JPS62103420A - Turbosupercharger - Google Patents

Abstract

PURPOSE:To prevent the hunting of valve motion from occurring, by making exhaust gases in two systems so as to separate from each other and act on an exhaust turbine of a turbocharger, while installing a flow dividing valve of this separated passage and a turbine bypass valve, securing the setting supercharging pressure, and opening each valve at a time when it comes to the supercharging pressure higher than the specified value. CONSTITUTION:In a turbine 4 to be rotated by exhaust out of a turbocharger, an exhaust passage 12 for cylinders 2a and 2b and an exhaust passage 13 for cylinders 2c and 2d are separated from each other and led to an inlet of the turbine 4. An on-off valve 19 is installed in an interconnecting hole 18 in a partition wall 10 between these passages 12 and 13, and furthermore another on-off valve 16 is also installed in a passage 15 bypassing the turbine 4, while each valve is opened or closed by output of an engine control unit (ECU) corresponding to engine speed 26 and supercharging pressure 27, thus control over the supercharging pressure takes place. At the time of variations in an engine driving state in a direction making the supercharging pressure go up, opening operation of each valve is carried out when it becomes higher than the setting supercharging pressure, thus valve opening or closing is prevented from hunting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides an improved exhaust turbo supercharging system in which exhaust gas is guided to a turbine from two independent systems of IJ+ air passages. It is b.

(Prior Art) Conventionally, as shown in, for example, Japanese Utility Model Application Publication No. 56-171630, the area between each cylinder of an engine and the turbine of a turbocharger, from the υ1 air manifold to the scroll chamber around the turbine, has been developed. The exhaust system is divided into two exhaust passages that independently guide exhaust gas from half of each cylinder to the turbine. Turbocharging at low speeds is achieved by effectively utilizing exhaust pulsation. There are known devices designed to increase the drive efficiency of the machine and improve torque. In addition, when configuring two independent exhaust passages in this way, the device in the above publication allows 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 intake pulsation is increased and effectively acts on the turbine, thereby increasing drive efficiency.

By the way, in the conventional device described above, in order to control the maximum boost pressure with a simple structure, an opening operation is performed between the exhaust passage of one of the two systems and the downstream side of the turbine when the boost pressure reaches a set value. However, in this case, when the bypass valve is opened, exhaust gas is released from only one exhaust passage to the bypass passage, so that the back side of both exhaust passages is There is a problem in that a pressure difference occurs, which causes variations in torque, etc., depending on the cylinder.

Therefore, in order to solve this problem, a communication hole that is opened and closed by a communication valve is provided between the exhaust passages, and when the bypass valve is closed, the communication valve is opened and the exhaust gas is transferred between the two exhaust passages. It is conceivable to make it available for distribution.

However, in this case, the bypass and communication valves are opened simply as soon as the boost pressure reaches the set value (', J).
If the communication valve is closed, the effect of exhaust pulsation is lost and the boost pressure drops rapidly, so in the operating range immediately after the boost pressure reaches the set value, the bypass valve J and the communication valve are The decrease in boost pressure due to the opening operation and the increase in boost pressure due to the closing of the bypass valve and communication valve are repeated, causing hunting in which the boost pressure fluctuates significantly, and the operating state changes. The problem of instability arises.

(Objective of the Invention) In view of these circumstances, the present invention improves the supercharger drive efficiency in the low speed range by providing two independent exhaust passages, and also improves the turbocharger drive efficiency in the low speed range by reducing the bypass passage connected to one (1) exhaust passage. To prevent a pressure difference from occurring between both exhaust passages while controlling the boost pressure with a valve, and also to prevent hunting from occurring in the operating range immediately after the boost pressure reaches the set value. The present invention provides an exhaust turbo supercharging device that can perform the following functions.

(Structure of the Invention) The present invention divides a JJI gas system of multiple cylinders into two systems and configures two exhaust passages each independently guiding exhaust gas to a turbine of a turbo supercharger. ,
a bypass passage that opens into one of the exhaust passages of the two exhaust passages and bypasses the turbine; a bypass valve that opens and closes the bypass passage to control the maximum boost pressure to a set value; and a communication valve that opens and closes the communication hole, and when the engine operating condition changes in the direction of increasing the boost pressure, the above-mentioned until the specified operating condition where the boost pressure is higher than the set value is reached. A control means is provided for stopping the opening operation of the bypass valve and the communication valve and opening the bypass valve and the communication valve in the predetermined operating state.

In other words, even after the boost pressure rises from the low boost range and reaches the set value, which is the original maximum boost pressure control value, the bypass will temporarily occur until the boost pressure becomes higher than the set value. The valve and communication valve are closed, and from this state the bypass valve and communication valve are opened to ensure that the boost pressure only drops to the set value at this time, and after that, the bypass valve maintains the boost pressure at the set value. It was designed so that

(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
8 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,
A compressor 6 is connected to the turbine 4 via a shaft 5 and incorporated into the intake system, and the turbine 4 is driven by the exhaust gas flow, and the compressor 6 rotates accordingly, causing the engine 1 to receive intake air. It is designed to supercharge. An exhaust gas inlet portion of the turbine housing 7 that accommodates the turbine 4 is connected to a downstream end of the exhaust manifold 8.

The exhaust manifold 8 is provided with a partition wall 10 that divides the exhaust system into two systems at a portion where the passages communicating with the exhaust boats 9 of the cylinders 2a to 2d converge. Further, the turbine housing 7 is also provided with a partition wall 11 corresponding to the partition wall 10 in the exhaust inlet portion and in the scroll chamber surrounding the turbine 4 following this. In this way, the exhaust systems of the cylinders 2a to 2d are divided into two groups by the partition walls 10 and 11, each of which independently guides the exhaust gas to the turbine 4.
The exhaust passages 12.13 of the system are constructed, and in the illustrated embodiment the first. an exhaust passage 12 communicating with the second cylinders 2a, 2b; 4th cylinder 2C.

The exhaust passage 13 is divided into an exhaust passage 13 and an exhaust passage 13 communicating with the exhaust passage 2d.

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. The bypass passage 15 is provided with a bypass valve 16.

This bypass valve 16 is opened and closed by an actuator 17 that operates according to the boost pressure to control the maximum boost pressure in normal times to a set value. When the supercharging pressure introduced into the spring 17b exceeds a set value predetermined by the spring 17b, the valve is opened to allow a portion of the exhaust gas to escape.

Further, a communication hole 18 is provided in the partition wall 10 between the two exhaust passages 12.13 to communicate the two exhaust passages 12.13, and a communication valve 19 is provided in the communication hole 18. This communication valve 19 is also opened and closed by an actuator 20 that operates according to the boost pressure, and is operated by the actuator 20 except when the operation is stopped.
The supercharging pressure introduced into the pressure chamber 20a of the spring 2
When the value is equal to or greater than the value determined by 0b, the communication valve 19 is opened. However, the valve fluid setting value between the communication valve 19 and the bypass valve 19 by this actuator 20 is
This is set lower than the set value for maximum boost pressure control by actuator 17 of No. 6.

Each of the actuators 17.20 has a pressure chamber 17a, 20a connected to a passage 21.22 and a three-way solenoid valve 23.
When the three-way solenoid valve 23 is turned on, supercharging pressure is introduced into each of the pressure chambers 17a and 20a, and the actuator 17. 20 is ready for operation and the three-way solenoid valve 23 is turned off, each pressure chamber 17 is
a, 20a is opened to the atmosphere and actuator 17.2
The opening operation of the bypass valve 16 and the communication valve 19 due to the opening of the bypass valve 16 and the communication valve 19 is stopped.

Further, 25 is a control unit (ECU) as a control means for the bypass valve 16 and the communication valve 19, and includes an engine rotation speed detection signal 26 and a supercharging pressure detection signal 2.
7 is input, and a control signal is output to the three-way solenoid valve 26. This control unit 27 controls the control unit 27 during acceleration when the engine operating condition changes in the direction of increasing boost pressure.
The three-way solenoid valve 23 is kept in the OFF state until a predetermined operating state (described later) in which the supercharging pressure is higher than the set value is reached, and the three-way solenoid valve 23 is switched to the ON state in the predetermined operating state. Also, during deceleration, the three-way solenoid valve 23 is turned on when the engine speed becomes a certain degree lower than the predetermined operating state.
I am trying to switch it from OFF to OFF. Incidentally, the detection of acceleration and deceleration may be performed, for example, by checking fluctuations in the engine speed, and the detection of the predetermined operating state may be performed using the engine speed detection signal 26 or the supercharging pressure detection signal 27.

The operation of this turbocharger will be explained with reference to FIG.

Fig. 2 shows the relationship between engine speed and supercharging pressure, and the supercharging pressure fluctuation characteristic when the bypass valve 16 and communication valve 19 are closed in the device of the present invention is shown by line A1 in this figure. In addition, if the communication valve 19 is always open, the exhaust system is approximately the same as the case where the exhaust passages are not divided into two systems (hereinafter referred to as [standard exhaust system]). The supercharging pressure fluctuation characteristics in the low speed range are unmatched! Be like ilB. In this way, when the communication valve 19 between the two exhaust passages 12.13 is closed, the supercharger drive efficiency is increased by the Ut air pulsations that are effectively transmitted from both exhaust passages 12.13 to the turbine 4. Therefore, the boost pressure in the low speed range is higher than when using the standard exhaust system.

Also, the rotation speed is higher than the predetermined operating state, and the bypass valve 16 and the communication valve 19 are connected to the actuator 1, respectively.
7.20, when the system is operated according to the supercharging pressure, when the supercharging pressure is about to exceed the set value 81, the bypass valve 16 is opened and the exhaust gas is released to the bypass passage 15. As a result, the boost pressure reaches the above set value P1.
On the other hand, the communication valve 19 is opened and both exhaust passages 12.13 are communicated with each other, so that both exhaust passages 12.
．． 13 is prevented from occurring.

By the way, 1. If you only want to control the maximum boost pressure and prevent the pressure difference between both exhaust passages 12 and 13,
It would be better if the bypass valve 16 and the communication valve 19 were opened when the boost pressure rose to the set value P1 (point In the immediately subsequent operating range, the bypass valve 16 and the communication valve 19 are repeatedly opened and closed, causing hunting in which the supercharging pressure fluctuates significantly as indicated by the broken line arrow. In other words, when the bypass valve 16 and the communication valve 19 are opened at the above point When the pressure decreases, the bypass valve 16 and the communication valve 1
9 closes and the supercharging pressure rises again to the set value P1, which is repeated.

Therefore, the control unit 25 controls the three-way electromagnetic system to maintain the three-way electromagnetic state during acceleration even after reaching the point The valve 23 is turned OFF to stop the actuating function of the actuator 17, 20, thereby preventing hunting. In other words, when the supercharging pressure reaches the set value P1, the mustard bypass valve 16 and the communication valve 19 are kept closed, and the supercharging pressure is applied to - as shown by line A'1 until point Y'. The boost pressure increase in this case is temporary and will not have any negative effect on the engine. Then, at the above point Y', the three-way solenoid valve 23 is turned to O based on the detection of the boost pressure or rotational speed NY at this time.
By switching to the N state, the bypass valve 16 and the communication valve 19 are opened, and even if the effect of exhaust pulsation is lost at this time, the supercharging pressure only decreases to the set value P1 as shown by line A2. After that, the supercharging pressure is maintained at the set value P1 as indicated by line A3, so hunting is prevented.

Further, according to this embodiment, when decelerating, the rotation speed first decreases from a high speed range and passes point Y, the bypass valve 16 is closed, but the valve opening pressure setting value P2 of the communication valve 19 is set low. While in the open state, the boost pressure decreases to mA4 in accordance with the characteristics of the standard exhaust system. For example, by switching the three-way solenoid valve 23 from the ON state to the OFF state at the rotation speed NX corresponding to the point After the boost pressure once rises from point X' to point X, the boost pressure continues to decrease along line A1. Hunting is thus prevented even during deceleration.

Note that the switching point at which the three-way solenoid valve 23 is turned ON during acceleration and the switching point at which the three-way solenoid valve 23 is turned OFF during deceleration are on the higher rotation side (higher boost pressure side) than point Y' in FIG. There is no problem even if it deviates slightly from point X' to the low rotation side. Further, the actuating means and control means for the bypass valves 16 and 19 are not limited to those in the above embodiments, and may be controlled using electric actuators such as lenoids.

(Effects of the Invention) As described above, the present invention configures two systems of υ1 air passages in order to enhance the effect of exhaust pulsation in the low speed range, and applies maximum boost pressure to the bypass passage opened to one of the exhaust passages. Since a bypass valve to be set is provided and a communication hole opened and closed by a communication valve is provided between both exhaust passages, the maximum supercharging pressure can be controlled without creating a pressure difference between both exhaust passages. Moreover, when the boost pressure increases, the bypass valve and the communication valve are opened only after the boost pressure reaches a predetermined operating state higher than the set value, so the bypass valve and the communication valve are not opened. Hunting can be prevented from occurring immediately after a state in which the engine is in a state where the engine is in a state where the engine is in a state where the engine is in a state where the engine is running, and the reliability of the operating state and the boost pressure control during such a transient period can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between engine speed and boost pressure. 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, 17... Actuator, 19... Communication valve, 20... Actuator, 25... Control I-roll unit.

Claims (1)

[Claims] 1. In an exhaust turbo supercharging device in which the exhaust system of a plurality of cylinders is divided into two groups and two exhaust passages are configured to independently guide exhaust gas to the turbine of a turbo supercharger, one of the two exhaust passages is a bypass passage that opens into one of the exhaust passages and bypasses the turbine; a bypass valve that opens and closes this bypass passage to control the maximum boost pressure to a set value; and a communication hole that communicates the two exhaust passages. and a communication valve that opens and closes this communication hole, and when the engine operating state changes in the direction of increasing the boost pressure, the bypass valve and the communication valve are opened until a predetermined operating state where the boost pressure is higher than the set value is reached. An exhaust turbo supercharging device characterized by comprising: control means for opening the bypass valve and the communication valve in the predetermined operating state by stopping the exhaust gas turbocharging device.