JPH02130221A - Intake air device for supercharger-fitted engine - Google Patents

Abstract

PURPOSE:To enable the heat of a supercharged air passage to be shielded for preventing it from being transmitted to an air introducing passage by arranging a relief passage for relieving excess air between the air introducing passage and the supercharged air passage. CONSTITUTION:In a low speed region in which only a primary-side turbosupercharger 9 is operated, since excess air is not relieved, air does not flow inside a relief passage 22, and the temperature of the relief passage 22 becomes low. Since the relief passage 22 is arranged between the air introducing passage 3b1 of a secondary-side turbosupercharger 10 and a supercharged air passage 3b2, the heat of the supercharged air passage 3b2 is shielded by the relief passage 22 so as not to be transmitted to the air introducing passage 3b1. Thus, the density of air in the air introducing passage 3b1 is heightened, and supercharging efficiency is enhanced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an improvement in an intake system for a supercharged engine.

(Prior art) Conventionally, as a supercharged engine, for example, Japanese Patent Application Laid-Open No. 59-1
As disclosed in Japanese Patent No. 45327, it is equipped with a low speed exhaust turbo supercharger and a high speed exhaust turbo supercharger, and when the speed is low, the low speed exhaust turbo supercharger is operated, and when the speed is high, the high speed exhaust turbo supercharger is operated. A so-called complete switching type is known, which optimizes supercharging efficiency. In this case, an exhaust pipe is connected to the turbine of each exhaust turbo supercharger, and a small amount of exhaust gas is supplied to the exhaust pipe of the stopped exhaust turbo supercharger to pre-rotate it. The turbocharger is designed to have a smooth start-up when it starts operating. Furthermore, a relief passage is provided to bypass the blower of each exhaust turbo supercharger, and a relief valve is provided in each relief passage, so that the relief valve of the stopped exhaust turbo supercharger can be opened to remove the surplus generated by pre-rotation. By relieving air, the pressure in the supercharging passage downstream of the blower is prevented from increasing, and the blower is made to rotate more easily.

Furthermore, Japanese Patent Application Laid-Open No. 59-160022 discloses that it is equipped with exhaust turbo superchargers for low speed and high speed, and also connects the intake passages on the downstream side of the intake of each of the exhaust turbo superchargers to the engine. discloses a so-called sequential turbo type supercharged engine in which a high-speed exhaust turbo supercharger is operated only at high speeds and high loads.

According to this system, at low speeds and low loads, only the low-speed exhaust turbocharger is operated, and the exhaust gas from the exhaust passage is intensively supplied to the turbine of the low-speed exhaust turbocharger to increase the boost pressure. At the same time, at high speeds and high loads, both the low speed and high speed exhaust turbo superchargers are operated, and the exhaust gas from the exhaust passage is supplied to the turbines of the two exhaust turbo superchargers to increase the intake flow rate. Appropriate boost pressure can be obtained while ensuring the same. Furthermore, when the high-speed exhaust turbo supercharger stops operating at low speed and low load, a small amount of exhaust gas is supplied to the turbine of this high-speed exhaust turbo supercharger to pre-rotate it, and when the high-speed exhaust turbo supercharger stops, the turbine is pre-rotated. The startup of this high-speed exhaust turbo supercharger is improved. In this case as well, a relief passage is provided that bypasses the blower of the high-speed exhaust turbo supercharger, and a relief valve is provided in each relief passage. By opening the opening to relieve excess air generated by the pre-rotation, it is possible to prevent the pressure in the supercharging passage downstream of the blower from increasing and to make it easier for the blower to rotate.

(Problem to be Solved by the Invention) By the way, a plurality of exhaust turbo superchargers are provided in this way, and a specific exhaust turbo supercharger is operated in a specific operating range and pre-rotated outside the specific operating range. In a supercharged engine, due to the layout of the intake passage around the exhaust turbo supercharger, there is an air introduction passage for supplying intake air to the specific exhaust turbo supercharger and pressurized air from the specific exhaust turbo supercharger. The supply supercharging passage is often located close to the supercharging passage.

In that case, the temperature of the intake air in the air introduction passage increases due to the heat from the supercharging passage, which becomes hot due to the pressurized air, leading to a problem in which the filling efficiency of the intake air deteriorates (and the supercharging efficiency decreases). .

The present invention has been made with attention to these points,
The purpose of this is to use the relief passage to shield heat from the supercharging passage so that it is not transmitted to the air introduction passage.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention are as follows:
A supercharged engine that is equipped with a plurality of exhaust turbo superchargers that pressurize intake air using the energy of exhaust gas, and a specific exhaust turbo supercharger is operated in a specific operating range and pre-rotated outside the specific operating range. Assuming that. On the other hand, a relief passage for relieving excess air generated by pre-rotation in the specified exhaust turbo supercharger, an air introduction passage for supplying intake air to the specified exhaust turbo supercharger, and a specific exhaust The structure is such that it is disposed between the supercharging passage and the supercharging passage through which pressurized air from the turbocharger is supplied.

(Function) With the above configuration, in the present invention, the specific exhaust turbo supercharger is pre-rotated outside the specific operating range, so that when the specific operating range is entered, the operation starts smoothly. In addition, excess air generated by pre-rotation in the specified exhaust turbo supercharger is relieved by the relief passage, so that the pressure in the supercharging passage downstream of the blower is prevented from increasing, and the blower rotates more easily.

On the other hand, when the specific operating region is entered, relief of surplus air is stopped, so air does not flow into the relief passage, and the temperature of the relief passage becomes low.

In that case, since the relief passage is arranged between the air introduction passage and the supercharging passage of the specified exhaust turbo supercharger, the heat in the supercharging passage is blocked by the relief passage and is difficult to be transmitted to the air introduction passage. This increases the density of air in the air introduction passage and improves supercharging efficiency.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a supercharged engine equipped with an intake system according to an embodiment of the present invention. In the figure, an exhaust passage 2 for discharging exhaust gas from an engine 1 has two branch exhaust passages 2a and 2b that extend independently from the engine 1. Further, the intake passage 3 through which the intake air of the engine 1 flows has two branch intake passages 3a and 3b that are branched downstream of the air flow meter 4 that detects the amount of intake air. 3b on the upstream side of the intercooler 5. In the intake passage 3 on the downstream side of the intercooler 5, a throttle valve 6. A surge tank 7 and a fuel injection valve 8 are provided.

A turbine Tp rotationally driven by exhaust gas is disposed in one branch exhaust passage 2a of the two branch exhaust passages 2a and 2b, and this turbine Tp is disposed in one branch intake passage 3a. It is connected to a blower Cp via a rotating shaft Lp. And these turbines 191
The primary side turbocharger 9 is configured with the rotating wheel Lp1 and the blower Cp as main elements. Similarly, the other branch exhaust passage 2b has a turbine T driven to rotate by exhaust gas.
s is arranged, and the other branch intake passage 3b
A blower Cs is disposed therein, and the turbine Tp and the blower Cs are connected by a rotating shaft Ls to form a secondary turbo supercharger 10.

And blowers Cp of branch intake passages 3a and 3b.

The passage portion on the upstream side of Cs is an air introduction passage 3a1.3b for supplying intake air to each of the blowers Cp and C8.
1, and the passage portions of the branch intake passages 3a and 3b on the downstream side of the blowers Cp and Cs are connected to each blower C.
They constitute supercharging passages 3az+3bz to which pressurized air from p and cs is supplied, respectively.

The air introduction passages 3a+ and 3b+ are formed so as to face each other in a straight line at branch portions branched from the intake passage 3, and pressure waves generated in one branch intake passage 3b are transmitted to the other branch intake passage. The configuration is such that it is easy to propagate to the airflow meter 3a side and difficult to propagate to the airflow meter 4 side.

An exhaust cut valve 11 is disposed in the secondary side branch exhaust passage 2b on the upstream side of the turbine Ts. This exhaust cut valve 11 operates in this branch exhaust passage 2b in a low rotation range.
This is provided in order to shut off the supply of exhaust gas to the secondary side turbocharger 109 turbine Ts and operate only the primary side turbocharger 9.

The exhaust cut valve 11 of the branch exhaust passage 2b on the secondary side
The upstream portion of the exhaust gas is connected to the upstream side of the turbine Tp of the primary side branch exhaust passage 2a via the communication passage 12. The communication passage 12 is connected to the exhaust passage 2 on the downstream side of both turbines Tp and Ts via a bypass passage 18 in which a waste gate valve 17 is disposed. A portion of the bypass passage 18 on the upstream side of the waste gate valve 17 is connected between the turbine Ts and the exhaust cut valve 11 in the branched exhaust passage 2b via the leakage passage 14 in which the exhaust leakage valve 13 is disposed. has been done.

The exhaust leak valve 13 is operated by a diaphragm actuator 16, and the pressure chamber of the actuator 16 is connected to the
It opens into the supercharging passage 3 B 2 on the downstream side of the blower Cp of the primary turbo supercharger 9 . This leakage valve 13 is configured so that the boost pressure P1 on the downstream side of the blower Cp is set to a predetermined value (for example, 5001 mHg) in the process of increasing the engine speed.
When this happens, the exhaust cut valve 11 is opened.
When the bypass passage 14 is closed, a small amount of exhaust gas flows through the bypass passage 14.
It is supplied to the turbine Ts through. Therefore, the turbine Ts starts rotating in advance (start of pre-rotation) before the exhaust cut valve 11 opens, improving the supercharging response when the exhaust cut valve 11 opens, and alleviating torque shock. ing.

Note that 19.20 is a diaphragm actuator that operates the exhaust gas cut valve 11 and the waste gate valve 17, respectively, and the operations of these actuators will be described later.

On the other hand, an intake cut valve 21 is disposed in the secondary side supercharging passage 3b on the downstream side of the blower Cp. Further, a relief passage 22 that bypasses the blower Cs is provided, and a relief valve 23 is disposed in this relief passage 22. The intake cut valve 21 is operated by a diaphragm actuator 24 as described later.

In addition, the relief valve 23 opens the relief passage 22 until a little before the intake cut valve 21 and the exhaust cut valve 1 open during the process of increasing the engine speed, and relieves excess air generated by pre-rotation. This prevents the pressure in the supercharging passage 3b2 between the blower Cs and the intake cut valve 21 from increasing due to the rotation of the blower C$ based on the opening operation of the exhaust leakage valve 13 when the exhaust cut valve 11 is closed. The blower Cs is designed to prevent this from happening and to make it easy for the blower Cs to rotate. Such a relief valve 23 is operated by a diaphragm actuator 25.

The control pressure conduit 26 of the actuator 24 that operates the intake cut valve 21 is a three-way valve 27 made of an electromagnetic solenoid valve.
connected to the output port of the

Also, an actuator 19 that operates the exhaust cut valve 11
The control pressure conduit 28 is connected to the output port of a three-way valve 29, which is also an electromagnetic solenoid valve. Furthermore, an actuator 250 controlling pressure conduit 30 for actuating the relief valve 23 is connected to an output port of a three-way valve 31 similar to that described above.

A control pressure conduit 32 of the actuator 20 that operates the wastegate valve 17 is connected to an output port of a three-way valve 33 consisting of an electromagnetic solenoid valve.

Three-way valves 27, 29.3 consisting of these electromagnetic solenoid valves
1 and 33 are controlled by a control circuit 35 configured using a microcomputer. This control circuit 35 controls each electromagnetic solenoid based on detected values such as engine speed Ne, intake air ff1Q, throttle opening TVO, and boost pressure Pl on the downstream side of the blower Cp of the primary side turbocharger 9. Control the valve.

Among the four electromagnetic solenoid valves, one manual boat of the three-way valve 29 is open to the atmosphere, and the input port of the other is connected to the negative pressure tank 43 via the conduit 36. Intake negative pressure Pn downstream of the throttle valve 6 is introduced into the negative pressure tank 43 via the check valve 37.

Further, the three-way valve 27 has one input port connected to the conduit 36.
The other input port is connected to the output port of the differential pressure detection valve 39 via a conduit 38.

As shown in FIG. 2, the differential pressure detection valve 39 has a casing 51 defined into three chambers 54, 55, and 56 by two diaphragms 52, 53, and an input port 54a in the chamber 54 and an input port 54a in the chamber 54. An input port 55a is opened in the chamber 55, and an output port 57 connected to the conduit 38 and an air release boat 58 are opened in the chamber 56. The boat 54a is connected to the downstream side of the intake cut valve 21 via the conduit 41,
A supercharging pressure P1 downstream of the primary blower Cp is introduced. Further, the boat 55a is connected to the upstream side of the intake cut valve 21 via the conduit 42, and introduces the pressure P2 on the upstream side of the intake cut valve 21 when the intake cut valve 21 is closed. There is. In this differential pressure detection valve 39, when the pressure difference between pressures P1 and P2 is large, a valve body 59 connected to both diaphragms 52 and 53 opens the boat 47 and introduces atmospheric air into the conduit 38. , when the differential pressure P2-Pi falls within a predetermined value ±ΔP, the boat 57 is closed by the spring 59. Therefore, three-way valve 27 connects conduit 26 to conduit 3.
8, the difference and pressure P2-PL are within the predetermined value ±
When it becomes larger than ΔP, the atmosphere is introduced into the actuator 24 and the intake cut valve 21 is opened. Further, when the three-way valve 27 connects the conduit 26 to the conduit 36, negative pressure is supplied to the actuator 24 and the intake cut valve 21 is closed.

On the other hand, when the three-way valve 29 connects the conduit 28 to the conduit 36, 1% negative pressure is supplied to the actuator 19 and the exhaust cut valve 11 is closed.
only is activated.

Furthermore, when the three-way valve 29 releases the conduit 28 to the atmosphere, the exhaust cut valve 11 is opened and the secondary side turbocharger 10 is operated.

The third figure shows the intake cut valve 21 and the exhaust cut valve 11.
Check the open/close status of exhaust leak valve 13 and waste gate valve 1.
7 and the open/closed states of the relief valve 23. This control map is stored in the control circuit 35.

Here, one input port of the three-way valve 31 is also opened to the atmosphere, and the other input port is connected to the negative pressure tank 43, and when the engine is running at low speed, the intake negative pressure Pn is connected to the conduit 30.
is introduced, and the IJ IJ-F valve 25 is connected to the relief passage 2.
2 is open, but in the process of increasing the engine speed Ne,
As shown in FIG. 3, before the intake cut valve 21 and the exhaust cut valve 11 open, the three-way valve 31
is switched to the atmosphere side by a signal from the control circuit 35, so that the relief valve 25 closes the relief passage 22.

Furthermore, supercharging pressure P1 is introduced into one input port of the three-way valve 33 through the control pressure conduit 15 of the actuator 16, and the engine rotation speed Ne and throttle opening TVO are set to exceed predetermined values and When the supply pressure P1 exceeds a predetermined value, the control circuit 35 opens the two-way valve 33 and introduces the supercharging pressure P1 into the actuator 20, which causes the wastegate valve 17 to open the bypass passage 18. There is. The other input port of the three-way valve 33 is open to the atmosphere, and when the actuator 20 is supplied with the atmosphere, the wastegate valve 17 is closed.

Next, the layout around the turbocharger will be explained based on FIGS. 4 to 6. An exhaust boat (not shown) for each cylinder is opened on one side of the engine 1, and an exhaust manifold is attached to the exhaust boat. The primary and secondary turbo superchargers 9 and 10 are disposed on the side of the exhaust manifold so that their rotational axes are coaxial, and the inlets of each turbine Tp and Ts are connected to the exhaust manifold. is flange connected to the Further, the air introduction passage 3b+ extending from the suction port of the blower Cs of the secondary side turbocharger 10 is reversed at the rear side of the blower Cs (left side in Figure 4) and faces forward (right side in Figure 4). , primary side turbocharger 10
Air introduction passage 3al extending from the suction port of one blower Cp
It merges with the intake passage 3 to form the intake passage 3, and further extends toward the front and upper side of the engine 1.

Further, the supercharging passage 3B2 extending from the discharge port of the blower Cp of the primary side turbocharger 9 faces rearward, while the supercharging passage 3B2 extending from the discharge port of the blower Cs of the secondary side turbocharger 10. faces forward, and these two supercharging passages 3a2+
3bz join together to form the intake passage 3, which faces forward and upward. Then, an intake cut valve 21 is provided in the supercharging passage 3b2 immediately upstream of this merging portion.

Further, one end of a relief passage 22 is connected to the supercharging passage 3b2 near the discharge port of the blower Cs of the secondary side turbocharger 10, and the other end of the relief passage 22 is connected to each blower Cp,
It is connected to the intake passage 3 on the intake upstream side of Cs.

A relief valve 23 is provided at the end of the relief passage 22 on the blower Cs side.

As shown in FIG. 5, the relief passage 22 is arranged between the air introduction passage 3b+ of the blower Cs of the secondary side turbocharger 10 and the supercharging passage 3b2. That is, the relief passage 22 is arranged parallel to both passages 3b, 3bz on the side opposite to the engine of the supercharging passage 3bz and on the engine side of the air introduction passage 3b+.

Further, as shown in FIG. 6, the engine is mounted on the vehicle so that its output shaft faces in the longitudinal direction of the vehicle body B. And the primary side and secondary side turbo superchargers 9, 10
The superchargers are arranged on the right side of the engine so that the rotation axes of the superchargers are coaxial and the rotation axes of the superchargers are parallel to the engine output shaft. In that case, the primary side turbocharger 9 is arranged in front of the secondary side turbocharger 10. Moreover, the blower C of the primary side turbocharger 9
p is arranged on the front side of the turbine Tp. Further, as shown in the figure, in the engine room of the vehicle body B, a radiator R is disposed in front of the engine, and the intercooler 5 is disposed in front of the radiator R.

Therefore, in the above embodiment, by operating only the primary side turbocharger 9 in the low rotation range, the exhaust gas from the exhaust passage 2 is transferred to the turbine T of the primary side turbocharger 9.
While a high supercharging pressure can be obtained with a high start-up by being concentratedly supplied to the exhaust passage 2
Exhaust gas from the engine is supplied to the turbines Tp and Ts of the two turbochargers 9 and 10, and an appropriate boost pressure can be obtained while ensuring the intake air flow rate.

In this case, in the low rotation range, excess air is not relieved, so no air flows into the relief passage 22, and the temperature of the relief passage 22 becomes low.

Since this relief passage 22 is arranged between the air introduction passage 3b+ of the secondary side exhaust turbo supercharger 10 and the supercharging passage 3bz, the heat of the supercharging passage 3b2 is shielded by the relief passage 22. This makes it difficult for the air to be transmitted to the air introduction passage 3b+, increasing the density of air in the air introduction passage 3b+, and improving supercharging efficiency.

In addition, the primary turbo supercharger 9 is disposed on the right side of the engine in front of the secondary turbo supercharger 10, and the blower Cp of the primary turbo supercharger 9 is located further than the turbine Tp. Since it is disposed on the front side, the supercharging passage 3a2 of the primary turbo supercharger 9 is strongly affected by the running wind and is cooled well.

Furthermore, since the intercooler 5 is disposed in front of the radiator R in the engine room of the vehicle body B, the cooling capacity of the intercooler 5 is increased.

In the above embodiment, a so-called sequential turbo type supercharged engine was described, but the primary turbo supercharger and the secondary turbo supercharger were switched depending on the operating range. The present invention can also be applied to a so-called complete switching type.

(Effects of the Invention) As explained above, the intake system for a supercharged engine of the present invention includes a plurality of exhaust turbo superchargers that pressurize intake air using the energy of exhaust gas, and a specific exhaust turbo supercharger is provided. In addition to operating the feeder in a specific operating range and pre-rotating it outside the specific operating range, a relief passage for relieving excess air generated by the pre-rotation in the specific exhaust turbo-supercharger is installed in the specific exhaust turbo-supercharger. Since it is placed between the air introduction passage for supplying intake air to the specified exhaust turbo supercharger and the supercharging passage to which pressurized air from the specified exhaust turbo supercharger is supplied, In addition to the basic effect that the relief in the relief passage prevents the pressure in the supercharging passage downstream of the blower from increasing and makes it easier for the blower to rotate, the relief in the relief passage The heat is shielded by the relief passage, making it difficult for it to be transmitted to the air introduction passage, increasing the density of the air in the air introduction passage, and improving supercharging efficiency.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is an overall system diagram of the engine, FIG. 2 is a sectional view of the differential pressure detection valve, FIG. 3 is a characteristic diagram showing the switching characteristics of each valve, and FIG. is a side view of the engine,
FIG. 5 is a front view of the engine, and FIG. 6 is a side view of the engine mounted on a vehicle. 3a, 3b--Branch intake passage, 3al, 3b+-Air introduction passage, 3a2, 3b2...Supercharging passage, 9°10
...Turbo supercharger, 22...Relief passage. Diagram

Claims (1)

[Claims] (1) Supercharging that is equipped with multiple exhaust turbo superchargers that pressurize intake air using the energy of exhaust gas, and a specific exhaust turbo supercharger is operated in a specific operating range and pre-rotated outside the specific operating range. In the equipped engine, a relief passage for relieving excess air generated by pre-rotation in the specified exhaust turbo supercharger is used as an air introduction passage for supplying intake air to the specified exhaust turbo supercharger, and an air introduction passage for supplying intake air to the specified exhaust turbo supercharger. An intake device for a supercharged engine, characterized in that it is disposed between a supercharging passage and a supercharging passage through which pressurized air from a supercharger is supplied.