JPH0960525A - Surging preventing device for supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a device to avoid surging in a total operating region, by providing an opening part in a location corresponding to an impeller inducer part of a casing, simultaneously with providing an opening/closing valve for opening/closing this opening part, opening/closing the opening/closing valve by a detection signal of supply air pressure, and adjusting a surge margin of an impeller. SOLUTION: A pressure sensor for detecting a supply air pressure is arranged, and this detected signal is input to a valve driving gear through an electric circuit line 10. That is at the time of operating a supercharger, when an electromagnet 18 is energized based on a detection output of the pressure sensor, the electromagnet 18 pulls an operating lever 16 of an operating mechanism 50, and a slit-shaped opening part 31 is opened by turning an opening/closing valve 11 in the clockwise direction with a support pin 15 serving as the support point, to be separated from a valve seat part 17. Then, a part of air in an inducer part is discharged to the outside from the opening part 31, and an amount of air passing through an impeller 1 is decreased. When assumed pressures Pu, Pe for upper/lower limit values in a region where an engine operating line is most adjacent to a surge line, the opening part 31 is opened when the supply air pressure P is in a state of Pe<P<Pu.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surging prevention device for a supercharger for an internal combustion engine.

[0002]

FIG. 6 shows a relationship between a compressor performance curve (air flow rate-pressure ratio characteristic) of a supercharger for an internal combustion engine (a diesel engine in this case) and an engine operating line. There is.

In FIG. 6, the outer side Z of the surging line (hereinafter referred to as a surge line) of the impeller and the diffuser is a surging area, and in a diesel engine, the supercharger does not cause surging during operation of the engine. The margin is referred to as a surging margin (abbreviated as "surge margin" below), and a certain value is specified, and a supercharger that is more suitable for the operating characteristics of the engine and the surge margin is selected.

The above surge margin, that is, {Q _O / Q _S −
1} (Q _S = air flow rate when surging occurs, Q _O = air flow rate during engine operation) is usually set to about 15%.

FIG. 5 shows a conventional example of a supercharger structure in which the surging flow rate is reduced and the choke flow rate is increased.

In FIG. 5, 01 is an impeller of a compressor, 02
Is a diffuser, and 03 is a casing. Slits 04 are opened at equal intervals in the circumferential direction on the outer circumference of the impeller 01 inlet on the inner circumference of the casing 03, and the slit 04 and the air suction port 06 are connected by a bypass passage 7. And constitutes a so-called casing treatment.

The air sucked into the suction port 06 receives the impeller 0
After being boosted within 1, it is sent to the diffuser 02 where it is further boosted. Impeller 0 in surging area
Part of the air sucked in 1 passes through the slit 04, passes through the bypass flow passage 05, and returns to the suction port 06 of the compressor,
A circulation flow S is formed. This reduces the surging flow rate.

However, as shown in FIG. 6, in the high pressure ratio type supercharger for a high power engine, the combination of the impeller 01 and the diffuser 02 causes the surge line indicating the surging of the impeller 01 and the diffuser 02. The vicinity of the intersection of the surge lines due to the surging tends to be closest to the engine operating line, and the surge margin tends to be the smallest. If an attempt is made to secure a sufficient surge margin in this region, the surge margin in the high pressure ratio region becomes excessive and the engine operates in a low efficiency region.

That is, in the supercharger with a casing treatment mechanism as shown in FIG. 5, the surging flow rate is reduced and the surge margin is expanded by the action of the casing treatment mechanism, but the surge margin is too large. Therefore, the maximum efficiency of the supercharger is lower than that of the supercharger without the casing treatment mechanism.

An object of the present invention is to provide a supercharger capable of adjusting the surge margin of the supercharger according to the operating state of the engine and avoiding surging without lowering the supercharger efficiency in the entire operating range. To do.

[0011]

The present invention solves the above-mentioned problems, and the first means thereof is to provide an opening at a portion of the casing corresponding to the impeller inducer portion, and to open the same. There is an on-off valve that opens and closes, and a pressure sensor that detects the air supply pressure in the air supply passage of the engine and the on-off valve is opened and closed by the detection signal of the air supply pressure from the pressure sensor to open the surge margin of the impeller. A surging prevention device for a supercharger, comprising: an opening / closing valve operating mechanism for adjusting.

According to such means, the surge margin can be adjusted by changing the amount of air passing through the impeller by the detection signal of the supply pressure which is a factor of the operating state of the engine. This makes it possible to avoid surging in the entire operating range of the engine without reducing the efficiency of the supercharger.

The second means of the present invention is the first means according to the first means, wherein the on-off valve is formed in the shape of a ring piece, and one end operation portion thereof is rotatably supported around a support pin.
The operation mechanism of the opening / closing valve is connected to the opening / closing valve, and an operation ring for rotating the opening / closing valve around the support pin by rotating in the circumferential direction to open / close the opening, and a detection from the pressure sensor. It consists of an electromagnet for rotating the operating ring by the supply pressure.

As a result, the adjustment range of the opening area of the opening portion is widened, and the on-off valve is operated with high accuracy by using the electromagnet.

As described above, according to the first and second means, the opening is set to open when the supply pressure of the engine is within a certain set value range. This set value is the pressure in the region where the engine operating line near the intersection of the compressor impeller surging and the diffuser surging approaches the surge line most. In this case, the pressure sensor provided in the air supply line to the engine detects the supply pressure, and within the set pressure range, the opening is opened and the surge flow rate is reduced. Thereby, surging of the supercharger can be avoided. Further, since the opening is closed when the engine is under a heavy load, it is possible to prevent the efficiency of the supercharger from being lowered, and it is possible to use the supercharger in a highly efficient region.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a turbocharger for a diesel engine according to an embodiment of the present invention, and FIG.
FIG. 3 is a detailed enlarged view of part A, and FIG. 3 is a view taken along the line BB of FIG.

1-3, 1 is an impeller of the compressor of the supercharger, 1a is an impeller of the impeller 1, 2 is a diffuser, 3 is a casing, 6 is an air suction port to the impeller 1, Reference numeral 8 is a diesel engine, and 9 is an air supply pipe that connects the outlet of the diffuser 2 and an intake port (not shown) of the engine 8.

Reference numeral 7 is a pressure sensor for detecting the supply pressure in the supply line. The supply pressure detection signal from the pressure sensor 7 opens and closes an on-off valve 11, which will be described later, via an electric line 10. Is transmitted to the valve drive device 18 for.

2 and 3 show the details of the on-off valve 11 and its mounting portion. In the drawings, a portion of the casing 3 located outside the impeller inducer portion 1b is circumferentially arranged. Slit-shaped openings 31 are provided at a plurality of locations, and the openings 31 are opened and closed by the opening / closing valve 11.

That is, the on-off valve 11 has the openings 31
Is formed in the shape of a ring piece that can be fitted in such a manner as to fill in, and an opening / closing lever 12 is fixed to one end thereof. A root portion of the opening / closing lever 12 is rotatably supported by a support flange 32 of the casing 3 via a support pin 15, and a tip end portion of the opening / closing lever 12 is connected to an operation ring 13 described later via an operation pin 14. Has been done.

The hole into which the operation pin 14 of the opening / closing lever 12 is fitted is a long hole which is long in the radial direction in consideration of the radial deflection of the opening / closing lever 12.

As shown in FIG. 3, the operation ring 13 is formed in an annular shape, and an operation lever 16 of the operation mechanism 50 is provided at at least one position in the circumferential direction of the operation ring 13, and an electromagnet 18 is attached to the operation lever 16. Are connected.

As described above, the detection signal of the supply air pressure is input to the electromagnet 18 from the pressure sensor 7 via the electric line 10. The electromagnet 18 receives the supply air pressure detection signal and the operating lever 16 is received. It is designed to give a circumferential operating force to. Reference numeral 19 is a return spring for the operation lever 16.

When the supercharger equipped with the surging prevention device constructed as described above is in operation, the pressure sensor 7 for detecting the supply pressure gives the electromagnet 1 the detection signal of the opening / closing valve "open".
8 is input, the electromagnet 18 pulls the operating lever 16 of the operating mechanism 50 in the direction of arrow A in FIG. As a result, the on-off valve 11 is rotated clockwise around the support pin 15 as a fulcrum to leave the valve seat portion 17 and open the slit-shaped opening portion 31.

As a result, a part of the air in the inducer 16 is discharged to the outside through the opening 31 and the amount of air passing through the impeller 1 is reduced.

On the other hand, the pressure sensor 7 causes the on-off valve to "close".
When the detection signal of is input to the electromagnet 18, the electromagnet 18 is demagnetized, and the opening / closing valve 11 is rotated in the direction opposite to the above (the direction of arrow B in FIG. 3) by the elasticity of the spring 19 to open the opening 31. It will be embedded and it will be closed.

As a result, the outflow of air from the opening 31 to the outside is stopped, and the impeller 1 of the compressor is operated with a normal amount of air. The operation mechanism 50 sets the open / close valve to be opened when the supply pressure in the supply pipe 9 is within a certain set range, and to be closed otherwise.

FIG. 4 shows the pressure performance curve of the supercharger according to the above embodiment. In FIG. 4, the pressures Pu and Pe in the region where the engine operating line comes closest to the surge line are set upper limits. Value, the lower limit value, the supply pressure P of the engine is Pe <
When P <Pu, the opening is open and the others are closed.

At low load when the supply pressure P of the engine is low, that is, P <Pe, the opening 11 is closed, the normal flow rate flows through the impeller, and the surge margin is sufficiently maintained.

When the supply pressure P is Pe <P <Pu, the opening 31 is opened, and a part of the air flowing into the impeller 1 from the suction port 6 is opened from the opening 31 to the casing 3.
To the outside of. This avoids surging.

When the engine has a high load P <Pu, the opening 31
Is closed, the surge margin is secured, and the casing 3
The reduction in efficiency due to the provision of the opening 31 in the opening 3
It disappears due to blockage of 1.

Further, in the case of Pe <P <Pu, unlike the conventional case, it is not necessary to take a large surge margin, so that it is possible to set the operating range at the time of high engine load to a region where the supercharger efficiency is high. Become. That is, it is not necessary to make the surge margin excessive under high load.

[0033]

The present invention is configured as described above.
According to the invention of claim 1, the operating state of the engine (supply pressure)
By changing the amount of air passing through the impeller, the surge margin can be automatically adjusted.
As a result, surging can be avoided in the entire operating range of the engine without reducing supercharger efficiency.

According to the invention of claim 2, in addition to the above, since the on-off valve is formed in a cantilever-supporting ring-like shape, the adjustment range of the opening area of the opening portion is widened, and the electromagnet There is also an effect that the opening / closing valve can be operated with high accuracy by using the valve.

[Brief description of drawings]

FIG. 1 is a configuration diagram of main parts of a supercharger and an engine according to an embodiment of the present invention.

FIG. 2 is an enlarged view of part A of FIG. 1 according to the above embodiment.

FIG. 3 is a view on arrow BB in FIG. 2 according to the embodiment.

FIG. 4 is a performance diagram of the supercharger according to the above embodiment.

FIG. 5 is a schematic configuration diagram of a conventional supercharger.

FIG. 6 is a performance diagram of a conventional supercharger.

[Explanation of symbols]

 1 Impeller 1a Impeller 1b Inducer part 2 Diffuser 3 Casing 7 Pressure sensor 8 Diesel engine 11 Open / close valve 12 Open / close server 13 Operating ring 16 Operating lever 18 Electromagnet 31 Opening 50 Operating mechanism

Claims (2)

[Claims] 1. A pressure sensor for detecting an air supply pressure in an air supply passage of an engine by providing an opening at a portion of a casing corresponding to an impeller inducer portion and an opening / closing valve for opening and closing the opening. And an operation mechanism of an on-off valve for adjusting the surge margin of the impeller by opening and closing the on-off valve according to a detection signal of the supply pressure from the pressure sensor, to prevent surging of a supercharger. apparatus. 2. The on-off valve is formed in the shape of a ring piece, and one end of the on-off valve is rotatably supported around a support pin,
An operation mechanism for the on-off valve is connected to the on-off valve, and an operation ring for rotating the on-off valve around the support pin to open and close the opening by rotating in a circumferential direction, and an operation ring from the pressure sensor. The surging prevention device for a supercharger according to claim 1, comprising an electromagnet for rotating the operation ring by the supply pressure of the engine.