JPH0454217A - Supercharging device for engine - Google Patents

Abstract

PURPOSE:To obtain a desired supercharging characteristic which can cope with demands, with a simple mechanism, by providing an internal compression releasing means in an internal compression type supercharger, and by operating the releasing means in accordance with an intake-air pressure downstream of both the throttle valve and supercharger. CONSTITUTION:In an internal compression type supercharger 6 which receives its drive force from an engine by way of a belt and pulley 15, air which is introduced into spaces defined by recesses 29a and protrusions 28a of a pair of rotors 28, 29 which are meshed with each other, and the inner wall of a casing 27 is compressed and is moved in the axial direction through the movement of the meshing points between the recesses 29a and the protrusions 28a in association with the rotation of the rotors 28, 29, and is then fed under pressure from a discharge port 32. In this arrangement, the supercharger 6 incorporates an internal compression releasing means 10 which has a piston member 33 slidably disposed in the end part of a casing 27 which abuts on the discharge side end part of the rotor 29, and which performs compression releasing operation in accordance with an intake air pressure upstream of both the throttle valve and supercharger.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine supercharging device equipped with an internal compression type supercharger driven by engine output.

(Prior art) Conventionally, there has been a technology that includes an internal compression type supercharger that is driven by the engine output shaft, and that uses an electromagnetic clutch or the like to switch the connection so that the supercharger is not driven depending on the operating condition. is known, for example, as seen in Japanese Utility Model Application Publication No. 82-74139.

(Problems to be Solved by the Invention) The internal compression type supercharger described above has a very large driving resistance in the non-supercharging state compared to a supercharger that does not perform internal compression, so it reduces the engine fuel efficiency in the light load range. The rate becomes f significantly. In addition, when the electromagnetic clutch is turned off and the supercharger stops driving, the drive resistance is large due to the internal compression type as described above, causing the supercharger to idle, and when the drive is stopped, the rotation is almost at a standstill. When the electromagnetic clutch is turned on to start driving from this drive stopped state, the torque shock becomes large. Therefore, if the area where the electromagnetic clutch is turned off and the drive of the supercharger is stopped is set narrowly to avoid the occurrence of torque shock, there is a problem that the fuel efficiency in the light load area further deteriorates.

On the other hand, the performance of improving engine output characteristics accompanying the drive of the supercharger is controlled in response to the driver's accelerator operation, etc., but for this purpose a separate dedicated electromagnetic solenoid or Providing an actuator that uses hydraulic pressure and its control system has the problem of a complicated configuration and a disadvantage in terms of cost.

Therefore, in view of the above circumstances, the present invention provides an engine that reduces the drive loss of the internal compression supercharger at light loads as much as possible while obtaining the desired supercharging characteristics that meet the demands with a simple mechanism. The purpose of this invention is to provide a supercharging device.

(Means for Solving the Problems) In order to achieve the above object, the engine supercharging device of the present invention provides an internal compression type supercharger with an internal compression release means, and the internal compression release means is connected downstream of the throttle valve. The supercharger is configured to operate in response to the intake pressure downstream of the supercharger.

(Function) In the engine supercharging device as described above, an internal compression type supercharger is provided with an internal compression release means for releasing the internal compression effect and reducing driving resistance, and this internal compression release means is provided downstream of the throttle valve. By operating the internal compression release means in accordance with the intake pressure downstream of the supercharger and the throttle valve downstream of the supercharger, in light load conditions where the intake negative pressure downstream of the throttle valve decreases, the internal compression release means is released and activated according to the operating condition, and the drive is activated. A region where the drive of the internal compression type supercharger is stopped in a state with little resistance, and the drive of the internal compression type supercharger is enabled to idle while the drive is stopped, thereby improving the torque shock at the start of drive, increasing the supercharging response, and stopping the drive of the supercharger. This is to improve fuel efficiency in the light load range.

In addition, the release of internal compression in the internal compression supercharger is controlled by fluctuations in the intake negative pressure downstream of the throttle valve in response to driver operation, and the internal compression is started in response to requests for supercharging such as acceleration. Along with supercharging,
The change in the operating state when transitioning to the supercharging request state enables good supercharging control to be performed while suppressing the occurrence of torque shock.

(Example) Hereinafter, each embodiment of the present invention will be described along with the drawings.

Embodiment 1 FIG. 1 shows a schematic overall configuration of an engine equipped with a supercharging device of this embodiment.

An air cleaner 3, an air flow meter 4, and a throttle valve 5 are interposed in the intake passage 2 that supplies intake air to the cylinder 1a of the engine 1 from the upstream side.
An internal compression supercharger 6 is disposed downstream. The internal compression type supercharger 6 is equipped with an internal decompression means 10 as described later.

Furthermore, an intercooler 8 is interposed in the intake passage 2 on the downstream side of the internal compression supercharger 6, and the downstream side of the surge tank 7 is formed into an independent intake passage 2a connected to each cylinder 1a. An injector 9 is provided to inject and supply fuel to 2a.

Further, a bypass passage 11 is connected to bypass the supercharger 6, and a bypass valve 12 is interposed in the bypass passage 11.

That is, one end of the bypass passage 11 is connected upstream of the supercharger 6 and downstream of the throttle valve 5, and the other end is connected downstream of the intercooler 8.

The bypass valve 12 mounted in the bypass passage 11 includes a valve body 12a that opens and closes the passage, and a diaphragm actuator 12b that lifts the valve body 12a, and a pressure chamber in which a spring 12d of the actuator 12b is compressed. 12c, the intake pressure downstream of the throttle valve 5 is introduced through the pressure introduction passage 13, and when this intake pressure (negative pressure) exceeds the set load of the spring 12d, the pressure is adjusted according to the magnitude of the negative pressure. The bypass passage 11 is opened by adjusting the opening degree.

The supercharger 6 is connected to the pulley 1 of the engine output shaft 16 by a pulley 15 equipped with an electromagnetic clutch 14.
The driving force from the controller 20 is transmitted via the belt 18, and a driving signal (on/off signal) from the controller 20 is output to the electromagnetic clutch 14, and the supercharger 6
The drive control is performed by controlling the connection relationship between the engine 1 and the engine 1.

The controller 20 receives an intake air amount signal from the air flow meter 4 that detects the intake air amount and an engine rotation speed signal from the rotation sensor 25 that detects the engine rotation speed in order to control the connection operation of the electromagnetic clutch 14. is input.

The controller 20 determines the operating range of the electromagnetic clutch 14 corresponding to the current operating state based on the engine load (for example, intake air amount) and engine speed, and switches the engagement state of the electromagnetic clutch 14. It is.

Here, an example of the structure of the screw-type internal compression type supercharger 6 and the structure of its internal compression release means 10 will be explained based on FIGS. 2 to 4.

The internal compression type supercharger 6 has a casing 27
Inside, two male and female rotors 28, 29 are combined so that they rotate in opposite directions (in the direction of the arrow in FIG. 4) with their respective spiral convex portions 28a and concave portions 29a meshing with each other. 29 shaft 30 is the casing 27
A pulley 15 is provided to protrude outward from the drive force to transmit the driving force.

A suction boat 31 is opened at one end of the casing 27 on the side opposite to the drive side, and the inside of the suction boat 31 is opened at the end face of the meshing portion that slides into one end of both the rotors 28 and 29. Air is supplied to the space around the outer periphery of 28 and 29. Further, a discharge port 32 is opened in the casing 27 located below the center of the other end portions of both the rotors 28 and 29. The intake passage 2 downstream of the throttle valve 5 is connected to the intake boat 31, and the intake passage 2 on the downstream side communicating with the intercooler 8 is connected to the discharge port 32.

The recesses 2 of the rotors 28 and 29 engage with each other.
The air flowing into the space between the convex portion 9a, the convex portion 28a, and the inner wall of the casing 27 is compressed in the axial direction so that the volume of the space gradually decreases due to the movement of the meshing point as the rotor 28°29 rotates. It is configured to transfer the liquid to the air and pump it from the discharge port 32.

On the other hand, the structure of the internal compression release means 10 for the internal compression structure as described above is such that the piston member 33 is slidably inserted into the end of the casing 27 that contacts the discharge side end of the rotor 29.
is arranged. The shaft 30 passes through the center of the piston member 33, and there are small pressure receiving portions 33a on both sides.
33b, and an inner chamber 34 is formed in the middle part. The small diameter pressure receiving part 33a can come into contact with the end surface of the rotor 29 and slides inside the small diameter cylinder. Large diameter pressure receiving part 33 at the other end
b slides inside a large diameter cylinder, and this large diameter pressure receiving part 33
The pressure of the piston chamber 35 acts on b, and a return spring 36 is compressed in the piston chamber 35.

A first passage 37 communicating with the piston chamber 35 and a second passage 38 communicating with the inner chamber 34 are formed in the casing 27, respectively. This first passage 37 includes a first air pipe 39 (one end of which opens into the intake passage 2 downstream of the supercharger 6 and upstream of the intercooler 8).
1) is connected, and intake pressure P2 (supercharging pressure) downstream of the throttle valve 5 and supercharger 6 is introduced. Further, a second air vibe 40 whose one end opens to the clean side of the air cleaner 3 upstream of the throttle valve 5 is connected to the second passage 38 to maintain atmospheric pressure Po.
will be introduced.

The piston member 33 moves to the right by the biasing force of the return spring 36, etc., and allows internal compression in the closed state where the small diameter pressure receiving portion 33a contacts the end of the rotor 29 and is sealed. is moved to the left and the small diameter pressure receiving portion 33g is separated from the end of the rotor 29, which is an open state in which internal compression is released.

The force F acting on the piston member 33 has a positive direction of action towards the open state, the atmospheric pressure is PO, the intake pressure immediately downstream of the throttle valve 5 is P1, the intake pressure downstream of the supercharger 6 is P2, the spring 36 If the biasing force is Ps, the area of the small diameter pressure receiving part 33a is Δ, and the area of the large diameter pressure receiving part 33b is B, then F=・(B-A)X (POP2)
It becomes Ps. Therefore, the piston member 33 opens and closes depending on the magnitude of the spring force and the area difference x pressure difference, and opens and closes in response to fluctuations in intake pressure accompanying changes in the opening degree of the throttle valve 5.

That is, FIG. 5 shows the fluctuation characteristics of the pressures Po, P, . When the throttle valve 5 is fully closed, the pressures P1 and P2 on the downstream side of the throttle valve 5 are in a large negative pressure state, and the piston member 33 moves to the left to release the internal compression of the supercharger 6, and the bypass valve 12 is opened. Operate. As the throttle valve 5 opens, the measured pressure p
,, p2 becomes negative pressure and rises to the atmospheric pressure side, and the intake pressure P1 downstream of the throttle valve 5 gradually becomes atmospheric pressure Po.
At the same time, the intake pressure P2 downstream of the supercharger 6 supplied to the engine 1 increases from the atmospheric pressure Po as the supercharger 6 is driven.

The bypass valve 12 gradually closes as the intake pressure P immediately downstream of the throttle valve 5 increases, and opens in a low throttle opening range where the differential pressure Po-P2 is a positive and large value. The piston member 33 starts to move to the right and gradually closes as the differential pressure decreases.

On the other hand, the OFF region of the electromagnetic clutch 14, that is, the region in which the supercharger 6 is not driven, is the low rotation light load region I, which includes idling and deceleration, as shown in FIG. It is a narrower area on the low load side (low intake pressure side) than the area below the line (2) where the bypass valve 12 opens, and the open area of the bypass valve 12 is the internal compression release area of the internal compression type supercharger 6. In other words, it is a narrower area on the low load side (low intake pressure side) than the area below line (3).

To explain the operation of the above embodiment, in a light load region with a small throttle opening, the internal compression supercharger 6
The internal compression release means 10 operates to release the internal compression, while the bypass valve 12 opens and intake air is supplied to the engine via the bypass passage 11. At this time, the driving resistance of the supercharger 6 decreases, and even when the electromagnetic clutch 14 is off, the rotor 28,29 can idle due to the intake air flow accompanying natural intake, and the torque when the electromagnetic clutch 14 is turned on and off is maintained. The occurrence of shock is suppressed.

Also, during acceleration when the throttle valve 5 is opened,
As the supercharger 6 starts to drive, the bypass valve 12 starts to close, and the internal compression release means 10 of the supercharger 6 starts to return to operation, increasing the supercharging pressure and increasing the engine output. ing.

Embodiment 2 The overall configuration of this embodiment is shown in FIG. 7, and structural examples of the internal compression decompression means of the internal compression type supercharger are shown in FIGS. 8 and 9. In the previous example, the throttle valve 5 was disposed upstream of the supercharger, whereas in this example, the throttle valve 5 is disposed downstream of the supercharger.

In FIG. 7, with respect to an intake passage 2 that supplies intake air to the engine 1, a throttle valve 5 is disposed at an inlet of a surge tank 7 downstream of an internal compression type supercharger 6 and an intercooler 8. Intake air that has passed through the air cleaner 3 and air flow meter 4 is supplied to the supercharger 6 at atmospheric pressure.

Further, a bypass valve 12 interposed in a bypass passage 11 that bypasses the supercharger 6 has a valve body 1.
Diaphragm actuator 12 that lifts 2a
Intake pressure P2 is introduced from the surge tank 7 portion downstream of the throttle valve 5 through the pressure introduction passage 13' into the pressure chamber 12c in which the spring 12d of b is compressed.
Further, the intake pressure P1 upstream of the throttle valve 5 is introduced into the chamber on the opposite side of the diaphragm through the auxiliary pressure introduction passage 13g. When the differential pressure across the throttle valve 5 exceeds the set load of the spring 12d, the bypass passage 11 is opened by adjusting the opening degree according to the magnitude of the differential pressure.

Furthermore, the controller 20 controls the electromagnetic clutch 14 that turns on and off the supercharger 6, and the setting of its operating range is the same as in the previous example.

Here, a structural example of the internal compression release means 50 attached to the screw-type internal compression type supercharger 6 of this example will be explained based on FIGS. 8 and 9.

The compression structure of the internal compression type supercharger 6 is provided in a screw type with a pair of rotors 28 and 29 similar to the previous example. The internal compression release means 50 includes a piston member 51 slidably disposed within the end of the casing 27 in contact with the discharge side ends of the rotors 28 and 29, and this piston member 51 differs from the structure of the previous example. There is no inner chamber 34 in the middle section. The inner end surface of the piston member 51 can come into contact with the end surface of the rotor 29, and the pressure of the discharge port 32 acts on the other end surface, while the pressure of the piston chamber 52 acts on the other end surface. is return spring 5
3 has been reduced.

The air passage 54 communicating with the piston chamber 52 is provided with an air vibe 55 (one end of which opens into the surge tank 7).
(Fig. 7) is connected to the supercharger 6.
And intake pressure P2 (supercharging pressure) downstream of the throttle valve 5 is introduced. As in the previous example, the piston member 51 has two states: a closed state in which it moves to the right and contacts the end of the rotor 29 to allow internal compression, and an open state in which it moves to the left and releases the internal compression by moving away from the end of the rotor 29. It operates according to the following conditions.

The force F acting on the piston member 51 has a positive direction of action toward the open state, an intake pressure downstream of the supercharger 6 as Pi, an intake pressure downstream of the throttle valve 5 as P2,
The biasing force of the spring is Ps.

If the piston area is A, then F=AX (P+ -P2) Ps. Therefore, the piston member 51 opens and closes depending on the magnitude of the spring force and the area x pressure difference, and opens and closes in response to fluctuations in intake pressure accompanying changes in the opening degree of the throttle valve 5.

That is, FIG. 10 shows the pressure P1. P2 fluctuation characteristics and the opening/closing characteristics of the piston member 51 and the bypass valve 12 are shown, and the changes in the intake pressure (supercharging pressure) P2 downstream of the throttle valve 5 supplied to the engine 1 are the same as in the previous example; The pressure P1 upstream of the valve 5 and downstream of the supercharger 6 increases from atmospheric pressure as the supercharger 6 operates, and as the throttle opening increases,
The pressure difference between the upper and lower parts of the throttle valve 5 is small and is the same in the fully open state.

Then, the bypass valve 12 is operated to open in a state where the differential pressure before and after the throttle valve 5 is large, and the piston member 51 of the internal compression release means 50 moves to the left to release the internal compression of the supercharger 6, and the throttle valve 5 As the throttle valve 5 opens, the bypass valve 12 and the piston member 51 close in response to a decrease in the pressure difference before and after the throttle valve 5, thereby acting to increase the supercharging pressure.

In this embodiment, the throttle valve 5 is provided in response to the condition that it is installed downstream of the supercharger 6, and the structure of the internal compression release means 50 is simpler than in the previous example. Other functions are the same as in Example 1.

Note that the structure of the internal compression means 10a of the first embodiment is also applicable to the case where the throttle valve 5 is disposed downstream of the supercharger 6.

(Effects of the Invention) According to the present invention as described above, the internal compression type supercharger is provided with an internal compression release means for releasing its internal compression action to reduce driving resistance, and the internal compression release means is disposed downstream of the throttle valve. By operating the internal compression release means in response to the intake pressure on the side and on the downstream side of the supercharger, in light load regions where supercharging is not required, the internal compression release means is released and activated, and the internal compression release means is released with little drive resistance. The compression type supercharger is stopped and allowed to idle while the drive is stopped, improving the torque shock at the start of drive and increasing the supercharging response.The area where the supercharger's drive is stopped is also expanded to improve the light load range. It is possible to improve the fuel efficiency of In addition, the release of internal compression in the internal compression supercharger is controlled by fluctuations in the intake negative pressure downstream of the throttle valve in response to driver operation, and the internal compression is started in response to requests for supercharging such as acceleration. It is possible to carry out supercharging, suppress the occurrence of torque shock due to changes in the operating state when transitioning to the supercharging request state, and perform good supercharging control to fully utilize the functions of the internal compression type supercharger. It is possible.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention, FIG. 1 is an overall configuration diagram of an engine supercharging device, FIG. 2 is a partially sectional plan view of an internal compression type supercharger, and FIG. Figure 4 is a cross-sectional side view of the same, Figure 5 is a characteristic diagram showing pressure changes in various parts corresponding to changes in throttle opening and operating characteristics of the bypass valve and supercharging pressure release means. Fig. 7 is a characteristic diagram showing the control region, Fig. 7 to Fig. 10 show a second embodiment of the present invention, Fig. 7 is an overall configuration diagram of an engine supercharging device, and Fig. 8 is an internal compression type supercharger. FIG. 9 is a partial cross-sectional plan view of the charger, FIG. 9 is a front view thereof, and FIG. 10 is a characteristic diagram showing pressure changes in various parts corresponding to changes in throttle opening and operating characteristics of a bypass valve and supercharging pressure release means. 1...Engine, 2...Intake passage, 5
... Throttle valve, 6 ... Internal compression type supercharger, 10.50 ... Internal compression release means, 11 ... Bypass passage, 12
...Bypass valve, 14...Electromagnetic clutch, 20...Controller, 27...
...Casing, 28.29 ...Rotor, 31
... Suction port, 32 ... Discharge boat, 33, 51 ... Piston member, 35.52.
... Piston chamber, 36.53 ... Spring, 39, 40.55 ... Air pipe. Figure 2 Figure 3 Figure Figure

Claims (2)

[Claims] (1) Engine supercharging characterized in that an internal compression type supercharger is provided with an internal compression release means, and the internal compression release means is activated in accordance with the intake pressure downstream of the throttle valve and downstream of the supercharger. Device. (2) The engine supercharging device according to claim 1, wherein the internal compression release means is released by a balance between intake pressure downstream of the throttle valve and downstream of the supercharger and atmospheric pressure.