JPH06323147A - Supercharger - Google Patents

Abstract

PURPOSE:To provide a supercharger capable of obtaining high charge pressure without surging. CONSTITUTION:A supercharger 1 is provided with a turbo air compressor 3 rotated by the driving force of an engine 13 to pressurize intake gas and then to supply it to the engine 13 through supercharge paths 31, 33, a surge sensor 5 which detects surging of the air compressor 3, and a valve means 11 which is positioned in a bypass path 47 connecting the paths 31, 33 to the intake side of the air compressor 3 and returning part of supercharged gas in a range the where the discharge pressure of the air compressor 3 is decreased when the sensor 5 detects surging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging device for pressurizing intake air of an engine.

[0002]

2. Description of the Related Art A supercharger 201 as shown in FIG. 3 is described in Japanese Patent Publication No. 3-500564. This is because the driving force of the engine input from the driven pulley 203 of the belt type continuously variable transmission via the electromagnetic clutch 205 is increased.
The speed is increased at 07, and the air compressor 209 is rotated to supercharge the engine.

[0003]

A graph 211 in FIG. 4 shows a supercharging characteristic of the air compressor 209 when the throttle valve of the engine is fully opened. Generally, in an air compressor, when the flow rate is small with respect to the pressure, surging (self-excited vibration) occurs in the piping system and the like. Graph 213
Indicates the surging limit of the air compressor 209, and the left side thereof is the surging region. Air compressor 209
For example, if the throttle valve is fully opened from the engine speed of 1000 to 1500 rpm for sudden acceleration while the vehicle that is supercharged at 100 km / n is running, the flow rate will almost increase due to the supercharging characteristics of the air compressor 209 as shown in graph 211. Instead, the pressure rises rapidly and enters the surging area as indicated by the diagonal lines. When surging occurs, the boost pressure pulsates and vibration noise is generated.

If an air compressor that is less prone to surging is selected to avoid surging, the supercharging characteristic becomes as shown in graph 215, and the supercharging pressure becomes insufficient and the engine output drops.

Therefore, an object of the present invention is to provide a supercharging device which can obtain a high supercharging pressure while avoiding surging.

[0006]

The supercharger of the present invention comprises:
A turbo type air compressor that is rotationally driven by the driving force of the engine to pressurize intake air and supply it to the engine through a supercharging air passage, a surging sensor that detects surging of the air compressor, the supercharging air passage and the air compressor. And a valve device which is arranged in a bypass path connecting the suction side of the air compressor and returns a part of the supercharged air to the air compressor within a range that does not reduce the discharge pressure of the air compressor when the surging sensor detects surging. To do.

[0007]

The air compressor is driven by the driving force of the engine to supercharge the engine. When the supercharging pressure rises as the engine speed rises and surging occurs, the surging sensor detects surging, and the valve device returns part of the supercharging air to the suction side of the air compressor through the bypass passage. . Therefore, the flow rate passing through the air compressor is increased and the reduction of the supercharging pressure due to bypassing the supercharging air is prevented.

In this way, the supercharging characteristic portion in the surging region is moved to the outside of the surging region due to the increase in the flow rate of the air compressor, and the surging is prevented in the entire region of the air compressor. Further, since surging is avoided in this manner, an air compressor having a sufficiently high boost pressure can be selected, and a required high engine output can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS.
It should be noted that members and the like without reference numerals are not shown.

As shown in FIG. 1, the supercharging device 1 of this embodiment comprises a centrifugal air compressor 3, a surging sensor 5, and a valve device 11 including a controller 7 and a valve 9.

The driving force of the engine 13 is transmitted from a crank pulley 17 connected to the crankshaft 15 to a belt type continuously variable transmission 21 via a belt transmission mechanism 19.
The belt type continuously variable transmission 21 transmits the input driving force of the engine to the speed increasing gear mechanism 23 while keeping the fluctuation range of the rotational speed small, and the speed increasing gear mechanism 23 speeds up the input driving force to increase the air speed. The impeller of the compressor 3 is rotated. The air compressor 3 pressurizes the intake air 27 sucked from the intake pipe 25 and is connected by the throttle valve 29 to the supercharged air passage 3
It is supplied to the cylinder 35 of the engine 13 via 1, 33. The piston 37 rotates the crankshaft 15,
The exhaust gas 39 is discharged from the exhaust pipe 41.

The surging sensor 5 is the air compressor 3
Is a G sensor which is attached to the compressor housing 43 for detecting the vibration of the system due to surging, and sends a surging detection signal 45 to the controller 7. Controller 7
Receives the surging detection signal 45 and opens the valve 9.
The valve 9 is provided with an actuator for opening and closing, and is arranged in a bypass passage 47 that connects the supercharging air passage 31 and the intake pipe 25. When the valve 9 is opened, part of the supercharged air returns to the suction side of the air compressor 3.
The controller 7 has a built-in timer function, and the valve 9 is closed when a predetermined time has passed.

The graph of FIG. 2 shows the flow rate performance of the air compressor 3 in which the vertical axis represents the discharge pressure P (corresponding to the pressure in the supercharging air passage 31) and the horizontal axis represents the flow rate Q. Graph 49
Is a supercharging characteristic of the air compressor 3 when the throttle valve 29 is fully opened. The dashed-dotted line graph 51 is the surging limit of the air compressor 3, and the left side thereof is the surging region. Also, graphs 53, 55, 57, 5
Reference numerals 9 and 61 are pressure curves when the rotational speed of the impeller is constant, and the rotational speed increases from the graph 53 to the graph 61.

When the throttle valve 29 is fully opened when the engine speed is relatively low,
Between the pressures P1 and P2, the graph 49 enters the surging area and surging occurs. When the surging occurs, a part of the supercharged air is returned to the air compressor 3 as described above, so that the flow rate of passage through the air compressor 3 increases from Q1 to Q1 'while maintaining the pressure P1 as it is.

Therefore, the supercharging characteristic of the air compressor 3 traces from the lower intersection A of the graphs 49 and 51 to the right on the graph 63 parallel to the horizontal axis by the increment of the flow rate Q, and then the pressure P1 rises to P2. Flow chart Q while following graph 65
Will increase. Pressure P when throttle valve 29 is fully opened
The time required for 1 to rise to P2 is normally 0.3 to 1 second, and the above-mentioned timer function of the controller 7 sets this pressure rise time. Therefore, when the pressure rises to P2, the valve 9 is closed and the supercharging characteristic returns to the graph 49 from the intersection B on the upper side of the graphs 49 and 51 through the graph 67.

In this way, even if the throttle valve 29 is fully opened, surging does not occur in the entire area of the air compressor 3, so that damage to the impeller and the supercharging air passages 31 and 33 is prevented. Further, since surging can be avoided in this way, it is possible to select the air compressor 3 having a high supercharging pressure, and the output of the engine 13 can be sufficiently increased. Further, the broken line in FIG. 2 shows the efficiency of the air compressor 3, and the efficiency is higher as the broken line on the inner side. Therefore, as shown by the position of the graph 65, the efficiency is improved when surging is avoided, and high efficiency is obtained on the high flow rate side.

Taking the state of pressure P1 as an example, the flow rate increases from Q1 to Q1 'when avoiding surging because the discharge flow rate of the air compressor 3 (the flow rate of the supercharging air passage 31).
Therefore, the flow rate supplied from the supercharging air passage 33 to the engine 13 is Q1. Here, Q1'-Q1 is the bypass flow rate.

It is also possible to use a valve with an adjustable opening in the valve device to adjust the opening while detecting the discharge pressure and flow rate of the air compressor to avoid surging. Further, the supercharger of the present invention may be used as a turbocharger in combination with an exhaust turbine, not as a mechanical supercharger as in the embodiment.

[0019]

According to the present invention, surging is detected by the surging sensor, and a portion of the supercharged air is returned to the air compressor so that the flow rate of the air compressor increases without lowering the discharge pressure. Therefore, it is possible to avoid surging, prevent damage to the air compressor, etc., and select an air compressor having a high boost pressure to sufficiently increase the engine output.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment.

FIG. 2 is a graph showing a flow rate characteristic of this embodiment.

FIG. 3 is a sectional view of a conventional example.

FIG. 4 is a graph showing a supercharging characteristic of a conventional example.

[Explanation of symbols]

 1 Supercharging Device 3 Air Compressor 5 Surging Sensor 11 Valve Device 13 Engine 31, 33 Supercharging Air Flow Path 47 Bypass Path

Claims (1)

[Claims] 1. A turbo type air compressor which is rotationally driven by a driving force of an engine to pressurize intake air and supply it to an engine through a supercharging flow path, a surging sensor for detecting surging of the air compressor, and the supercharging. Equipped with a valve device that is arranged in a bypass line that connects the air flow path and the suction side of the air compressor and returns a portion of the supercharged air to the air compressor within the range that does not reduce the discharge pressure of the air compressor when the surging sensor detects surging. A supercharging device characterized in that