JPH066937B2 - Control device for engine with supercharger - Google Patents

Description

TECHNICAL FIELD The present invention relates to an engine provided with a supercharger, and more particularly to a control device for such an engine.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been proposed an engine with a supercharger capable of selectively performing an operation with a high boost pressure characteristic or an operation with a low boost pressure characteristic according to an operating state.

Then, it is also considered that the engine is equipped with knock control means for avoiding knock by delaying the ignition timing in accordance with the knock amount.

[Problems to be solved by the invention]

However, in the conventional means as described above, when the operating state with the high boost pressure characteristic is switched to the operating state with the low boost pressure characteristic, the retard amount remains unchanged during the operation with the high boost pressure characteristic. Since it is stored, there is a problem that the output sharply decreases with the switching to the operation with the low boost pressure characteristic, and a shock occurs at the time of the switching.

The present invention is intended to solve such a problem, and it is possible to prevent a shock from occurring by eliminating a sudden decrease in output at the time of switching to an operating state with a low boost pressure characteristic. An object is to provide a control device for an engine with a feeder.

[Means for solving problems]

Therefore, the control device for the engine with the supercharger of the present invention is
In an engine with a supercharger capable of selectively performing operation with a high boost pressure characteristic or operation with a low boost pressure characteristic according to the operating state, knock control means for performing control for avoiding knock, and the above high boost A supercharging pressure characteristic switching control means for controlling switching between the operation with the supercharging pressure characteristic and the operation with the low supercharging pressure characteristic is provided. It is characterized in that ignition timing control means for advancing the ignition timing by an amount corresponding to a decrease in supercharging pressure due to switching to an operating state in the pressure supply characteristic is provided.

[Work]

With the above configuration, the ignition timing is advanced by an amount corresponding to the amount by which the supercharging pressure is reduced in accordance with the switching from the operating state with the high supercharging pressure characteristic to the operating state with the low supercharging pressure characteristic. Is done.

〔Example〕

A control device for an engine with a supercharger as one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of relevant parts, and FIG. 2 is an electric circuit for explaining an ignition timing control means thereof. FIGS. 3 to 6 are graphs for explaining the respective actions, FIGS. 7 to 9 are flow charts for explaining the actions, FIGS. 10 (a) to (c) and FIG. 11 (a). ~ (C)
Are waveform diagrams for explaining the action respectively, 12th,
FIG. 13 is a schematic view showing a modified example of each boost pressure characteristic switching actuator, and 14th and 15th are respectively 12th and 12th.
14 is a graph for explaining the operation of the thing shown in FIG.

As shown in FIG. 1, this engine has a supercharger (turbocharger) 3.
Is a turbine 4 installed in the exhaust passage 2 of the engine,
A compressor 5 driven by a turbine 4 installed in an intake passage 1 of the engine is provided.

Further, a bypass passage 2a is connected to the exhaust passage 2 so as to bypass the portion where the turbine 4 is disposed, and a wastegate valve 6 for opening and closing the bypass passage 2a is provided in the bypass passage 2a.

Further, a pressure responsive actuator 7 for opening and closing the waste gate valve 6 is provided. This actuator 7 has a first diaphragm 9 and a second diaphragm 10 having the same diameter in its casing.
The diaphragm 9 is connected to the waste gate valve 6 via the first rod 8, and the second diaphragm 10 is connected to the second rod 15 which is detachable from and attachable to the first diaphragm 9.

In addition, the actuator 7 has a large set load.
It has a return spring 13 and a second return spring 14 with a small set load, and the first return spring 13 is mounted between the casing and the first diaphragm 9 so that the first diaphragm 9 and the first rod 8 can be mounted. The wastegate valve 6 is urged in the closing direction via the second return spring 14 so that the second return spring 14 is loaded between the casing and the second diaphragm 10 to move the second rod 15 from the first diaphragm 9 through the second diaphragm 10. It is biased in the direction to separate it.

Further, the actuator 7 has a first pressure chamber 11 and a second pressure chamber 12, the first pressure chamber 11 is formed between the first diaphragm 9 and the second diaphragm 10, and the second pressure chamber 12 is the first pressure chamber 12. First through two diaphragms 10
It is formed adjacent to the pressure chamber 11.

By the way, a first control passage 16 is connected to the first pressure chamber 11, and a pressure passage 19 as a second control passage is connected to the second pressure chamber 12.

The first control passage 16 is connected to the atmosphere passage 17 and the pressure passage 19 via a solenoid valve 18 as an electromagnetic switching valve.

The atmosphere passage 17 is the intake passage portion on the upstream side of the compressor.
The pressure passage 19 is connected to the intake passage portion 1b on the downstream side of the compressor. As a result, the atmospheric pressure is introduced through the atmosphere passage 17, and the compressor downstream side pressure in the intake passage 1 is introduced through the pressure passage 19.

Further, the solenoid valve 18 has a solenoid coil 18a that receives a signal from the controller 20, and when the solenoid coil 18a is excited, the plunger 18b is attracted against the return spring 18c, so that the first control passage When the atmospheric pressure is introduced to 16, while the solenoid coil 18a is de-excited, the plunger 18b
The pressure on the compressor downstream side is introduced into the first control passage 16 by being pushed by the return spring 18c. Thus, the atmospheric pressure or the compressor downstream side pressure is selectively introduced into the first pressure chamber 11 through the first control passage 16, and the compressor downstream side pressure is introduced into the second pressure chamber 12 through the pressure passage 19. be introduced.

Therefore, deenergize the solenoid coil 18a,
Similarly to the second pressure chamber 12, when the compressor downstream side pressure is applied to the first pressure chamber 11, the load in the closing direction of the wastegate valve 6 need only be considered to be due to the first return spring 13. It operates as an actuator having a low supercharging pressure characteristic as shown by reference character α in the figure and substantially having only the first diaphragm 9. However, when the solenoid coil 18a is excited and atmospheric pressure is applied to the first pressure chamber 11, in this case, the load in the closing direction of the wastegate valve 6 is caused by both the first return spring 13 and the second return spring 14. Therefore, it is possible to obtain a high supercharging pressure characteristic as shown by a symbol β in FIG. 3, and as a result, the supercharging pressure is controlled to be high.

As a result, this engine can selectively operate with the high boost pressure characteristic β or with the low boost pressure characteristic α.

From a different point of view, it can be said that the supercharging pressure-engine speed characteristic of the present engine can be set as shown by reference characters a and b as shown in FIG.

Here, the characteristic a shows the case where the pressure on the compressor downstream side is introduced into the first pressure chamber 11 to make the pressures acting on the first pressure chamber 11 and the second pressure chamber 12 the same, and the characteristic b shows the first pressure chamber.
The case where atmospheric pressure is introduced into the pressure chamber 11 is shown. Further, in this engine, even if the actuator 7 malfunctions, it can be suppressed within the range indicated by the symbol d in FIG. On the other hand, in the conventional device in which the pressure acting on the actuator leaks to the atmosphere through the leak passage, the supercharging pressure may rise abnormally, as indicated by the symbol c in FIG.

By the way, the knock sensor 21 is attached to an engine block or the like, and the signal K from the knock sensor 21 is transmitted.
Knock detection circuit 2 that integrates S and outputs an integrated voltage RS
1'is provided, and the knock integrated voltage (analog signal) RS from the knock detection circuit 21 'is supplied to the controller 2
Supplied to zero.

Further, a rotation speed sensor 22 for detecting the engine rotation speed N and an air flow sensor 23 for detecting the intake air amount of the intake passage 1 are provided.
The detection signals of both 2 and 23 are digital signals.

Although it is generally said that the air flow sensor 23 malfunctions due to intake pulsation or the like in a low speed and high load state of the engine, in the present embodiment, an intercooler 24 is provided on the downstream side of the air flow sensor 23 to appropriately adjust the dimensions of the air cleaner portion. As a result, the above-mentioned intake pulsation hardly occurs, and it is considered that the measurement reliability or accuracy of the air flow sensor 23 is sufficiently high.

Further, a water temperature sensor 26 for detecting the engine cooling water temperature by an analog signal is provided.

Further, a throttle sensor 30 for detecting the opening (throttle opening) Θ of the throttle valve 25 by an analog signal is provided.

And these sensors 21, 22, 23, 26, 30
The signal from is input to the controller 20. The controller 20 has functions such as knock control means M1 and supercharging pressure characteristic switching control means M2.

Here, the knock control means M1 performs control for avoiding knock by controlling the retard angle amount at the time of ignition, and the boost pressure characteristic switching control means M2 is the knock control means M.
When the lower limit absolute ignition timing determined by the operating state with the high supercharging pressure characteristic β is exceeded by retarding by 1, the operating state with the high supercharging pressure characteristic β and the operation with the low supercharging pressure characteristic α are performed. It controls switching between states.

The knock control means M1 will be described. The knock control means M1 firstly stores a basic ignition timing characteristic map (regular) which stores an ignition timing determined from engine load information (A / N; A is intake air amount information, N is engine speed information) and engine speed information N. Two types are prepared for gasoline and premium gasoline). Further, the knock control means M1 has a correction means for correcting the ignition timing information corresponding to the engine operating state from such a map to the retard side according to the knock amount information from the knock detection circuit 21 '.

That is, the knock control means M1 is supplied to the knock control means M1 from various sensors with intake air amount information A, engine speed information N, knock amount information and reference signal information (this information is 18 in crank angle).
It has a 0 ° cycle and controls energization start timing and ignition timing) and crank angle information (the reference signal information and crank angle information are taken in from the distributor 27) are input, and the correction means responds to the knock amount. The retarded ignition signal is transmitted to the ignition coil 2
It is adapted to be supplied to the power transistor 29 with 8. As a result, the power transistor 29 is turned on and off at a predetermined timing, and the primary current of the ignition coil 28 is interrupted.

By the way, as the actual ignition timing, a value that takes into account the basic ignition timing obtained from the basic ignition timing characteristic and an ignition timing learning coefficient K1 set according to the degree of knock is adopted. For example, the learning coefficient K1 is set as follows. That is, if the knock integrated voltage is between the predetermined voltages V1 and V2 (V1> V2), the value of the learning coefficient K1 is held, but if it is larger than V1, the value of K1 is set to 1 at predetermined time intervals. When it is smaller than V2, the value of K1 is incremented by one every predetermined time.

Although the value of the learning coefficient K1 is backed up by the battery, the initial value of the learning coefficient K1 when the ignition key is turned on immediately after the computer is mounted is set to an appropriate value according to the resolution.

Here, FIG. 5 shows the relationship with the absolute advance engine speed when the throttle valve 25 is fully opened. In FIG. 5, reference numeral e indicates a base advance angle characteristic for premium gasoline, f indicates a base advance angle characteristic for regular gasoline, and g indicates an advance angle characteristic obtained by the learning result.

Further, in FIG. 5, the symbol h indicates the exhaust temperature limit characteristic determined by the high supercharging pressure characteristic β.

That is, the following can be seen from FIG. At a certain engine speed N ₀ , the maximum amount that can be retarded is determined by the sum of the amount θ ₁ that determines the learned value and the amount θ ₂ that is determined by the exhaust temperature limit, that is, the retard amount exceeds the lower limit of θ ₁ + θ _2. If the ignition timing is lowered, knock cannot be avoided by the knock control means M1. In fact, whether or falls below such a lower limit ignition timing, a knock integral voltage the ignition timing knocking integrated voltage Vr which is dependent on the learning coefficient K1 (K1) (which has the information of the theta ₁₎ dependent and the engine speed It is determined whether or not the sum with Vr (N) (which has the information of θ ₂ above) exceeds the set value Vr ₀ .

Next, the supercharging pressure characteristic switching control means M2 will be described.
That is, in this means M2, for example, it is detected that the vehicle is accelerating, the solenoid coil 18a is turned on, and the operation with the low boost pressure characteristic α is switched to the operation state with the high boost pressure characteristic β. During the operation with the supercharging pressure characteristic β, when the value is delayed by knock control and the above value Vr (K1) + Vr (N) becomes Vr ₀ or more, the solenoid coil 18a is turned off to reduce the supercharging. The operation is switched to the pressure characteristic α.

Here, the flow of processing by the supercharging pressure characteristic switching control means M2 is shown in FIG.

When the engine speed is high, the amount θ ₂ determined by the exhaust temperature limit becomes smaller, so θ ₁ determined by the learned value
[That is, the knock integrated voltage Vr (K1)] may be switched to the operating state with the low supercharging pressure characteristic α only when the value exceeds the set value.

By the way, the ignition timing control means M3 for advancing the ignition timing by an amount corresponding to the amount of decrease in the supercharging pressure accompanying the switching from the operating state with the high supercharging pressure characteristic β to the operating state with the low supercharging pressure characteristic α is provided. It is provided. That is, this ignition timing control means M3
According to the above, the supercharging pressure characteristic switching control means M2 outputs the command signal for switching from the operating state with the high supercharging pressure characteristic β to the operating state with the low supercharging pressure characteristic α and the high level retard issued from the controller 20. The release signal CS is supplied to the constant current discharge circuit 31 shown in FIG. 2, and this circuit 31 forcibly discharges the knock integrated voltage RS of the knock detection circuit 21 ', so that the high boost pressure characteristic β is operated. The retard amount that depends on the knock amount is reduced, that is, advanced.

In this way, since the ignition timing is forcibly returned to the basic ignition timing at the time of such switching, the apparent ignition timing is advanced by θ ₀ as shown in FIG. 6, and the output is significantly reduced. It can be prevented.

That is, at the time of the above switching, unless the delay amount that depends on the knock amount during operation with the high boost pressure characteristic β is reduced,
Even when operating with the low supercharging pressure characteristic α, if the retard amount is reflected as it is, that is, if the ignition advance angle does not change at all at the time of switching, for example, if it is switched at point P in FIG. The output decreases by PS ₀ because the point moves to the point Q '. On the other hand, according to the present apparatus, the output is not lowered because the point moves from P to Q.

Note that FIG. 6 shows the throttle valve 25 at a certain engine speed.
Shows the output-ignition advance angle characteristic when the engine is fully opened.
In the figure, reference numeral i indicates a high supercharging pressure characteristic, and reference numeral j indicates a low supercharging pressure characteristic.

Here, the flow of processing by the ignition timing control means M3 is shown in FIG.

Further, the knock sensor 21 when the knock does not occur
10 is a waveform diagram of the input signal signal to the input terminal, the output signal KS of the knock sensor 21 and the knock integrated voltage RS, respectively.
Shown in (a), (b), and (c), an input vibration signal to the knock sensor 21 when a knock occurs, an output signal KS of the knock sensor 21 and a knock integrated voltage RS (in this case, RS is indicated by a symbol r). By the way, the waveform diagrams of (forcibly discharged and charged at the point S) are respectively shown in FIG. 11 (a),
Shown in (b) and (c).

With the above-described configuration, during actual engine control, for example, in the initial stage of acceleration in which knocking is unlikely to occur (when accelerating in a state where the engine combustion chamber temperature is below a predetermined value), the first
By introducing the atmospheric pressure into the pressure chamber 11 and selecting the high supercharging pressure characteristic β, the supercharging pressure is increased as compared with the steady high load operation. This gives it outstanding acceleration performance.

However, during steady high load operation in which the ignition timing retard amount due to knock continues beyond a certain value, specifically when operating with the high boost pressure characteristic β, if knock cannot be avoided by knock control, Compressor downstream pressure is introduced into the first pressure chamber 11 at an appropriate timing, and the first pressure chamber 1
By making the pressures of the first and second pressure chambers 12 the same and selecting the other low supercharging pressure characteristic α, knocking and rise in exhaust temperature (exhaust temperature) are avoided.

Then, at the same time as switching to the operation with the low supercharging pressure characteristic α, the ignition timing is advanced by an amount corresponding to the decrease in the supercharging pressure. Specifically, the knock integrated voltage RS of the knock detection circuit 21 ′ is set to the first value.
Since the forced discharge is performed as shown in FIG. 1 (c), the above switching can be smoothly performed without causing a decrease in output. In this way, even if the actuator 7 is erroneously operated, the supercharging pressure is prevented from rising abnormally, and excellent acceleration performance can be exhibited in the initial stage of acceleration, resulting in a decrease in output during the switching transition period. Instead, it is possible to reliably prevent knock and increase in exhaust temperature in the steady high load operation range.

The function of the ignition timing control means M3 can be provided by software processing.

In this case, the detection signal is the knock sensor output signal KS described above.
And the time when this signal KS is high is input to the CPU of the controller 20 or the detection signal is made equal to the knock sensor output signal KS described above for a certain period (ignition interval time or constant Signal KS at time)
Whether or not was high is input to the CPU of the controller 20.

Then, as long as knocking occurs, the ignition retard value is increased, and if knocking does not occur, the integration function of reducing it is performed by software in the CPU.

Therefore, the control for reducing the retard amount is also performed by accelerating the memory storing the retard amount by a necessary amount when it is desired to advance the angle by only the software in the CPU.

Note that FIG. 9 shows the flow of processing by this software.

Further, as the actuator, those shown in FIGS. 12 and 13 can be used. In the actuator 7'shown in FIG. 12, the first diaphragm 9'has a larger area than the second diaphragm 10 ', and the actuator 7 "shown in FIG. 13 has the second diaphragm 10" having a larger area. 1
It has a larger area than the diaphragm 9 ″. When the diameter between the diaphragms is changed in this way, as shown in FIG. 12, supercharging pressure characteristics α ′ and β ′ (characteristic α ′ Can be obtained by introducing the pressure on the downstream side of the compressor into the first pressure chamber 11 ′, and the characteristic β ′ can be obtained by introducing atmospheric pressure into the first pressure chamber 11 ′.
The supercharging pressure characteristics α ″ and β ″ as shown in the fifteenth (characteristic α ″ indicates that the compressor downstream side pressure is introduced into the first pressure chamber 11 ″, and characteristic β ″ indicates the atmospheric pressure in the first pressure chamber 11 ″. Introduced) can be obtained.

When the area between diaphragms is changed, the characteristics shown in Fig. 4
The slopes of a and b also change.

In FIGS. 12 and 13, reference numerals 8'and 8 "are first rods, 12 'and 12" are second pressure chambers, 13' and 13 "are first return springs, and 14 'and 14" are second. The return springs 15 'and 15 "indicate the second rods, and the respective members exhibit substantially the same functions as the respective members of the above-described embodiment indicated by the reference numeral without a dash.

〔The invention's effect〕

As described in detail above, according to the control device for an engine with a supercharger of the present invention, it is possible to selectively perform an operation with a high supercharging pressure characteristic or an operation with a low supercharging pressure characteristic according to an operating state. In a turbocharged engine, knock control means for performing control for avoiding knock and supercharging pressure for controlling switching between operation with the high supercharging pressure characteristic and operation with the low supercharging pressure characteristic. With the characteristic switching control means, the ignition timing is advanced by an amount corresponding to the amount of decrease in the supercharging pressure accompanying the switching from the operating state with the high supercharging pressure characteristic to the operating state with the low supercharging pressure characteristic. With a simple configuration that ignition timing control means is provided,
The output does not suddenly decrease at the time of switching from the operating state with the high supercharging pressure characteristic to the operating state with the low supercharging pressure characteristic, which provides an advantage that the switching can be performed without shock.

[Brief description of drawings]

FIG. 1 shows a control device for an engine with a supercharger as one embodiment of the present invention. FIG. 1 is a configuration diagram of a main part thereof, and FIG. 2 is an electric circuit diagram for explaining an ignition timing control means thereof. ,
3 to 6 are graphs for explaining the respective actions,
7 to 9 are flow charts for explaining the operation, and FIG.
11 (a) to 11 (c) and FIGS. 11 (a) to 11 (c) are waveform diagrams for explaining the operation thereof, and FIGS. 12 and 13 are modification examples of the boost pressure characteristic switching actuators. The schematic diagrams shown in FIGS. 14 and 15 are graphs for explaining the operation of the components shown in FIGS. 12 and 13, respectively. 1-intake passage, 1a-compressor upstream-side intake passage part, 1b-compressor-downstream-side intake passage part, 2-
・ Exhaust passage, 2a ・ ・ Bypass passage, 3 ・ ・ Turbocharger (supercharger), 4 ・ ・ Turbine, 5 ・ ・ Compressor, 6 ・ ・ Wastegate valve, 7,7 ′, 7 ″ ・
Actuator, 8, 8 ', 8 "... First rod, 9,
9 ', 9 "... first diaphragm 10,10', 1
0 "... second diaphragm, 11, 11 ', 11" ...
1st pressure chamber, 12, 12 ', 12 "... 2nd pressure chamber, 1
3,13 ', 13 "... First return spring, 1
4,14 ', 14 "... Second return spring, 1
5, 15 ', 15 "... second rod, 16 ... first control passage, 17 ... atmosphere passage, 18 ... solenoid valve, 18
a .. Solenoid coil, 18b .. Plunger, 18
c ... Return spring, 19 ... Pressure passage (second control passage), 20. Controller, 21 .. Knock sensor, 21 '.. Knock detection circuit, 22 .. Rotation speed sensor, 23 .. Air flow sensor, 24 ... Intercooler, 25 ... Throttle valve, 26 ... Water temperature sensor, 27
.. Distributor, 28 .. Ignition coil, 29 .. Power transistor, 30 .. Throttle sensor, M1 .. knock control means, M2 .. Supercharging pressure characteristic switching control means, M3 .. Ignition timing control means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F02P 5/15 D

Claims (1)

[Claims] 1. A knock control means for performing control for avoiding knock in an engine with a supercharger capable of selectively performing an operation with a high supercharging pressure characteristic or an operation with a low supercharging pressure characteristic according to an operating state. And a supercharging pressure characteristic switching control means for controlling switching between the operation with the high supercharging pressure characteristic and the operation with the low supercharging pressure characteristic, and the operation with the high supercharging pressure characteristic. A supercharger, characterized in that ignition timing control means is provided for advancing the ignition timing by an amount corresponding to a decrease in supercharging pressure due to switching from the state to the operating state with the low supercharging pressure characteristic. Engine control device.