JPS591332B2 - Turbine compartment for turbocharger - Google Patents

Description

Detailed Description of the Invention The present invention is installed in a reciprocating internal combustion engine, etc., uses its exhaust energy to drive a turbine, and uses the driving rotational force to compress air via a coaxial compressor. This relates to the turbine casing of a supercharger that increases the amount of air to the internal combustion engine for supercharging and increases output.
In order to operate the supercharger effectively within all operating ranges of an internal combustion engine, we aim to use energy effectively in all ranges from low speeds to high speeds, and aim for high effective pressure operation at low speeds and low fuel consumption of the supercharger. This is the purpose.

Figures A, 13, and C show examples of conventional supercharging systems, respectively, where a is the engine, b is the turbine, and cl.
In the compressor, d indicates a gas passage, and e indicates an air passage.

However, in a normal supercharging system as shown in Figure 1A, since the turbine casing in turbine b is a fixed nozzle, efficiency decreases and engine performance deteriorates except where the supercharger is optimally matched. .

In particular, there is a problem in that low-speed performance and partial load performance deteriorate because matching is usually performed at high speed.

In Fig. 1B, in order to match the low speed, a part of the gas in the high-speed, large-flow section is released to the atmosphere without going through the turbine by the wastegate f, and the boost pressure is maintained at a predetermined pressure, improving the engine's low-speed performance. However, the performance at the part where the gas passage d is released deteriorates, resulting in a loss of energy.

In Fig. 1C, a variable turbine structure is used in which the angle of the vane nozzle q or the area of the vaneless nozzle is changed in order to solve the problems of the methods A and B, but such a structure is very difficult. There is a problem that it is expensive, and for this reason, it has been considered to use an inexpensive scroll switching type, but there are problems such as poor performance because it cannot use low-speed gas pulses and there is exhaust interference. It had

The present invention forms a scroll for an exhaust turbine with a simple structure and low pumping loss that is suitable for a small flow rate of exhaust gas, and substantially enlarges the scroll when a large flow rate is used, so that it can be used over a wide range of engines. This system is designed to always form an optimal scroll for a range of flow rates, and includes a gas introduction section where the gas flow paths are separated by a partition plate on the outer periphery of the turbine wheel, and each gas flow in the gas introduction section. The first channel is separated into two channels in the longitudinal direction of the axis of the turbine wheel by a partition wall so as to communicate separately with the channel, and the first nozzle is opened in an appropriate range on the outer periphery of the turbine wheel. A second nozzle is formed to communicate with the scroll and each gas flow path of the gas introduction part and surround the outer periphery of the first nozzle, and a second nozzle is opened on the outer periphery of the turbine wheel other than the opening of the first nozzle. A second scroll having a single flow path structure is integrally formed, and an adjustment valve for controlling the inflow of gas to the second scroll is provided at a connecting portion between the gas introduction part and the second scroll. This relates to a turbine casing for a supercharger.

Normally, reciprocating internal combustion engines are susceptible to exhaust interference when the exhaust gas flow rate is small (at low rotation speeds), and in the case of multi-cylinder engines, the piping conditions are such that the exhaust gas from cylinders with adjacent explosion order is transferred to the turbine impeller. However, according to the present invention, during low flow rate operation, the scroll has a structure in which the gas is separated and guided in the longitudinal direction of the shaft to the vicinity of the impeller to avoid the above-mentioned exhaust interference, thereby reducing exhaust interference. This makes it possible to effectively utilize the exhaust valve, and when the exhaust gas flow is large (at high rotation speeds), the exhaust pulsation usually decreases and the boost pressure becomes higher than the exhaust gas pressure, which is close to a steady state. A single cross-section scroll is advantageous because it is less affected by exhaust interference and has low flow resistance, so when a large flow rate occurs, a part of the gas automatically flows into the single cross-section scroll, resulting in a substantially large capacity. It was designed so that

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

Figure 2 shows an example in which an exhaust turbine supercharger is installed in a 6-cylinder engine dynamic pressure supercharging system, and two groups are installed to prevent exhaust gases from each engine cylinder 23 to 2f of engine 1 from interfering with each other. The pipes 3a and 3b lead to the turbine casing 5 of the supercharger 4 to rotate the turbine wheel, and the rotation drives the coaxial compressor 6 to compress the air 7, and the air 7 is compressed into each cylinder of the engine 1. I am trying to supercharge 2a to 2f.

The present invention relates to the structure of the turbine casing 5,
FIGS. 3 to 8 show an example thereof.

A gas introduction device having a partition plate 9 for connecting the pipes 3a and 3b divided into the two groups and separately guiding the gas divided into the two groups in the longitudinal direction of the axis of the turbine impeller 8. parts 10a, 10b, and a first scroll 13a that guides the gas from the gas introduction parts 10a, 10b to the first nozzle part 12 on the outer periphery of the turbine wheel 8 while being completely separated by the partition wall 11.
, 13b are provided.

Further, on the outer periphery of the first scrolls 13a, 13b, a second scroll 15 having a single flow path structure communicates with the gas introducing portions 10a, 10b and guides the gas to the second nozzle portion 14 on the outer periphery of the turbine wheel 8 without separating the gas. will be established.

Although the first scrolls 13a and 13b are operated when the gas flow rate is low, and their effective energy is small, it is necessary to maintain turbine efficiency even when the gas flow rate is low.

Therefore, the gas cannot pass through the second scroll 15 (
In order to minimize pumping loss in the case of a small flow rate, the size range a of the nozzle portions 12 of the first scrolls 13a and 13b is set to a required size of 1/2 or more of the circumference.

Further, an adjustment valve 16 is provided at a position in the second roll 15 close to the gas introduction portions 10a, 10b.
For example, a control unit 17 consisting of a diaphragm and a spring operated by the boost pressure of air compressed and discharged from the blower 14 is provided, and the link 1
The opening degree of the adjustment valve 16 is adjusted via the control valve 8.

The illustrated adjustment valve 16 is an example of a butterfly valve fixed to a valve stem 19 that rotates together with the link 18.

According to the above configuration, when the engine 1 is at low to medium speed and under partial load, the engine 1 operates without exhaust interference by the first scrolls 13a, 13b and by effectively utilizing exhaust pulses.

In addition, the pulse utilization and capacity A/R in the first scrolls 13a and 13b are small, that is, independent scrolls for small flow rates are installed and formed separately, so the cross-sectional area of the flow path is reduced and the gas flow rate is increased. By doing so, the exhaust energy utilization rate increases and the blower booth - discharge pressure (flow rate)
increases significantly.

When said boost reaches a certain limit value (generally an engine strength condition), the control unit 17 is activated;
The regulating valve 16 is opened via the link 18 and a -portion of the gas is sent to the second roll 15.

Therefore, the capacity of the turbine casing 5 is substantially increased compared to before the control operation, and the boost is kept constant.

Also, due to the opening operation of the adjustment valve 16, the second scroll 15
The gases that are divided into two groups from the gas introduction portions 10a and 10b flowing into the chamber are mixed after the adjustment valve.

This is because the pulsation effect becomes smaller at high speeds, so there is no need to provide the partition wall 11 as in the case of the first scrolls 13a and 13b, and rather, if such a wall is provided, the pipe resistance increases. This is because it has a single flow path structure.

In addition, the (n) section A/R and the inflow area (angle 360-a) of the second scroll 15 are set such that the first scroll capacity is such that a uniform flow occurs when the regulating valve 16 is fully opened at the maximum flow rate. ) is determined in relation to portion A/R and angle a.

This distribution can be freely selected by matching to the engine (
In general, matching is done at a medium speed), but the nozzle portions 12 of the first scrolls 13a and 13b are
Good performance can be exhibited by having a range α of /2 or more.

The A/R and inflow range of each scroll are expressed by the following equation.

A/R (1): First scroll 13a, 13b turned on/
RA/R(II): A/Rα of the second scroll 15: Gas inflow range β1 of the first scrolls 13a, 13b: Pulsation utilization rate of the partition wall structure of the first scrolls 13a, 13b, about 1.1 to 1.2 β2: Pulsation utilization rate of 15th roll 15 about 1.0 9th
Figures 11 to 11 show other embodiments of the regulating valve 16 according to the present invention, and are provided with a rotary valve 16' that adjusts the inflow of gas to the second roll 15 by rotating the valve stem 20 intermittently. .

In the figures, the same reference numerals as above indicate the same parts.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and that other types of regulating valves may be used, and that the constituent parts are not limited to the shapes shown in the figures. It goes without saying that various changes may be made without departing from the gist of the invention.

According to the turbocharger turbine casing of the present invention described above, the following excellent effects are exhibited.

(1) Generally, when applying a variable mechanism to a supercharger, it tends to be expensive to ensure a certain level of performance, and when a low-cost type is used, the performance decreases, but the present invention is very simple. It is possible to provide a turbine casing that can be implemented at low cost with a simple structure and has high performance.

(ii) In the case of a turbine casing similar to the present invention, the switching of the scroll is simplified, resulting in poor low speed performance such as exhaust interference and dynamic pressure not being utilized at low speeds. The first scroll is separated by a partition wall and has an inlet nozzle range of 1/2 or more, making it possible to utilize dynamic pressure.

The second scroll, which is used in conjunction with large flow rates, forms a pulcon-type casing flow path that reduces resistance as much as possible and avoids exhaust interference, ensuring high efficiency.

(1) Highly efficient operation at large flow rates is possible with almost the same reliability and price as a wastegate built into the turbine casing.

(V) Having a single flow path structure on the outer periphery of the first scroll, which is separated by a partition wall and has a first nozzle part opened in a required range α on the outer periphery of the turbine wheel, other than the first nozzle part. By providing a second scroll with a second nozzle opening on the outer periphery of the turbine wheel,
By reducing the number of passages in the first scroll that open to the outer periphery of the turbine wheel to the minimum necessary two, the opening width and cross-sectional area of the passages in the first nozzle part can be reduced. Efficiency can be improved, and the scroll capacity can therefore be changed while maintaining high turbine efficiency from small to large flow rates.

[Brief explanation of the drawing]

FIGS. 1A, B, and C are explanatory diagrams showing examples of conventional supercharging systems, respectively. FIG. 2 is an overall explanatory diagram showing an example of a supercharging system for a 6-cylinder engine. FIG. 3 is an embodiment of the present invention. A cutaway side view showing an example, FIG. 4 is a view taken in the 1v direction of FIG. 3, FIG. 5 is a view taken in the ■ direction of FIG. 7 is a view taken in the v11 direction of FIG. 4, FIG. 8 is a view taken in the v111 direction of FIG. 4, FIG. 9 is a cutaway side view showing another embodiment of the regulating valve, and FIG. FIG. 11 is an explanatory diagram showing a state in which the adjustment valve shown in FIG. 9 is in operation. 1 is an engine, 3a, 3b are pipes, 4 is a supercharger, 5 is a turbine chamber, 8 is a turbine wheel, 9 is a partition plate, 10a,
10b is a gas introduction part, 11 is a partition wall, 12 is a first nozzle part, 13a, 13b is a first scroll, 14 is a second nozzle part, 15 is a second scroll, 16, 16' is an adjustment pal '7', 17 indicates a control unit.

Claims (1)

[Claims] 1. On the outer periphery of the turbine wheel, there is a gas introduction section in which the gas flow paths are separated by a partition plate; a first scroll having a flow passage separated into two and having a first nozzle opened in an appropriate range on the outer periphery of the turbine wheel; a second roll having a single flow path structure formed so as to surround the outer periphery of the first nozzle and having a second nozzle opened on the outer periphery of the turbine wheel other than the opening of the second nozzle; A turbine casing for a supercharger, characterized in that an adjustment valve for controlling the inflow of gas to the second scroll is provided at a connection portion between the gas introduction section and the second scroll.