JPH087060Y2 - Supercharging pressure control device for internal combustion engine equipped with turbocharger - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boost pressure control device for an internal combustion engine equipped with a turbocharger, and more particularly to reducing the boost pressure in response to a signal from at least one knocking sensor. The present invention relates to a supercharging pressure control device for an internal combustion engine equipped with a turbocharger capable of performing

[0002]

2. Description of the Prior Art A device of this kind is known from German Patent No. 3,028,944. In such a device as well, the supercharging pressure is likewise designed to be able to be reduced in accordance with a knocking signal, in which case the supercharging pressure is not electronically controlled in advance, so that the optimum supercharging pressure can be adjusted. In addition, the characteristic value of the supercharging pressure is read out from the memory according to the parameter for controlling the supercharging pressure, and when the rough supercharging pressure is controlled in advance according to this characteristic value, the supercharging pressure should be controlled according to the knock limit. I can't. For this reason, in the conventional device, the knock limit is often exceeded, so complicated knock control is required according to the knocking strength, and it is impossible to further optimize the boost pressure. Furthermore, in the conventional supercharging pressure control, the adjusting device such as a solenoid valve for adjusting the supercharging pressure is driven to the saturation limit value, and the life of the adjusting device is shortened.
There was a problem that stable and reliable supercharging pressure control was difficult.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned drawbacks of the prior art by providing a turbocharger capable of stable and optimum supercharging pressure control according to the operating state of each internal combustion engine. An object of the present invention is to provide a supercharging pressure control device for an internal combustion engine equipped with the device.

[0004]

In order to achieve this object, the present invention comprises a turbocharger capable of reducing the boost pressure in response to signals from at least one knock sensor. a supercharging pressure control apparatus for an internal combustion engine, a target value of the supercharging pressure (plsoll) of the internal combustion engine load (GP) machine
It is read from the characteristic signal generator (41) relating to the parameter of the rotational speed (n), and the actual value of the boost pressure (PLis
t) is obtained by the supercharging pressure sensor, and the supercharging pressure is controlled by comparing the target value with the actual value.
0) and a regulating device (21, 23) connected to the latter stage of the closed loop control circuit and capable of regulating the boost pressure.
Signal generation circuit (46) for generating pulse signals for driving
In a supercharging pressure control device for an internal combustion engine equipped with a turbocharger having: a control duty ratio (ST) of a pulse signal for driving the adjusting device (21, 23) has a predetermined minimum value and a predetermined maximum value. is limited between the closed loop control circuit of the boost pressure can be blocked in a predetermined operating state of the internal combustion engine, an ignition
Time is adjustable in response to at least one signal of the knock sensor, and a turbocharger is operating effectively
An identification circuit (61) for identifying whether
Adjustment of ignition timing is that the turbocharger is operating effectively
If identified, turbocharger is not working effectively
We adopted a configuration that is narrower than when it was identified as No.

[0005]

With this structure, the supercharging pressure is maximized according to the respective drive states (load, rotation speed) via the values stored in the storage device, the fuel consumption is reduced, and the exhaust gas is further reduced. It becomes possible to optimally adjust the value to be preferable. As a result, the knocking phenomenon does not appear in the first place or occurs very rarely, and even if it appears, it can be overcome very quickly by reducing the supercharging pressure or adjusting the ignition timing.

The preferred embodiments and improvements can be obtained from the configurations described in the dependent claims.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows a schematic structure of a control device according to the present invention. In the figure, reference numeral 10 is an internal combustion engine, in which the air required for combustion is an air filter 11, It is supplied via an air flow sensor 12, a compressor 13 of an exhaust gas turbocharger 14, a supercharge cooler 15 and an air distributor 16. On the other hand, the exhaust gas is exhausted through the exhaust gas port 17, the exhaust gas turbine 18 of the turbocharger 14, and the exhaust pipe 19. The exhaust gas turbine 18 is bypassed via a bypass passage 20, and a supercharging pressure control valve 21 is arranged in this bypass passage. The supercharging pressure control valve 21 is used for the compressor 13
The spring 2 is supplied by the supercharging pressure supplied from the pipe 22 through the pipe 22.
It can be released against the urging force of. Again pipe 22
The solenoid valve 23 is provided in the
The supercharging pressure control valve 21 is adjusted by controlling the supercharging pressure supplied via 2. Bypass 20 in principle
Of course, it is also possible to provide only one solenoid valve in the.

An electronic control unit 24, preferably a microprocessor, is provided, by means of which the solenoid valve 23 and the ignition control unit 25 are controlled via a signal train with a predetermined duty ratio ST. It The ignition control device 25 is supplied with a signal Δαz from the electronic control device 24, which makes it possible, for example, to adjust the ignition timing of the knocking operation in the internal combustion engine in a backward direction. The ignition timing can be adjusted according to another parameter P, and optionally a signal stored in memory, as is well known by the ignition control device 25. Such a parameter is a signal from the air flow sensor 12, a temperature signal, or the like.

In FIG. 1, the wiring to the spark plug of the internal combustion engine is shown by an arrow for the sake of simplicity.

A reference mark signal BM and a rotation speed signal n obtained from a crankshaft 26 of an internal combustion engine via a sensor 27 are input to the electronic control unit 24. In principle, it is also possible to use signals synchronized with other crankshafts, such as those obtained from ignition distributors and the like. Furthermore, the electronic control unit 24 has two knocking sensors 28,
The knocking signal K obtained from 29 is input. Again 2
Instead of using one knock sensor 28, 29, it is possible to use one knock sensor or several knock sensors. In that case, when a plurality of knocking sensors are used, each cylinder is provided with a knocking sensor. When using multiple knocking sensors, a signal Z identifying the cylinder is required to process the knocking signal. This signal can be obtained from the reference mark sensor, which makes it possible to know from which cylinder the knocking signal is coming.

Further, a signal PL from a supercharging pressure sensor 30 arranged in the air distributor 16 and a signal GP from a throttle valve position sensor 31 are input to the electronic control unit 24. The sensor 31 detects the position of the throttle valve 32 arranged in the air supply passage of the internal combustion engine and generates a signal related to the load. Of course, in principle, it is also possible to detect the position of the accelerator pedal or use another load signal.

In the apparatus having such a structure, first, when a knocking phenomenon occurs, a knocking signal K is generated, whereby the ignition is delayed so that the knocking phenomenon is restored. This is done, for example, by adjusting the ignition timing so as to gradually delay the ignition timing when the knocking phenomenon occurs, and gradually returning to the original value when the knocking phenomenon ends. Such adjustment of the ignition timing is, for example, German Patent No. 3
No. 09046. Further, at the same time or after a predetermined time elapses after the ignition timing is delayed, the supercharging pressure control valve 21 arranged in the bypass passage 20 of the turbine 18 is opened to reduce the supercharging pressure of the supercharger. To be

It is also obvious that a control device for controlling the injection of the internal combustion engine must be provided in addition to the control device described above. These controls are not shown here for the sake of simplicity of the drawing. In addition, electronic control unit 2
It goes without saying that the ignition control device 25 and the injection control device can be respectively constituted by individual microprocessors and can be realized by one computer. In principle, such a control can be performed even for a device having one or more carburetors and not performing fuel injection.

FIG. 2 shows a schematic configuration of the electronic control unit 24 as a block diagram, in which the rotation speed signal n is input to the characteristic signal generators TVL and PLsoll which are composed of the storage devices 40 and 41. , The value stored here is read. These storage devices or characteristic signal generators can be composed of ROM, PROM, EPROM or the like. Further, these storage devices 40, 4
1 is a load signal GP1 obtained from the throttle valve position signal GP.
Is entered. Further, the comparison stage 42 has a signal GP1 signal GP2
In addition, the signal obtained from the ignition timing adjustment is input. These will be described in detail later. This comparison stage 4
The signal GP1 is taken out as an output signal from 2. Further, the signal GP is guided to the processing circuit 43 having the D component (differential characteristic) and the digital filter 44 connected to the subsequent stage, and the value of ΔGPmin or less is suppressed by this filter, whereby the signal GP2 is formed.

The value stored in the storage device 40 is input to the signal generating circuit 46 via the comparison stage 45, where a predetermined duty ratio S is obtained according to the value obtained from the storage device 40.
A pulse voltage with T is obtained, by means of which the solenoid valve 23
The position of is controlled. This duty ratio is preferably limited to between 15 and 85%. The output of the storage device 41 is connected to the comparison stage 48 via the low pass filter 47. The comparison stage 48 is further fed with the signal PList from the sensor 30 which measures the actual value of the boost pressure. The output of the comparison stage 48 is input to the comparison stage 45 via a switching element 49, a closed-loop regulator 50 preferably having a PI characteristic and a limiting circuit 51.

A reference mark signal BM and a knocking signal K from a knocking sensor are input to the knocking control unit 52. An output signal Δαzk is generated by the knocking control unit 52, which causes the ignition timing to be delayed if knocking combustion occurs. This output signal is inputted via the changeover switch 53 to either one of the limiting circuits 54 and 55 for selectively limiting the value Δαzk to the value of αzmax1 or αzmax2. In that case, the limiting value αzmax1 of the limiting circuit 54 is determined according to the rotational speed n. Both limit circuits 54, 55
Is input to the comparison stage 56, whose output is the signal Δαz.
Is input to the ignition control device 25.

The output signal of the knocking control unit 52 is further converted into a switching element 57 and a low pass filter 58.
Is input to the comparison stage 59 via. A value αzm that changes in relation to the rotation speed is further input to the comparison stage 59.
This value corresponds to a predetermined maximum allowed ignition timing delay adjustment signal. The output of the comparison stage 59 is input to the comparison stage 42 via the regulator 60.

A discrimination circuit 61 is provided for discriminating the driving state of the internal combustion engine whether the exhaust gas turbocharger 14 is operating effectively or not.
In addition, the switching elements 49 and 57 are controlled. This identification is performed based on the fact that the turbocharger is not operating effectively when the load GP and the rotational speed n are in predetermined states. When the turbocharger is not operating effectively, both switching elements 49 and 57 are opened and the output of the knocking control unit 52 is connected to the control circuit 55. Further, the control of the switching element and the changeover switch described above can be performed directly via the storage devices 40 and 41. This is because each value stored in the storage device is associated with a predetermined boost pressure. Therefore, when the supercharging pressure becomes equal to or lower than the predetermined limit value, it can be considered that the turbocharger is not operating effectively.

The basic features of the embodiment shown in FIG. 2 are:
The supercharging pressure is controlled in advance to a predetermined value by the characteristic signal TVL stored in the storage device 40 according to the rotational speed n and the load GP (position of the throttle valve). A predetermined duty ratio is associated with each of n and the value of the storage device 40 accessed by GP or GP1. With this, the opening of the bypass passage 20 is controlled via the signal generating circuit 46 and the supercharging pressure is predetermined. Is adjusted to the value of. When the load fluctuation is constant or slow, the signal GP is the signal GP1.
It corresponds to (does not consider knocking). On the other hand, when the load is rapidly changed by the driver, the supercharging pressure is increased by the processing circuit 43 for a short time to a value higher than a new steady value or decreased to a value below the new steady value (D component). Thereby, the response characteristic of the turbocharger is improved.

The load change speed (change rate) is a predetermined value (Δ
In the case of GPmin) or less, the output signal of the processing circuit 43 is suppressed by the filter 44. Another closed loop control circuit for controlling the boost pressure is connected to the control circuit for controlling the boost pressure (open loop) in an overlapping manner, that is, in parallel. This closed-loop control circuit corrects the supercharging pressure which has already been roughly adjusted to a predetermined value, whereby a more accurate adjustment is performed. The closed loop control circuit is stored in the storage device 41 and is used for the rotational speed n and the load GP1.
Characteristic signal PLsol for setting the target value of boost pressure according to
generate l . This target value is delayed and input to the comparison stage 48 via the low-pass filter 47. In that case, supercharging
Since the pressure formation is gradually performed, it is read from the storage device 41.
The target supercharging pressure to be issued gradually according to the supercharging pressure formation process.
Set the delay time of the low pass filter 47 to increase or decrease
To do .

Subsequently, the control deviation is input to the controller 50, which preferably has a PI characteristic, and its correction value is limited by the limiting circuit 51.
Is limited to a value between ± 20%, for example. The correction value obtained by this control is subsequently added to the set value of the duty ratio in the comparison stage 45 and input to the signal generator 46. Here, the operation signal is limited to a duty ratio of 15 to 85%, for example. The influence of the tolerances of the exhaust gas turbocharger and the components of the bypass valve on the boost pressure and the dynamic characteristics can be compensated for by this closed-loop control circuit. This control circuit is activated only when there is an effective boost pressure via the switching element 49. this
Closes if the turbocharger is not working effectively
Is it unnecessary to adjust the correct boost pressure by the loop control circuit?
It is .

When the knocking signal K appears, the ignition timing is, as is well known, the knocking control unit 52.
Is gradually adjusted in the direction of delay, and this is continued until the knocking phenomenon stops. In that case, knock control
The unit 52 generates an output signal Δαzk indicating the retard amount.
However, the ignition timing is adjusted in the direction of delay according to its size.
It is . When the turbocharger is operating effectively, the ignition timing adjustment based on knocking is limited to the value of αzmax1. This limit means that the turbocharger is working effectively
If the ignition timing is delayed too much, the exhaust gas temperature will rise
To prevent the overcharger from being thermally overloaded , the limit is controlled according to the engine speed n in order to make an accurate adjustment. When the turbocharger does not operate effectively, the changeover switch 53 operates and the limit value αz
max2 (greater than αzmax1) is valid, which allows for greater ignition timing adjustments.

When the knocking is slight or rare, adjustment of the ignition timing is generally sufficient to escape the knocking region. However, knocking continues, which causes the ignition timing adjustment to be delayed further.
Output signal Δαz from the knocking control unit
If k increases and reaches the value of αzm (which is preferably changed in relation to the engine speed), a further reduction of the boost pressure is carried out. In that case, since the low-pass filter 58 forms an average value, the supercharging pressure decreases only when knocking continues or repeats. By changing the value GP1 of the load from the comparison stage 42 via the regulator 60, closed-loop or open-loop control for supercharging pressure is performed. When the supercharging pressure is controlled by such a knocking phenomenon, it is performed when the amount of fuel having knock resistance becomes low or the intake air temperature becomes too high. In this way, the internal combustion engine is effectively protected from the dangers that result from knocking. Further, the control of the supercharging pressure based on knocking by the switching element 57 is performed only when the turbocharger is operating effectively. This enabled the turbocharger
Boost pressure is not so high when not operating
This is because there is no need to let it .

In the case of a simple embodiment, the switching elements 49, 57 and the switching device 53 can be omitted. In this case, one limiting circuit 54 is provided.

It is also possible to additionally use other conventional means to bring the operation of the internal combustion engine out of the knocking region if a further knocking phenomenon occurs. Such means are, for example, a method of injecting water, introducing a substance that reduces knocking, or changing a mixture of fuel and air.

As described above, according to the embodiment of the present invention, the boost pressure is maximized according to each driving state (load, rotation speed) via the value stored in the storage device, and the fuel consumption is increased. Is reduced, and the exhaust gas value can be optimally adjusted to be preferable. As a result, the knocking phenomenon does not appear in the first place or occurs very rarely, and even if it appears, it can be overcome very quickly by reducing the supercharging pressure or adjusting the ignition timing.

Further, according to the embodiment of the present invention, in addition to the advantage that the supercharging pressure can be accurately adjusted by electronic means, the ignition timing is adjusted to be delayed when knocking occurs through a single knocking control unit. As a result, it is possible to obtain the effect that the boost pressure can be reduced. This has a relatively low cost for controlling the boost pressure and ignition timing, and knocking can usually be overcome by adjusting the ignition timing very quickly, so that the reduction in boost pressure is The advantage is that it can be suppressed only in extreme cases, such as when adjusting the ignition timing is not sufficient. In this way it is possible in the normal case to reduce the influence on the rotational torque.

[0029]

As described above, according to the present invention, when the adjusting device for adjusting the supercharging pressure by the closed loop control according to the comparison between the actual value and the target value of the supercharging pressure is pulse-driven, the control duty ratio of the pulse signal is increased. because There is limited between predetermined minimum and maximum values, with an adjusting device can prolong the life of it is lost adjusting device driven by saturation limit value, tone
Since extreme driving signal for driving the section device is suppressed, it is possible to closed-loop control to be stable. Further, since the closed-loop control circuit for controlling the supercharging pressure can be shut off in a predetermined operating state of the internal combustion engine, accurate supercharging pressure control is unnecessary.
In some cases it may be possible to shut off the closed loop control circuit
it can. Furthermore, if the turbocharger is operating effectively
Controls the ignition timing more narrowly,
Excessive ignition timing when the turbocharger is operating effectively
Is adjusted backwards, resulting in higher exhaust gas temperatures
To prevent the turbocharger from being thermally overloaded
Will be possible .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a principle configuration of an apparatus according to the present invention.

FIG. 2 is a block diagram showing a more detailed configuration of an electronic control device.

[Explanation of symbols]

 10 Internal Combustion Engine 11 Air Filter 12 Air Flow Sensor 13 Compressor 14 Exhaust Gas Turbocharger 15 Supercharge Cooler 18 Turbine 19 Exhaust Pipe 20 Bypass Path 21 Supercharging Pressure Control Valve 23 Electromagnetic Valve 24 Electronic Control Device 25 Ignition Control Device 26 Crankshaft 28, 29 Knocking sensor 30 Supercharging pressure sensor 31 Throttle valve position sensor 32 Throttle valve 40, 41 Storage device 46 Signal generating circuit 47 Low-pass filter 50 Controller 51 Limiting circuit 52 Knocking control unit 54, 55 Limiting circuit 60 Regulator 61 Identification circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02D 43/00 R F02P 5/15 5/152 5/153 F02P 5/15 H (72) Inventor Bernhard Miller Germany 7000 Stuttgart 1 Rechenstraße 31 (72) Creator Siegfried Rohde Germany 7141 Schwieber Dingen Memerweg 1 (72) Creator Herbert Schram Germany 7000 Stuttgart 1. Im Götzen 25 (72) Inventor: Walter Fies Germany 7132 Illingen Schuzinger Strasse 54 (56) References JP 57-153968 (JP, A) JP 57-157016 (JP) , A) JP-A-53-40123 (JP, A) JP-A-54-109529 (JP, A) JP-A-57-146023 (JP, A)

Claims (10)

[Scope of utility model registration request] 1. A supercharging pressure control device for an internal combustion engine, comprising a turbocharger capable of reducing the supercharging pressure according to a signal from at least one knocking sensor. The target value (PLsoll) is the internal combustion engine load (GP)
And a characteristic signal generator (41) relating to the parameters of the engine speed (n) and the actual value of the boost pressure (P
List) is obtained by the supercharging pressure sensor, and the supercharging pressure is controlled by comparing the target value with the actual value.
0), and a signal generator circuit (46) for generating a pulse signal for driving an adjusting device (21, 23) connected to the latter stage of the closed loop control circuit and capable of adjusting the boost pressure. In a supercharging pressure control device for an internal combustion engine equipped with a feeder, a control duty ratio (ST) of a pulse signal for driving the adjusting device (21, 23) is limited between a predetermined minimum value and a predetermined maximum value, the closed loop control circuit of the boost pressure can be blocked in a predetermined operating state of the internal combustion engine is adjustable ignition timing in response to at least one signal of the knock sensor, and turbocharger operating effectively Identify what
An identification circuit (61) is provided to adjust the ignition timing.
If the turbocharger is identified as working
If the turbocharger is identified as not working effectively
A supercharging pressure control device for an internal combustion engine equipped with a turbocharger, which is restricted to be narrower than the above . 2. A supercharging pressure characteristic signal is stored in a memory device (40), and the supercharging pressure signal read from the memory device according to the load of the internal combustion engine and the engine speed and the closed loop control circuit. The supercharging pressure control device for an internal combustion engine having a turbocharger according to claim 1, wherein the adjusting device is driven according to a signal. 3. The supercharging pressure control device for an internal combustion engine having a turbocharger according to claim 1, wherein the target value of the supercharging pressure is guided to a low-pass filter (47). 4. The turbocharger according to claim 1, wherein a load of the internal combustion engine is processed by a processing circuit (43) having a differential characteristic. Supercharging pressure control device for internal combustion engine. 5. A delay in ignition timing when knocking occurs.
Generate an output signal that indicates the amount of angle and set the magnitude of that output signal.
A turbo control according to any one of claims 1 to 4 , further comprising a knocking control unit (52) for controlling the ignition timing in a delayed direction, and controlling the boost pressure according to the output signal. A boost pressure control device for an internal combustion engine including a feeder. 6. A low pass filter (5) for outputting the output signal.
8) The supercharging pressure control device for an internal combustion engine equipped with the turbocharger according to claim 5 , which leads to 8). 7. compared in comparison stage said output signal to a predetermined value (αzm), claim when said output signal exceeds the predetermined value, characterized in that to reduce the supercharging pressure of 5 Or a supercharging pressure control device for an internal combustion engine, comprising the turbocharger according to 6 . 8. The supercharging pressure control device for an internal combustion engine having a turbocharger according to claim 7 , wherein the predetermined value is changed according to the engine speed. 9. The turbocharger is not operating effectively.
The supercharging pressure control device for an internal combustion engine having a turbocharger according to any one of claims 1 to 8 , characterized in that the closed-loop control circuit is shut off when identified . 10. The control device is a control valve (23) to which a signal of a predetermined duty ratio is applied, and the control valve controls the cross section of the bypass passage leading to the turbocharger (14). A supercharging pressure control device for an internal combustion engine, comprising the turbocharger according to any one of claims 1 to 9 .