JPH0128266Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a maximum speed limiting device for a vehicle equipped with a supercharged engine equipped with a supercharger such as a turbocharger.

The present invention is an improvement over the prior art shown in FIG. 1 (patent application filed on March 1, 1980 by the present applicant). In this prior art, a differential pressure-operated maximum speed limiting valve b is disposed in a relief passage a that relieves a portion of intake air downstream of a supercharger, and a first pressure introduction system that guides atmospheric pressure to a pressure impulse chamber c is provided. A passage switching device that connects two pressure introduction passages, d and a second pressure introduction passage e that guides the pressure of intake air downstream of the supercharger, and selectively switches between the two pressure introduction passages according to the vehicle speed. f, and a throttle device g is arranged in a common passage of the first pressure introduction line d and the second pressure introduction line e.

In the apparatus shown in FIG. 1, the relief passage a is connected to the surge tank h, and the middle part of the relief passage a is used as the pressure chamber i corresponding to the pressure chamber c of the maximum speed limiting valve b. A second pressure introduction line e is connected to the surge tank h. Further, as the throttle device g, there is one whose non-return function is opposite in direction.
The device is equipped with a pair of non-return functions j and k.

When the vehicle speed is lower than the set maximum speed, the surge tank h is passed through the second pressure introduction line e.
The passage switching device f is configured such that the pressure inside is guided to the pressure impulse chamber c, and the maximum speed limiting valve b is configured such that there is almost no differential pressure between the pressure impulse chamber c and the pressure chamber i. The valve is in a closed state. On the other hand, when the vehicle speed exceeds the set maximum speed, the vehicle speed switch m of the speedometer operates and the passage switching device f
is switched, and the pressure chamber c is connected to the first pressure introduction path d.
Since the pressure chamber c and the pressure chamber i are communicated with the atmosphere through the
is in an open state. As a result, a portion of the intake air in the surge tank h is relieved from the relief passage a.

In the prior art described above, immediately after the passage switching device f is switched, the throttle is installed in order to prevent the pressure in the pressure chamber c from rapidly increasing or decreasing, and to prevent the maximum speed limiting valve b from opening and closing rapidly. A device g is installed. The function of the throttle device g prevents a sudden drop in engine output or a sudden recovery during intake relief or output recovery, thereby improving drivability.

However, the throttle device g in the prior art described above transfers the pressure of intake air in the surge tank h to the second pressure introduction system e.
When the pressure is introduced into the pressure chamber c through the surge tank h, a delay effect is always exerted, so that the pressure in the pressure chamber c rises with a time lag relative to the rise in pressure in the surge tank h. Therefore, during a sudden acceleration operation at a set maximum speed or lower, a pressure difference is generated between the pressure chamber i and the pressure chamber c, and there is a possibility that the maximum speed limiting valve b opens and an intake air leak occurs.

In order to reliably prevent intake air leakage during sudden acceleration operation in the prior art described above, the present invention directly supplies intake air pressure downstream of the supercharger in addition to the first pressure introduction system and the second pressure introduction system. A third pressure introduction line leading to the pressure chamber is provided, and the passage switching device is configured to selectively switch the pressure introduction passages of these three lines according to the vehicle speed. shall be.

The present invention will be explained in detail below based on embodiments shown in the drawings.

In the embodiment shown in FIG. 2, the present invention is applied to an automobile equipped with a turbocharger 5 and whose supercharging blower is used as a supercharger 2. A surge tank 6 and a carburetor 7 are arranged downstream of the supercharger 2 in the intake passage 1. In addition, a blow-off valve (safety valve) is installed at a suitable location downstream of the turbocharger 2 in the intake passage 1, which automatically opens when the boost pressure exceeds a predetermined pressure, relieves the intake air to the atmosphere, and lowers the boost pressure. 8 is placed.

On the other hand, an exhaust turbine 10 of the turbocharger 5 is disposed in the exhaust passage 9, and a waste gate passage 11 that bypasses the exhaust turbine 10 is disposed. Furthermore, a waste gate opening/closing valve 12 is provided to open and close the gate of the waste gate passage 11, and when the supercharging pressure of the intake passage 1 reaches a predetermined pressure (a pressure slightly lower than the operating predetermined pressure of the blow-off valve 8), the waste gate opens and closes. By opening the valve 12 and bypassing a portion of the exhaust gas to the wastegate passage 11, the output of the exhaust turbine 10 is reduced.

As described above, when the supercharging pressure of the intake air pressurized by the supercharger 2 reaches a predetermined pressure, firstly by the wastegate on-off valve 12 and then by the blow-off valve 8, The engine output is suppressed in two stages, which in turn suppresses the increase in vehicle speed.

The surge tank 6 has a relief passage 1 that releases a part of the intake air in the surge tank 6 to the atmosphere.
3 is connected. And this relief passage 13
Differential pressure operated maximum speed limiting valve 3 that opens and closes this valve.
are arranged. The maximum speed limiting valve 3 includes a pressure chamber 14 that forms a part of the relief passage 13 (therefore communicates with the surge tank 6), a pressure chamber 16 containing a return spring 15, and a pressure chamber 14. A diaphragm 17 operated by a pressure difference with the pressure chamber 16, and a valve body 21 fixed to the diaphragm 17 to open and close the relief passage 13.
It consists of a diaphragm valve.

The pressure chamber 16 includes a first pressure introduction line 24 that introduces atmospheric pressure through the throttle device 4, a second pressure introduction line 25 that introduces the pressure of the intake air in the surge tank 6 through the throttle device 4, and The three pressure introduction passages A of the third pressure introduction line 26 which directly introduce the pressure of the intake air in the surge tank 6 are connected. Further, a passage switching device 18 is provided for selectively switching the pressure introduction passages A of the three systems according to the vehicle speed.

In the device shown in FIG. 2, the passage switching device 18 is constituted by an electromagnetic four-port switching valve, and this passage switching device 18 includes a surge tank communication pipe 27, an atmosphere communication pipe 28, a throttle device communication pipe 29, and a bypass device. A pipe 30 is connected. and the first
The pressure introduction system 24 is composed of an atmosphere communication pipe 28 → passage switching device 18 → throttle device communication pipe 29 → throttle device 4 → common pipe 31, and when the passage switching device 18 is in a position where the first pressure introduction system 24 is opened, When switching,
The pressure in the pressure chamber 16 is released to the atmosphere via the throttle device 4. The second pressure introduction system 25 is composed of a surge tank communication pipe 27 → passage switching device 18 → throttle device communication pipe 29 → throttle device 4 → common pipe 31. When switched to the opening position,
The pressure of intake air in the surge tank 6 is introduced to the pressure chamber 16 via the throttle device 4.
The third pressure introduction line 26 is composed of a surge tank communication pipe 27 → passage switching device 18 → bypass pipe 30 → common pipe 31, and when the passage switching device 18 switches the third pressure introduction line 26 to a position where it opens. When,
The pressure of the intake air in the surge tank 6 is directly guided to the pressure chamber 16.

The path switching device 18 is located at a position where only the first pressure introduction path 24 is opened in response to an electric signal from a vehicle speed switch 20 of the speedometer 19 when the vehicle speed exceeds a set maximum speed (for example, 190 km/h). When the vehicle speed is below the set maximum speed and the preset speed is slightly lower than this (for example, 170
Km/h), the vehicle speed switch 20 is configured to switch to a position in which only the second pressure introduction line 25 is opened by an electric signal from the vehicle speed switch 20. Further, when the vehicle speed is lower than the preset speed, the passage switching device 18 switches the third pressure introduction line 2
It is in the switching position where only 6 is opened.

The diaphragm device 4 has a reverse check function 1 having opposite directions.
A pair of apertures 22 and 23 with a check function are provided. The first check function restrictor 22 is connected to the first pressure introduction line 24
When the valve is opened, it prevents the supercharged air in the pressure chamber 16 from being rapidly released to the atmosphere, and performs a speed control function that allows the maximum speed limiting valve 3 to open gradually. . The second restrictor 23 with a non-return function causes the air at the supercharging pressure to rapidly enter the pressure chamber 16 when the first pressure introduction line 24 is switched from the open state to the second pressure introduction line 25 open. It performs a speed control function to prevent the maximum speed limit valve 3 from flowing into the air and to gradually close the maximum speed limit valve 3. By optimally setting the respective throttling amounts of the pair of check function restrictors 22 and 23, the relief passage opening operation and relief passage closing operation of the maximum speed control valve 3 can be performed optimally. . Note that the aperture device 4 is
It is also possible to use one aperture as shown in the figure. Further, in FIG. 2, 32 is the engine body.

In the embodiment shown in FIG. 3, the passage switching device 18 is composed of two electromagnetic three-port switching valves 18a and 18b, and is configured to perform the same function as the embodiment shown in FIG. . In other words, when the vehicle speed exceeds the set maximum speed, the first pressure introduction path 2
4, when the vehicle speed is between the set maximum speed and the set reserve speed, the second pressure introduction line 25 is opened, and when the vehicle body speed is less than the set reserve speed, the third pressure introduction line 26 is opened. Okay, speedometer 1
Under the control of the vehicle speed switch 20 of 9, both the switching valves 1
8a and 18b are configured to be switched.
Incidentally, instead of one of the switching valves 18b, it is also possible to employ an on-off valve 18c shown in phantom lines in FIG. may include.

The present invention can be configured in various ways other than those shown in the above embodiments. For example, in the embodiment shown in FIG. 2, the third pressure introduction line 26 is connected to the surge tank communication pipe 27 → passage switching device 18 - → by → throttle pass pipe 30, device communication pipe 29 → throttle device 4 → common pipe 31. The path switching device 18 can be configured to be configured. Further, in the above embodiment, the tip of the relief passage 13 is opened to the atmosphere, and the intake air is relieved to the atmosphere when the maximum speed limiting valve 3 is opened. It can be configured to be relieved at a certain point or at an appropriate location in the exhaust passage 9. Furthermore, although the relief passage 13, the second pressure introduction line 25, and the third pressure introduction line 26 are connected to the surge tank 6 in the above embodiment, they are connected to the downstream side of the supercharger 2 other than the surge tank 6. It may also be connected to an appropriate position in the intake passage 1 of. Furthermore, in the above embodiment, a part of the relief passage 13 also serves as a pressure introduction passage that directly introduces the pressure of the intake air downstream of the supercharger into the pressure chamber 14 of the maximum speed limiting valve. The introduction passage and the pressure chamber 14 may be provided independently.

Since the present invention has the above-mentioned configuration, similar to the prior art described above, the sudden opening and closing movement of the maximum speed limiting valve is avoided, thereby preventing a sudden drop or sudden recovery of engine output during intake relief or output recovery. Drivability can be improved.

In addition, in this invention, until the vehicle speed reaches a speed close to the set maximum speed (set preliminary speed), the pressure of the intake air downstream of the supercharger is transferred to the pressure chamber of the maximum speed limiter via the third pressure introduction line. As a result, the maximum speed control valve can be reliably kept closed because it is guided directly.
It is possible to solve the problem of intake air leakage during sudden acceleration driving, which was seen in the prior art.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of the main parts of a maximum speed limiter developed prior to the present invention, Fig. 2 is a system diagram of an embodiment of the present invention, and Fig. 3 is a main part of another embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Intake passage, 2... Supercharger, 3... Maximum speed limiting valve, 4... Throttle device, 13... Relief passage, 16... Pressure chamber, 18... Passage switching device, 2
4...first pressure introduction system, 25...second pressure introduction system, 26...third pressure introduction system.

Claims (1)

[Scope of utility model registration request] A maximum speed limiting valve configured to open the relief passage when the differential pressure between the pressure chamber and the pressure chamber exceeds a predetermined value is provided in the relief passage that relieves a portion of the intake air downstream of the turbocharger. A first pressure introduction system that introduces atmospheric pressure through a throttle device into the pressure impulse chamber, a second pressure introduction system that leads the pressure of intake air downstream of the supercharger through a throttle device, and Three systems of pressure introduction passages of a third pressure introduction system that directly introduces the pressure of intake air downstream of the turbocharger are connected, and a pressure introduction passage that directly introduces the pressure of intake air downstream of the turbocharger is connected to the pressure chamber. , when the vehicle body speed exceeds the set maximum speed in the pressure introduction path including the first pressure introduction system path and the third pressure introduction system path, only the first pressure introduction system path is opened and the vehicle body speed is set. When the vehicle body speed is below the maximum speed and exceeds a set reserve speed slightly lower than this, only the second pressure introduction system is opened, and when the vehicle body speed is below the set reserve speed, the third pressure introduction system is operated to open. A maximum speed limiting device for a vehicle equipped with a supercharged engine, characterized by being equipped with an aisle switching device.