JPS6256329B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable nozzle control device for an exhaust turbocharger mainly used in automobiles. As shown in Figure 1, exhaust turbo superchargers equipped with a variable nozzle mechanism increase fuel efficiency by increasing the nozzle opening in proportion to the increase in boost pressure to avoid unnecessary increases in boost pressure. As shown in Fig. 2, the nozzle opening is reduced in inverse proportion to the amount of accelerator depression, thereby reducing the amount of pumping work of the engine during partial load. be done.

The purpose of the present invention is to optimally control the nozzle mechanism so that the relationship between the engine rotation speed and the engine torque has the characteristics shown in FIG. 3, which is a combination of both characteristics shown in FIGS. 1 and 2. It has been done.

The present invention will be described in detail below based on a first embodiment shown in FIGS. 4 and 5. Reference numeral 1 denotes a variable nozzle mechanism provided in the exhaust passage at the turbine inlet of an exhaust supercharger for a diesel engine (not shown). 2 is a movable ring, 3 is a swinging arm whose one end is locked to a pin 4 of the movable ring and the other end is pivotally connected to the exhaust passage wall via a pin 5, and 6 is the other end of the swinging arm. It is an integrally mounted vane. A large number of these swing arms 3 and vanes 6 are arranged along the circumference of the movable ring 2, and a nozzle is formed between each vane 6. 7 is a movable ring 2 via rings 8 and 9.
an operating rod connected to and rotating around a pin 10;
When the operating rod rotates clockwise, the opening of the nozzle increases, and when the rod rotates counterclockwise, the opening of the nozzle decreases. 11 is an actuator formed by an air cylinder, and a spring 14 is installed between the piston 12 and the cylinder 13.
The right end of the rod 15 is pivotally connected to the operating rod 7, and the left chamber of the air cylinder 13 is communicated with the intake passage 11' side of the exhaust supercharger to introduce boost pressure. 16 is a fuel injection pump, 17 is a governor,
18 is an accelerator pedal connected to a load control lever 20 via a control rod 19; 21 is a load detection lever that rotates around a pin 22; one end thereof is connected to the cylinder 13; the other end is linked 2
They are each pivoted to 3.

The piston 12, the cylinder 13, the spring 14, the rod 15, the load detection lever 21, and the intake passage 11' of the exhaust supercharger communicating with the left chamber of the air cylinder 11 form a control means.

Next, the operation of this embodiment will be explained.
The arrows shown in the figure indicate the direction of movement of each member. When the accelerator pedal 18 is in the state shown by the two-dot chain line, that is, when the load is low such as idling, the piston 12, cylinder 13, load detection lever 21, and load control lever 20 are in the position shown by the two-dot chain line. Then, the operating rod 7 rotates clockwise from the illustrated state, the movable ring 2 also rotates clockwise, and the nozzle opening degree increases. Therefore, the exhaust flow resistance in the exhaust passage is small,
Pump work can be reduced. Next, when the accelerator pedal 18 is depressed as shown by the solid line to achieve a full load condition, the load control lever 20 is rotated clockwise via the control rod 19. Then, the load detection lever 21 rotates counterclockwise around the pin 22, the cylinder 13 is displaced to the left by a distance B as shown by the solid line, and the nozzle opening degree is controlled to become smaller. That is, the characteristics shown in FIG. 2 are obtained. On the other hand, as the amount of fuel injected from the fuel injection pump 16 increases, the boost pressure increases, which acts on the left chamber of the cylinder 13 as a detection signal, and as a result, the piston 12 is moved by the spring 1.
4, the rod 15 is displaced to the right by a distance A as shown in FIG. In other words, as shown in FIG. 1, when the boost pressure increases, the nozzle opening increases in proportion to the increase, thereby suppressing engine overspeed. According to this embodiment, the amount of depression of the accelerator pedal 18 is detected by the control means, and the control amount B is
Further, since the boost pressure is detected and the control amount A is controlled, so that the target value S is obtained as a result, the nozzle opening degree can be adjusted smoothly.

As a result, the nozzle opening becomes smaller as the amount of depression of the accelerator pedal 18 increases, and the nozzle opening becomes larger as the boost pressure increases, so that control is performed smoothly over the entire operating range. Ru. Furthermore, the amount of depression of the accelerator pedal is large,
The nozzle opening is the smallest at low speed and high load when the boost pressure is low, improving the supercharging effect, increasing the excess air ratio, and improving combustion efficiency.

Although the first embodiment described above was applied to a diesel engine, it may also be applied to a gasoline engine as in the second embodiment of the present invention shown in FIG. That is, the load detection lever 21 constituting the control means
is linked to the throttle valve 25 of the carburetor 24, and is configured to transmit the amount of depression of the accelerator pedal 18 from the load control rod 19 to the load detection lever 21 via the intermediate link 26. is the same as in the first embodiment. Note that 27 is a fuel main nozzle.

In both the first and second embodiments, the actuator 11
Although an air cylinder was used as an air cylinder, a diaphragm type actuator 28 shown in FIG.
Furthermore, it goes without saying that the variable nozzle mechanism 1 can be appropriately applied to a structure in which the variable nozzle mechanism 1 is provided not on the exhaust passage side but on the intake passage side.

As described above, the present invention provides a variable nozzle mechanism that is provided in either the exhaust passage or the intake passage of an exhaust turbo supercharger and controls the flow rate of exhaust or intake air. Actuator that opens and closes the nozzle,
Control to operate the actuator in the direction of closing the opening of the variable nozzle in response to an increase in the amount of accelerator depression and in the direction of opening the opening of the variable nozzle in response to an increase in boost pressure of the exhaust turbo supercharger. The engine output torque characteristics shown in Fig. 3 can be obtained, and the turbine efficiency in the low speed and high load range can be increased, the excess air ratio can be increased, and the combustion efficiency can be improved. It is something that you have.

[Brief explanation of the drawing]

Figure 1 is a curve diagram of the relationship between boost pressure and nozzle opening in an exhaust supercharger with a variable nozzle mechanism, Figure 2 is a diagram of the relationship between load control lever position and nozzle opening, and Figure 3 is a diagram of the relationship between the nozzle, etc. Opening curve diagram,
FIG. 4 is a system diagram in the first embodiment of the present invention, FIG. 5 is a relationship diagram between the control amount and target value in the same embodiment, and FIG. 6 is a partial system diagram in the second embodiment of the present invention. FIG. 7 is a sectional view of a modified example of the actuator. 1: variable nozzle mechanism, 11: actuator,
11': Intake passage, 18: Accelerator pedal, 2
1: Load detection lever.

Claims (1)

[Claims] 1 In an exhaust turbo supercharger equipped with a variable nozzle mechanism installed in either the exhaust passage or the intake passage to control the flow rate of exhaust or intake air, the variable nozzle is connected to the variable nozzle mechanism to open and close the variable nozzle. an actuator, the actuator is operated in a direction to close the opening of the variable nozzle in response to an increase in the amount of depression of the accelerator, and in a direction to open the opening of the variable nozzle in response to an increase in boost pressure of the exhaust turbo supercharger; 1. A variable nozzle control device for an exhaust turbo supercharger, characterized by comprising a control means for controlling the exhaust gas.