JPH02201022A - Control device for engine with supercharger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a supercharged engine in which a plurality of superchargers are arranged in parallel.

(Prior art) Conventionally, Japanese Unexamined Utility Model Publication No. 178329/1983,
As described in Publication No. 259722, etc., two turbo superchargers, a primary and a secondary turbo supercharger, are installed in parallel in an engine, and an exhaust cupto valve and By providing intake cut valves and opening and closing these cut valves, in the low flow region of the intake air layer, only the primary side turbo supercharger performs supercharging, and in the high flow region, the secondary side turbo supercharger performs supercharging. Engines called twin-turbo or sequential turbo engines that operate a feeder are known.

By the way, in such a sequential turbo,
The switching conditions for switching the secondary turbocharger from an inactive state to an active state, or conversely from an active state to an inactive state, are such that there is a large difference in boost pressure before and after switching, so that the torque shock at the time of switching is small. It was common practice to set the intake air amount line to a line that does not cause air flow. However, if the switching conditions are set only by such an equal intake air amount line, there will be large variations in switching timing in areas of high engine load, and it will not be possible to reliably reduce torque fluctuations during switching. A problem has arisen. This is mainly a problem due to the detection accuracy of the air flow meter that detects the amount of intake air, and also,
This is also a problem due to the characteristics of the amount of intake air. In other words, as shown in Figure 1, a normal air flow meter has a high intake air! However, since the switching line of a sequential turbo corresponds to the point where this voltage is saturated, the accuracy of detecting the switching point set on the approximately equal intake air amount line is originally Also, as shown in Figure 2, a characteristic of sequential turbos is that the change in intake air amount is small near the switching point even if the engine speed increases. This makes it more difficult to accurately detect the switching point based on the amount of intake air. Moreover, the equal intake air amount line itself, which is the switching point, has large variations due to characteristic errors of the primary side supercharger, and the influence of this variation is particularly noticeable as the load increases. Therefore, if the switching line is simply set based on the amount of intake air, switching in a high load region will become uncertain and torque shock may not be prevented.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and is designed to ensure torque shift by reliably switching the high-flow side supercharger between activation and deactivation in a sequential turbo, especially in a high engine load region. The purpose is to obtain a control device that can prevent the above.

(Structure of the Invention) The present invention sets the switching conditions for the sequential turbo ζ based on the equal intake air amount, and also takes into account the element of engine rotation speed that can be detected reliably in setting the switching conditions on the high load side. This system is designed to increase the reliability of switching, and its configuration is as follows.

In other words, the supercharged engine control gli device according to the present invention has at least a blower and a turbine of a first supercharger that are operated on the low flow rate side of the intake air amount, and a second turbocharger that is operated on the high flow rate side of the intake air amount. Is the feeder blower and turbine parallel to the intake passage and exhaust passage, respectively? In this supercharged engine, the switching conditions are such that the second supercharger is switched from an inactive state to an active state and from an active state to an inactive state based on an equal intake air amount. is set, and the switching condition is shifted to the higher engine rotation side with respect to the intake air amount as the engine load becomes higher.

(Operation) The first supercharger operates at least when the engine is in a low flow region, and the second supercharger operates when the engine is in a high flow region. The switching of this second supercharger from an inactive state to an operating state and from an operating state to an inactive state is based on the intake air amount such that the torque fluctuation due to switching is small, and this is set at high load. This is done under switching conditions that are shifted to the higher rotation side. In other words, on the high load side, switching is performed based on setting conditions that have a larger element of engine rotation speed.

(Example) Examples will be described below based on the drawings.

FIG. 3 is an overall system diagram of an embodiment of the present invention.

In this embodiment, the engine f01 is a reciprocating two-cylinder engine, and exhaust passages 202 and 203 are provided independently of each other in correspondence with each cylinder. And, in one of those two exhaust passages 202 and 203 is the turbine of the primary turbo supercharger 104! 05, and a turbine 107 of a secondary turbocharger 106 is disposed on the other side. Two exhaust passages 1.02i0
3 merge into one line downstream of both turbines 105 and 107, and are connected to a silencer (not shown).

Further, the intake passage 109 is divided into two downstream of an air cleaner (not shown), and the blower I11 of the primary turbo supercharger 104 is in the middle of the first branch passage 11O, and the blower I11 of the primary turbo supercharger 104 is in the middle of the second branch passage 112. A blower 113 of a secondary turbo supercharger +06 is installed. These branch passages 110° and 112 are formed so as to face each other at the branch part and to extend substantially straight on both sides. Also,
Two branch passages 110.112 are connected to each blower 111113.
They rejoin downstream. Then, an intercooler 114 is disposed in the intake passage 109, which has become one again, and a surge tank 115 is disposed downstream of the intercooler 114, and a throttle valve 116 is disposed between the intercooler 114 and the surge tank 115. It is set up. Further, the downstream end of the intake passage 109 branches into two independent intake passages 117 and 118 corresponding to each cylinder of the engine 101, and is connected to each intake boat (not shown). These independent intake passages 117 and 118 have fuel injection valves 119 and 1, respectively.
20 are arranged.

An air flow meter 121 is provided on the upstream side of the intake passage 109, located upstream of the branch of the first and second branch passages 110, 112, and detects intake air jet.

The two exhaust passages 102, 103 are communicated with each other by a relatively small diameter communication passage +22 upstream of both the primary and secondary turbochargers 104, 105. In the exhaust passage 103 in which the secondary turbine +07 is disposed, an exhaust caputo valve 123 is provided immediately downstream of the opening position of the communication passage 122. Further, a bypass passage 125 is formed which extends from the middle of the communication passage +22 and communicates with the combined exhaust passage 1.24 of the turbines 105° and 107th flow. A waste gate valve 127 is provided. and,
A leak passage + 28 is formed that communicates the upstream portion of the waste gate valve 127 of the bypass passage 125 and the downstream of the exhaust cut valve + 23 of the exhaust passage +03 connected to the secondary turbine 107, and the leak passage 128 has a diaphragm type actuator 129 An exhaust leak valve 130 is provided which is linked to the exhaust leak valve 130 .

The exhaust cut valve 123 is linked to a diaphragm type actuator 131. Meanwhile, the secondary turbo supercharger! Branch passage 1 where blower 113 of 06 is installed
12, an intake cut valve 132 is disposed downstream of the blower 113. This intake cut valve 132 is composed of a butterfly valve, and is also a diaphragm type actuator 1.
33. In addition, a relief passage 134 is formed in the branch passage +12 on the secondary side so as to bypass the blower 113.
34 is provided with a diaphragm type intake relief valve 135.

The actuator 12 that operates the exhaust leak valve 130
The pressure chamber 9 is connected via a conduit 136 to a branch passage 11 in which a blower I11 of the primary turbocharger 104 is disposed.
It is connected to the downstream side of the blower 111 of No. 0. When the pressure downstream of the blower 111 exceeds a predetermined value, the actuator 129 is actuated to open the exhaust leakage valve 130, thereby allowing a small amount of exhaust gas to pass through the bypass passage 128 when the exhaust cupto valve 123 is closed. Flowing to the secondary side turbine! 07. Therefore, the secondary turbo supercharger 106 starts rotating before the exhaust cut valve 123 opens. During this time, since the intake relief valve is opened as will be described later, the rotation of the secondary turbo supercharger +06 increases, the transient response when the exhaust cut valve opens is improved, and the torque shock is alleviated.

The actuator 13 that operates the intake cut valve 132
The pressure chamber 3 is connected to the output port of the electromagnetic solenoid type three-way valve 138 by a conduit +37. Further, the actuator 131 that operates the exhaust cut valve 123 is
Another three-way valve 140 of electromagnetic solenoid type is connected by conduit 139.
connected to the output boat. Plus, an intake relief valve! The pressure chamber of the actuator +41 that operates 35 is
Another three-way valve 143 of electromagnetic solenoid type is connected by conduit 142.
connected to the output boat. Intake relief valve 135
As will be described later, the relief passage 13 is closed until a predetermined time when the exhaust cut valve 123 and the intake cut valve 132 are opened.
Leave 4 open. As a result, the leak passage 12
Secondary turbo supercharger 1 by exhaust gas flowing through 8
When the 06 is pre-rotated, the pressure of the intake cut valve 1321 flow increases to prevent it from entering the surging region, and also prevents the blower! Increase the rotation of 13.

The actuator 126 operating the wastegate valve 127 is connected by a conduit 144 to the output port of another three-way valve 145 of the electromagnetic solenoid type.

The above four electromagnetic solenoid type three-way valves 138, 140.1
43 and 145 are controlled by a control unit 146 configured using a microcomputer. The control unit 146 has an engine speed R1.
In addition to the intake air mQ, the throttle opening TVO, the boost pressure Pl of the primary side blower I11, etc. are input, and the control described below is performed based on these.

One input port of the electromagnetic solenoid type three-way valve 138 for controlling the intake cut valve 132 is connected to the negative pressure tank 148 via the conduit I47, and the other input port is connected to the negative pressure tank 148 via the conduit I47.
49 to the output port 17 of the differential pressure detection valve 150, which will be described later.
Connected to 0.

Intake negative pressure downstream of the throttle valve 116 is introduced into the negative pressure tank 14g via a check valve 151. Further, one input port of the three-way valve 140 for controlling the exhaust cut valve is open to the atmosphere, and the other input port is
It is connected via a conduit 152 to the conduit I47, which is connected to the negative pressure tank 148. On the other hand, one input port of a three-way valve 143 for controlling the intake relief valve 135 is connected to the negative pressure tank 148, and the other input port is open to the atmosphere. In addition, waste gate valve 127
One manual port of the three-way control valve 145 is open to the atmosphere, and the other input port is connected by a conduit 154 to the conduit 136 communicating with the downstream side of the primary blower 11, 1.

As shown in FIG. 4, the differential pressure detection valve 150 has three chambers 164, 165.
It is divided into 66 sections. The first input port +67 is opened in the first chamber 1641 at one end, and the inner surface of the casing 161 and the first diaphragm 1
A compression spring 168 is disposed between the spring 62 and the spring 62 .

In addition, a second input port 16 is provided in the middle second chamber 165.
In the third chamber +66 at the other end, an exit capo 170 is opened at the center of the end wall of the casing 161, and an atmosphere release boat 171 is opened at the side wall. and,
The first diaphragm 162 includes a second diaphragm 1
A valve body I72 is fixedly provided, passing through the valve body 63 and extending toward the output port 170 of the third chamber 166.

First input port! 67 is connected by conduit 173 to the third
As shown in the figure, it is connected downstream of the intake cut valve 132, and introduces the boost pressure PI downstream of the primary blower III into the first chamber +64.

The second input port 169 is also connected upstream of the intake caputo valve 132 by a conduit 174, and thus is connected to the intake caputo valve 132 when the intake caputo valve 132 is closed.
The pressure P2 on the upstream side is introduced 4''.The pressure PI introduced from this two-man powered boat 167.
When the difference in P2 is greater than or equal to a predetermined value, the valve body 172 opens the output port 170. This output port 170 is connected to the conduit [49
is connected to one of the input ports of a three-way valve 138 for controlling the intake cut valve 132. Therefore, the three-way valve 138 connects the conduit 137 connected to the pressure chamber of the actuator 133 for operating the intake cut valve 132 to the differential pressure detection valve 1.
When the differential pressure P2-PI becomes larger than a predetermined value while the actuator 133 is in communication with the conduit 149 connected to the output port 50, the atmosphere is introduced into the actuator 133, and the intake cut valve 132 is opened. Also, connect the three-way valve 138 or the conduit 137 on the actuator 133 side to the negative pressure tank 1.
48, negative pressure is supplied to the actuator 133, and the intake cut valve 1
32 is closed.

On the other hand, when the three-way valve 140 for controlling the exhaust cut valve I23 connects the conduit +39 connected to the pressure chamber of the actuator 131 for operating the exhaust caputo valve 123 to the conduit 152 on the negative pressure tank +48 side, It is closed by supplying negative pressure to the actuator. Further, when the three-way valves 1 and 10 release the conduit +39 on the output side to the atmosphere 4-, the exhaust cupto valve 123 is opened and supercharging by the secondary turbo supercharger 106 is performed.

FIG. 5 shows the intake cut valve i32. exhaust cut valve 123,
This is a control map showing the open/close states of the intake relief valve 135 and the waste gate valve 127 as well as the open/close state of the exhaust leak valve 130. This map is stored in the control unit 146, and based on this map, the four electromagnetic solenoid type three-way valves 138, 140, 143, 1
45 controls are performed.

In this control map, the lines that define the opening/closing conditions for the intake relief valve 135, exhaust cut valve 123, and intake cut valve 132 are based on the equal intake air amount line, and are changed depending on the engine speed on the high load side. It is set in a cut shape.

In a region where the engine speed R is low or the intake air amount Q is small, the intake relief 135 is open, and the exhaust leak valve 130 is opened to pre-rotate the secondary turbocharger 106. When the engine speed reaches R2 or the intake air amount reaches Q2, the intake relief valve 135 is closed, and the pressure downstream of the secondary blower 113 increases until the exhaust caputo valve 123 opens. And Q4-R4
When the line is reached, the exhaust caputo valve +23 opens, and then when the Q6-R6 line is reached and the intake cut valve 132 is opened, supercharging by the secondary turbo supercharger 106 starts, and from this Q6-R6 line, the primary and enters the supercharging region with both secondary superchargers.

Intake cut valve 132. The exhaust cut valve 123 and the intake relief valve 135 have a slight hysteresis from the high flow rate side to the low flow rate side, that is, the Q shown by the broken line in FIG.
It is switched by 6 lines: 5-R5, Q3-R3, and Qllll.

Note that the bent portions of each of these lines are on the so-called no-load line or load-load line.

The wastegate valve 127 is opened when the engine speed R and the throttle opening TVO exceed a predetermined value and the supercharging pressure P1 of the primary side blower flow exceeds a predetermined value.

The above Q1 to Q6 and R1-R in this control map
6 is set as shown in FIG.
~Q6 is made larger in lower speed gears, and R3-R6 are made higher in lower speed gears. This is in order to prevent torque shock from occurring even when changing gears, in line with the characteristic that the boost rises quickly during acceleration in low gears, especially -, but slows down in high gears. The values are set to their respective optimal values.

7 and 8 show the intake caputo valve I23. in this embodiment. Exhaust cut valve 132 and intake relief valve +
35 is a flowchart for executing the above control of No. 35. Note that S indicates each step.

Further, F is a flag, and the state of this flag (FI~
The meaning of 6) is as shown in Figure 5,
In each case, the previous transition was a transition from the high flow rate side to the low flow rate side of the Ql-R1 line (F=1), Q
2-R2 line transition from low flow rate side to high flow rate side (F=2), Q3R3 line transition from high flow rate side to low flow rate side (F=3), Q4-R4 line low flow rate This is the transition from the flow rate side to the high flow rate side (F=4), and the transition from the high flow rate side to the low flow rate side of the Q5-R5 line (F=5)
, a transition from the low flow rate side to the high flow rate side of the Q6-R6 line (F=6). The steps will be explained below.

First, in FIG. 7, the system starts and initialization is performed at Sl. At this time, the flag is set to I.

Next, input the intake air IQ, engine speed R, and gear G in S2. Then, in S3, map values Ql-Q6 for each gear. Read R1 to R6. And S4
go to

In S4, it is checked whether the flag F is 1, that is, whether the previous transition was from the high flow rate side to the low flow rate side of the QI-R1 line. Note that initially F=1, so this determination is YES.

If F=1, then go to S5 to determine whether Q is greater than Q2 this time, and if YES, then go to S6 to see if R is greater than R2 this time. If YES in S5 and S6, the process goes to S7 and sets the flag F to 2, and in S8 the intake relief valve is controlled to close (atmospheric pressure is introduced into the actuator).

Also, the determination in either S5 or S6 is N.

If so, just return.

If the determination in S4 is NO, go to S9 and check whether the flag Fh<'% is true, that is, whether the previous transition was from the low flow rate side to the high flow rate side on any line. See if it was there.

Then, if YES in S9, go to SIO and F=2
In other words, it is determined whether the previous transition was from the low flow rate side to the high flow rate side of the Q2-R2 line, and if F=2, go to Sll.

In Sll, it is determined whether this time Qh<Q4 or not, and if No, then in SI2 it is determined whether or not this time Rh<R4 or not. And S11 and SI2
If YES in both cases, the process goes to SI3 and sets the flag F to 4, and in S14 the exhaust cut valve is controlled to be opened (negative pressure is introduced into the actuator).

Further, when the determination of either Sll or S+2 is No, the process goes to S15 to check whether Q is smaller than Ql this time.

If No in S15, it is checked in S16 whether R is smaller than R1 this time. If YES in either S15 or S16, go to S17 and set the flag F to 1, and control the opening of the intake relief valve at 51B (introduce negative pressure to the actuator). and S
If all the determinations in I6 are NO, the process directly returns.

If the SIO judgment is NO, go to SI9 and check whether the flag F is 4, that is, if the previous transition was Q4-R.
It is determined whether there has been a transition from the low flow rate side to the high flow rate side of the 4th line.

If YES in 519, check whether Q is larger than Q6 this time in S20, and if YES, then in S21
Now check whether R is greater than R6. And S
If both determinations in S20 and S21 are YES, S
22, the flag F is set to 6, and in S23, the intake cut valve is controlled to open (the actuator is communicated with the differential pressure detection valve side).

Further, if NO in either S20 or S21, the process goes to S24, and it is determined whether Q is smaller than Q3, and if NO, it is determined in S25 whether R is smaller than R3. If YES in either S24 or S25, the process goes to S26 and sets the flag F to 3, and in S27 the exhaust cut valve is controlled to close (atmospheric air is introduced into the actuator).

If the determination in S19 is NO, it means that F=6, that is, the previous transition was from the low flow rate side to the high flow rate side of the Q6-R6 line, and in this case, go to S28 and change the current flow rate. It is determined whether Q is smaller than Q5, and if NO, then in S29 it is determined whether R is smaller than R5 this time.

If YES in either 528 or S29, go to S30, set flag F to 5, and S31
Controls the intake cut valve to close (introduces negative pressure to the actuator). Further, if the determinations in S828 and S29 are both NO, the process directly returns.

Next, the flow when the determination in S9 is NO will be explained with reference to FIG.

If NO in S9, the process goes to S41 to determine whether flag F is 3, that is, whether the previous transition was from the high flow rate side to the low flow rate side of the Q3-R3 line.

If YES, then in S42 this time Qh<
Determine whether it is smaller than Ql, and if No, S4
3, it is determined whether this time Rh<R1.

If YES in either S42 or S43, go to S44 and set flag F to 1, then,
In S45, the exhaust cut valve is controlled to open.

If both S4.2 and S43 are NO, go to S46 and check whether Q is greater than Q4.
If YES, it is determined in S47 whether Rh<R4. If the determinations in S46 and S47 are both YES, the process goes to S48 to set the flag F to 4, and then, in S49, control is performed to open the exhaust caputo valve. Further, if NO in either 946 or S47, the process directly returns.

If No in S41, it means F-5, and in this case, go to S50 to determine whether Q is smaller than Q3, and if NO, go to S51 to determine whether R is smaller than R3. do. If YES in either S50 or S51, the flag F is set to 3 in S52, and then the exhaust caputo valve is controlled to be closed in S53.

If the determinations in S50 and S51 are both No, S
54, determine whether Q is greater than Q6, and return Y
If it is ES, then it is checked in S55 whether R is greater than R6. If the determinations in S54 and S55 are both YES, the process goes to S56 to set the flag F to 6, and then, in S57, control is performed to open the intake cut valve.

Also, N in either S54 or S55.

When , it returns as is.

In the above embodiment, the switching line set as the equal intake air amount line is cut at the engine speed on the high load side so that it stands straight up as shown in Fig. 4, but this switching line , the high load side may stand up with a slight incline.

(Effects of the Invention) Since the present invention is configured as described above, in a sequential turbo, even if there are variations in the equal intake air amount line or detection errors due to characteristic errors of the low flow side supercharger, etc., the engine Torque shock can be prevented by reliably switching the operation of the high-flow side supercharger in a high-load region.

[Brief explanation of the drawing]

Fig. 1 is an output characteristic diagram of an air flow meter, Fig. 2 is a characteristic diagram showing the relationship between engine speed and intake air amount in a turbocharged engine, and Fig. 3 is an overall system diagram of an embodiment of the present invention. , Fig. 4 is a sectional view of the differential pressure detection valve in the same embodiment, Fig. 5 is a control characteristic diagram of the same embodiment, and Fig. 6 is a sectional view of the differential pressure detection valve in the same embodiment.
Tables showing the setting values in the characteristic diagrams in Figures 7 and 8.
The figure is a flowchart for executing control in the same embodiment. 101: Engine, 104 niblimari turbo supercharger,
106: Secondary turbo supercharger, 123: Exhaust cut valve, 132: Intake cut valve, 146: Control unit.

Claims (1)

[Claims] (1) At least the blower and turbine of the first supercharger that operates on the low flow rate side of the intake air amount and the blower and turbine of the second supercharger that operate on the high flow side of the intake air amount are connected to the intake passage and the exhaust passage, respectively. In a supercharged engine arranged in parallel, the second supercharger is switched from an inactive state to an active state and from an active state to an inactive state based on an equal intake air amount. A control device for a supercharged engine, characterized in that a switching condition is set, and the switching condition is shifted to a higher engine speed side with respect to the above-mentioned equal intake air amount as the engine load is higher.