JPH0667832U - Exhaust brake device - Google Patents

Abstract

(57) [Summary] [Purpose] The braking force of the exhaust brake can be easily changed while the vehicle is running, and a reliable braking force can be obtained even in the low speed rotation range of the internal combustion engine. [Structure] Supercharging means 5 driven by engine exhaust
7, means 56 for changing the capacity of the supercharging means 57, means 51 for detecting the depression amount of the accelerator pedal 50, means 55 for setting the capacity of the supercharging means 57, and means for instructing the operation of the exhaust brake. 52, a means 53 for comparing the depression amount of the accelerator pedal 50 with a preset depression amount when the commanding means 52 is on, and a supercharging means 57 for the supercharging means 57 when the comparison result is less than the preset depression amount. The control means 54 drives the capacity changing means 56 so that the capacity becomes the set value of the capacity setting means 55.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exhaust brake device for a vehicle equipped with an internal combustion engine equipped with a variable displacement supercharger.

[0002]

[Prior art]

 In addition to the foot brake, vehicles such as trucks are known to be equipped with an exhaust brake device that closes the exhaust pipe as an auxiliary braking means to increase the pressure in the combustion chamber and brake the drive wheels. In a vehicle equipped with an internal combustion engine equipped with a turbocharger, as disclosed in Japanese Utility Model Laid-Open No. 1-131830, the nozzle vanes that change the capacity of the turbocharger during operation of the exhaust brake are fully opened, and the turbocharger is opened. It is known that the response of an exhaust brake is improved by increasing the flow rate of exhaust gas to a shutter provided in an exhaust pipe.

[0003]

[Problems to be solved by the device]

 However, in the above-mentioned conventional exhaust brake device, since the control of the exhaust brake is controlled by closing and opening the shutter, it is difficult to change the braking force according to the weight of the load, etc. When the exhaust brake is operated in the high-speed rotation range of the internal combustion engine, the exhaust pipe is protected by discharging part of the exhaust gas from the shutter so that the pressure in the exhaust pipe does not rise above the set value. In the low speed rotation range, the exhaust pressure was low, and the exhaust brake could not provide sufficient braking force.

Therefore, the present invention provides an exhaust brake device that makes it possible to easily change the braking force of the exhaust brake during traveling and obtains a reliable braking force even in the low speed rotation range of the internal combustion engine. With the goal.

[0005]

As shown in FIG. 1, the present invention provides a supercharging means 57 driven by engine exhaust, a means 56 for changing the capacity of the supercharging means 57, and an accelerator pedal 50. Means 51 for detecting the depression amount of the vehicle, means 55 for presetting the capacity of the supercharging means 57, means 52 for instructing the operation of the exhaust brake, and the accelerator pedal 50 described above when the command means 52 is on. Means 53 for comparing the amount of depression with the preset amount of depression, and when the comparison result is less than the preset amount of depression, the capacity of the supercharging means 57 becomes the set value of the capacity setting means 55. And a control means 54 for driving the capacity changing means 56.

[0006]

[Action]

 When the exhaust brake command means is turned on and the accelerator pedal is loosened to less than a predetermined depression amount, the control means drives the capacity changing means based on the set value of the capacity setting means to change the capacity of the supercharging means. change. Here, if the set value of the capacity setting means is set to the minimum value, the back pressure applied to the combustion chamber of the internal combustion engine is increased in order to regulate the flow rate of the exhaust gas passing through the supercharging means, so It is possible to reliably perform the braking by the exhaust brake, and by changing the set value of the capacity setting means according to the weight of the vehicle, it is possible to easily obtain the braking force according to the running state.

[0007]

【Example】

 2 to 3 show an embodiment in which the present invention is applied to a vehicle equipped with a diesel engine.

2 to 3, an exhaust pipe 2 is connected downstream of a turbocharger 1 driven by receiving exhaust gas supplied from an exhaust port (not shown) of a diesel engine (hereinafter referred to as engine).

As shown in FIG. 3, the turbocharger 1 houses a turbine rotor 11 that rotates by the energy of the exhaust gas from the engine, and the turbocharger 1 has a coaxial outer periphery on which the turbocharger 1 is mounted. A plurality of nozzle vanes 12 for changing the capacity are rotatably supported. By rotating the nozzle vane 12 between the fully open position and the fully closed position in the figure, the flow rate of the exhaust gas flowing into the turbocharger 1 is controlled, so that the capacity of the turbocharger 1 is set to the maximum capacity and the minimum capacity. It can be set to any volume between.

A nozzle vane 12 that changes the capacity of the turbocharger 1 is driven by a diaphragm 7 that expands and contracts according to the negative pressure supplied. The diaphragm 7 is connected to a crank 72 pivotally supported by the turbocharger 1 via a rod 71, and the reciprocating motion of the diaphragm 7 is converted into a motion in the rotational direction by the crank 72 and is housed inside the turbocharger 1. The crank vane 12 and the nozzle vane 12 are connected via a link or the like (not shown), and the nozzle vane 12 is driven by the expansion and contraction of the diaphragm 7.

The diaphragm 7 is supplied with a negative pressure from a vacuum pump 9 connected through a pipe 70, and a solenoid valve 8 for controlling the negative pressure supplied by the vacuum pump 9 is provided in the pipe 70. .

The solenoid valve 8 is composed of a pressure control valve or the like, and the diaphragm 7 is expanded and contracted in response to the negative pressure set by the solenoid valve 8, and when the diaphragm 7 extends toward the maximum extension position, the nozzle vane 12 will While rotating to the fully open position (maximum capacity of the turbocharger 1) shown in Fig. 3, when the diaphragm 7 contracts toward the most contracted position, the nozzle vanes 12 also rotate to the fully closed position (minimum capacity of the turbocharger 1). , The capacity of turbocharger 1 is changed.

The solenoid valve 8 is driven by a control unit 3 composed of a microcomputer or the like, and the control unit 3 outputs a signal from a position sensor 5 for detecting the depression amount of an accelerator pedal 4 and a driver's cab (not shown) or the like. Based on a signal from a switch 6 that is provided in the vehicle to instruct the operation of the exhaust brake and a setter 12 that is also provided in the operator's cab and that sets the braking force of the exhaust brake, when the exhaust brake is operating. The negative pressure of the solenoid valve 8 is controlled, and the exhaust shutter 20 which is interposed in the exhaust pipe 2 to close and open the exhaust pipe 2 is controlled. At the closed position of the exhaust shutter 20, a part of exhaust gas is allowed to pass therethrough to protect the internal pressure of the exhaust pipe 2 from exceeding a predetermined value.

The setting device 12 is composed of, for example, a rotatable volume, and the control unit 3 has a braking force of an exhaust brake, that is, a capacity of the turbocharger 1 according to a rotational position of the volume. Is preset.

While the vehicle is traveling, the control unit 3 controls the capacity of the turbocharger 1 by driving the solenoid valve 8 according to the depression amount of the accelerator pedal 4 from the position sensor 5 and the engine speed (not shown). While controlling the supercharging pressure to the engine (not shown), when the switch 6 is operated by the driver, the control for braking the vehicle by the exhaust brake is performed.

The control flow of the control unit 3 during braking by the exhaust brake will be described in detail with reference to the flowchart of FIG.

First, the control unit 3 determines whether or not the switch 6 is on. If the switch 6 is on, it is determined that the operation of the exhaust brake is instructed, and the process proceeds to S2, while the switch 6 is turned on. If it is off, it is determined that the vehicle is traveling normally and the process proceeds to S7.

In step S2, the depression amount of the accelerator pedal 4 is read from the position sensor 5, and in step S3, it is determined whether the read depression amount is less than a preset depression amount, that is, whether the accelerator pedal 4 is closed. .

If it is determined in S3 that the accelerator pedal 4 is less than the predetermined depression amount, the exhaust brake is operated in the processing from S4 onward, and if the depression amount is the predetermined value or more, it is determined that the vehicle is running. The process proceeds to S7.

In step S4 of operating the exhaust brake, the braking force set by the setter 12, that is, the set value of the capacity of the turbocharger 1 is read. In S5, the control unit 3 drives the solenoid valve 8 to adjust the negative pressure to be supplied to the diaphragm 7, and drives the diaphragm 7 so that the nozzle vane 12 is in the rotating position corresponding to the set value of the capacity.

The diaphragm 7 rotates the crank 72 by displacing the rod 71 according to the change in the negative pressure adjusted by the solenoid valve 8 to rotate the nozzle vane 12 to a predetermined position, and the nozzle vane 12 rotates. The flow rate of exhaust gas from an engine (not shown) is controlled according to the position.

Here, in order to increase the braking force of the exhaust brake in the low speed rotation range of the engine, when the setting device 12 is set to the maximum value of the braking force (not shown), the diaphragm 7 moves from the electromagnetic valve 8 to the maximum value. Is supplied to the contracted position and the nozzle vane 12 is rotated to the fully closed position shown in FIG. 3 via the rod 71 and the crank 72 to minimize the capacity of the turbocharger 1. Therefore, the flow rate of the exhaust gas passing through the turbocharger 1 is regulated, the pressure of the exhaust gas on the upstream side of the turbocharger 1, that is, on the combustion chamber side (not shown) rises, and braking force can be applied to the drive wheels (not shown). .

Further, in S6, the exhaust shutter 20 is closed to block the exhaust gas of the engine (not shown) to further increase the back pressure applied to the combustion chamber and reliably apply the braking force to the drive wheels. At this time, a part of the exhaust gas passes from the exhaust shutter 20, but since the flow rate of the exhaust gas is regulated in the turbocharger 1 according to the set value of the braking force, it is sufficient even in the low speed rotation range of the engine not shown. It is possible to secure a sufficient braking force.

On the other hand, the release of the exhaust brake is performed by turning off the switch 6 or depressing the accelerator pedal 4 by a predetermined amount or more, and the determination of S1 or S3 in the above flowchart becomes NO and the normal traveling is performed. The process proceeds to S7 and S8, which are middle processing.

In S7, the turbocharger 1 controls the supercharging pressure to be supplied to the engine (not shown) according to the amount of depression of the accelerator pedal 4. Although not described in detail, for example, the engine speed and load The capacity of the turbocharger 1 is calculated in accordance with the above, and the nozzle vane 12 is calculated through the diaphragm 7 by controlling the negative pressure of the solenoid valve 8 based on the calculated capacity in the same manner as when the exhaust brake is operated. The turbocharger 1 pumps the intake air at a predetermined supercharging pressure, so that the vehicle can be propelled according to the depression amount of the accelerator pedal 4.

Further, in S8, the exhaust shutter 20 is opened to smooth the flow of exhaust gas downstream of the turbocharger 1 and rotate the turbine rotor 11 efficiently.

In the exhaust brakes in S4 to S6 described above, the case where the braking force of the exhaust brake is improved in the low speed rotation range of the engine has been described. However, the braking force of the exhaust brake is changed according to the change of the vehicle weight. Alternatively, for example, when the weight of goods loaded on the vehicle is large, the braking force is set to the maximum value side by the setter 12, that is, the turbocharger 1 is set to the minimum capacity side when the exhaust brake is activated. By setting the braking force to the minimum value side by the setter 12 when there are few loaded cargos or when the vehicle is empty, that is, by setting the turbocharger 1 to the maximum capacity side when the exhaust brake is activated, it does not depend on the cargo to be loaded. Braking can be performed at a constant deceleration rate to improve driving performance, and the braking force of the exhaust brake is installed in the driver's seat. The scale 12 makes it possible to change easily even while traveling.

In the above embodiment, the capacity of the turbocharger 1 at the time of operating the exhaust brake was manually set by the setter 12. However, although not shown, means for detecting the engine speed is connected to the control unit 3. , The capacity of the turbocharger 1 may be changed according to the detected number of revolutions. For example, by setting the maximum capacity in the high speed rotation range, while setting the minimum capacity in the low speed rotation range, the rotation speed of the engine can be reduced. A stable braking force can be obtained without being affected by the influence.

Further, in the above-mentioned embodiment, the example in which the nozzle vanes 12 for changing the capacity of the turbocharger 1 are driven by the diaphragm 7 is shown, but the invention is not limited to this, and although not shown, a solenoid or It may be a hydraulic actuator or the like.

Further, although the exhaust shutter 20 is provided downstream of the exhaust pipe 2, if the sufficient braking force can be obtained by making the capacity of the turbocharger 1 variable, the exhaust shutter 20 need not be provided.

[0031]

[Effect of device]

 As described above, according to the present invention, since the braking force by the exhaust brake can be changed by the set value of the capacity setting means, the braking force of the exhaust brake can be changed according to the running condition such as the weight of the vehicle and the rotation speed of the engine. It is possible to easily change the setting even in the middle of the engine, so that the driving performance can be improved and the stable braking force can be obtained even in the low speed rotation range of the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of an essential part showing a turbocharger.

FIG. 4 is a flowchart showing a control flow.

[Explanation of Codes] 1 Turbocharger 3 Control unit 4 Accelerator pedal 5 Depression amount sensor 6 Switch 8 Solenoid valve 7 Diaphragm 11 Nozzle vane 12 Setting device 51 Depression amount detecting means 52 Command means 53 Comparison means 54 Control means 55 Capacity setting means 56 Capacity Changing means 57 Supercharging means

Claims (1)

[Scope of utility model registration request] 1. A supercharging means driven by exhaust gas from an engine, a means for changing a capacity of the supercharging means, a means for detecting a depression amount of an accelerator pedal, and a means for presetting a capacity of the supercharging means. A means for instructing the operation of the exhaust brake, a means for comparing the depression amount of the accelerator pedal with a preset depression amount when the instruction device is on, and the comparison result is less than the preset depression amount. An exhaust brake device, comprising: a control means for driving the capacity changing means so that the capacity of the supercharging means becomes a set value of the capacity setting means.