JPS60249621A - Supercharge pressure control device in engine provided with supercharger - Google Patents

Abstract

PURPOSE:To obtain a satisfactory acceleration characteristic in accordance with the shift position of a speed change unit, by increasing the maximum supercharge pressure for a predetermined time upon acceleration above that upon normal operation, and as well by changing the time of the increase control therefor, etc. in accordance with the shift position of the speed change unit. CONSTITUTION:A supercharge pressure control device is provided therein with a maximum supercharge pressure control device 13 for controlling the maximum supercharge pressure downstream of an exhaust turbo-type supercharger 6 to a set value. In this arrangement, there are provided an acceleration detecting means 26 for detecting the accelerating condition of an engine 1 and a shift position detecting means 22 for detecting the shift position of a speed change unit. Further, a supercharge pressure adjusting means 27 controls the maximum supercharge pressure control means 13 in accordance with output signals from the detecting means 26, 22. That is, control is made such that upon detection of an accelerating condition the maximum supercharge pressure is increased above the above-mentioned set value for a predetermined time, and the control time of increase control of the maximum supercharge pressure or the controlled increase value is changed in accordance with the shift position of the speed change unit.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a supercharged engine in which the maximum boost pressure downstream of the supercharger is controlled to a set value. The present invention relates to boost pressure control devices, and particularly to measures for improving acceleration while ensuring engine reliability and durability.

(Prior art) Conventionally, a supercharger is installed in the intake passage of an engine, and by supercharging the intake air with the supercharger, the filling efficiency of the intake air of the engine is improved and the direction of the intake air is increased. It is widely known that

Conventionally, in such a supercharged engine, as disclosed in Japanese Unexamined Patent Publication No. 57-'+'4eO23, there is a method for controlling the maximum supercharging pressure downstream of the supercharger. Equipped with a maximum boost pressure control device, the maximum boost pressure downstream of the turbocharger is controlled to the set value, thereby preventing engine damage due to an abnormal increase in boost pressure and improving engine reliability. It is designed to effectively improve the filling efficiency and exit direction while ensuring durability.

By the way, conventionally, in such a supercharging pressure control device for a supercharged engine, for example, Japanese Patent Application Laid-Open No. 57-157017 discloses
As disclosed in the publication, when the engine accelerates when the engine throttle valve opens beyond a predetermined opening degree, the maximum boost pressure downstream of the supercharger is set in advance within a range that can reliably prevent engine damage. The acceleration performance of the engine is improved by raising it for a predetermined period of time and controlling it to a higher value than in normal times (set value).

(Problems and Issues to be Solved by the Invention) By the way, when setting the predetermined period for increasing the maximum boost pressure as described above, for example, when accelerating at a low gear, the acceleration time is If the above predetermined period is set short assuming that the acceleration time is short, in acceleration operation at a high gear position where acceleration performance is poor and acceleration time is long, the above predetermined period will elapse during the acceleration operation, and at this point Since the maximum supercharging pressure will return to the set value, it will not be possible to effectively improve the acceleration performance. In other words, if the above predetermined period is set to be long according to the acceleration time at a high gear, during acceleration operation at a low gear with a short acceleration time, the maximum overspeed will continue until the predetermined period has elapsed even after reaching the high rotation range. Since the supply pressure is controlled to increase, this is unfavorable from the viewpoint of engine reliability and durability.

Also, when setting the maximum boost pressure increase value,
If you set the above increase value low assuming that the gear ratio is large and does not require much driving force, such as acceleration operation at a low gear, then acceleration at a high gear where the gear ratio is small and requires a large driving force. While it is not possible to expect much improvement in acceleration performance during driving, if the above increase value is set high to match the driving force at high gears, the driving force will become excessive when accelerating at low gears, which will reduce engine reliability. Durability becomes an issue.

The present invention has been made in view of this point, and its purpose is to increase the maximum boost pressure for a predetermined period of time compared to normal times when the engine accelerates as described above.
By changing the increase control of this maximum boost pressure either periodically or quantitatively depending on the shift position of the transmission, engine reliability and durability are ensured, and the performance is always maintained regardless of the shift position of the transmission. The aim is to obtain excellent acceleration performance.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention includes a supercharger 6 interposed in the intake passage 2 for intake supercharging as shown in FIG. , and a maximum boost pressure control device 13 for controlling the maximum boost pressure downstream of the supercharger 6 to a set value, in a supercharging pressure control device for a supercharged engine, detecting an acceleration state of the engine. an acceleration detection means 26 for detecting the shift position of the transmission; a shift position detection means 22 for detecting the shift position of the transmission; Detection means 22
The supercharger adjusting means 27 receives the output of the supercharger and changes at least one of the predetermined time period and the maximum supercharging pressure according to the shift position of the transmission.

Here, the supercharging pressure adjusting means 27 lengthens the culm waste period during which the shift position of the transmission detected by the shift position detecting means 22 is at a high stage, or increases the maximum supercharging pressure.

(Function) With the above configuration, in the present invention, when the engine accelerates, the maximum boost pressure downstream of the supercharger is controlled to rise above the set value for a predetermined period of time, and the control to increase the maximum boost pressure is controlled by the transmission. By changing the control time or the control increase value according to the shift position, in other words, the higher the shift position, the greater the driving force required for acceleration, the worse the acceleration performance, and the longer the acceleration time. By lengthening the culm dust period at a high position or increasing the maximum supercharging pressure, good acceleration performance corresponding to the shift position can be obtained.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. 2 and the following drawings.

FIG. 2 shows an embodiment of the present invention, in which 1 is an engine, 2 is an intake passage for supplying intake air to the engine 1, 3 is an exhaust passage for discharging exhaust gas from the engine 1, and 4 is an intake passage. a throttle valve disposed at 2 for controlling the intake air amount;
is a surge tank provided downstream of the throttle valve 4 in the intake passage 2.

6 is an exhaust turbo type supercharger, and the supercharger 6 is driven by a turbine 6a interposed in the exhaust passage 3 and a shaft 6C connected to the turbine 6a interposed in the intake passage 2. The compressor 6 is composed of a connected compressor (blower) 6b, and a turbine 6a rotates by the exhaust gas flow.
b is driven, and intake air is supercharged to the engine 1 by the rotational drive of the compressor 6b.

The exhaust passage 3 is provided with a bypass passage 7 that bypasses the turbine 6a of the supercharger 6.
A wastegate valve 8 for opening and closing the bypass passage 7 is disposed in the bypass passage 7, and the wastegate valve 8 is controlled to open and close by a wastegate actuator 9.

The waste goo 1-actuator 9 is composed of a pressure-responsive diaphragm device, and includes a diaphragm 9a linked to the waste gate valve 8, a pressure chamber 9b and an atmospheric chamber 9C partitioned by the diaphragm 9a, and the atmospheric chamber 9C. The pressure chamber 9b includes a spring 9d compressed therein and urging the wastegate valve 8 in the closing direction.
The compressor 6 of the supercharger 6' via the boost pressure communication passage 10
b is connected downstream to the intake passage 2 upstream of the throttle valve 4, and introduces the boost pressure downstream of the supercharger 6 (compressor 6b) into the pressure chamber 9b, while the atmosphere communication passage 11 and the air communication passage 11 It is communicated with the atmosphere through an air filter 12 provided at the opening at the tip, and the pressure chamber 9b is opened to the atmosphere. Therefore, the pressure chamber 91) of the wastegate actuator 9 is connected to the supercharger 6 (compressor 6).
b) When downstream boost pressure is introduced through the boost pressure communication passage 10, the diaphragm 9a is biased against the biasing force of the spring 9d, closing the wastegate valve 8 and opening the bypass passage 7. As a result, part of the exhaust gas flow bypasses the turbine 6a of the supercharger 6 and flows down, thereby suppressing the rotation of the turbine 6a and the rotation of the compressor 6b. (Con 7
Repressor 6b) Decrease the downstream supercharging pressure. On the other hand, when the pressure chamber 9b is opened to the atmosphere through the atmosphere communication passage 11, the wastegate valve 8 is operated to close by the biasing force of the spring 9d, thereby closing the bypass passage 7.
All of the exhaust gas flows to the turbine 6a of the supercharger 6, and the reduction in supercharging pressure downstream of the supercharger 6 due to the rotation suppression of the turbine 6a is stopped and controlled to increase. A wastegate-type maximum boost pressure control device 13 is configured to control the maximum boost pressure downstream of the engine 6.

Furthermore, a first control valve 14 for controlling opening and closing of the boost pressure communication passage 10 is interposed in the middle of the boost pressure communication passage 10, and a first control valve 14 is provided in the middle of the atmosphere communication passage 11. A second control valve 15 that controls opening and closing is provided.

Both control valves 14 and 15 are connected to a control unit 16 so as to be able to send and receive signals, and the control unit 16 includes a rotation speed sensor 1 that detects the engine rotation speed.
7. Water temperature sensor 18 that detects engine temperature based on engine cooling water temperature; Intake air temperature sensor 19 that detects intake air humidity
, a throttle opening sensor 20 for detecting the opening of the throttle valve 4. A pressure sensor 21 that detects the pressure (supercharging pressure) in the intake passage-2 upstream of the throttle valve 4 downstream of the supercharger 6 (compressor 6b), and a shift position as a shift position detection means that detects the shift position of the transmission. Each detection signal of the sensor 22 is input, and these sensors 17 to 22
The control unit 16 controls the first
．． It is configured to operate and control the second control valve j4.15 to feedback control the maximum boost pressure downstream of the supercharger [6 (compressor 6b) to the target boost pressure (set value) according to the engine operating state. ing.

Here, each of the control valves 14 and 15 is preferably constructed from a duty solenoid valve in terms of control accuracy, but may also be constructed from a proportional solenoid valve. Furthermore, using a normally open first control valve 14 and a normally closed second control valve 15 is advantageous because the boost pressure will be controlled to lower the boost pressure in the event of a failure in the control system. This is preferable in terms of ensuring the reliability of the engine 1. Also, when controlling the boost pressure mentioned above, the thrower 1
A signal from an air flow sensor that detects the amount of intake air may be used in place of the air opening sensor 20, or a signal from an air flow sensor may be used in place of the pressure sensor 21.

In addition, upstream of the first control valve 14 in the boost pressure communication passage 10, the boost pressure downstream of the supercharger 6 (for example, 5001
11111H! A pressure regulating valve 23 is provided to reduce the pressure of +> and adjust the supercharging pressure applied to the pressure chamber 9b of the wastegate actuator 9 to a substantially constant value (for example, 200m+n1-1<1>. Note that 24 and 25 are orifices provided in the boost pressure communication passage 10 and the atmosphere communication passage 11, respectively, and both orifices 24.25 are designed to improve the stability of the pressure transmission effect by narrowing the passage area of each communication passage 10.11. The caliber is set to an appropriate diameter, taking into consideration safety and prevention of overshoot.

Next, the operation of the control unit 16 will be explained based on the operation flow shown in FIGS. 3 and 4. First, in the basic flowchart of boost pressure control shown in FIG.
7 engine rotational speed N1 engine cooling water temperature w1 from water filter sensor 18 intake air temperature Ta1 from 19 air temperature sensor 19 throttle opening θ from throttle angle sensor 20 and shift position TM from shift position sensor 22 Signal data are input, and in step s2, a target supercharging pressure Po is calculated using the following formula based on these signal data.

Po = KXPa ase Here, K is a correction coefficient, and engine coolant temperature T
w, intake air temperature Ta1, acceleration correction amount, etc.

Next, in step S3, signal data of the actual supercharging pressure Pa is input from the pressure sensor 21.

Then, in step S4, the first and second control valves 1, which will be described later, are activated based on the difference between the actual boost pressure Pa and the target boost pressure Po.
The pulse width tp due to the proportional control in the duty ratio control of 4.15 is calculated by the formula (PG: proportional gain) of t p = pGx (Pa - Po ), and in step Ss, the current actual supercharging pressure pa (n ) and the previous actual boost pressure pa (n-1>
(n) -Pa(n-+)) (DG: differential gain), and in step S6 these pulse widths t
P.

The control pulse width t (=t p +t o
) is calculated.

Next, in step S7, the magnitude of the actual supercharging pressure Pa and the target supercharging pressure Po is compared and determined in order to determine the control direction, and when Pa - Po >Q is YES, step S7 is performed.
By driving the first control valve 14 at step 8, the boost pressure downstream of the supercharger 6 is regulated to a constant pressure by the pressure regulating valve 23, and the maximum boost pressure control device 13 (west goo 1-actuator 9) is adjusted to a constant pressure. In addition to the pressure chamber 9b), the actual boost pressure Pa is set to the target boost pressure P.

On the other hand, when Pa-po <Q is No, the second control valve 15 is driven in step S9, so that the maximum boost pressure control device 13 (the pressure chamber 9b of the wastegate actuator 9) is lowered to the atmosphere. The actual supercharging pressure Pa is controlled to increase to the target supercharging pressure PD, and thereafter, the process returns to step S1 to repeat the same control operation.

On the other hand, during acceleration operation, an operation based on the acceleration correction subroutine shown in FIG. 4 is performed to correct the maximum boost pressure to be higher than the target boost pressure Po for a predetermined period of time in order to improve acceleration performance. This acceleration correction subroutine is called and executed between step S+ and step s2 of the basic boost pressure control flow. That is, in step Sa, it is determined whether the acceleration flag is "1" or not, and when the acceleration flag = 1 (YES), it is determined that acceleration correction is in progress and the process immediately moves to step Se.
On the other hand, when the answer is No, which is acceleration ra-ragoo, it is determined that acceleration correction is not in progress, and the process moves to step sb.

In step sb, it is determined whether the throttle opening θ is larger than a predetermined value C+ and whether the rate of change dθ/dt of the throttle opening is larger than a predetermined value C2. In this case, it is determined that the acceleration correction conditions are not satisfied, and the process immediately proceeds to step 3i, in which it is determined whether the maximum boost pressure correction coefficient CAcc(n) is the basic value I (111), and the CA QC If (n) = 1 (YES), it ends and CACC(+1>≠1
When the answer is No, the process moves to step sh.

On the other hand, if the determinations in step sb are both large YES, it is determined that the acceleration correction condition is satisfied, and step S
After setting the acceleration flag to "1" in step Sd, the map Mat is set to increase the maximum boost pressure for a predetermined period of time in step Sd.
) (N>, reads the correction coefficient CACC of the maximum boost pressure according to the engine speed N, and also reads the correction coefficient CACC from Map (TM
) to the correction time TA cc according to the shift position of the transmission.
Load. Here, the above Map (TM) shows that the higher the shift position, the longer the correction time TACC. The speed is set to 20 seconds. Thereafter, in step Se, the correction time TACC (Ill) is gradually decreased by subtracting "1" at a time, and in step Sf, TACC
Determines whether or not becomes “0”, and determines whether N of TAcc-+o
When it is O, return to the original position and repeat the above operation to obtain TACC-
Wait until it becomes 0. Then, when TACC=O becomes YES, the acceleration flag is set to "O" in step S9, and then
In step sh, the acceleration correction coefficient is controlled to be completed without causing torque shock by subtracting the correction coefficient CAcc(n) by a constant value C3 to gradually decrease the acceleration correction coefficient at a constant gradient.

Therefore, the acceleration detection means 26 detects the acceleration state of the engine 1 by determining θ>C+ and dθ/dt>Cz in step sb of the acceleration correction subroutine.
is configured. Further, when detecting the acceleration state of the engine in step sb of the acceleration correction subroutine,
Correction coefficient CA of maximum boost pressure in steps Sd to Sf
A supercharging pressure adjusting means 27 that increases the target supercharging pressure PD with cc and makes this correction time TACC longer as the shift position is higher according to the shift position of the transmission.
is configured.

Therefore, in the above embodiment, the maximum boost pressure downstream of the supercharger 6 during acceleration operation of the engine is set to be lower than the target boost pressure (set value) by the correction coefficient CACC for a predetermined period (correction time TACC).
Since the engine speed is raised during this period, acceleration performance can be improved without affecting the reliability of the engine 1.

Moreover, at this time, the correction time TACC, which is the maximum boost pressure increase control time, is made longer as the gear shift position of the transmission is higher, so that acceleration performance is improved when accelerating at a lower gear. When accelerating at a high gear position, the above correction time T
ACC corresponds to the acceleration time at each shift position, thus ensuring engine reliability and durability.
Good acceleration performance can always be obtained regardless of the shift position.

In the above embodiment, the higher the shift position of the transmission is, the better the correction time TACC is. However, the maximum boost pressure correction coefficient CAcc is increased to increase the maximum boost pressure increase value. In that case, the increase value of the maximum boost pressure corresponds to the acceleration driving force at each shift position, and similarly good acceleration performance can be obtained at each shift position. Also,
It is also possible to have both of them, that is, to increase both the correction fR interval TACC and the correction coefficient CACC as the shift position becomes higher, which is preferable because acceleration performance can be further improved.

Furthermore, the present invention is not limited to the above embodiments,
It also includes various other modifications. for example,
In each of the embodiments described above, the boost pressure control is performed by feedback control based on the detection of the actual boost pressure, but position feedback control may also be performed based on the opening degree of the waste gate valve 8 in combination with this.

Further, in the above embodiment, an exhaust turbo type supercharger is used as an example of the supercharger for intake supercharging, but other known superchargers such as a pump type supercharger can be used.

In addition, although a wastegate type maximum boost pressure control device for controlling the boost pressure downstream of the turbocharger has been described in the above embodiment, the present invention also provides It is also applicable to various methods such as a relief method that directly controls pressure.

(Effects of the Invention) As explained above, according to the supercharging pressure control device for a supercharged engine of the present invention, the control for increasing the maximum supercharging pressure is shifted according to the shift position of the transmission during acceleration operation. Changes have been made so that the higher the gear position, the longer the control time or the higher the control increase value, ensuring engine reliability and durability while always providing good acceleration performance regardless of the transmission shift position. Therefore, acceleration performance can be further improved.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention, Figures 2 to 4
The drawings illustrate an embodiment of the present invention, Fig. 2 is a general schematic diagram, Fig. 3 is a flowchart explaining the basic operation of the control unit, and Fig. 4 is a flowchart explaining the subroutine for acceleration correction. Char 1 is a diagram. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake passage, 6... Supercharger, 8... Waste gate valve, 13... Maximum boost pressure control device, 16... Control unit, 22...・
Shift position sensor (shift position detection means), 26...
Acceleration detection means, 27... supercharging pressure adjustment means. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A supercharger equipped with a supercharger installed in the intake passage for intake supercharging, and a maximum boost pressure control device for controlling the maximum boost pressure downstream of the supercharger to a set value. A supercharging pressure control device for a charged engine includes an acceleration detection means for detecting an acceleration state of the engine, a shift position detection means for detecting a shift position of a transmission, and a boost pressure control device for detecting a maximum boost pressure for a predetermined period of time. supercharging pressure adjusting means for raising the supercharging pressure higher than the set value (and receiving the output of the shift position detecting means and changing at least one of the predetermined period or the maximum supercharging pressure according to the shift position of the transmission); A supercharging pressure control device for a supercharged engine, characterized by comprising: (2) The supercharging pressure adjusting means lengthens the predetermined period or increases the maximum supercharging pressure as the shift position of the transmission determined by the shift position detecting means is higher. A supercharging pressure control device for a supercharged engine according to paragraph 1.