JPH03117693A - Screw type engine-driven supercharger - Google Patents

Abstract

PURPOSE:To enhance an output as well as restrain energy loss by providing a control valve for opening an inlet at a high load but closing it at a low load in the inlet opened to a side surface. CONSTITUTION:A suction inlet is constituted of a main inlet (a first inlet) 18 exposed to the end surface of a rotor 25 in the axial direction and a second inlet 26 opened to the side surface thereof. In the second inlet 26, there is provided a control valve 28 for opening the second inlet 26 at a high load but closing it at a low load. Capacity can be changed according to the magnitude of a load. Therefore, not only an output can be enhanced at the high load but also energy loss can be restrained at the low load.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw-type mechanical supercharger that supercharges an engine by pressurizing intake air through internal compression.

[Conventional technology]

As a conventional supercharger of this type, for example, Japanese Patent Application Laid-Open No. 63-1
A screw-type mechanical supercharger disclosed in Japanese Patent No. 70524 is known. This supercharger includes a housing, a screw-shaped male rotor disposed within the housing and having a plurality of ropes, and a plurality of flutes disposed within the housing and meshing with the lobes of the male rotor. When these two rotors are rotated, the space formed between the recess of the rotor and the inner wall of the housing gradually becomes smaller and moves in the axial direction of the rotor. In this way, the intake air drawn from the intake boat at one end of the housing in the rotor axial direction is taken into the space, compressed, and discharged from the discharge port at the other end of the housing in the rotor axial direction.

With such a screw type mechanical supercharger, there is no problem when the load is high, but when the load is low, the air supplied from the supercharger to the engine becomes excessive.

At this time, since the above-mentioned supercharger once increases pressure by internal compression and then releases the pressure from the discharge port, driving loss occurs due to unnecessary compression stroke, and pressure difference at the discharge port occurs. This causes noise.

Therefore, in the screw type mechanical turbocharger disclosed in the above publication, a control valve is provided on the side of the discharge side, and this control valve is opened at low load to push excess air back to the intake side. This controls the amount of intake air supplied to the engine.

[Problem to be solved by the invention]

However, in the conventional configuration described above, the screw-type mechanical supercharger performs the extra work of pushing excess air back to the intake side at low loads, resulting in energy loss due to bomb loss, leading to a decrease in fuel efficiency. There is a problem with this.

In addition, as another configuration, a configuration in which the intake air amount of the supercharger is regulated by a throttle valve during low load has been previously proposed. However, in such a configuration, since the flow rate is regulated by the throttle valve, turbulent flow of intake air occurs at that location, resulting in energy loss. Also, since air is taken into the engine via the throttle valve,
The engine's job is to suck in air,
This also causes a problem of energy loss and a similar reduction in fuel efficiency.

[Means to solve the problem]

In order to solve the above-mentioned problem, the screw type mechanical supercharger of the present invention has a male rotor and a female rotor that are provided in an intake passage communicating with the engine and are supported in parallel. In a screw-type mechanical turbocharger that rotates while meshing with each other, gas from the upstream side of the intake passage is sucked in from the suction port and then discharged from the discharge port to the downstream side of the intake passage. It consists of a first suction port opened at the end face and a second suction port opened at the side. It is characterized by being equipped with a control valve that

[For production]

According to the above configuration, when the load is high, the control valve that opens and closes the second suction port is opened, so that there is sufficient space between the first and second suction ports between the outer rotor and the female rotor. You can get air intake. Therefore, in the screw type mechanical supercharger, the rotation of the male rotor and the female rotor performs a stroke of intake → compression → discharge, and intake air pressurized to a predetermined pressure can be supplied to the engine.

On the other hand, when the load is low, the above control valve is closed, so after this control valve is closed, intake air is supplied between the male rotor and the female rotor only from the first intake port. . The closing operation of the control valve described above is performed, for example, during intake from the second intake port. In addition, in this device, the intake air amount is controlled by the closing operation of the control valve as described above, so unlike when regulating with a throttle valve, there is no energy loss in controlling the intake air amount. Does not occur.

When the control valve is closed as described above, the amount of intake air is insufficient for the volume of the room formed between the male and female rotors, and in a screw type mechanical turbocharger, the flow of intake → expansion → compression → discharge is insufficient. The process is carried out. This prevents excessive intake air from being supplied to the engine at low loads.

In the operation of the screw type mechanical supercharger at low load as described above, the male and female rotors are rotated by the expansion operation of the intake air during the expansion stroke after the control valve is opened.
Furthermore, energy loss can be suppressed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 10.

As shown in FIG. 2, the screw-type mechanical supercharger 9
It is provided in the intake passage 5 which communicates with the air intake passage 5. A piston 3 is slidably inserted into a cylinder 2 of an engine 1, and a combustion chamber 4 is formed by the cylinder 2 and the piston 3.

The combustion chamber 4 is connected to the intake passage 5 whose other end is open to the atmosphere. This intake passage 5 includes, in order from the combustion chamber 4 side, an injector 6 for supplying fuel to the intake air, a surge tank 7, an ink cooler 8 for cooling the discharge air of the screw-type mechanical supercharger 9, and the above-mentioned screw-type mechanical supercharger 9. A mechanical supercharger 9, a throttle valve 10 for finely adjusting the intake flow rate of the intake passage 5, an air flow meter 11 for detecting the intake flow rate, and an air cleaner 12 are provided.

The screw-type mechanical supercharger 9 rotates when the power of the crankshaft 13 of the engine 1 is transmitted, internally compresses air taken in from the main suction port 18 and the auxiliary suction port 19, and discharges it from the discharge port 34. It is designed to pressurize the intake air. Further, a bypass pipe line 14 is provided between the screw type mechanical supercharger 9 and the surge tank 7.

The above screw type mechanical supercharger 9 is shown in FIGS. 1 and 3(a) (
It is connected to the upstream side and the downstream side of the intake passage 5 by a housing 15 shown in FIGS. 4(a) and 4(b). The housing 15 includes a housing main part 16 in which a male rotor 24 and a female rotor 25 (described later) are arranged in parallel in a compression chamber 20, and an upstream connecting part 1 connected to the upstream side of the intake passage 5.
7. The compression chamber 20 is formed by a male cylinder 16a that accommodates a male rotor 24 and a female cylinder 16b that accommodates a female rotor 25, and these male cylinders 16a and female cylinders 16b communicate with each other. On the upstream end surface of the housing main portion 16, a first
A main suction port 18 and an auxiliary suction port 19 are formed as suction ports.

The main suction port 16 includes an end wall 23 that partially covers the upstream end surface of the housing main portion 16, and male and female cylinders 1 that separate the compression chamber 20 and the auxiliary passage 21, which will be described later.
The male and female rotors 2 are separated by the partition wall portions 22 of 6a and 16b.
They are formed in the parallel direction of 4 and 25. An auxiliary passage 21 is formed between the auxiliary suction port 19 and the compression chamber 20 by the partition wall portion 22 and the peripheral wall of the housing main portion 16 . The auxiliary passage 21 communicates with the compression chamber 2o via an opening 26 formed in the partition wall 22 and serving as a second suction port.

An intake air amount control device 27 is provided on the peripheral wall of the nozzle main portion 16 at the location where the opening 26 is formed. This intake air amount control device 27 has a control valve 28 which is provided to be movable forward and backward and opens and closes the opening 26 of the partition wall 22. This control valve 28 includes a valve portion 28 that can open and close the opening 26.
a, connected to this valve part 28a, and housing main part 16
It has a rod portion 28b that penetrates the peripheral wall of and projects to the outside. The valve part 28a has an oval outer shape extending in the direction in which the male cylinder 16a and the female cylinder 16b of the housing main part 16 are arranged side by side, and the face facing the housing main part 16 is located on the male side and the female side. It has a shape that can be flush with the inner peripheral surfaces of the cylinders 16a and 16b. The rod portion 28b is connected to the seat plate 29a of the diaphragm 29, and the outer peripheral portion of the diaphragm 29 is connected to the bolt 31 along with the device case 30.
・It is fixed to the housing main part 16 by. Diaphragm 29, device case 30 and housing main part 1
6 is in an airtight state, and a pressure chamber 32 is formed between the diaphragm 29 and the device case 30.

The device case 30 and seat plate 29a in this pressure chamber 32
A spring 33 is arranged between the seat plate 29a and the control valve 28 to urge the seat plate 29a toward the control valve 28.

The pressure chamber 32 described above is connected to the surge tank 7 by a bypass line 14 connected to the device case 30. Therefore, the opening and closing operations of the control valve 28 are controlled by the pressure supplied from the surge tank 7 to the pressure chamber 32 through the bypass line 14.

The relationship between the pressure in the pressure chamber 32, the torque T of the engine 1, and the engine speed is shown in FIG. 5, and the relationship between the pressure in the pressure chamber 32 and the opening degree of the control valve 28 is shown in FIG. 6
It looks like the picture. That is, as shown in FIG. 6, the control valve 28 is fully closed due to negative pressure when the pressure in the pressure chamber 32 is -300 mmHg or less, and when the pressure in the pressure chamber 32 is -100 mm 11 g or more, the biasing force of the spring 33 overcomes the negative pressure. It is fully opened,
-300 to -100mm11g is an intermediate opening. Further, as shown in FIG. 5, the pressure in the pressure chamber 32 increases as the torque T of the engine 1 increases.

Further, a discharge port 34 for discharging pressurized air to the downstream side of the intake passage 5 is formed in a side wall of the housing main portion 16 at a location opposite to the location where the intake air amount control device 27 is disposed. There is.

On the other hand, the male rotor 24 housed in the male cylinder 16a of the compression chamber 20 has a screw shape having three ropes 24a, as shown in FIGS. 3(b) and 4(b). I am doing it. The female rotor 25 housed in the female cylinder 16b has five flutes (grooves) 25a shaped to correspond to the ropes 24a of the male rotor 24. These male and female rotors 24 and 25 are connected to individual drive shafts 24b and 25.
The power of the engine 1 transmitted to 25b causes the rotation of the engine,
The male cylinder 16a and the female cylinder 16b engage with each other at a communicating portion.

Therefore, when the male and female rotors 24 and 25 rotate, the space formed between the recesses of the male and female rotors 24 and 25 and the inner wall of the housing main portion 16 gradually becomes smaller and the rotors 24 and 25 rotate. The intake air moves in the axial direction (to the left in FIG. 1) and is taken into the space, compressed by the internal compression, and discharged from the discharge port 34.

In the above configuration, when the load is high, the pressure supplied from the surge tank 7 to the pressure chamber 32 via the bypass pipe 14 causes the screw type mechanical supercharger to Control valve 2 of intake air amount control device 27 provided at 9
8 is full throttle. Therefore, air is taken into the compression chamber 20 of the housing main portion 16 through the main suction port 18 and the auxiliary suction port 19 . At this time, the intake air from the auxiliary suction port 19 is passed from the auxiliary passage 21 to the compression chamber 2 through the opening 26 of the partition wall 22.
reaches 0. The intake air taken into the compression chamber 20 is taken between the rotating male rotor 24 and female rotor 25, and the rotation angle θ of the male and female rotors 24 and 25 shown in FIG.
The intake air is pressurized based on the change in the inter-rotor volume V due to the change in the rotor volume and the change in the inter-rotor pressure P due to the change in the inter-rotor volume shown in Fig. 8, and the pressurized air is The engine 1 is supercharged by being discharged from the discharge port 34 into the intake passage 5.

That is, as shown in FIG.
The relationship between the rotation angle θ and the inter-rotor volume ■ of No. 5 is a, -+b
, -+(,→d, -+eI. First, air is taken in between a1 and b, and as the male and female rotors 24 and 25 rotate, the inter-rotor volume ■ changes. Thereafter, when the inter-rotor volume becomes 1 at bl, the space formed between the two rotors 24 becomes closed, and compression is performed from b1 to c1 to d. Note that the inter-rotor volume V does not change between b, -+(-, and substantial compression occurs between c and → d1. After that, d
, when the inter-rotor volume V becomes V2, the discharge port 34
The discharge to the intake passage 5 is started from d1 to e0, and pressurized intake air is discharged from d1 to e0.

Further, as the inter-rotor volume (2) changes as described above, as shown in FIG. 8, the inter-rotor pressure P changes to the above value a.

Corresponding to the changes in -+l), -+(, -+d, -+6., a.

→b2→c2→d2→c2 changes as shown in e2→
At d2, the inter-rotor volume becomes V due to compression.

The pressure increases as the temperature changes from (1) to (2). d2→e2
In this case, discharge is performed under a constant pressure state, and the engine 1 is thereby supercharged.

On the other hand, at low load, the intake air amount control device 270 control well 28
is fully open at the beginning of the intake stroke, and due to the pressure supplied to the pressure chamber 32 via the bypass line 14, the pressure shown in FIG.
As shown in b), it becomes fully closed during the intake stroke. Therefore, air is taken into the compression chamber 20 of the housing main part 16 from the main suction port 18 and the auxiliary suction port 19 at the beginning of the intake stroke, and from the middle of the intake stroke, air is taken only from the main suction port 18. . The intake air taken into the compression chamber 20 is then supplied to the intake passage 5 on the downstream side through the steps shown in FIGS. 9 and 10.

That is, as shown in FIG. 9, the male and female rotors 24, 2
The relationship between the rotation angle θ and the inter-rotor volume V of No. 5 is h, →i
, −*j, −+, −+1. It changes linearly as shown by −+mI. First, between h and j1, the inter-rotor volume ■ increases, and when the inter-rotor volume reaches V3 at 11, the control valve 28 is fully closed. Therefore, 11 → 1
In between, an expansion stroke is performed due to insufficient intake air amount. Note that the space between the two rotors 24 and 25 becomes closed when the volume between the rotors becomes ■1 at jl, and 1 at jI→
Since the inter-rotor volume (2) does not change between 1 and 2, substantial expansion occurs between i and j1. After that, k.

→ Compression takes place between 11 and at 21, the inter-rotor volume ■ becomes ■2
When 2. →Discharge is performed between m1.

In addition, as shown in FIG. 10, as the inter-rotor volume ■ changes, the inter-rotor pressure P changes from h1→iI−+
jl→kl−+! Corresponding to the change of 1→m1, 112→
i2->j2-+, and changes as shown by →l, 2-+m. First, between h2 and h12, the inter-rotor pressure P is constant and the inter-rotor volume is ■.

In 12→j2→2, the pressure decreases as the inter-rotor volume changes from ■3 to ■1 due to expansion.

At k2→2□, the inter-rotor volume increases from ■1 to ■ due to compression.
2, the pressure increases. At 12 → m2,
Discharge is performed under constant pressure. At this time, the intake air supplied to the downstream side of the intake passage 5 is in a negative pressure state, and the intake air to the engine 1 does not become excessive.

In this device, as described above, when the load is high, the control valve 28 of the intake air amount control device 27 is fully opened, and air is taken in from the opening 26 that communicates with the main suction port 18 and the auxiliary suction port 19. When the load is low, the control valve 28 is fully closed and air is taken only from the main suction port 18, so that the capacity can be changed depending on the level of the load. Therefore, when the load is low, intake air can be supplied to the engine 1 at an appropriate pressure while suppressing energy loss.

〔Effect of the invention〕

As described above, the screw-type mechanical supercharger of the present invention has a male rotor and a female rotor that are provided in an intake passage communicating with an engine and are pivotally supported in parallel, and these rotors rotate while meshing with each other. In a screw type mechanical supercharger that sucks gas from the upstream side of the intake passage through the suction port and discharges it from the discharge port to the downstream side of the intake passage, the above-mentioned suction port has the following characteristics:
The rotor consists of a first suction port that opens at the end face in the axial direction of the rotor, and a second suction port that opens on the side surface. This configuration includes a control valve that closes at times.

Therefore, the capacity can be changed depending on the level of load. As a result, while improving output at high loads,
This has the effect of suppressing energy loss during low loads and improving fuel efficiency.

[Brief explanation of drawings]

1 to 10 show an embodiment of the present invention. FIG. 1 is a partially sectional front view showing a screw-type mechanical supercharger. FIG. 2 is a schematic overall configuration diagram showing the intake system. FIG. 3(a) is a bottom view showing the screw type mechanical supercharger when the control valve is open. FIG. 3(b) is a side view of the same. FIG. 4(a) is a bottom view showing the screw type mechanical supercharger when the control valve is closed. FIG. 4(b) is a side view of the same. FIG. 5 is a graph showing the relationship between engine speed, engine torque, and pressure in the pressure chamber of the intake air amount control device. FIG. 6 is a graph showing the relationship between the intake negative pressure and the opening degree of the control valve. FIG. 7 is a characteristic diagram showing the relationship between the rotor rotation angle and the inter-rotor volume under high load. FIG. 8 is a pressure-volume diagram showing the relationship between the inter-rotor pressure and the inter-rotor volume under high load. FIG. 9 is a characteristic diagram showing the relationship between the rotor rotation angle and the inter-rotor volume at low load. FIG. 10 is a pressure-volume diagram showing the relationship between the inter-rotor pressure and the inter-rotor volume at low load. 1 is an engine, 9 is a screw type mechanical supercharger, 13 is a crankshaft, 14 is a bypass pipe, 18 is a main suction port (first
19 is an auxiliary suction port, 20 is a compression chamber, 24 is a male rotor, 25 is a female rotor, 26 is an opening (second suction port)
, 27 is an intake air amount control device, 28 is a control valve, 29 is a diaphragm, 3° is a device case, 32 is a pressure chamber, 33 is a spring, and 34 is a discharge port.

Claims (1)

[Claims] 1. It has a male rotor and a female rotor that are provided in an intake passage communicating with the engine and are pivotally supported in parallel, and by rotating while meshing with each other, the upstream of the intake passage is In a screw-type mechanical turbocharger that sucks gas from the side through the suction port and discharges it from the discharge port to the downstream side of the intake passage, the above-mentioned suction port has a first opening at the end surface in the axial direction of the rotor.
It consists of a suction port and a second suction port opened on the side, and the second suction port is provided with a control valve that opens the second suction port when the load is high and closes the second suction port when the load is low. A screw-type mechanical supercharger characterized by: