in the description or figures.

[0016]

FIG. 1 shows a fuel injection system for a direct injection internal combustion engine having a high-pressure fuel injection system according to the present invention. This fuel metering system 1
Are configured as a common rail (CR) fuel metering system.

Reference numeral 2 designates a fuel storage container. This fuel storage container is connected to the preliminary discharge pump 3. The preliminary discharge pump 3 is formed, for example, as an electric fuel pump. Fuel reaches the high-pressure pump 5 from the preliminary discharge pump 3 via the conduit 4. The high-pressure pump 5 is connected to a high-pressure accumulator 6. The high-pressure accumulator 6 is configured as a high-pressure accumulator (rail).
The high-pressure accumulator 6 is connected via a fuel line 7 to a high-pressure injection valve 8 (so-called injector). High pressure accumulator 6
Is connected via a pressure control valve 9 to the low-pressure region of the fuel metering system 1 and, in the present embodiment, to the fuel storage container 2.
The pressure control valve 9 is formed as a proportional valve and can be operated using a magnetic coil 12.

The area of the fuel metering system between the output of the high-pressure pump 5 and the input of the pressure control valve 9 is shown as the high-pressure area. The pressure in this high pressure region is
0 is detected. Fuel storage container 2 and high-pressure pump 5
The area of the fuel metering system between and is shown as a low pressure area.

Reference numeral 11 designates a control device for an internal combustion engine. This control device performs control or adjustment on the fuel metering system 1. The control device 11 controls the magnetic coil 12 of the pressure control valve 9 by applying a control signal A to the high-pressure injection valve 8. For this purpose, the output signal p_r of the pressure sensor 10 and a different output signal n of another sensor 13, for example a speed sensor, are evaluated.

The control device 11 also adjusts the accumulated pressure p_r existing in the high-pressure accumulator 6. The accumulated pressure p_r is the high pressure pump 5
Is increased by constantly delivering fuel to the high pressure accumulator 6. In order to reduce the accumulated pressure p_r, the fuel from the high-pressure accumulator 6 can be guided to the low-pressure region of the fuel metering system 1 via the pressure control valve 9. According to the present invention, the control device 11 has a preliminary control unit that is connected in front of the control unit. Thereby, the adjustment process is decisively shortened. This leads to an increase in adjustment speed and an increase in adjustment accuracy.

FIG. 2 shows a part of the preliminary control of the method for adjusting the accumulated pressure p_r according to the present invention. The pre-control according to the present invention is performed by the pressure control valve 9 between the flow rate dmkrdsv passing through the pressure control valve 9, the electric control amount tadsvvst of the pressure control valve 9, and the accumulated pressure p_r generated in the high-pressure accumulator 6. It takes advantage of the fact that it has a unique proportional relationship. This relationship is filed in a property map, from which a third quantity is determined based on the two quantities of data each time.

In FIG. 2, the electric control amount tadsvvst of the pressure control valve 9 and the accumulated pressure prbk generated in the high-pressure accumulator 6 are estimated as the initial amounts of the preliminary control. To determine both initial quantities, the flow rate d through the pressure control valve 9
mkrdsv is used. This flow rate dmkrdsv
Is modeled from the difference between the fuel mass dmkrhdp delivered from the high-pressure pump 5 to the high-pressure accumulator 6 and the fuel mass dmkrhdev injected into the combustion chamber of the internal combustion engine via the high-pressure injection valve 8.

The fuel mass dmkrhdp supplied via the high-pressure pump 5 is determined by the stroke volume VHHDP of the high-pressure pump 5.
, Fuel density RHOKR, and internal combustion engine speed nmo
t and the efficiency ETANH of the high-pressure pump 5 depending on the rotation speed
DP and temperature dependent efficiency ETATH of high pressure pump 5
It is obtained from the product with DP. The fuel mass dmkrhdev injected through the high-pressure injection valve 8 is determined by the rotational speed n of the internal combustion engine.
It is obtained from the product of mot, the dimensionless quantity rk and the calibration coefficient KRKMK. The dimensionless quantity rk represents "relative fuel",
By being proportional to the mass of fuel injected into the combustion chamber,
The target torque is obtained.

The electric control amount tadsvv of the pressure control valve 9
To determine st, the target pressure prsoll for the adjustment is used as the pressure accumulation p_r.

In order to obtain the accumulated pressure prbk, the control amount taprbk actually generated together with the adjustment of the accumulated pressure p_r is determined.
Is used as an electrical control variable. When the accumulated pressure p_r applied in the accumulator changes, it is necessary to increase or decrease the control amount of the pressure control valve 9 only for a short time. This control variable does not directly affect the pressure change. Therefore, the predetermined component of this control variable must be subtracted from the duty ratio tadsv used for pressure calculation. The resulting accumulated pressure prbk is determined by the gradient dprs of the target pressure prsoll.
oll is determined via the addition amount taadpr depending on the ll. Alternatively, the amount of multiplication is also conceivable. Pressure control valve 9
An additional control variable is also applied to cause a pressure change of the accumulated pressure p_r.

In the system including the high-pressure accumulator 6 and the control unit, a delay in the system reaction also occurs. In order to take this delay into account, a filter is arranged in a branch of the preliminary control unit for modeling the electric control amount taprbk.

The resistance of the magnetic coil 12 of the pressure control valve 9 and the effective electric control amount also depend on the temperature. Therefore, the temperature tdsv of the pressure control valve 9 is modeled within the framework of the preliminary control, and the electric control amount t is obtained via the calibration coefficient fttadsv.
It is considered under adsv or tadsvvst.
The temperature tdsv of the pressure control valve 9 is modeled by the temperature of the internal combustion engine, the temperature of the surrounding air (alternatively, the temperature of the intake air), the electric control amount tadsv, and the speed of the vehicle driven by the internal combustion engine. It is performed in consideration of.

Within the framework of the pre-control, the quantity dm to be modeled
krdsv and prsoll or dmkrds
v and taprbk are the corresponding characteristic maps TADSV
SOL or KFPRBK, and using these characteristic maps, the electric control amount tadsvvs of the pressure control valve 9
The output amount of t or the output amount of the accumulated pressure prbk generated in the high-pressure accumulator 6 is estimated from the preliminary control.

[Brief description of the drawings]

FIG. 1 shows an advantageous embodiment of a fuel metering system for a direct injection internal combustion engine according to the invention.

FIG. 2 shows an advantageous embodiment of the functional diagram of the accumulator regulation method according to the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel metering system 2 Fuel storage container 3 Pre-discharge pump 4 Conduit 5 High-pressure pump 6 Accumulator 7 Fuel conduit 8 Injection valve 9 Pressure control valve 10 Pressure sensor 11 Controller 12 Magnetic coil 13 Sensor

Continuation of the front page F term (reference) 3G066 AA02 AB02 AC09 BA19 BA51 CA39U CD03 CD26 CE22 CE29 DC11 DC18 3G084 BA14 DA05 EA04 EB08 EB12 3G301 HA01 HA04 JA03 JA18 LB06 LC01 LC10 MA11 NB01 NC01 NC02 NE17 PB08Z

Claims (14)

[Claims] 1. A method for regulating the accumulated pressure (p_r) present in an accumulator (6) of a fuel metering system (1) of a direct injection internal combustion engine using an electrically controllable pressure control valve (9). An adjustment of the type which leads the fuel from the accumulator (6) via the pressure control valve (9) to the low pressure region of the fuel metering system (1) in order to reduce the accumulated pressure (p_r). In the method, a pre-control is performed prior to the regulation, and within the framework of the pre-control, depending on the flow rate (dmkrdsv) passing through the pressure control valve (9) and the accumulated pressure (p_r), the pressure control valve The electric control amount (tadsv) of (9)
vst) or the flow rate (dmkrdsv) passing through the pressure control valve (9) and the pressure control valve (9)
An accumulating pressure (p_r) generated in the accumulator (6) depending on the electrical control amount (taprbk) of the adjusting device. 2. An accumulator (p_p) generated in said accumulator (6).
r) to a characteristic map (TADSVSOL; KFPRBK)
The method of claim 1, wherein the method is used to determine 3. The flow rate (dmkrdsv) passing through the pressure control valve (9) is changed by the fuel mass (dmkrhdp) delivered from the high-pressure pump (5) of the fuel metering system (1) to the pressure accumulator (6). 3. The method as claimed in claim 1, wherein the difference is determined from the difference between the fuel mass (dmkrhdev) injected into the combustion chamber of the internal combustion engine via the injector (8) of the fuel metering system (1). 4. An accumulator (p_r) for obtaining an electric control amount (tadsvvst) of the pressure control valve (9).
Use the target pressure of adjustment (prsoll) as
A method according to any one of claims 1 to 3. 5. The control unit according to claim 1, wherein a control amount (taprbk) actually generated together with the adjustment of the storage pressure is used as the electrical control amount in order to obtain the generated storage pressure (p_r). Method. 6. The temperature (tds) of the pressure control valve (9).
v), and taking the temperature into account when determining the electrical control amount (tadsvvst) of the pressure control valve (9) or the accumulated pressure (p_r) generated in the accumulator (6).
A method according to any one of claims 1 to 5. 7. The temperature (tds) of the pressure control valve (9).
7. Modeling v) from the temperature of the internal combustion engine, the temperature of the surrounding air, the control variable (tadsv) of the pressure control valve (9) and / or the speed of the motor vehicle driven by the internal combustion engine. the method of. 8. A control element for a control device (11) for a direct injection internal combustion engine, for example a read-only memory (ROM) or a flash memory, in which a program is stored; A control element for a control device (11) for a direct injection internal combustion engine, which is executable on a processor and is suitable for implementing the method according to any one of the preceding claims. 9. A fuel metering system (1) for a direct injection internal combustion engine, comprising a high-pressure pump (5), wherein the high-pressure pump (5) is provided from a low-pressure region of the fuel metering system (1). The fuel is delivered to the pressure accumulator (6) at a high pressure, and has an injection valve (8). The fuel from the pressure accumulator (6) is injected into the combustion chamber of the internal combustion engine via the injection valve (8). It has an electrically controllable pressure control valve (9),
_R), the fuel from the pressure accumulator (6) is led to the low pressure region of the fuel metering system (1) via the pressure control valve (9), whereby the pressure accumulator ( In the fuel metering system of the type in which the accumulated pressure (p_r) existing in 6) is adjusted, a pre-control unit is connected in front of the adjusting unit, and within the frame of the pre-control, the pressure control valve (9) The electric control amount (tadsvvs) of the pressure control valve (9) depends on the flow rate (dmkrdsv) passing through the pressure control valve and the accumulated pressure (p_r).
t) is determined, or depending on the flow rate (dmkrdsv) passing through the pressure control valve (9) and the electrical control amount (taprbk) of the pressure control valve (9), the accumulated pressure (p_r) is determined. A fuel metering system, characterized in that: 10. The fuel metering system according to claim 9, wherein the generated accumulated pressure (p_r) can be determined by using a characteristic map (TADSVSOL; KFPRBK). 11. A direct injection internal combustion engine having a combustion chamber, wherein fuel is injected into the combustion chamber using a fuel metering system (1), wherein the fuel metering system (1) A high-pressure pump (5) for sending fuel from a low-pressure region of the fuel-fuel metering system (1) at a high pressure to an accumulator (6), and an injection for injecting fuel from the accumulator (6) into a combustion chamber of an internal combustion engine. It has a valve (8) and a pressure control valve (9) that can be electrically controlled, and the accumulated pressure (p_r) generated in the accumulator (6) is adjusted via the pressure control valve (9). In the adjustment, the fuel from the pressure accumulator (6) is led to a low pressure region of the fuel metering system (1) via a pressure control valve (9) to reduce the pressure (p_r). In the direct injection type internal combustion engine of the type performed by Are, in advance control in the frame, depending on the flow rate (Dmkrdsv) and the accumulator (P_r) passing said pressure control valve (9), electrical control of the pressure control valve (9) (Tadsv
vst) or the pressure control valve (9)
A direct injection type internal combustion engine characterized in that the accumulated pressure (p_r) generated is determined depending on the flow rate (dmkrdsv) passing through the pressure control valve and the electrical control amount (taprbk) of the pressure control valve (9). 12. The direct-injection internal combustion engine according to claim 11, wherein the generated pressure accumulation (p_r) can be obtained by using a characteristic map (TADSVSOL; KFPRBK). 13. A control device (11) for a direct injection internal combustion engine having a combustion chamber, wherein fuel is injected into the combustion chamber using a fuel metering system (1), The high-pressure pump (5) for sending the fuel from the low-pressure region of the fuel-fuel metering system (1) to the pressure accumulator (6) at a high pressure and the fuel from the pressure accumulator (6) to the internal combustion system. The control device (11) has an injection valve (8) for injecting into a combustion chamber of the engine, and the control device (11) is capable of electrically controlling a pressure accumulation (p_r) existing in the pressure accumulator (6). 9)
The fuel is supplied from the pressure accumulator (6) via the pressure control valve (9) to the fuel metering system (1) to reduce the pressure (p_r). The control device of the type performed by being guided to a low-pressure region according to (1), wherein the control device (11) has a pre-control unit connected upstream of a regulating unit, and within the framework of pre-control, the pressure control valve The electric control amount (tadsv) of the pressure control valve (9) depends on the flow rate (dmkrdsv) passing through (9) and the accumulated pressure (p_r).
vst) or the pressure control valve (9)
(Dmkrdsv) and pressure control valve (9)
A control device for a direct injection internal combustion engine, characterized in that the resulting accumulated pressure (p_r) can be determined depending on the electric control amount (taprbk) of the internal combustion engine. 14. The control device according to claim 13, wherein the generated pressure accumulation (p_r) can be obtained by using a characteristic map (TADSVSOL; KFPRBK).