JPS6231621Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a control device for a mechanical supercharger driven by the shaft output of an internal combustion engine.

As a control device for a positive displacement mechanical supercharger such as a Roots blower type or a vane type, a control device as shown in FIG. 1 has been proposed.

When the load on the internal combustion engine 1 is light, the clutch 2 is in the disengaged state, but when a large load is required such as during acceleration or climbing, that is, when the amount of operation of the accelerator pedal exceeds a preset position. Detecting this, the accelerator pedal switch 3 and the control device 4 bring the clutch 2 into the connected state, and the mechanical supercharger 5 is activated. This avoids driving loss in the low load range of the mechanical supercharger 5.

Further, in this device, an intake bypass passage 6A is formed between the suction side passage 7 and the discharge side passage 8 of the mechanical supercharger 5, and a normally closed valve device 6B interposed in the middle is used as a throttle valve. Opening/closing is controlled via an actuator 11 that responds to the differential pressure between the front and rear of the valve 9. When the internal combustion engine 1 is stopped, the spring 12
The valve device 6B is closed due to the force, but after the engine has started and at low load, the differential pressure across the throttle valve 9 is large, so the device 6B is open.
The intake air does not pass through the mechanical supercharger 5.

In other words, the intake air is passed through the bypass passage 6A to the engine 1.
This avoids an increase in suction loss.

On the other hand, the differential pressure becomes smaller as the load increases, so the valve device 6B moves in the direction of closing in proportion to the load, and accordingly, the internal combustion engine 1 is supercharged and its output increases. (Refer to SAE Paper No. 81006) However, in such a conventional mechanical supercharger control device, the normally closed intake bypass valve device 6B is operated by the actuator 11 which is operated by the differential pressure across the throttle valve 9. Since the valve device 6B is configured to be driven, when the conduits 12a and 12b that introduce differential pressure to the actuator 11 are damaged, or when the diaphragm 13 of the actuator 11 is damaged, the valve device 6B remains closed, and the mechanical supercharger 5 is rotating, the discharge pressure rises abnormally even under light load, resulting in damage to the supercharger 5 and the internal combustion engine 1.

In addition, the clutch 2 in Fig. 1 has been abolished and the supercharger 5 has been replaced.
If the pressure is controlled as described above, the discharge amount per rotation of the supercharger 5 is set to be appropriate when the throttle valve 9 is fully open, so the throttle If the intake bypass valve device 6B starts to close while the tutle valve 9 is half open, the discharge pressure of the supercharger 5 will increase unnecessarily, causing unnecessary work, and the efficiency of the internal combustion engine will deteriorate. arise.

The present invention was developed with a focus on these conventional problems.The bypass valve is normally energized to open to ensure that it opens in the event of a failure in the control system, and the bypass valve is energized to open at a specified high engine load. It is an object of the present invention to provide a control device for a mechanical supercharger that can be closed reliably and quickly to exhibit the desired supercharging function.

To this end, the present invention provides a bypass passage that communicates the suction side passage and the discharge side passage of a mechanical supercharger driven by the shaft output of an internal combustion engine, a valve device that opens and closes this bypass passage, and this valve device. In a mechanical supercharging device equipped with an actuator that drives the
The actuator is configured to drive the valve device to close when negative pressure is introduced, and includes a biasing means for biasing the valve device to be normally open, a load detection means for detecting the engine load state, and a load detection means for detecting the engine suction negative pressure. a negative pressure storage means for storing negative pressure; a valve means for selectively supplying atmospheric pressure or negative pressure from the negative pressure storage means to the actuator; and a control system for driving the valve means to supply negative pressure.

Hereinafter, the present invention will be explained based on the drawings. Note that substantially the same parts as in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, the intake bypass valve device 6B is opened and closed via an actuator (diaphragm device) 15. As shown in FIG. Atmospheric pressure is introduced into one chamber 15A of the actuator 15, and engine negative pressure generated downstream of the throttle valve 9 is basically introduced into the other chamber (pressure chamber) 15B via piping 14. (inhalation pressure) is derived. room 15
A spring 16 is interposed in B as a biasing means for opening the valve device 6B when the internal combustion engine 1 does not require supercharging (this spring 16 may be installed at another location).

The above negative pressure is applied to the tank 1, which is a negative pressure storage means with an appropriate capacity, via the piping 14 and the check valve 17.
Stored at 8.

The negative pressure stored in the tank is transferred to the normally closed first solenoid valve of the two solenoid valves 19 and 20 serving as valve means for selectively supplying the atmosphere or negative pressure to the actuator pressure chamber 15B. 19 to the pressure chamber 15B of the actuator 15. Also,
A normally open second solenoid valve 20 is provided to communicate or shut off the pressure chamber 15B to the atmosphere.

The opening and closing of the two electromagnetic valves 19 and 20 are reciprocal, so if a three-way electromagnetic valve is used, the electromagnetic valves 19 and 20 can be combined into a single valve.

Next, the load condition is detected and the valve device 6B (electromagnetic valve 1
9 and 20) will be explained. Reference numeral 21 denotes a battery, one end of which is grounded, and the other end connected to a switch 22 serving as a load detection means that closes when the throttle valve 9 opens to a certain extent. One end of the switch 22 is connected to the solenoid valves 19 and 2.
0, and one end of the wiring of the solenoid valves 19 and 20 is grounded.

Note that a blow-off valve 23 is provided between the supercharger 5 and the throttle valve 9 to release air to the atmosphere when the discharge pressure of the mechanical supercharger 5 exceeds a set value.

In the above configuration, when the internal combustion engine 1 is started,
On the downstream side of the throttle valve 9, the intake pressure becomes negative pressure. Therefore, the check valve 17 opens and the tank 18
The air inside the tank 18 is sucked out, and the tank 18 becomes under negative pressure.

When the internal combustion engine 1 is under low load, the switch 22 is open, so the first solenoid valve 19 is closed and the second solenoid valve 20 is open.

Therefore, the pressure chamber 15B of the actuator 15 is at atmospheric pressure, and the valve device 6B is in an open state based on the elasticity of the spring 16 (as shown).

Next, in order to increase the output of the internal combustion engine 1, when the throttle valve 9 is opened to a certain opening degree, the switch 22 is closed, so the second solenoid valve 20 is closed and the first solenoid valve 19 is opened. Thus, the negative pressure of the tank 18 is introduced into the pressure chamber 15B. Therefore, the valve device 6B is fully closed against the force of the spring 16.
Supercharging starts.

In order to reduce the output of the internal combustion engine 1 from this state, when the throttle valve 9 is closed to a certain opening degree, the switch 22 is opened, so the second solenoid valve 2 is opened.
0 is open, and the first solenoid valve 19 is closed.

Then, the pressure chamber 15 of the actuator 15
B becomes atmospheric pressure, and the force of the spring 16 opens the valve device 6B again.

In this way, the valve device 6B closes only when the engine 1 reaches a predetermined high load state to enable supercharging, but since it is always biased in the open direction, if the valve device 6B closes under a high load, If, for example, the piping 14a on the downstream side of the solenoid valve 19 is damaged while it is closed, the valve device 6B performs a fail-safe operation in which it operates in the valve opening direction as the negative pressure to the actuator 15 decreases.

Therefore, damage to the engine 1 and the supercharger 5 in the event of equipment failure can be avoided. In addition, since the valve device 6B is immediately fully opened from the closed state during supercharging upon transition to the low-load operating range, the problem of unnecessary supercharging pressure occurring during the transition period does not occur.

FIG. 3 shows another embodiment.

In this embodiment, when controlling the opening and closing of two electromagnetic valves 19 and 20 that govern the flow of operating pressure to the actuator 15, switches 22 and 2 are sequentially opened and closed depending on the opening degree of the throttle valve 9.
This differs from FIG. 2 in that a pressure switch 25 is provided which opens and closes depending on the pressure on the downstream side of the throttle valve 4 and the throttle valve 9. To explain the operational relationship between the switch 24 and the switch 22, it is set so that when the throttle valve 9 is opened, the switch 24 is first opened, and when the throttle valve 9 is further opened, the switch 22 is closed. . The pressure switch 25 is set to open when the pressure reaches a certain level of negative pressure, and to close under other conditions.

Now, when the throttle valve 9 is opened to a certain opening degree in order to increase the output of the internal combustion engine 1, the switches 24 and 25 are first closed, and the second solenoid valve 2 is closed.
0 is closed. Further, when the throttle valve 9 is opened and reaches a certain opening degree, the switch 22 is closed and the first electromagnetic valve 19 is opened.

On the other hand, when the throttle valve 19 is closed from the supercharging operation state, the first solenoid valve 19 first closes, and then the second solenoid valve 20 opens, in contrast to the above.

In this way, when supplying negative pressure to the actuator 15, the second solenoid valve 20 for introducing atmospheric air closes, and similarly, when cutting off negative pressure, first solenoid valve 19 for introducing negative pressure closes. close. Therefore, there is no risk of losing the negative pressure in the tank 18 when the second solenoid valve 20 opens or closes, and the tank 18 can thus be made smaller.

Further, when the throttle valve 9 is suddenly closed, the pressure switch 25 is opened due to the sudden increase in the suction negative pressure, and the second electromagnetic valve 20 is immediately opened, so that the valve device 6B is immediately opened. Therefore, it is possible to reliably avoid a problem in which the opening operation of the valve device 6B is delayed during deceleration and the supercharging pressure becomes relatively excessive.

In addition, a microcomputer or the like is provided to control the opening or closing operation of the throttle valve 9 by controlling the switch 2.
2, it is also easy to electronically control the sequential operation of the two electromagnetic valves 19 and 20,
This allows more precise control.

As explained above, according to this idea,
Since the intake bypass valve device is always energized to be open and forced to fully close only when supercharging is required, there is no need to install negative pressure introduction piping to the actuator to drive the valve device. Even if the actuator's diaphragm were to be damaged, the effect of this system is to ensure that the discharge pressure of the mechanical supercharger does not rise abnormally and damage the supercharger itself or the internal combustion engine. .

As mentioned above, it is possible to use the discharge pressure from a mechanical supercharger as a pressure source to drive the actuator, but the discharge pressure only increases for a very short time when high load is required. Moreover, its absolute value may be suppressed due to engine output and durability requirements, so it is not always possible to secure the necessary amount of pressure. Additionally, if you try to make full use of the discharge pressure, a part of the engine power will be used to drive the actuator, which will result in losses, since mechanical superchargers are driven by an internal combustion engine. may occur. In this point,
The present invention uses the strong suction negative pressure that is generated when the throttle valve closes during deceleration, so a strong pressure source can be maintained at all times, and the actuator and bypass valve device can be operated reliably and quickly. It will be done. Moreover, it goes without saying that no power loss can occur in this case.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional example. FIG. 2 is a schematic diagram of an embodiment of the present invention. FIG. 3 is a schematic diagram of another embodiment. 1...Internal combustion engine, 5...Mechanical supercharger, 6A...
...Intake bypass valve passage, 6B... Valve device for intake bypass, 7... Suction side passage of supercharger, 8... Discharge side passage of supercharger, 9... Throttle valve, 1
5...actuator (diaphragm device), 1
9,20... Solenoid valve.

Claims (1)

[Scope of utility model registration request] A mechanical supercharger driven by the shaft output of an internal combustion engine includes a bypass passage that communicates a suction side passage and a discharge side passage, a valve device that opens and closes this bypass passage, and an actuator that drives this valve device. In the mechanical supercharging device, the actuator is configured to drive the valve device to close when negative pressure is introduced, and includes a biasing means for biasing the valve device to be normally open, and a load detection device for detecting an engine load state. means, negative pressure storage means for storing engine suction negative pressure, valve means for selectively supplying atmospheric pressure or negative pressure from the negative pressure storage means to the actuator, and the load detection means. A control device for a mechanical supercharger, comprising: control means for driving the valve means so as to supply negative pressure to the actuator at a predetermined high load.