JPH02301691A - Discharge port shape controlling mechanism for mechanical drive type lysholm supercharger - Google Patents

Abstract

PURPOSE:To reduce the drive power of a supercharger during low load of an engine by forming at least part of the wall face of a discharging port and providing a piston with free movement back and forth for a screw rotor. CONSTITUTION:During unsupercharged operation, e.g. a suction-side static pressure conductive pipe 12 from an inlet pipe 61 on the downstream side of a suction port 6 is led through an operation room 10 on the back pressure side of pistons 8, 9 via a conductive pipe 15 to set the pistons 8, 9 apart from rotors 4, 5 by the use of a difference from a total of pressure on the discharge side which the face on screw rotors 4, 5 side of the pistons 8, 9 experiences. In this case, as distances between the pistons 8, 9 and the end faces of the rotors 4, 5, respectively, get bigger, air which is enclosed in the tooth space portions of the rotors 4, 5 is reflected to the side of the suction port 6 through non- meshing tooth space portions, as shown by arrow marks F5, F6, without being discharged as compression air, and it is only stirred without being raised in pressure and not discharged out of a discharge port 7 as high-pressure air so that the supercharged operation is not performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a mechanically driven Lysholm type supercharger having a variable discharge port shape.

[Prior art]

Conventionally, in order to increase engine output and torque, combustion air has been supercharged using a mechanically driven supercharger that is connected to the output shaft of the engine. In a mechanically driven supercharger, the amount of combustion air is supplied to the engine in proportion to the engine speed, regardless of the engine load, which worsens the engine's fuel consumption rate at low loads. There was a problem with letting them do it.

A mechanically driven Lysholm supercharger equipped with a clutch is known as a method of preventing the deterioration of the engine's fuel consumption rate at low loads (see Figure 1). , is connected via an electromagnetic clutch C to a pulley e which is connected by a belt to a pulley d provided on the output shaft of engine b and is driven, and when the engine load is low, the electromagnetic clutch C is disconnected and the supercharger a is not driven. combustion air is supplied through a separately provided air supply bypass pipe (not shown).

Here, in the Lysholm type supercharger a, a pair of rotor chambers are formed in the casing, which are parallel in the axial direction and are made up of cylindrical spaces with Japanese characters partially different from each other on the side surfaces, and the rotor chambers mesh with each other in the rotor chambers. A pair of screw rotors are arranged,
A suction port and a discharge port are provided on the wall of the rotor chamber, and as the screw rotor rotates, the air sucked in from the suction port is trapped in the tooth groove, and the meshing portion of both screw rotors moves toward the discharge port side. The tooth groove portion is opened to a discharge port, and the compressed air is discharged to the discharge port.

[Problems solved by the invention]

In the above-mentioned mechanically driven Lysigorm type supercharger having a known electromagnetic clutch, the electromagnetic flange is frequently engaged and disengaged under normal operating conditions, so the reliability of the electromagnetic clutch, noise during engagement and disassembly, and durability are affected. There were other problems.

An object of the present invention is to solve the above-mentioned problems and, in a mechanically driven Lysholm type supercharged automobile engine, reduce the driving power of the supercharger when the engine is under low load, and perform supercharging only when the engine is under high load. It is an object of the present invention to provide a mechanically driven Lysigolum type supercharger that can be used.

[Means to solve the problem]

In order to achieve the above object, a mechanically driven Lysholm type supercharger discharge port shape control mechanism of the present invention is connected to an output shaft of an automobile engine, and has a pair of screw rotors. (hereinafter referred to as supercharger)
In this method, a piston is provided which forms at least a part of the wall surface of the discharge port and is movable forward and backward relative to the screw coater, and by moving the piston forward and backward, compression is not performed when supercharging is not required.

A static pressure derivation pipe is branched from the upstream side of the suction port, and a total pressure derivation pipe for the discharge pressure is branched from the downstream side of the discharge port, and the suction side static pressure derivation pipe and the discharge side total pressure derivation pipe are connected via a three-way valve. It is preferable that the piston is moved back and forth by being switchably communicated with the back pressure side of the piston.

Further, a solenoid may be used as a means for moving the piston forward and backward.

Furthermore, the rotation of an electric motor or the like may be transmitted to the piston via a gear or a worm gear to move the piston forward or backward.

[Effect]

The discharge port shape control mechanism of the mechanically driven Rishichorum type supercharger of the present invention configured as described above is set such that supercharging is not performed when the engine is under low load or when the cooling water temperature is low. Under these conditions, the piston moves away from the screw rotor, creating a space between the piston and the screw rotor, which releases air, which returns to the suction port through the tooth grooves that do not mesh, and air is in a state where it is only stirred and the pressure is not increased.

Furthermore, when performing supercharging, the piston is brought close to the screw rotor and maintained at a predetermined distance to function as a normal compressor.

When using static pressure on the suction side and total pressure on the discharge side as a means of driving the piston, when not supercharging, switch the three-way valve to connect the suction side static pressure lead-out pipe from the upstream side of the suction port to the back pressure side of the piston. Through communication, static pressure on the suction side is guided to the back pressure side of the piston, and due to the difference between the discharge pressure and the discharge pressure applied to the surface of the piston on the screw coater side, the piston moves away from the screw rotor, circulating air and lowering the discharge pressure. .

Next, when performing supercharging, connect the discharge side total pressure lead-out pipe from the downstream side of the discharge port to the back pressure side of the piston to guide the discharge side total pressure to the back pressure side of the piston. Due to the difference between the total pressure on the discharge side and the pressure applied to the surface of the piston on the screw rotor side when the piston is away from the screw rotor, the piston approaches the screw rotor and forms a predetermined gap therebetween.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 2 is a cross-sectional view of a supercharger to which the present invention is applied, in which a pair of rotor chambers 2.3 are arranged in parallel in the axial direction in the casing 1, and are made up of cylindrical spaces that partially change from side to side. A pair of screw rotors 4.5 are arranged in the rotor chamber 2.3 to rotate while meshing with each other, and a suction port 6 is provided on an end surface of the rotor chamber 2.3, and a discharge lower is provided on the side wall of the opposite end. are provided respectively, and as the screw rotor 4.5 rotates, the air sucked in from the suction port 6 is trapped in the tooth groove, and the meshing portion of both screw rotors 4.5 moves toward the discharge lower side, compressing the air and compressing the air. Compressed air is discharged to the discharge lower by opening the groove to the discharge lower.

A piston 8 is mounted on the end face of the rotor chamber 2.3 on the side where the discharge lower is located.
．． 9 are provided to be movable forward and backward, respectively, and an operating chamber 1O is formed on the back pressure side of the piston 8.9.

The drive shaft 41.51 of the screw rotor 4.5 is connected to the gear 4
2.52, a boot 1 is provided at the extended end of the drive shaft 41 and is driven by a pulley (not shown) provided on the output shaft of the engine via a belt.

When the piston 8.9 approaches the screw rotor 4.5 during supercharging as shown in FIG.
．． 5 mesh with each other, rotate in the opposite direction as shown by arrows F, P, suck air through the suction port 6 (arrow F,), and trap it in the tooth groove of the screw rotor 4.5. The meshing portion of the screw rotor 4.5 is compressed by moving toward the discharge lower side, and the tooth groove portion is opened to the discharge lower to discharge compressed air to the discharge lower on the side wall of the rotor chamber 2.3 (arrow F4).

The driving power L1 of the supercharger at this time is given by the following equation.

P, : Suction pressure ■ : Suction volume P2 : Discharge pressure k : Specific heat ratio of compressible gas When the piston 8.9 is away from the screw rotor 4.5 when supercharging is not required as shown in Fig. 4, the screw rotor Since the distance between the piston 8.9 and the end face of the screw rotor 4.5 is large, the air trapped in the tooth groove portion of 4.5 is not discharged as compressed air, as shown by arrows F3 and F.

As shown in the figure, the air flows back to the suction port 6 side through the tooth grooves that are not engaged, is only stirred, and is not pressurized, so that high-pressure air is not discharged from the discharge lower and supercharging is not performed.

The driving power of the supercharger at this time is P in the above equation.
, =P, so LL=0.Actually, a small amount of driving power is required for stirring, but it is negligible.

In an example of the measured values shown in FIG. 5, the curve I is the driving power Lt relative to the rotational speed during supercharging, and the curve ■ is the driving power Lt relative to the rotational speed when supercharging is not required.

So, there it is.

As mentioned above, the driving power during non-supercharging can be reduced without using an electromagnetic clutch, and the transmission mechanism between the engine output shaft and the supercharger is simplified, increasing the degree of freedom in installation. Since air is circulated inside the aircraft, there is no need for bypass piping during low loads, freeing up installation space in the engine room.

Furthermore, since the position of the piston can be adjusted linearly, the discharge pressure can be linearly controlled by controlling the distance between the screw rotor and the piston to an appropriate value.

Next, referring to FIGS. 6 and 7, an explanation will be given of a piston driving means that uses static pressure on the suction side and total pressure on the discharge side.

One end of the suction side static pressure derivation pipe 12 is opened in the side wall of the intake pipe 61 connected upstream of the suction port 6 of the supercharger, and the discharge side total pressure is led out into the discharge pipe 71 connected downstream of the discharge lower. tube 13
is opened, and the other ends of the suction side static pressure outlet pipe 12 and the discharge side total pressure outlet pipe 13 are respectively connected to the three-way valve I4, and the three-way valve 14 is connected to the back pressure side of the piston 8.9 through the conduit 15. Connect to chamber 10.

When not supercharging, as shown in FIG. 6, by switching the three-way valve 14, the suction side static pressure outlet pipe 12 from the intake pipe 61 on the upstream side of the suction port 6 is connected to the working chamber on the back pressure side of the piston 8.9. lO
through the conduit 15, the suction side static pressure is guided to the working chamber IO on the back pressure side of the piston 8.9, and the discharge side total pressure received by the surface of the piston 8.9 on the screw rotor 4.5 side is The difference causes the piston 8.9 to move away from the screw rotor 4.5, allowing air to circulate and reducing the discharge pressure.

Next, when performing supercharging (see Fig. 7), the discharge side total pressure lead-out pipe I3 from the discharge pipe 7I on the downstream side of the discharge port is connected to the piston 8.
．． The total pressure on the discharge side is guided to the working chamber 10 on the back pressure side of the piston 8.9, and the piston 8.
．． Due to the difference between the total pressure on the discharge side of the back pressure side of the piston 8.9 and the pressure applied to the surface of the piston 8.9 on the screw rotor 4.5 side when the piston 8.9 is away from the screw rotor 4.5, the piston 8.9 approaches the screw rotor 4.5, forms a predetermined gap therebetween, performs compression, and discharges high-pressure air, thereby performing supercharging.

With this configuration, the piston can be moved forward and backward without requiring a special drive source, and the configuration can be simplified.

Next, a method using a solenoid as the piston driving means shown in FIGS. 8 and 9 will be described.

A solenoid 16 is installed in the working chamber 10 on the back pressure side of the piston 8.9.
The piston 8.9 is moved forward and backward by energizing the solenoid 16 using the piston rod 81.91 protruding from the back surface of the piston 8.9 as an iron core.

According to this configuration, the piston can be moved forward or backward as desired with a simple structure.

Although a case has been described in which the piston rods 81 and 91 are iron cores, the method of movement by the solenoid 16 is not limited to this, and it goes without saying that any known means can be adopted as appropriate.

Further, in the case of driving a piston using an electric motor as shown in FIG. The worm gear 17 provided at the tip of the output shaft 18 of the piston rod 81.91
The screw grooves 82 and 92 are engaged with each other.

The rotation of the electric motor 19 rotates the worm gear 17 via the output shaft 18, moving the piston rod 81.91 in the axial direction and moving the piston 8.9 forward and backward.

Although only the supercharger of an engine has been described above, the present invention is not limited to this, but can be applied to an industrial supercharged engine, a Richulme compressor, a vacuum pump, etc. .

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

It is possible to reduce the driving power when not supercharging without using an electromagnetic clutch, and the transmission mechanism between the engine output shaft and the supercharger is simplified, increasing the degree of freedom in installation.
Since the air is circulated inside the supercharger, bypass piping is not required at low loads, freeing up installation space in the engine room.

Furthermore, since the position of the piston can be adjusted linearly, the discharge pressure can be linearly controlled by controlling the distance between the screw rotor and the piston to an appropriate value.

In addition, by switchably introducing static pressure on the suction side and total pressure on the discharge side to the back pressure side of the piston via a three-way valve, the piston can be moved forward and backward without the need for a special drive source. can be simplified.

Furthermore, the construction can be simplified by using a solenoid or an electric motor.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram of a conventional supercharged engine, Fig. 2 is a sectional view of a supercharger according to the present invention, Figs. 3 and 4 are explanatory diagrams of operation, FIG. 5 is a graph showing an example of an actual measured value of driving power with respect to the rotational speed of a supercharger to which the present invention is applied; FIGS. 6 and 7 are schematic diagrams showing an example of a piston driving means; FIG.
Figures 9 and 9 show an example of other piston driving means +1
! ! FIG. 10 is a schematic diagram showing an example of a further different piston driving means. l...Casing, 2.3...Rotor chamber, 4.5...Screw rotor, 6...Suction port, 7...Discharge port, 8.9...Piston, IO... - Piston back pressure side working chamber, 11... Pulley, 12... Suction side static pressure outlet pipe, 13... Discharge side total pressure outlet pipe, 41, 51... Drive shaft, 14... Three sides Valve, 61...Intake pipe, C...Discharge pipe.

Claims (4)

[Claims] (1) In a mechanically driven Lysholm supercharger that is connected to the output shaft of an automobile engine and has a pair of screw rotors, the supercharger forms at least a part of the wall surface of the discharge port and is movable toward and away from the screw rotor. A discharge port shape control mechanism for a mechanically driven Lysholm type supercharger, characterized in that a piston is provided and the piston is moved back and forth so that compression is not performed when supercharging is not required. (2) The suction side static pressure is derived from the upstream side of the suction port, and the discharge side total pressure is derived from the downstream side of the discharge port, and the suction side static pressure and the discharge side total pressure are transferred to the piston through the three-way valve. Claim (1) characterized in that it is switchably introduced to the back pressure side of the
Discharge port shape control mechanism of the mechanically driven Lysholm type supercharger described. (3) The discharge port shape control mechanism for a mechanically driven Lysholm type supercharger according to claim (1), wherein the piston is moved forward and backward using a solenoid. (4) The shape of the discharge port of the mechanically driven Lysholm supercharger according to claim (1), wherein the rotation of an electric motor or the like is transmitted to the piston via a gear or a worm gear to move the piston forward or backward. Control mechanism.