JPH0361618A - Supercharger for engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine supercharging device. In particular, the present invention relates to a supercharging device for an engine with so-called internal compression, in which intake air is compressed between an intake inlet and an intake outlet.

[Prior art]

There are various types of supercharging devices used in internal combustion engines. Among these, supercharging devices with internal compression such as the screw type are attracting attention because they can increase volumetric efficiency and have the potential to improve overall adiabatic efficiency. When using this type of supercharger with internal compression, it is necessary to reduce the pumping losses that occur during low-load or part-load operating conditions of the engine due to the internal compression of the supercharger. be.

Normally, the supercharger is connected to a drive means via an electromagnetic clutch, and the electromagnetic clutch is disconnected to cut off the drive of the supercharger when the engine is operating in a state where supercharging is not required. However, this type of supercharging device has a large driving resistance and is difficult to idle when the supercharging device is not driven, so that the shock caused by the clutch engagement when the electromagnetic clutch changes from the disengaged state to the engaged state becomes large. In order to prevent this shock, the clutch must be engaged in a relatively low rotation range even in low-load operating conditions where supercharging is not required, which increases the load on the engine unnecessarily.

Therefore, it is desirable to eliminate or significantly reduce the internal compression of the supercharger during engine operating conditions that do not require supercharging. When the internal compression of the supercharger disappears or is significantly reduced, the supercharger is able to idle in the non-driving state, and when the clutch is engaged, the difference between the rotation speed of the drive side and the rotation speed of the supercharger increases. There will no longer be a significant difference in

As a result, the shock caused by clutch engagement can be reduced, and the advantage is that the rotational speed at which the clutch is engaged can be increased in low-load operating conditions.

Japanese Unexamined Patent Publication No. 63-1.70524 discloses a method for reducing the effective stroke of the screw supercharger during partial load operation in a supercharging device that uses a screw supercharger in combination with a turbo supercharger. It has been proposed to reduce pumping losses. That is, in this known supercharging device, a screw type supercharger is provided with a valve that slides in the axial direction, and by moving this valve, the intake inlet side is opened and the effective stroke of the supercharger is reduced. It is composed of

This known screw supercharger has the problem that during low load or part load operation of the engine, the effective stroke of the supercharger is only reduced, so that internal compression still remains and the pump losses cannot be sufficiently reduced. be.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to effectively reduce internal compression under low load or partial load operating conditions in a supercharging system for an engine having internal compression.

[Means to solve the problem]

In order to solve the above problems, the present invention provides means for making a plurality of compression chambers of a type of supercharging device with internal compression communicate with each other at the end face of the housing. That is, the engine supercharging device according to the present invention includes a housing, a rotor disposed rotatably about an axis within the housing, and the housing includes a center housing portion disposed surrounding the rotor; It is comprised of end housing parts disposed at both axial ends of a center housing part. The housing forms a plurality of circumferentially adjacent compression chambers between the housing and the rotor. The housing also includes an intake inlet that communicates with at least one of the plurality of compression chambers;
an intake discharge port that communicates with at least one of the compression chambers that does not communicate with the intake inlet, and the compression chamber is cut off from communication with the intake inlet from the suction area where the compression chamber communicates with the intake inlet as the rotor rotates. It is configured to pass through an internal compression area where the volume is gradually reduced as the rotor rotates and generate internal compression, and then sequentially move to a discharge area that communicates with the intake and discharge ports. The present invention provides an engine supercharging device of this type, in which an opening is formed in at least one of the end housing portions in a range extending over a plurality of compression chambers in a plurality of regions, and is movable in the axial direction into the opening. The engine is characterized by having a piston arranged therein and a driving means for moving the piston in the axial direction depending on the operating state of the engine.

[Effect]

In the present invention, a piston that is movable in the axial direction is disposed in at least one of the end housing parts of the supercharger in a range that spans a plurality of compression chambers in a plurality of regions, and the piston Usually, by holding this piston in contact with the end surface of the rotor, each compression chamber can be partitioned off and independent from each other. When the driving means is actuated to move the piston away from the rotor end face in an engine operating region that does not require the engine, for example in a no-load or low-load engine operating region, compression chambers in different regions communicate with each other. , the internal compression of the supercharger will be released. For example, a compression chamber in the internal compression region communicates with a compression chamber in the suction region and a compression chamber in the discharge region to remove compression.

The piston can be formed to completely cover the end of one rotor, allowing communication between the compression chambers over a wide area.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 show an engine supercharging device according to an embodiment of the present invention. This supercharging device 1 has a pair of rotors 3.4 arranged in a housing 2. The rotor 3 is
The rotor 4 is a female rotor having a threaded groove 3a formed in a spiral shape, and the rotor 4 is a male rotor having a threaded thread 4a formed in a spiral shape. These rotors 3.4 are arranged parallel to each other within the housing 2, and the threaded thread 4a of the male rotor 4 engages with the threaded groove 3a of the female rotor 3, as shown in FIG. The housing 2 consists of a center housing 2a and end housings 2b and 2C attached to both ends of the center housing 2a. In this embodiment, both the end housings 2b and 2C are the center housing 2.
Although it is formed separately from the center housing 2a, one may be formed integrally with the center housing 2a.

As shown in FIG. 3, the rotor 3.4 forms a plurality of compression chambers 2d, 2e adjacent to each other in the circumferential direction between the rotor 3.4 and the housing 2. An intake inlet 5 opening in the axial direction is formed in the end housing 2b. A bearing plate 6 is attached to the end housing 2C, and an end plate 7 is attached to the bearing plate 6. The rotor 3.4 has its axes 3b, 4
b is rotatably supported in the end housing 2b by a bearing 8 on the one hand, and on the other hand by a bearing 10 on the plate 6.
It is rotatably supported by. The bearings are on the outside of the plate 6, and the shafts 3b, 4b of the rotor 3.4 are provided with gears 3C%4C meshing with each other. End plate 7 has bearings 11 and 12.
The shaft 13 is supported coaxially with the shaft 3b of the rotor 3 via the shaft 3b. A pulley 14 is arranged on the shaft 13, and this pulley 14 is operated by an electromagnetic clutch 15 provided on the shaft 13.
It is detachably coupled to the shaft 13. Gear 1 is on shaft 13
6 is provided, and this gear 16 meshes with a gear 17 provided on the shaft 4b of the rotor 4. In the center housing 2a,
An intake/discharge port 18 is formed at the end on the end housing 2c side.

Although not shown in the figure, the pulley 14 is connected to a pulley provided on the engine crankshaft via a belt.
When the electromagnetic clutch 15 is in the connected state, the rotor 3.4 of the supercharger I is rotationally driven by the crankshaft of the engine. When the rotor 3.4 is driven, as it rotates,
The compression chamber 2d formed within the housing 2 moves in the circumferential direction, and its volume gradually decreases to cause internal compression. This state is shown in FIGS. 4(a), (b), (C1, (d), and (el).

In FIG. 4(a), the arrow indicates the direction of rotation of the rotor 3.4, and the arrow 3.4 formed between the rotor 3 and the housing 2
compression chambers 2 (1-L 2d-2, 2d-3 and three compression chambers 2 formed between the rotor 4 and the housing 2)
All of e-1, 2e-2, and 2e-3 are in the suction region communicating with the intake inlet 5, but the compression chamber 2 has the most advanced phase.
d-1 and 2e-1 are located just before the communication with the intake port 5 is cut off.

In FIG. 4(b), the compression chambers 2d-1 and 2e-1 are disconnected from the intake inlet 5, and these two compression chambers 2d-1 and 2e-1 are communicated with each other and are in the internal compression area. be. FIGS. 4(C) and 4(d) sequentially show the states after the position of FIG. 4(b). As is clear from the figures, the compression chambers 2d-1 and 2e-1 have the most advanced phase. gradually decreases in volume and the intake air inside is compressed. FIG. 4 Fdl shows the most advanced state of compression, and the compression chambers 2d-1 and 2e-1 are at positions just before opening to the intake and discharge ports 18. A region 36 indicated by a shaded line in FIGS. 2 and 3 is a discharge region of the supercharged air, and this discharge region 36 communicates with the intake/discharge port 18. The compression chambers 2d-1 and 2e-1 whose phase is most advanced are the fourth
Immediately after passing the position shown in FIG. 4(d), the air enters this discharge region 36, and thereafter, as shown in FIG. 4 (eJ), the volume is further reduced and the intake air is discharged to the discharge port 18.

Therefore, in a normal supercharging operation state, air sucked into the supercharging device l from the intake inlet 5 is compressed before reaching the discharge region 36, and the air is compressed in the discharge region 36, where the air is
The air is discharged from the air into the intake passage 20.

As shown in FIG. 3, in this embodiment of the invention:
An opening 37 is formed in the end housing 2C at a position that covers the entire end surface 3C of the rotor 3 on the intake/discharge port 18 side. A piston 38 is arranged in this opening 37 so as to be freely slidable in the axial direction. The piston 38 is supported by a bearing 39 on the shaft 3b of the rotor 3. piston 38
is urged toward the end surface 3C of the rotor 3 by a plurality of springs 40 arranged at intervals in the circumferential direction. A solenoid 41 is provided to drive the piston 38 in a direction away from the end surface 3C of the rotor 3. When the solenoid 41 is excited, the piston 38 separates from the end surface 3C of the rotor 3. As a result, the piston 38 and the rotor 3
A gap is formed between the rotor 3 and the end face 3C, and the compression chambers 2d formed between the rotor 3 and the housing 2 communicate with each other. Therefore, the intake air in the compression region can flow to the suction region or the discharge region, and the internal compression is released.

The solenoid 40 is energized and drives the piston 38 in a particular operating region of the engine, such as a low load or no load operating region of the engine. As shown in FIG. 2, the bearing 39 that supports the piston 38 has a flange 39a located adjacent to the end surface of the rotor 3. As shown in FIG. piston 38
has a stepped portion 38a corresponding to this flange 39a,
The fitting between the step portion 38a and the flange 39a of the bearing 39 can be expected to improve sealing performance using the labyrinth effect. If necessary, piston 38
A labyrinth groove may be formed on the sliding surface.

In the illustrated embodiment, a communication passage 44 is formed in the end housing 2C of the housing 2, which connects a chamber 42 behind the piston 38 to a passage 43 leading to the intake/discharge port 18. In this configuration, in a normal operating state in which the solenoid 41 is not excited, the discharge pressure from the intake and discharge port 18 is guided to the chamber 42 behind the piston 38, and urges the piston 38 toward the end surface 3C of the rotor 3. do. Therefore, the seal between the piston 38 and the end surface 3C of the rotor 3 can be ensured.

In the illustrated embodiment, the opening 37 of the end housing 2C and the piston 38 that slides within the opening 37 are formed at positions corresponding to the end surface of the female rotor 3. In this type of supercharger, the female rotor 3 has a smaller diameter than the male rotor 4, so by adopting this arrangement, a reliable decompression effect can be achieved with a piston having a small area. Also, the piston 38 is pulled by the rotor 3 by a tension spring.
If the configuration is such that the solenoid is biased away from the rotor 3 and pressed against the end surface 3C of the rotor 3, no electric power is required to excite the solenoid during low-load operation of the engine, which is advantageous in terms of fuel economy. .

〔effect〕

As described above, in the present invention, an opening is formed in the end housing portion adjacent to the end surface of the rotor in a range extending over a plurality of compression chambers adjacent to each other in the circumferential direction, and this opening has a Since we have provided a piston that can move the piston in the axial direction according to the operating state of the engine, the inside of the supercharger can be moved by driving the piston in an operating state of the engine that does not require supercharging. Compression can be reliably released.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a screw type supercharging device showing one embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the supercharging device of the present invention, and Fig. 3
The figure is a cross-sectional view, Figure 4 (a) (b) (C) (d)
(e) is a schematic diagram showing a change in volume of the compression chamber, and FIG. 5 is a sectional view taken along the line V-V in FIG. 2. ■...Supercharger, 2...Housing, 3...
・Female rotor, 3a...Thread groove, 4...Male rotor, 4a...Thread strip, 5...Intake inlet, 18.
...Intake/discharge port, 37...Opening, 38...Piston 40...Spring, 41...Solenoid Fig. 1 e 3a

Claims (1)

[Claims] (1) Consisting of a housing and a rotor disposed rotatably around an axis within the housing, the housing includes a center housing portion disposed to surround the rotor, and both axial ends of the center housing portion. and an end housing portion disposed in the rotor, the housing forming a plurality of circumferentially adjacent compression chambers between the housing and the rotor, and the housing having at least one of the plurality of compression chambers. an intake inlet communicating with the intake inlet; and an intake outlet communicating with at least one of the compression chambers not communicating with the intake inlet, and as the rotor rotates, the compression chamber communicates with the intake inlet. The area is cut off from communication with the intake inlet, and as the rotor rotates, the volume is gradually reduced to cause internal compression, and the air is sequentially moved to the discharge area that communicates with the intake and discharge ports. In the engine supercharging device according to the present invention, at least one of the end housing portions has an opening formed in a range extending over a plurality of compression chambers in a plurality of regions, and the opening includes a piston movable in an axial direction; A supercharging device for an engine, characterized in that a driving means for moving the piston in the axial direction according to the operating state of the engine is provided.