JPS62101832A - Exhaust turbosupercharger device - Google Patents

Abstract

PURPOSE:To reduce variation in supercharging pressure by providing a connecting hole between two exhaust passages, providing a connecting valve in said connecting hole, and controlling said valve in accordance with load, in a device in which exhaust gas is introduced into the turbine of a turbosupercharger independently from two systems of exhaust passages. CONSTITUTION:A partition wall 10 is provided in a part in which passages connected to exhaust ports 9 are collected, in the exhaust manifold 8 of a four- cylinder engine 1, to form two systems of exhaust passages 12, 13 which independently introduce exhaust gas to the turbine 4 of a turbosupercharger 3. Also, a connecting hole 21 which is opened and closed by means of a connecting valve 22 is provided on the partition wall 10, and the connecting valve 22 is controlled by a valve opening adjusting means including an actuator 23. And, the connecting valve 22 is controlled by an ECU 27 in such a way that its opening is reduced on the low-rotation and low-load side, while increased on the high-rotation and high-load side, of an operating area under the opening condition of a bypass valve 16 in a bypass 15 which connects the exhaust passage 12 to an exhaust passage 14 on the lower course of the turbine 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an exhaust turbocharger in which exhaust gas is guided to a turbine through two independent exhaust passages.

(Prior Art) Conventionally, as shown in, for example, Japanese Utility Model Application Publication No. 56-171630, exhaust gas in the range from the exhaust manifold to the scroll chamber around the turbine between each cylinder of the engine and the turbine of the turbocharger has been developed. By dividing the system into two exhaust passages that independently guide exhaust gas from half of each cylinder to the turbine, the exhaust pulsation can be used effectively to drive the turbocharger in the low speed range. Some are known that are designed to increase efficiency and improve torque. In addition, when configuring two independent exhaust passages in this way, the device in the above publication allows the exhaust gas from cylinders whose exhaust strokes are not consecutive to be guided to the exhaust passages of the same system. Even if the exhaust gases of consecutive cylinders are guided to the exhaust passage of the same system, the exhaust pulsation is increased and exerts a positive effect on the turbine, thereby increasing drive efficiency.

By the way, in the above conventional device, in order to control the maximum boost pressure with a simple drawing, a bypass valve that opens at the set boost pressure is installed between the exhaust passage of one of the two systems and the downstream side of the turbine. However, in this case, when the set supercharging pressure is reached and the bypass valve is opened, exhaust gas is released from only one exhaust passage to the bypass passage, so both exhaust gases are There are 4 differences in back pressure in the exhaust passage, and 15 differences in torque etc. occur between cylinders.

Therefore, in order to solve this problem, a communication hole that is opened and closed by a valve is installed between the exhaust passages, and when the bypass valve is activated, the communication hole is opened and the exhaust air is opened between both exhaust passages. One possibility is to prevent gas from flowing. However, in this case, in order to avoid a pressure difference between the two exhaust passages even when there is a large amount of exhaust gas released to the bypass passage Ql, it is necessary to form the communication hole with a relatively large diameter. If the communication hole is fully opened when the bypass valve is opened, the effect on exhaust pulsation will be lost and the boost pressure will drop rapidly. Therefore, in the operating range immediately after the boost pressure reaches the set boost pressure, the boost pressure decreases due to the opening of the bypass valve and the communication hole as described above, and the bypass valve and communication hole open accordingly. The increase in supercharging pressure due to valve closing is repeated, causing hunting in which the supercharging pressure fluctuates significantly, resulting in a problem that the operating state becomes unstable.

(Objective of the Invention) In view of the above circumstances, the present invention improves the turbocharger drive efficiency in the low speed range by using two independent exhaust passages, and also increases the turbocharger drive efficiency in the low speed range by using the bypass valve in the bypass passage connected to one exhaust passage. While controlling the boost pressure, it prevents a pressure difference between both exhaust passages, and also prevents hunting near the operating range where the boost pressure reaches the set boost pressure to properly control the boost pressure. The present invention provides an IF air turbocharging device that can perform the following steps.

(Structure of the Invention) The present invention divides the +Jl air system of multiple cylinders into two groups (i.e., separates the +Jl air system into two groups, and configures two systems of IL+l ventilation, each of which independently guides the exhaust gas to the turbine of the turbocharger. In an exhaust turbo supercharging device in which a bypass passage is provided between the passage and the downstream side of the turbine, and a bypass valve that opens at a set boost pressure is provided in this bypass passage, a ,
A communication valve is provided that opens when the bypass valve is opened to communicate the two exhaust passages, and a valve opening adjustment means that varies the opening degree of the communication valve, and a valve opening adjustment means that changes the operating range in which the bypass valve is in the open state. On the other hand, on the low rotation, low load side, the opening degree of the communication valve is reduced, and on the high rotation, high load side, the opening degree of the communication valve is increased by 1 J. The means are provided.

With this configuration, in the operating range where the bypass valve is closed, the communication valve is also closed and supercharging occurs due to the action of exhaust pulsation.
If the drive efficiency is increased and the bypass 47 is removed, -
The two communication valves are also opened to prevent a force difference between the two airways, and the opening degree of the communication valve is reduced in the operating range where the amount of exhaust gas released from the bypass passage is small. Attenuation of the exhaust pulsation is suppressed by 1-1, and a sudden drop in 4〒supercharging)F is prevented.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which the device of the present invention is applied to a four-cylinder engine, and 1 is an engine, and 2
a to 2d are each cylinder of the engine 1. Further, 3 is a turbo supercharger, which includes a turbine 4 incorporated in the exhaust system,
The turbine 4 is equipped with a compressor 6 connected to the turbine 4 via a pipe 5 and incorporated into the intake system. It is designed to supercharge the intake air. The exhaust gas inlet portion of the turbine housing 7 that accommodates the F turbine 4 is connected to the first downstream end of the exhaust manifold 8 .

In the exhaust manifold 8, an exhaust system is installed at a portion where the passages communicating with the exhaust bows 1-9 of each cylinder 2a to 2d converge.
1! A partition wall 10 is provided to divide the partitions into 10 parts. Also, within the turbine housing 7, a partition wall 11 corresponding to the above-mentioned partition v10 is provided.
．． 11, the exhaust system of each cylinder 2a to 2d is divided into two groups, and two systems of exhaust passages 12, 13 for independently guiding exhaust gas to the turbine 4 are configured. ．． Exhaust passage 1 communicating with second cylinders 2a and 2b
2 and 3. Exhaust passage 1 communicating with fourth cylinders 2C and 2d
It is divided into 3.

A bypass passage 15 that bypasses the turbine 4 is provided between the exhaust passage 12 of one of the two systems and the exhaust passage 14 on the downstream side of the turbine 4, and this bypass passage 15 is integrated into the turbine housing 7, for example. is formed. A bypass valve 16 is provided in the bypass passage 15, and the bypass valve 16 supplies the supercharging pressure in the intake passage 18 downstream of the compressor 6 to the pressure chamber 17 through a passage 19.
It is opened at a set supercharging pressure by an actuator 17 that leads to a.

Further, a communication hole 21 is formed in the partition wall 10 between the two exhaust passages 12 and 13, and a communication valve 22 is provided in the communication hole 21.
is established (). The communication valve 22 is opened by the actuator 23 when the bypass valve 16 is opened,
This actuator 23 also serves as a valve adjusting means that can change the valve opening speed in two stages. That is, the actuator 23 is connected to the first
A diaphragm 23a, a first pressure chamber 23b formed on one side of the diaphragm 23a, a second diaphragm 23d having an O-rad 23C attached thereto, the tip of which is movable by a partial stroke near the first diaphragm 23a, and the second diaphragm 23d. The second formed on one side
The boost pressure is introduced into the second pressure chamber 23e through the passage 24, and the first pressure chamber 23b is provided with a pressure chamber 23e.
Atmospheric pressure or supercharging pressure is selectively introduced through the passage 25 and the three-way solenoid valve 26. When the supercharging pressure introduced into the second pressure chamber 23e reaches the set supercharging pressure, the communication valve 22 is opened by a predetermined opening degree, and when the supercharging pressure is further introduced into the first pressure chamber 23b. The communication valve 22 is fully opened.

Reference numeral 27 denotes a control unit (ECLJ) as a control means for controlling the valve opening adjustment means, which inputs an engine rotation speed detection signal 28 and controls the three-way solenoid valve 2.
A control signal is output to 6.

After the bypass valve 16 is opened, the control unit 27 releases the first pressure "l 23b" of the actuator 23 to the atmosphere at a relatively low rotation speed and low load side, that is, supercharges only the second pressure chamber 23e. Pressure is introduced and the communication valve 22 is opened only to a predetermined degree, and at high rotation and high load side, supercharging pressure is introduced into the first pressure chamber 23b and the communication valve 22 is fully opened. Three-way solenoid valve 26 switching system rJI
For example, the three-way solenoid valve 26 can be turned off at a predetermined rotational speed Ny.

The operation of this turbocharger will be explained with reference to FIGS. 2 and 3.

Figure 2 shows the relationship between engine speed and boost pressure. In this figure, the solid line △ indicates the boost pressure fluctuation characteristic when using the device of the present invention, and the broken line B indicates the case where the exhaust system is not divided into two systems (
The graphs show the boost pressure fluctuation characteristics in the low speed range of the ``standard exhaust system'' (hereinafter referred to as the ``standard exhaust system''). In this way, when the exhaust system is constituted by two independent exhaust passages 12, 13, the supercharger drive efficiency is increased by the υ1 air pulse vJ, so the supercharging pressure in the low rotation range is increased. Therefore, in this case, the point X where the boost pressure reaches the set boost pressure po+ is on the lower rotation side than the point Y where the boost pressure reaches the set boost pressure PO when using the start exhaust system.

Then, as soon as the supercharging pressure reaches the set supercharging pressure po, the bypass valve 16 is opened, and a part of the exhaust gas is released into the bypass passage 15 at the rotation speed higher than the current rotation speed Nx. , the boost pressure is prevented from increasing beyond the set boost pressure Po.

Furthermore, in the operating range where the bypass valve 16 is open, the communication valve 22 between both exhaust passages 12, 13 is also opened. however,
By controlling the actuator 23 described above via the three-way solenoid valve 26 by the control 1 unit 27, the communication valve 22 is turned off until the predetermined rotation speed Ny approximately corresponds to the above point Y, as shown in FIG. It is opened by a predetermined opening degree, and the above predetermined [! The communication valve 22 is fully opened when the number of rotations is 11 or higher. In this case, in order to prevent a pressure difference from occurring between the two exhaust passages 12 and 13, it is necessary to ensure that the communication valve 22 can secure a flow rate of exhaust gas that is the maximum of 1/2 of the exhaust gas released to the bypass passage 15. However, in the operating range up to the predetermined rotational speed NV, there are few exhaust gas escape barriers, so the opening degree of the communicating valve 22 in this operating range is set small correspondingly, and the gold lit of the communicating valve 22 is set small. The opening is sufficiently wide (set) to satisfy the above requirements even when the gas release standard is at its maximum.

In this way, when the bypass valve 16 is closed and the exhaust gas is released to the bypass passage 15, a pressure difference is prevented from occurring due to the exhaust gas flowing between the two exhaust passages 12 and 13 through the communication valve 22. Moreover, the supercharging pressure can be appropriately controlled without causing hunting. In other words, if the communication valve 22 is fully opened at the same time as the bypass valve 16 is opened at the above point The supercharging pressure line I3 suddenly drops to 1:, and the supercharging pressure low F (u) repeats the operation in which the bypass valve 16 and the communication valve 22 are closed and the supercharging pressure reaches its upper limit, causing hunting. On the other hand, if the opening degree of the communication valve 22 is reduced in the range from point
The hunting mentioned above will be prevented. Further, at the L distribution predetermined rotational speed Ny or higher, even if the effect of the °C exhaust pulsation is lost due to the communication valve 22 being fully opened, the set supercharging pressure can be maintained, so hunting does not occur.

In the above embodiment, the opening degree of the communication valve 22 is switched in two stages, but by using a proportional solenoid or the like as the actuator of the communication valve 22, the opening degree of the communication valve 22 can be changed at high speeds and high loads. It may be changed steplessly to increase the size. Further, the opening degree of the communication valve 22 may be controlled depending on the engine speed and the load.

(Effects of the Invention) As described in F below, the present invention provides a turbocharger in which a bypass passage equipped with a bypass valve is provided between one of the two exhaust passages and the downstream side of the turbine. In addition to providing a communication valve that opens when the valve is opened, the opening of this communication valve is made small in the operating range immediately after the opening operation, and is made large in the high rotation and high load side, so that the above-mentioned bypass valve opens. Even when the cylinder is closed, it is possible to prevent pressure differences from occurring in both exhaust passages and make the torque of each cylinder uniform, and it is also possible to properly control the boost pressure without causing hunting. be.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between engine speed and boost pressure, and Fig. 3 is a diagram showing the relationship between engine speed and the opening of the communication valve. FIG. DESCRIPTION OF SYMBOLS 1... Engine, 2a-2d... Cylinder, 3... Turbo supercharger, 4... Turbine, 12.13... Exhaust passage of 2 systems, 15... Bypass passage, 16... ...Bypass valve, 22...Communication valve, 23...Actuator, 27...Control: L unit. Patent Applicant Mazda Co., Ltd. Representative Patent Attorney Etsushi Kotani Patent Attorney Chief 1) Masamukai Patent Attorney Yasuo Neya @@ Yasaken

Claims (1)

[Claims] 1. Divide the exhaust system of multiple cylinders into two groups and configure two exhaust passages each independently guiding exhaust gas to the turbine of the turbocharger, and install a bypass between one of the exhaust passages and the downstream of the turbine. In an exhaust turbo supercharging device, which is provided with a passage and a bypass valve which is opened at a set boost pressure in the bypass passage, the exhaust passage is provided between the two exhaust passages and which is opened when the bypass valve is opened. A communication valve is provided, and a valve opening adjustment means is provided to vary the opening degree of the communication valve, and the opening degree of the communication valve is adjusted in the low rotation and low load side of the operating range where the bypass valve is open. and a control means for controlling the valve opening degree adjusting means so as to make the opening degree of the communication valve small and to increase the opening degree of the communication valve on the high rotation and high load side.