JPH04246262A - Device for controlling self-ignition internal- combustion engine - Google Patents

Abstract

PURPOSE: To precisely adjust the quantity of fuel in a control device for a self-ignition type internal combustion engine. CONSTITUTION: In a control device for a self-ignition type internal combustion engine, a first actuator 80 determines an initiation of fuel injection, and a second actuator 130 determines a fuel amount QK to be injected. Target values SBS of positions of the first actuator 80 are recorded on a map 90 with various operation parameters. A target values RW of the second actuator 130 is compensated in accordance with a signal indicating an initiation of injection, and a signal QK indicating the fuel amount QK. With this arrangement, a constant torque can be ensured at an arbitrary rotational speed upon arbitrary initiation of injection.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a control device for a self-ignition internal combustion engine, and more particularly, a first actuator that determines the start of fuel injection, and a second actuator that determines the amount of fuel to be injected. The present invention relates to a control device for a self-ignition internal combustion engine, in which target values of a first actuator are stored in at least one map according to various operating parameters.

0002

[Prior Art] This type of control system is DE-OS35.
22414 (US-A4619233). In the control system for an internal combustion engine described in the publication, a first actuator determines the timing of fuel injection, and a second actuator determines the amount of fuel to be injected. In that case, the first actuator is a reciprocating slider. In this system, the adjustment of the first actuator also affects the amount of fuel. To compensate for this effect, the actuation signal for actuating the second actuator, which determines the amount of fuel to be injected, is corrected using a correction factor. This correction factor is dependent on the rotational speed and the actual position of the first actuator (reciprocating slider).

Corrections of this type using coefficients that depend only on the rotational speed and the actual position of the reciprocating slide are not sufficient for accurately regulating the injection quantity.

[0004] In the above-described devices, the fuel quantity becomes inaccurate. If the actuator which influences the amount of fuel to be injected is adjusted in a defined manner, the fuel amount differs depending on the adjustment of the reciprocating slide. It would be desirable to be able to adjust the two quantities, injection initiation and fuel quantity, completely independently of each other. It has been found that sufficient correction is not possible when using correction coefficients that only take into account the rotational speed and the reciprocating slider position.

With the devices shown in the prior art, it is not possible to adjust the amount of fuel to be injected completely independently of the start of injection. This results in an inaccurate amount of fuel being injected.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for a self-igniting internal combustion engine which allows the fuel quantity to be regulated as precisely as possible.

[0007]

[Means for Solving the Problem] The above problem has a first actuator that determines the start of fuel injection, and a second actuator that determines the amount of fuel to be injected, and has a first actuator that determines the amount of fuel to be injected. In a control device for a self-ignition internal combustion engine in which a target value of a second actuator is stored according to various operating parameters, the target value of the second actuator is corrected according to a signal indicating the start of injection and a signal indicating the fuel amount. resolved.

[0008]

According to the device of the present invention, a constant injection amount can be guaranteed when target values for the injection amount are set at arbitrary rotational speeds and reciprocating slider positions. This is made possible by being able to take into account all influences on the fuel quantity via the multidimensional pump map. By using the map, the target value of the movement amount of the control rack or the target value of the injection amount is corrected according to the reciprocating slider position, the rotation speed, and the control rack position.

Advantages and preferred embodiments of the invention are set out in the dependent claims. That is, it becomes possible, for example, to keep the torque provided by the internal combustion engine constant regardless of the start of injection.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below using examples shown in the drawings.

In the following, the apparatus of the present invention will be explained using a reciprocating slider type pump as an example. However, the device of the invention is not limited to use with reciprocating slider pumps. The device can also be used in other high-pressure fuel pumps in which the start of injection and the amount of fuel injected can be adjusted independently of each other.

FIG. 1 shows a block circuit diagram of a fuel metering device according to the present invention. Through the respective control circuits,
A regulating device (hereinafter referred to as first actuator) which determines the start of the supply or injection, as well as a second regulating device (hereinafter referred to as second actuator) which determines the amount of fuel to be injected, is activated. The internal combustion engine 10 is supplied with fuel necessary for combustion via a high-pressure fuel pump 20. In this case, the sensor 30 detects the start of the respective fuel injection, ie the start of injection or the start of delivery of the injection pump. However, a sensor for detecting the actual position of the first actuator 80 can also be provided.

Sensor 40 detects a signal corresponding to the amount of fuel supplied to internal combustion engine 10. Typically this is the position (travel) RWI of the control rack.

However, for other types of pumps,
Signals such as injection duration or other signals indicating the value of the amount injected can also be used. Various sensors 50
detects the operating status of the internal combustion engine. That is, for example, a sensor that detects the rotation speed N of the internal combustion engine 10 is provided.

The output signal of sensor 30 passes via subtraction point 60 to first controller 70 which drives first actuator 80 . This first actuator 80 regulates the start of fuel metering. At the second input of the subtraction point 60, the output signal SBS of a map (map data generator) 90 is applied, which forms the setpoint value for the start of injection. This map 90
The rotation speed N and the desired fuel amount Q are input from the calculation unit 100.
A signal related to K is input.

The sensor 40 detects the actual movement amount (actual position of the control rack) RWI of the control rack. The second controller 120 controls the amount of fuel supplied to the internal combustion engine according to the output signal of the subtraction point 110.
A control signal for the actuator 130 is formed. The second actuator displaces the control rack in this embodiment.

A second input of the subtraction point 110 is applied with the output signal of a map 140 which sets the target value of the control rack position. Various signals are input from the calculation unit 100 to this map 140 for setting the position of the control rack. For example, a signal indicating the rotational speed and a signal indicating the desired fuel amount QK. Furthermore, the output signal of the first controller 70 or the output signal of the map 90 is applied to the map 140 .

The calculation unit 100 is particularly provided with an engine map 170. The output signal of the map 90 or the output signal of the first controller 70 is also applied to this engine map. Furthermore, a signal indicating the desired torque MD and rotational speed N is applied to the engine map 170.

Arithmetic unit 100 processes various signals. These signals are first of all the signals detected by a sensor 50 installed in the internal combustion engine, and also the signals of other sensors 160 relating to, for example, air temperature, air pressure or fuel temperature. A device 150 provides a signal indicative of the driver's intent, which is at its simplest an accelerator pedal position sensor.

Next, the functions of the control device will be explained. The calculation unit 100 calculates the desired fuel amount QK according to various parameters such as the driver's intention, desired torque, external environmental quantities, etc., and also according to various operating parameters of the internal combustion engine.

[0021] In that case, preferably the arithmetic unit processes the signal relating to the desired engine torque MD. In that case, an engine map 170 is required which forms the amount of fuel QK to be injected according to various parameters, such as torque, for example.

The signal QK corresponding to the desired amount of fuel and the rotational speed signal N are supplied not only to the map 90 that determines the start of injection but also to the map 140 that determines the amount of movement of the control rack.

[0023] In some cases, it may be preferable to provide torque control. This is the case, for example, when different injection start target values can be set at certain engine operating points. The engine operating point is defined by constant torque and constant rotational speed. A value QK regarding the amount of fuel to be injected is set from the map 170 according to the desired torque, rotational speed N, and injection start. In this case, the value of the amount of fuel to be injected is particularly preferably read from the engine map 170 on the basis of a comparison between the desired torque and the actual torque.

An injection start target value SBS is read from the map 90 for determining the injection start. This value is a subtraction point of 60
, the actual injection start value SB detected by the sensor 30
Compared to I. Based on the comparison between the target value and the actual value for the start of injection, the first controller 70 controls the first actuator 8.
Calculate a drive signal of 0. For this purpose, the first controller 70
A displacement map is provided. This map outputs a value indicating the position of the first actuator.

The map 140 provides the second controller 120 with a target value RW for the amount of movement of the control rack based on the rotational speed and the desired amount of fuel. This value is compared at a subtraction point 110 with the actual amount of movement RWI detected by the sensor 40. The second controller 120 generates a signal according to the result of the comparison. This signal causes actuator 130
is adjusted.

The first actuator 80 determines the start of injection of the fuel pump, and the second actuator 130 determines the injection period of the injection pump. two actuators 8
0,130 can also be formed as a pure actuator. In other words, the actuator can take a position given by the output signal of the controller. However, preferably also the respective controller sets the current flowing through the actuator. Sensors on each actuator detect the current flowing through the actuator. The actuator controllers compare this current to actuator current target values set by the respective controllers and calculate new actuator currents based on this comparison.

In the first actuator, a first controller 70 particularly preferably sets the target value for the actuator position. A sensor detects the position of the first actuator 80 . A first actuator controller controls the actual position of the first actuator to a predetermined target value.

A feedback control device of this type functions satisfactorily only if the adjustment of the injection start has no effect on the injection quantity. If this is not the case, this effect must be taken into account. According to the present invention, the effect that the start of injection has on the amount of fuel injected is determined by the map 140 that determines the amount of movement of the control rack by transmitting a signal indicating the start of injection.
This can be considered by supplying

That is, the map 140 is supplied with a signal indicating the position of the first actuator. This signal is, for example, the output signal of the first controller 70. to the device,
If a first actuator controller is provided for moving the position of the first actuator to the position set by the first controller 70, the actual value or target value of this first actuator controller is provided. can be used. Otherwise, the output signal of the first controller 70 is used. This signal corresponds to the setpoint value of the first actuator controller.

Particularly preferably, the output signal of the map 90 of the injection start target value is used for the correction. This method has the advantage of not requiring feedback of the position of the actuator.

Furthermore, a control device of this type only operates satisfactorily if the adjustment of the injection start does not influence the torque output from the internal combustion engine. If this is not the case, this effect must be taken into account. According to the present invention, by supplying a signal indicating the start of injection to the map 170 that determines the amount of fuel QK to be injected, it is possible to take into account the influence that the start of injection has on torque. Particularly preferably, during the correction, the output signal of the map 90, which defines the target value for the start of the injection, is used for the correction.

FIG. 2 illustrates the necessity of correcting the amount of movement of the control rack based on the start of injection. In FIG. 2, the camshaft angle NW is plotted on the x-axis, and the amount of fuel injected QK is plotted on the y-axis. For two different injection starts, two
Two metering states are listed. At the same time, the fuel injection amount is listed. That is, the amount adjusted at the time of injection start SBA and the amount adjusted at time of injection start SBB in periods D1 and D2 are shown, respectively. Note that each metering with period D2 is twice as long as the metering with period D1.

If metering is carried out in the feed period D1 at the start of injection SBA, a feed amount QA1 occurs. On the other hand, the feed amount QB1 occurs at the injection start SBB. The feed amount QB1 supplied in that case is larger than the feed amount QA1 by a predetermined coefficient F1 (1.2 times in this embodiment).

If metering takes place in period D2 at the start of injection SBA, a feed quantity QA2 occurs. In contrast, injection starts S
Regarding metering at BB, the feed amount is QB2. In that case, the feed amount QB2 becomes larger than the feed amount QA2 by a coefficient F2. In addition, the feeding amount Q is determined according to the feeding period, that is, the amount of movement of the control rack (control rack position).
Different values result for the ratio of B (metering at the start of injection SBB) and feed quantity QA (metering at the start of injection SBA). If, as in the prior art, the target value of the control rack is corrected only according to the start of feed and the number of rotations, erroneous values will occur. According to the invention, this correction must also be related to a signal indicating the magnitude of the injection period or fuel metering period. Possible signals of this type are the feed period, the injection period, the target displacement value RW of the control rack, the target injection quantity value, the actual displacement value RWI of the control rack, or the interval from the start of injection to the end of injection.

According to the present invention, in order to correct the amount of movement of the control rack according to the start of injection and the amount of injection,
Various methods are possible and are illustrated in FIG. FIG. 3(a) shows a particularly simple and preferred method. The map 140 shows the control rack movement amount target value RW, desired injection amount QK, rotation speed N, and injection start SB.
is stored according to the signal indicating. The injection start signal is
For example, a target value read from the map 90 according to the start of injection is used. Furthermore, the actual value or setpoint value of the actuator controller, which determines the position of the first actuator or the actuator current, can also be used. Furthermore, it is also conceivable to use the output signal of the first controller 70.

If none of these signals are available, other suitable alternative quantities may also be used. In systems with solenoid valve control, it is also possible, for example, to use switching points of the solenoid valve.

In that case, the map must do the following: That is, the target value RW of the second actuator 130 must be corrected according to the feed start, rotation speed, and injection amount target values.

This method makes it possible to completely compensate for the influence of the feed start on the amount of fuel injected. The four-dimensional pump map 140 shows an inversion of the hydraulic characteristics of the pump, that is, the feed rate characteristic value (map value). The following can be said about the feed rate characteristic value. That is, the injection quantity is dependent on the actual value of the displacement of the control rack, the rotational speed and the start of the feed. For the pump map, the target value of the control rack movement is a function of the desired fuel amount, rotational speed, and delivery start. This method ensures a constant injection quantity when a certain desired fuel quantity is set at any rotational speed and at any delivery start. The influence of fuel temperature on the supply amount can be taken into consideration, for example, by enlarging the map in one dimension.

In that case, the following must be taken into account by the map. In other words, the amount of fuel to be injected QK
The target value QK must be corrected according to the start of injection.

FIG. 3(b) shows the structure of the map 140 in detail. Maps are generally constructed in three dimensions, but since a four-dimensional map is required here, a large number of three-dimensional maps are provided side by side. This makes it possible to use simple and arbitrary memory elements. Each of the maps 310, 320, and 330 stores values for the case where the injection start is constant. The calculation of the movement target value of each control rack in accordance with the start of injection is carried out within the calculation circuit 300 by an interpolation method.

A first proposal for implementation is shown in FIG. 3(c). Three maps are required for implementation. That is, each map defining the end position of the injection start actuator and one map for the average position (center position) of the injection start actuator are required. The map 310 stores the control rack movement amount target value RW(G) regarding the maximum possible injection start value SBG. The map 320 stores the control rack movement amount target value RW (M) regarding the average injection start value SBM, and the map 330 stores the control rack movement amount target value RW (M) regarding the minimum possible injection start value SBK. (K) is stored.

In the first step 350, the injection starts S.
B is detected. In this case, the pump delivery start or actual injection start is used, and it is also possible to use the measured position of the first actuator, the setpoint value for the start of injection or the current setpoint value of the controller for the actuator.

Following the detection of the start of injection, decision block 3
At 60, it is checked whether the injection start SB is greater than a threshold. This check determines whether the start of injection is greater or less than the average start of injection SBM. In that case, the calculation is done according to the following formula:

RW = RW(M) + (RW(G)−RW(M)
)*(SBX-SBM)/(SBG-SBM) However, R
W indicates a desired movement amount target value of the control rack regarding the actual injection start SBX. The movement amount target value of the control rack is calculated by the calculation circuit 300 according to the above-mentioned formula and is output. This calculation is performed in step 370.

If decision step 360 detects that the start of injection is less than the threshold, then step 38
0, calculation is performed according to the following formula.

RW = RW(K) + (RW(M)−RW(K)
)*(SBX-SBK)/(SBM-SBK) In the second embodiment, the movement amount RW(M) of the control rack with respect to the average injection start value is stored in the map 320 according to the rotation speed and fuel amount. Furthermore, the map 310 includes
Map value DR of difference data regarding smaller injection start value
W(K) is stored, and a map value DRW(G) of difference data regarding a larger injection start value is stored in the map 330 according to the rotational speed and fuel amount.

The calculation is performed in step 3 as shown in FIG. 3(c).
70 and 380.

For small injection start values, the following equation applies:

RW = RW(M) + DRW(K)*(SBM−
SBX)/(SBM-SBK) For large injection start values, the following equation applies:

RW = RW (M) + DRW (G) * (SBX-
SBM)/(SBG-SBM) For a given configuration,
An engine map 170 is also provided. In that case,
The value of the movement amount RW of the control rack can be replaced by the value of the fuel amount QK to be injected, and the value of the fuel amount QK to be injected can be replaced by the value of the torque MD. By doing so, it becomes possible to completely correct the influence of the start of injection on the output torque. Regarding the engine map 170, it can be said that the amount of fuel QK to be injected is a function of the desired torque, rotational speed and injection start. This ensures a constant torque at any rotational speed and at any start of injection.

This method is particularly preferably used in fuel pumps in which the start of injection can be adjusted independently of the feed rate. This is the case, for example, with reciprocating slider pumps. In this type of pump, a first actuator for adjusting the reciprocating slider position and a second actuator for adjusting the control rack position are provided. The control rack determines the amount of fuel to be injected. The position of the reciprocating slider determines the start of injection.

In devices of this type, the setpoint and actual values of the reciprocating slider position are particularly preferably used for the correction instead of the injection initiation. This value can be easily derived from the map 90 output signal. Therefore, other sensors are not required. This provides the advantage that there are no sensors to fail. Therefore, this device provides greater operational safety than a device that detects the start of injection using a separate sensor.

In other embodiments, the actual reciprocating slider position is detected. This signal is supplied to a map 140 regarding the target value of movement of the control rack or a map 170 for the engine. However, this device has the disadvantage that the sensor may fail. However, compared to using setpoint values, the advantage is that a very precise signal is obtained for the initiation of injection.

This device can also be used in a fuel injection pump in which the start and end of injection are determined by a solenoid valve. In this device, the time when the solenoid valve is turned on or off determines the start and end of injection of the fuel pump. When used in this device, the above-mentioned devices can and should be designed accordingly and in each case appropriate signals can or should be used.

[0055]

As is clear from the above description, according to the present invention, the amount of fuel can be adjusted as accurately as possible in a control system for a self-ignition internal combustion engine.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram schematically showing a control device of the present invention.

FIG. 2 is a diagram showing the relationship between the amount of fuel fed and the camshaft angle.

FIGS. 3A, 3B, and 3C are block diagrams each illustrating the operation of the present invention.

[Explanation of symbols]

10 Internal combustion engine 20 High pressure fuel pump 30 Injection start sensor 40 Control rack position sensor 50 Operating state sensor 70, 120 Controller 80, 130 Actuator 90, 140, 170 Map

Claims (11)

[Claims] 1. A first actuator (80) that determines the start of fuel injection and a second actuator (130) that determines the amount of fuel (QK) to be injected, and at least one map (90). the first actuator (8
In a control device for a self-ignition internal combustion engine in which a target value (RW) of a second actuator (130) is stored according to various operating parameters, the target value (RW) of the second actuator (130) is a signal indicating the start of injection and a fuel quantity (QK). A control device for a self-ignition internal combustion engine, characterized in that the control device is corrected according to a signal indicating. 2. The fuel injection system according to claim 1, wherein the signal (QK) indicating the amount of fuel is determined according to the driver's intention and/or desired torque (MD), and is corrected according to the signal indicating the start of injection. A control device for the self-ignition internal combustion engine described above. 3. In at least one map (170), a signal (QK) indicating the fuel quantity is stored according to the rotational speed, the signal indicating the start of injection and the desired torque (MD). Alternatively, the self-ignition internal combustion engine control device according to 2. 4. A target value (RW) of the second actuator is stored in at least one map (140) according to the rotational speed, a signal indicating the start of injection and a signal indicating the fuel quantity (QK). The control device for a self-ignition internal combustion engine according to any one of claims 1 to 3. 5. Claims 1 to 4, characterized in that the target value (RW) of the second actuator (130) is corrected by the map (140) according to a signal indicating the start of injection, the rotation speed, and the injection period. The control device for a self-ignition internal combustion engine according to any one of the above. 6. Claims 1 to 5, characterized in that a signal indicating a positional target value (SBS) of the first actuator or an actual position of the first actuator is used as a signal indicating the start of injection. The control device for a self-ignition internal combustion engine according to any one of the above. 7. Self-igniting internal combustion engine according to claim 1, characterized in that the setpoint value (SBS) of the position of the first actuator is related at least to the desired fuel quantity and to the rotational speed. Engine control equipment. 8. Any one of claims 1 to 7, wherein the first actuator is a reciprocating slider.
A control device for a self-ignition internal combustion engine according to paragraph 1. 9. A control device for a self-igniting internal combustion engine, characterized in that the second actuator is an adjusting device for adjusting a control rack. 10. A claim characterized in that the map (140) is formed from at least three maps with a constant injection start, and the target value of the second actuator is determined by interpolation based on these three maps. 10. A control device for a self-ignition internal combustion engine according to any one of Items 1 to 9. 11. One map stores an average injection start target value, and another map stores a difference value, or another map stores a large injection start value and a small injection start value. The control device for a self-ignition internal combustion engine according to any one of claims 1 to 10.