JPS6137767Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in turbine equipment.

In a diesel engine, the energy of the exhaust gas discharged from the cylinder is used to drive the exhaust gas turbine, and a blower coaxial with the turbine pressurizes the intake air, increasing the amount of air supplied into the cylinder. A supercharger is used.

BACKGROUND OF THE INVENTION In recent years, diesel engines have become significantly more powerful and supercharged, and as a result, the performance of diesel engines has become increasingly dependent on the performance of the supercharger.

Exhaust gas temperature, fuel consumption rate, etc. are factors used to evaluate the performance of a diesel engine, but in general, when a high-efficiency, high-performance supercharger is adopted, the exhaust gas temperature and fuel consumption rate decrease, and the heat load caused by these decreases. This reduction improves the reliability of each combustion part of the engine. Furthermore, as the exhaust gas temperature decreases, the supercharger outlet exhaust gas temperature also naturally decreases.

On the other hand, since the exhaust gas discharged from the supercharger still has a considerable amount of heat, exhaust gas energy is often recovered by an exhaust gas boiler. In this exhaust gas boiler, the exhaust gas temperature has a large effect on the boiler heat transfer area, so the higher the exhaust gas temperature is, the better.

However, if a high-performance, high-efficiency supercharger is used to reduce the fuel consumption rate of a diesel engine,
Since the exhaust gas temperature decreases, the amount of evaporation in the exhaust gas boiler becomes insufficient. As a countermeasure, it is necessary to increase the heat transfer area of the boiler or increase the exhaust gas temperature, but a drop in the exhaust gas temperature often causes a steam shortage especially in the winter when the outside air temperature drops.

If the exhaust gas temperature can be raised during the winter when the exhaust gas temperature decreases, the exhaust gas boiler can be designed without increasing the boiler heat transfer area.

Conventional devices for increasing the temperature of exhaust gas at the outlet of a supercharger at any time include the following.

(a) A device that bypasses a portion of the exhaust gas sent from the exhaust gas pipe to the supercharger, as shown in Figure 1. In the figure, 01 is a cylinder, 02 is an exhaust gas pipe, 03 is a supercharger, 04 is an exhaust gas boiler, 05 is an exhaust gas bypass pipe, 06 is a valve, and arrow A indicates the atmosphere.

In this device, since the valve 06 of the exhaust gas bypass pipe is exposed to high temperatures, there are problems with the sealing performance and operability of the valve.

(b) A device that increases passage resistance by installing a valve in the exhaust gas outlet passage of the exhaust gas turbine turbocharger.
As shown in the figure. In the figure, numbers 01 to 04
Up to this point, the same members as in FIG. 1 are shown, and 07 is a valve.

In this device, in order to increase the passage resistance,
The engine's operating line (relationship between gas flow rate and pressure) shifts, making it more likely to cause surging and making stable operation difficult.

The purpose of this invention is to control the exhaust gas temperature at the exit of the turbocharger by changing the turbine side efficiency η _t of the turbocharger, and to create a turbine that can prevent the heat transfer area of the exhaust gas boiler from increasing. An object of the present invention is to provide a device that includes a movable ring surrounding a blade tip of a turbine blade, and a drive device that adjusts a gap between the blade tip of the turbine blade and an inner periphery of the movable ring. That's what I prepared for.

Conventional devices that change the efficiency of the turbine to control the exhaust gas temperature are shown in section (b), but they increase passage resistance and cause surging problems.

This invention changes the distance between the turbine blade and the nozzle cover (the gap between the tips of the turbine blades), which has a great effect on the turbine side efficiency, and changes the turbine side efficiency and realizes exhaust gas temperature control without problems such as surging. .

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

FIG. 3 is a sectional view showing a supercharger turbine section of one embodiment of the present invention, and FIG. 4 is a view taken in the direction of arrow A in FIG. 3.

In the figure, a turbine blade 2 is attached to the exhaust inlet side of a supercharger turbine rotor 1. A nozzle cover 3 is attached to the outer periphery of the turbine blade 2. A turbine blade tip gap 4 is provided between the turbine blade 2 and the nozzle cover 3 to prevent the turbine blade 2 from coming into contact with the nozzle cover 3.

When the turbine blade 2 rotates, gas leakage through the gap 4 reduces the amount of work, so the gap 4 is made as small as possible without contact between the turbine blade 2 and the nozzle cover 3.

Therefore, if it becomes possible to change the gap 4 arbitrarily from the outside, the turbine work amount can be changed, and therefore the blower work amount can also be changed. As a result, the exhaust gas temperature at the exhaust gas turbine inlet and outlet also changes.

Therefore, the annular nozzle cover 3, which is separated from the nozzle cover body 3a, is composed of several divided pieces in the circumferential direction, and all or part of each divided piece is connected to the push rod 5, thereby controlling the turbine rotor. It is movable in the radial direction.

A push rod 5 provided on the split piece engages with a cam 8 provided at the tip of a drive shaft 6 from an external active force source 7. Spring receivers 9, 10 and a spring 11 are provided around the push rod 5, and the spring receiver 9 is mounted on a mounting base 13 provided on the casing fixing part. The guide bush 14 supports the middle of the push rod 5. Also, pushyrod 5,
The cam 8, spring receivers 9, 10, and spring 11 are in the protective box 12.
and a mounting base 13 to protect it from exhaust gas. The bearing 15 supports the drive shaft 6.

The operation in the case of the above configuration will be described.

The push rod 5 is powered by a cam 8 powered by an external power source 7.
is moved to a selected position against the spring force of the spring 11 and held at that position.
is moved and held in the radial direction. That is, the gap 4 is made variable and its amount is adjusted.

The present invention as described above has the following effects.

(1) Since the turbine blade tip gap 4 can be adjusted, it is possible to raise the exhaust gas temperature of a diesel engine with an exhaust gas turbine supercharger by any amount at any time. If you take this into consideration and install a boiler with a large heat transfer area, this phenomenon can be solved. Also, in this case,
There is no problem of surcing like with the back pressure increase method.

(2) Since the turbine blade tip clearance 4 is variable, it is not affected by aging, etc., and it is possible to maintain the optimum clearance at all times, which is effective in maintaining engine performance.

Although the exhaust gas turbine supercharger for an internal combustion engine has been described above, the present invention can be applied to all other types of turbines, including turbines.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing a conventional exhaust gas turbine supercharger outlet exhaust gas temperature raising device, respectively. FIG. 3 is a sectional view showing a supercharger turbine section of an embodiment of the present invention, FIG. 4 is a view taken along arrow A in FIG. 1... Turbine rotor, 2... Turbine blade, 3
... Nozzle cover, 4 ... Turbine blade tip gap, 5 ...
Push rod, 6... Drive shaft, 7... External power source, 8... Cam, 11... Spring.

Claims (1)

[Scope of utility model registration request] A movable ring that is divided into a plurality of parts along the circumferential direction and surrounds the blade tips of the turbine blade, in which the exhaust gas passage from the turbine is equipped with a boiler for recovering energy from the exhaust gas. , a drive device connected to the movable ring and moving the movable ring in the radial direction of the turbine rotor to adjust the gap between the blade tip of the turbine blade and the inner periphery of the movable ring. Turbine equipment.