JPH05288065A - Exhaust control device of engine with supercharger - Google Patents

Abstract

PURPOSE:To miniaturize an exhaust control valve and the actuator thereof by reducing the operating angle of an exhaust control valve provided on the turbine side of a secondary turbo supercharger, in an engine with the supercharger of a sequential turbo type. CONSTITUTION:The valve body 55a of an exhaust control valve 55 is bent loosely and connect to the bottom part of the turbine housing 50d of a secondary turbo supercharger 50, and the operating angle of fully closing and opening of a valve body 55f are set to an acute angle in the inside of the valve body 55a. A miniature type actuator 56 in which a stroke is reduced is connected to the exhaust control valve 55 so as to carry out opening/closing operation by negative pressure and positive pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust control device for a supercharged engine that operates a plurality of turbochargers in a sequential turbo manner as a vehicle engine, and more specifically, to a secondary turbocharger. Exhaust control valve.

[0002]

2. Description of the Related Art In recent years, as a supercharged engine for a vehicle, a multi-cylinder exhaust system is equipped with primary and secondary turbochargers in parallel, and the turbocharger is operated in a sequential turbo system. Things have been proposed. In this sequential turbo type, the primary turbo supercharger is configured to be able to constantly supercharge, and an exhaust control valve, an intake control valve, a supercharging pressure relief valve, etc. are provided on the secondary turbocharger side. And, for example, operating only the primary turbocharger in single turbo mode in the low speed range,
In the high speed twin turbo mode, the secondary turbo supercharger is first preliminarily rotated, and then both turbo superchargers are operated to obtain an optimum engine output characteristic according to the running state. Here, the actuator of each control valve described above operates by using negative pressure, positive pressure and atmospheric pressure of the intake system in consideration of safety and durability against high heat of the supercharger.

By the way, the exhaust control valve of the secondary turbocharger has a butterfly valve structure having a large diameter and is switched between fully closed and fully opened. For this reason, the stroke and shape of the actuator are affected by the layout of the valve body of the exhaust control valve, such as the fully closed position, the fully opened position, and the working angle. In this type of engine, a large number of parts are arranged around the engine body and there is not enough space, so it is particularly desirable to reduce the stroke of the actuator and downsize it.

Conventionally, the above-mentioned sequential turbo type engine with a supercharger is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-20102
There is a prior art of Japanese Patent No. 3 publication. Here, it is shown that an exhaust pipe is connected to the turbine side of the secondary turbocharger at a substantially right angle, and an exhaust cut valve is provided in the exhaust pipe so as to open and close at an operating angle of 90 degrees.

[0005]

By the way, in the above-mentioned prior art, since the exhaust cut valve is constructed with an operating angle of 90 degrees, it is necessary to set this actuator also to a long stroke corresponding thereto. Leading to an increase in size. There is also a problem that the valve chamber of the exhaust cut valve requires a large space corresponding to the operating angle and becomes large in size.

The present invention has been made in view of this point, and in an engine with a supercharger of a sequential turbo type, the operating angle of an exhaust control valve attached to the turbine side of a secondary turbocharger is reduced, The objective is to downsize the exhaust control valve and its actuator.

[0007]

In order to achieve the above object, the present invention provides a primary turbocharger and a secondary turbocharger arranged in parallel in an intake and exhaust system of an engine. In the engine with a supercharger, the secondary turbocharger has an exhaust control valve at least on the turbine side and is configured to operate only in the twin turbo mode. Is connected to the turbine housing side of the secondary turbocharger by gently bending the valve body, and is configured to set the operating angle of full closing and full opening of the valve body to an acute angle inside this valve body. The actuator is connected.

[0008]

According to the above construction, the exhaust control valve is fully closed by the actuator in the single turbo mode during engine operation, and the exhaust control valve is fully opened by the actuator in the twin turbo mode. When the exhaust control valve is opened and closed, the operating angle of the valve element is set to an acute angle, so that the stroke of the actuator can be shortened.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, an overall configuration in the case where a primary and secondary turbocharger is mounted on a horizontally opposed engine as a supercharged engine will be described. Reference numeral 1 denotes an engine body of a horizontally opposed engine, in which left and right banks 3 and 4 of a crankcase 2 are provided with a combustion chamber 5, an intake port 6, an exhaust port 7, an ignition plug 8, a valve mechanism 9 and the like. There is. With this engine structure, primary and secondary turbochargers 40 and 50 are arranged near the left and right banks 3 and 4, respectively. As an exhaust system, the common exhaust pipes 10 from the left and right banks 3 and 4 are connected to the turbines 40a and 50a of both turbochargers 40 and 50, and the exhaust pipes 11 from the turbines 40a and 50a are combined into one exhaust pipe 12. Merge and catalytic converter 13, muffler 14
Be communicated to.

As the intake system, the intake pipes 16 and 17 branched from the air cleaner 15 are connected to the blowers 40b and 50b of the turbochargers 40 and 50, respectively, and the intake pipes 18 and 50 from the blowers 40b and 50b are connected to each other. 19 is connected to the intercooler 20. And the intercooler 20
To a chamber 22 via a throttle body 27 having a throttle valve 21, and from the chamber 22 to each cylinder of the left and right banks 3 and 4 via an intake manifold 23. In addition, as an idle control system, an idle control valve 25 and a check valve 26 that opens with negative pressure are provided in a bypass passage 24 between the intake manifold 23 and the downstream side of the air cleaner 15, so that the intake air amount is controlled during idle or during deceleration. It is designed to be controlled.

As a fuel system, an injector 30 is arranged near the port of the intake manifold 23, and the fuel pump 3
The fuel passage 33 from the fuel tank 32 having the number 1 is connected to the injector 30 with the filter 34 and the fuel pressure regulator 35. The fuel pressure regulator 35 adjusts according to the intake pressure, whereby the fuel pressure supplied to the injector 30 is always kept at a constant height with respect to the intake pressure, and the fuel injection control is performed by the pulse width of the injection signal. It is possible to do. As an ignition system, it is connected to the ignition plug 8 so that an ignition signal from the igniter 36 is input.

Next, the control system of the primary turbocharger 40 will be explained. Exhaust gas is always introduced into the turbine 40a to operate, and compressed air is supplied from the blower 40b during load operation in which the throttle valve 21 is opened. It is like this. A waste gate valve 41 having a diaphragm actuator 42 is provided on the turbine side. A control pressure passage 44 having a duty solenoid valve 43 is provided in the pressure chamber of the actuator 42 between the upstream side and the downstream side of the blower 40b, and the duty solenoid valve 43 leaks the boost pressure to generate the control pressure. Acting on the actuator 42 to increase or decrease the opening degree of the waste gate valve 41 to control the boost pressure. Here, for example, when the duty ratio is large, the control pressure decreases due to the increase in the leak amount, the opening degree of the waste gate valve 41 is decreased, and the supercharging pressure is increased. On the contrary, when the duty ratio becomes small, the opening degree is increased by the high control pressure to reduce the supercharging pressure.

On the other hand, since the supercharging is always possible, if the throttle valve 21 is suddenly closed during deceleration, the blower 40
Pressurized air is confined to the downstream side of b, and a high load in this case is applied to the turbocharger 40, and abnormal noise such as a sigh is generated. For this reason, the leak passage 46 having the relief valve 45 is provided between the upper and downstream sides of the blower 40b. The relief valve 45 is configured to be closed by a spring and opened with a negative pressure. When the deceleration is performed, the relief valve 45 is opened with the negative pressure of the manifold to leak the pressurized air contained therein, thereby preventing the abnormal noise from being generated.

Explaining the control system of the secondary turbocharger 50, the waste gate valve 51 similar to that on the primary side controls the boost pressure individually by the control pressure passage 54 having the actuator 52 and the duty solenoid valve 53. It is provided in. An exhaust control valve 55 having a diaphragm type actuator 56 is provided in the exhaust pipe 10 upstream of the turbine 50a, and an intake control valve 58 having a similar actuator 57 is provided downstream of the blower 50b, and an exhaust control valve 58 of the blower 50b is provided. A relief passage 59 having a supercharging pressure relief valve 60 is connected between the upper side and the lower side.

Explaining the operation control system of each of these valves, the passage 61 from the intake manifold 23 has a check valve 62 and is communicated with a surge tank 63 to store a negative pressure when the throttle valve is fully closed and a pulsating pressure. Is designed to buffer. In one spring chamber of the supercharging pressure relief valve 60, a negative pressure passage 64 from the surge tank 63 and a positive pressure passage 65 due to supercharging pressure downstream of the intake control valve 58 are provided with a switching solenoid valve 70 and a passage 66. They are communicated with each other via an electric signal, and a negative pressure acts to open them, and a positive pressure acts to close them.

The actuator 57 of the intake control valve 58 is
Positive pressure is always applied to one chamber by the positive pressure passage 67, and the positive pressure passage 65 and the negative pressure passage 64 are connected to the spring chamber via the switching solenoid valve 71 and the passage 68. Then, a negative pressure is applied to the spring chamber by an electric signal to close the intake control valve 58, and the spring control force is applied to open the intake control valve 58. The actuator 56 of the exhaust control valve 55 has a second chamber for switching between atmospheric pressure and negative pressure in one chamber.
The switching solenoid valve 74 is communicated via the passage 69, and the first switching solenoid valve 73 for switching the positive pressure and the negative pressure is communicated to the other chamber via the passage 75. Then, the electric signal applies atmospheric pressure to one chamber and applies negative pressure to the other chamber to close the exhaust control valve 55, and applies negative pressure to one chamber and positive pressure to the other chamber to operate the exhaust control valve. Open 55.

Explaining various sensors, a differential pressure sensor 80 is provided so as to detect a differential pressure upstream and downstream of the intake control valve 58, and an absolute pressure sensor 81 is connected to the intake pipe pressure by a switching solenoid valve 76. It is provided to select and detect atmospheric pressure. Further, the engine body 1 is provided with a crank angle sensor 82, a knock sensor 83, and a water temperature sensor 84, and a cam angle sensor 85 is provided so as to face a cam rotor (not shown) that is connected to the cam shaft of the valve mechanism 9, and the exhaust pipe 10 is provided with an O2 sensor 86, and the throttle valve 21
Is provided with a throttle opening sensor 87, and an intake air amount sensor 88 is provided immediately downstream of the air cleaner 15.

The overall structure of the electronic control system will be described with reference to FIG. First, the control unit 100 operates the I / O
101, CPU 102, RAM 103, backup R
It has an AM 104, a ROM 105, and a constant voltage circuit 106, and processes a signal. Also, the ignition switch 9
0, the relay 91 is turned on to supply electric power from the battery 92 to the constant voltage circuit 106, and the drive circuit 107 causes the relay 9 to operate.
3 is turned on to drive the fuel pump 31 by energization. I
/ O101 inputs signals from various sensors 80-88,
From the drive circuit 107 to various switching solenoid valves 70, 7
1, 73, 74 and 76, switching signals, duty solenoid valves 43 and 53, duty signals, injector 3
The injection signal is output to 0, the control signal is output to the idle control valve 25, and the ignition signal is output to the igniter 36.

As shown in FIG. 4 (a), the CPU 102 has a low relationship between the secondary turbocharger operation start set values Nb and Nc at high and low loads and the basic fuel injection amount set value Tps. The single turbo mode is determined under the conditions of low load medium speed and high load low speed. Then, an open signal is output to the switching solenoid valve 70 to open the boost pressure relief valve 60 to leak the boost pressure downstream of the blower on the secondary side.
At the same time, a closing signal is output to the first and second switching solenoid valves 73 and 74 to close the exhaust control valve 55, shut off the introduction of exhaust gas to the secondary turbocharger 50, and switch the solenoid valve 71. Output a close signal to the intake control valve 58
Is closed and the secondary turbocharger 50 is deactivated to bring the primary turbocharger 40 into the independent operating state.

In the case other than the above conditions, the twin turbo mode is determined, and the preliminary rotation mode is determined at the beginning of this mode. In the pre-rotation mode, first, a closing signal is output to the switching solenoid valve 70 to output the boost pressure relief valve 60.
Closed, and then the first and second switching solenoid valves 73,
An open signal is output to 74 to open the exhaust control valve 55, and an open signal is output to the switching solenoid valve 71 to output the intake control valve 5
The opening and closing control is performed sequentially with a delay so as to open 8.
As a result, the exhaust gas is introduced into the secondary turbocharger 50 to be preliminarily rotated, and thereafter, the twin turbo mode is substantially performed.

Further, the engine speed N in each mode
Based on the basic fuel injection amount Tp and the target fuel injection amount Tp, the target supercharging pressure Pt is set to a proper height in the single turbo region and a proper height higher than that in the twin turbo region as shown in FIG. Then, a deviation Δp between the target supercharging pressure Pt and the actual supercharging pressure Pb of the absolute pressure sensor 81 is calculated, and a correction amount according to the deviation Δp is determined. So in single turbo mode,
A duty signal corresponding to this correction amount is output to the duty solenoid valve 43 on the primary side, and the supercharging pressure of the primary turbocharger 40 is changed by the opening degree of the waste gate valve 41. In the twin turbo mode, the duty signal based on the operation distribution of both turbochargers 40, 50 is used as a primary and secondary duty solenoid valve 4.
3 and 53, and the supercharging pressures of both superchargers 40 and 50 are varied according to the opening of the waste gate valves 41 and 51. Thus, the actual supercharging pressure Pb is always the target supercharging pressure Pb.
Feedback control is performed so as to follow t.

The exhaust control valve 55 will be described in detail with reference to FIG. First, the secondary turbocharger 50
A turbine housing 50d and a blower housing 50e are connected to both sides of the center housing 50c,
Immediately after the right bank of the engine body 1, the blower housing 5
It is mounted substantially horizontally in the longitudinal direction of the vehicle body with 0e facing forward. The valve body 55a of the exhaust control valve 55 is connected to the lower portion of the turbine housing 50d, and the actuator 5
In a state in which 6 is in close proximity to the secondary turbocharger 50, it is installed upright from the valve body 55a at the lower rear portion to the front blower housing side.

The exhaust control valve 55 is an upstream open type,
A valve port 55b is formed on the turbine housing side of the valve body 55a, a wide valve chamber 55d is formed upstream of this valve port 55b via a horizontal valve seat 55c, and the exhaust pipe 10 is connected to the valve chamber 55d. .. The valve chamber 55d is
In particular, the rear wall portion 55h is formed by inclining forward at a predetermined acute angle θ and gently bending forward with respect to the valve port 55b. Then, inside the valve chamber 55d, the valve seat 5
A valve shaft 55e is horizontally provided in the rear part near 5c, and a valve body 55f having a larger diameter than the valve port 55b contacts the valve seat 55c on an arm 55g integrated with the valve shaft 55e.
It is attached so as to close 5b. Further, since the exhaust passage is also formed by being bent forward due to the shape of the valve chamber 55d, the valve body 55f is in the fully open position in a state of being inclined along the rear wall portion 55h, and thus the operating angle between fully closed and fully opened is 90. It is set to an acute angle smaller than degrees.

The actuator 56 is of a diaphragm type, and the exhaust control valve 55 is set to an acute working angle as described above, and accordingly, the stroke is shortened correspondingly and the size is reduced. A rod 56b integral with the diaphragm inside the case 56a is extended downward, and this rod 56b is rotatably connected to the valve shaft 55e via a lever 56c.

Next, the operation of this embodiment will be described. First, when the engine is operating, for example, in the single turbo mode of low load and medium speed, the first and second switching solenoid valves 73, 74 are switched by an electric signal from the control unit 100.
At this time, the atmospheric pressure is supplied to one chamber of the actuator 56 and the negative pressure is supplied to the other chamber, and the rod 56b is retracted. Therefore, the arm 55g of the exhaust control valve 55 is horizontally operated by the lever 56c, the valve body 55f contacts the valve seat 55c to fully close the valve port 55b, and this closed state is maintained. The introduction of E into the secondary turbocharger 50 is blocked.

Next, when the twin turbo mode is set at the high speed, the first and second switching solenoid valves 73, 74 are operated by the electric signal from the control unit 100 in the preliminary rotation mode.
Then, a negative pressure is supplied to one chamber of the actuator 56 and a positive pressure is supplied to the other chamber, and the rod 56b is extended.
Therefore, the arm 55g of the exhaust control valve 55 swings downward, the valve body 55f moves away from the valve seat 55c in the upstream direction, and the valve port 55b opens. Then, the valve body 55f is brought into contact with the inclined rear wall portion 55h, fully opened, and held in this open state. Therefore, the exhaust gas E flows from the valve chamber 55d to the valve port 55b.
The secondary turbo supercharger 50 is introduced into the turbine housing 50d of the secondary turbo supercharger 50 through the above, so that the secondary turbo supercharger 50 first preliminarily rotates and then substantially operates.
At this time, the exhaust gas of the exhaust pipe 10 is smoothly introduced into the turbine housing 50d with a small resistance by the valve body 55a of the exhaust control valve 55 that is gently bent.

The embodiment of the present invention has been described above. However, even in the case where the exhaust control valve is of the downstream opening type, the operating angle may be similarly acute.

[0028]

As described above, according to the present invention, in the engine with a sequential turbocharger, the exhaust control valve provided on the turbine side of the secondary turbocharger is configured to have an acute working angle. Therefore, the stroke of the actuator can be shortened and the size can be reduced. Since the exhaust control valve has a structure in which the valve chamber is gently bent in the valve body, the structure is simple and the shape of the valve chamber is small. Further, the flow path resistance of the exhaust gas is reduced, the flow of the exhaust gas is improved, and the output can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a partial cross-section of an embodiment of an exhaust control device for an engine with a supercharger according to the present invention.

FIG. 2 is a configuration diagram showing an entire engine with a supercharger.

FIG. 3 is an overall circuit diagram of a control system.

FIG. 4 is a diagram showing a map of each turbo mode and a target supercharging pressure.

[Explanation of symbols]

 1 Engine Body 10, 11, 12 Exhaust Pipe 16, 17, 18, 19 Intake Pipe 40 Primary Turbocharger 50 Secondary Turbocharger 50d Turbine Housing 55 Exhaust Control Valve 55a Valve Body 55f Valve Body 56 Actuator

Claims (2)

[Claims] 1. A primary turbo supercharger and a secondary turbo supercharger are arranged in parallel in an intake and exhaust system of an engine, and the primary turbo supercharger is configured to always operate. Has an exhaust control valve at least on the turbine side and is configured to operate only in twin turbo mode.In the exhaust control valve, the exhaust control valve has a gentle valve body on the turbine housing side of the secondary turbocharger. A supercharged engine, characterized in that the exhaust control valve is connected to the exhaust gas control valve by bending, and is configured to determine an operating angle for fully closing and fully opening the valve body inside the valve body, and an actuator is connected to the exhaust control valve. Exhaust control device. 2. The exhaust control valve is formed by bending a valve chamber inside a valve body upstream of a valve port on the turbine housing side via a valve seat, and the valve body is in contact with the valve seat inside the valve chamber. The exhaust control device for the engine with a supercharger according to claim 1, wherein the exhaust control device is configured to be closed and abutted against an inclined wall portion to be fully opened.