JPH0521636Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable displacement turbocharger for a vehicle.

[Conventional technology]

Vehicles such as automobiles are equipped with a turbocharger as described in Japanese Utility Model Application Publication No. 111324/1983 in order to improve the output characteristics of the engine. A variable displacement turbocharger has been developed to optimally control this turbocharger depending on operating conditions.

FIG. 4 shows an example of such a variable displacement turbocharger. With this variable displacement turbocharger,
Engine speed detection means 21, engine load detection means 22, and boost pressure detection means 23 are connected to a control unit 24, which gives a command to a solenoid valve 25, and an actuator 26 can control the variable blade 27 steplessly according to the operating state. It has a structure.

In a freight vehicle equipped with the variable displacement turbocharger described above, an exhaust brake device as shown in FIG. 5, for example, is usually disposed in the exhaust system.

In this exhaust brake device, when the exhaust brake switch 31, the clutch switch 32, and the accelerator switch 33 are operated to the ON state and air is supplied to the air cylinder 34, the exhaust shutter 35 is operated to open the exhaust pipe 36. occlusion,
This can be done by increasing the braking effect of engine braking. Then, the accelerator switch 33 is
The signal from the engine load detecting means 22 turns on when the accelerator lever is not depressed (in the idling state).

[The problem that the idea aims to solve]

Therefore, in a freight vehicle equipped with the variable displacement turbocharger described above, the accelerator switch 33
The ON state of the engine is detected by the engine load detection means 22.
However, if the engine load detecting means 22 is provided, the circuit of the control unit 24 becomes more complicated, leading to an increase in cost. It is desirable to eliminate the engine load detection means 22 and to control the variable displacement turbocharger only by the engine rotation speed detection means 21. However, in such a case, the engine rotation speed detection means 2
If only 1 is used, when the exhaust brake is activated, the variable blade 2
It is difficult to provide a signal to interlock 7.
Therefore, the operation of the variable vane 27 is independent of the exhaust brake, and when the exhaust brake is activated, the exhaust gas with high pressure and large fluctuations flows into the turbine side of the variable displacement turbocharger, so that the variable blade 27 can be opened at any desired opening. There is a possibility that a certain variable blade 27 may vibrate greatly and cause a failure.

The present invention was made to solve the above-mentioned problems, and its purpose is to provide a variable displacement turbocharger that eliminates and protects the variable blade from vibration even when controlling the variable blade based only on the engine speed. It is to provide.

[Means to solve the problem]

To achieve the above object, the present invention includes an engine rotation speed detection means and a signal from only the engine rotation speed detection means to reduce the blade opening when the engine rotation speed is low, and to reduce the blade opening when the engine rotation speed is high. In a variable displacement turbocharger equipped with a control unit that controls the opening degree of the variable blades to increase the opening degree, an accelerator switch and an exhaust brake hand switch are connected to the input side of the control unit, and an exhaust shutter switch is connected to the output side of the control unit. At the same time, the control unit is connected to the solenoid valve that controls the actuator of the engine. When the engine speed is high, the blade opening is controlled to be small, and when the engine speed is high, the blade opening is The present invention is characterized in that it is configured to output a control command to fully open the variable blade in all ranges of engine speed.

[Effect]

In the present invention, when the exhaust brake is activated, the variable vane is fully opened by the controller unit via the solenoid valve at the same time. Therefore, the exhaust gas guided to the turbine side of the variable displacement turbocharger body easily flows between the variable blades, does not apply large pressure to the variable blades, and pressure fluctuations are reduced.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A variable displacement turbocharger according to an embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

In FIGS. 1 and 2, 1 is a variable displacement turbocharger main body, and a plurality of variable blades 2 are disposed on the turbine side of the main body. A first actuator 3 controls the opening degree of the variable blade 2 steplessly. Reference numeral 4 denotes a first solenoid valve, which is connected to the first actuator 3 and also to the compressor 5.

6 is an exhaust shutter installed in the middle of the exhaust pipe 7,
It is actuated by a second actuator 8 consisting of an air cylinder. A second solenoid valve 9 is connected to the second actuator 8, and an air reserve tank 10 is connected to the second solenoid valve 9.

Reference numeral 11 denotes a control unit, to which an engine speed detection means 12, an exhaust brake hand switch 13, and an accelerator switch 14 are connected to the input side, and a first solenoid valve 4 and a second solenoid valve to the output side.
It is connected to the solenoid valve 9. This control unit 11 has a control amount calculation circuit that continuously calculates the opening degree of the variable blade 2 according to the engine speed, and an amplifier circuit, and stores a flowchart shown in FIG. Control is executed based on the chart. In addition, in the figure, 15 is an accelerator lever.

Next, the operation of this embodiment will be explained based on FIG. 3.

First, the engine rotation speed is read by the engine rotation speed detection means 12 (S1). Next, in S2, it is determined whether the exhaust brake hand switch 13 is in the ON state. When the exhaust brake hand switch 13 is in the OFF state (exhaust brake is not activated), even if the OFF signal is input to the controller unit 11, no command is sent to the first solenoid valve 4 that controls the opening of the variable vane 2. not give. Therefore, the engine speed signal is transmitted to the control unit 11.
is input to the first electromagnetic valve 4, and the actuator 3 continuously controls the variable blade 2 to the set value. That is, when the exhaust brake hand switch 13 is OFF, the accelerator switch 14
Regardless of whether the engine speed is ON or OFF, the blade opening of the variable blade 2 is controlled to be small when the engine speed is low, and to be increased when the engine speed is high, based only on the engine speed detection means 12. (S6, S7).

In S2, exhaust brake hand switch 13
When it is determined that the
From this, it is determined whether the driver has taken his or her feet off the vehicle and the vehicle is in an idling state. If it is determined to be OFF, proceed to S6. When it is determined to be ON, proceed to S4. In S4, controller unit 11
transmits an operation command to the actuator 8 via the second solenoid valve 9, and closes the exhaust shutter 6 (the exhaust brake is activated). At the same time, a command is sent to the first solenoid valve 4, and the actuator 3 fully opens the variable blade 2.

That is, at the same time as the exhaust shutter 6 is closed, the actuator 3 fully opens the variable blade 2 in all engine speed ranges (S5).

According to the above configuration, even when the opening degree of the variable blade 2 is controlled only by the engine rotation speed, the variable blade 2 is fully opened at the same time as the exhaust brake is activated, even without an engine load detection means. Therefore, when the exhaust brake is activated, when the high-pressure exhaust gas generated by the exhaust brake is guided to the turbine side of the variable displacement turbocharger main body 1, it easily flows between the variable blades 2 and applies a large pressure to the variable blades 2. This also reduces pressure fluctuations. Therefore, the variable blade 2 can be protected without greatly vibrating.

Further, according to the above configuration, the accelerator switch 1
4 is ON or OFF, the blade opening of the variable blade 2 is controlled to be small when the engine speed is low, and to be large when the engine speed is high, based only on the engine speed detection means 12. This improves acceleration response.

[Effect of idea]

As described above, according to the variable displacement turbocharger according to the present invention, even if the opening degree of the variable blades is controlled only by the engine speed, the variable blades can be activated simultaneously with the activation of the exhaust brake even without an engine load detection means. Fully open. Therefore, when the exhaust brake is activated, when the high-pressure exhaust gas generated by the exhaust brake is guided to the turbine side of the variable displacement turbocharger body, it easily flows between the variable vanes, and the pressure is reduced without applying large pressure to the variable vanes. The fluctuation of will also become smaller. Therefore, the variable blade does not vibrate greatly,
This has the effect of being able to protect this.

Further, when the exhaust brake is activated, it is based only on the engine rotation speed detection means 12, regardless of whether the accelerator switch is ON or OFF, so that the acceleration response is improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of a variable displacement turbocharger according to an embodiment of the present invention, Fig. 2 is a detailed explanatory diagram of the variable vane in Fig. 1, and Fig. 3 is a flowchart showing the execution procedure of control by the control unit. , FIG. 4 is a circuit diagram of a conventional variable displacement turbocharger, and FIG. 5 is a circuit diagram of a conventional exhaust brake device. 1...Variable displacement turbocharger body, 2...
Variable blade, 4...First electromagnetic valve, 6...Exhaust shutter, 8...Second actuator, 9...Second electromagnetic valve, 11...Control unit, 12...Engine rotation speed detection means, 13... Exhaust brake hand switch, 14... accelerator switch.

Claims (1)

[Scope of utility model registration request] An engine rotation speed detection means and a variable blade opening are configured to reduce the blade opening when the engine rotation speed is low and to increase the blade opening when the engine rotation speed is high based on a signal from only the engine rotation speed detection means. In a variable capacity turbocharger equipped with a control unit that controls the engine speed, an accelerator switch and an exhaust brake hand switch are connected to the input side of the control unit, and a solenoid valve that controls the actuator of the exhaust shutter is connected to the output side. When the exhaust brake hand switch is off, the control unit reduces the blade opening of the variable blade when the engine speed is small, regardless of whether the accelerator switch is on or off, based only on the engine speed detection means. When the engine speed is large, the variable blade is controlled to increase in size, while when the accelerator switch is on and the exhaust brake hand switch is on, the variable blade is controlled to increase in size through the solenoid valve at the same time as the exhaust brake is activated. A variable capacity turbocharger characterized in that it is configured to output a control command to fully open the opening of the variable displacement turbocharger.