JPS61255220A - Variable nozzle device of exhaust gas turbine supercharger - Google Patents

Abstract

PURPOSE:To increase a supercharger pressure during low load running of an engine and to provide excellent engine performance responding to every operation condition, according to the method wherein a part of an exhaust passage on the upper stream of a nozzle is partitioned by a partition 4 to form a passage for control, and the passage for control is opened and closed by an opening and closing mechanism. CONSTITUTION:A partition 4 is welded to an exhaust inlet casing 3 to form a partition passage 4 (part E), and one of the exhaust gas passages of a nozzle 2 is situated independently from other passage. A block plate support 5, a block plate 7 supported by a bearing 6 are mounted to the exhaust gas incoming side of the parttion 4. A shaft 8 is screwed in the block plate 7, is positioned by a positioning pin 17, and a lever 9, positioned by a rotation preventing plate 15, is secured to the shaft 7 by means of hexagonal nut 13 and spring seat metal 14. With the lever 9 controlled, the block plate 7 is rotated through the shaft 8 to control incoming of exhaust gas to the part E. This enables lowering of an exhaust gas temperature through increase of a charging pressure, and permits reduction of production of dirt of a supercharger.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable nozzle device for an exhaust gas turbine supercharger using an axial flow turbine. 1 [Conventional technology,
] The diesel engine and on-board supercharger are matched to operate with high efficiency at loads of 80 to 100.
When operating in a low load range such as deceleration operation or port maneuvering, the efficiency of the supercharger decreases, resulting in a decrease in supply pressure.

When the supply pressure decreases, the amount of air charged into the combustion chamber decreases,
As a result of the decrease in air volume in the atrium, the exhaust gas temperature increases.
There are concerns that high temperatures will have a negative impact on the engine.

As a means to deal with this problem, a number of variable nozzle devices have been considered in order to shift the matching point of the supercharger to the low load range and improve the temperature conditions at low loads, but the structure is complicated. There is a high possibility of failure, and in particular, there is a possibility that moving parts may cause reverse malfunction due to deposits of combustion residue (hereinafter referred to as dirt).

Figures 4(a) and 4(b) are structural diagrams of a conventional turbocharger. Exhaust gas discharged from each cylinder of the engine is collected in the exhaust pipe, and the exhaust gas is connected to the exhaust inlet casing as shown in Figure 4. 23, is throttled by the nozzle 24 to increase its velocity, and its flow direction is bent, and then flows into the turbine blade 21.

Furthermore, the state changes in the turbine blade 21 in a similar manner, causing the turbine rotor 22 to rotate, and then being discharged from the exhaust outlet casing 25.

A centrifugal blower (not shown) is attached to the turbine rotor 22 on the opposite side of the turbine blades 2.
It has a structure that feeds air to the engine through the rotation of No. 2.

The blades of the nozzle 24 are fixed, and the area through which the exhaust gas passes is constant.As the load on the engine decreases, the amount of exhaust gas discharged decreases, and the speed at which the exhaust gas passes through the nozzle 24 becomes slower. The applied operating energy is reduced and the rotational speed of the turbine rotor 22 is reduced.

When the rotational speed of the turbine rotor 22 decreases, the amount of air discharged from the centrifugal blower decreases, and the temperature of the exhaust gas from each cylinder increases. When the exhaust gas temperature rises, problems arise such as adverse effects on the seat surface of the exhaust valve and dirt on the supercharger.

Therefore, during low load operation of the engine, it is necessary to reduce the exhaust gas passage area of the nozzle 24 and increase the exhaust gas passage speed to increase the amount of air discharged from the blower. As a method of reducing the passage area of the exhaust gas of the nozzle 24 and increasing the speed when the engine is under low load, there is a method of rotating the nozzle blades 31 arranged around the entire circumference as shown in FIG. The nozzle blade 31 is supported by the nozzle outer ring 32 and the nozzle inner ring 33 via the bushing 34, and is rotatable.
:9 There is a high possibility that malfunction will occur, and if even one malfunction occurs, all the nozzle blades 31 will stop moving. This method has the disadvantage of having a complicated structure including links and low reliability.

[Problem that the invention seeks to solve]

The purpose of the present invention is to eliminate the drawbacks of the conventional device, increase the boost pressure during low load operation of the engine, ensure good safe operation of the engine under all operating conditions, and provide a simple structure. The present invention provides a variable nozzle device for an exhaust gas turbine supercharger.

[Failure to solve the problem]

In the variable nozzle device for an exhaust gas turbine supercharger according to the present invention, a part of the exhaust passage upstream of the nozzle is partitioned by a partition plate to provide an exhaust passage having an opening/closing mechanism, and further includes a seal portion of the opening/closing mechanism. A means for supplying sealing air to the movable part is added to achieve the above object.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In Figures 1 and 2, a partition plate 4 is welded to the exhaust inlet casing 3, forming a partition passage 4 (hereinafter abbreviated as section E) and connecting one of the exhaust gas passages of the nozzle 2 with another passage. It is made independent (see Figure 2). A closing plate 7 supported by a temporary closing support 5 and a bearing 6 is attached to the end of the partition plate 4 on the exhaust gas inflow side. A shaft 8 is screwed into the closing plate 7 and positioned by a positioning pin 17. A lever 9 positioned by a rotation stopper plate 15 is fixed to the shaft 8 by a hexagonal nut 13 and a spring washer 14. By operating the lever 9, the closing plate 7 is rotated via the shaft 8, and the E part is rotated. The inflow of exhaust gas into the engine can be controlled.

The lever 9 can be fixed to the exhaust inlet casing 3 by a hexagonal bolt 10 and a spring washer 11 in an open position, a closed position, and any desired position. Is there a l? between the bearing 6 and the exhaust inlet casing 3?
Gas sealed with Tsukin 12. The air piping from the engine's air supply pipe is connected to the 0 part 9, and the bearing 6. Axis 8.
An air passage is provided in the closing plate 7.

Three sets (the number is arbitrary) of this device are attached to the exhaust inlet casing 3, and each variable nozzle device can be operated independently.

Next, the operation of the above embodiment will be explained.

During regular operation, if the lever 9 is fixed in the open position, it can be operated in the same way as a conventional supercharger.

During operation in a low load range, the lever 9 is fixed in the closed position to block the exhaust gas from flowing into the section E, thereby reducing the gas passage area of the nozzle 2. When the exhaust gas passage area is reduced, the exhaust gas passage speed can be increased even under the same load, the rotation speed of the turbine rotor 1 can be increased, the supply pressure can be increased, and the exhaust gas temperature can be lowered.

Since the present invention uses a variable nozzle device with three nozzles (the number is arbitrary), the passage area of the nozzle 2 can be changed in stages according to the load.

Also, if you set it to match the normal operating range with one set closed and the second set open, if an unfavorable condition for the engine called surging occurs due to aging of the hull or dirt on the supercharger, the shutoff will close. Surging can be avoided by opening the variable nozzle device 1.

By using the variable nozzle device for a turbocharger according to the present invention, the supply air can be used as sealing air for the exhaust gas by taking advantage of the fact that the supply pressure is always higher than the exhaust pressure. That is 6
The sealing air that flows in through the pipe (not shown) flows out from the gap between the bearing 6 and the shaft 8 (section F in FIG. 3) and the gap between the closing plate 4 and the temporary closure 5 (section G in FIG. 3). This prevents dirt from adhering to these gaps and prevents malfunctions from occurring.

〔Effect of the invention〕

As mentioned above, in the first invention, a part of the exhaust passage upstream of the nozzle is partitioned by a partition plate, and at least one control passage is provided, and the control temperature can be lowered. It is possible to reduce dirt on the supercharger and extend the life of the supercharger and engine.

Furthermore, according to the second invention, in addition to the effects of the first invention, the supply air is used as sealing air for the exhaust by taking advantage of the fact that the supply pressure is always higher than the exhaust pressure, so that the supply air is placed upstream of the nozzle. It is possible to further prevent dirt from adhering to the gap in the provided opening/closing mechanism for the exhaust passage, and it is possible to greatly reduce the possibility that the opening/closing mechanism will malfunction.

[Brief explanation of the drawing]

1 to 3 relate to a variable nozzle device for an exhaust gas turbine supercharger according to the present invention, in which FIG. 1 is a cross-sectional view of a main part, FIG. 2 is a cross-sectional view taken along line DD in FIG. 1, and FIG. is an enlarged view of the opening/closing mechanism section of the exhaust passage E, FIGS. 4 and 5 are conventional examples, and FIG. 4(a) is a sectional view of the exhaust gas turbine section, and FIG. 4(l)
is a view in the direction of arrow A in FIG. 4(a), FIG.
FIG. 5(b) is a sectional view taken along line BB in FIG. 5(a). 2... Spout, 4... Partition plate 5-15... Opening/closing mechanism, E... Partition passage, F, G... Seal part of opening/closing mechanism,
Movable part, C... means for supplying sealing air.

Claims (2)

[Claims] (1) A variable nozzle device for an exhaust gas turbine supercharger comprising a control passage in which a part of the exhaust passage upstream of the nozzle is partitioned by a partition plate, and an opening/closing mechanism for opening and closing the control passage. . (2) Provide a control passage in which a part of the exhaust passage upstream of the nozzle is partitioned with a partition plate, and an opening/closing mechanism that opens and closes the control passage, and further seal the sealing part and movable part of this opening/closing mechanism. A variable nozzle device for an exhaust gas turbine supercharger, comprising means for supplying air.