JPS5856340Y2 - internal combustion engine with supercharger - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an internal combustion engine with a supercharger, and more particularly to an internal combustion engine with an exhaust turbine type supercharger that is designed to achieve higher output and lower fuel consumption.

In a conventional internal combustion engine with a supercharger, when the discharge pressure of the supercharger (i.e., the boost pressure of the engine) is increased in order to obtain even higher output, the combustion pressure within the cylinder increases as the boost pressure increases. Therefore, there is a limit to the increase in the discharge pressure of the supercharger due to the strength of the engine.

However, if the compression ratio of the engine is lowered in order to suppress the maximum pressure inside the cylinder, poor combustion will occur during low-output operation, so there is a limit to the reduction of the compression ratio, and in the end, internal combustion engines with a supercharger The current situation is that attempts to obtain even higher output by increasing the discharge pressure of the supercharger have reached their limits.

The present invention was developed in consideration of the current situation, and the internal combustion engine with a supercharger of the present invention is provided with a branch pipe at the exhaust gas inlet of the exhaust turbine of the supercharger, and an on-off valve is installed in the branch pipe. A small exhaust turbine is connected through the turbocharger, and when the engine output is high, the opening/closing valve is opened to extract a part of the exhaust gas introduced into the exhaust turbine of the supercharger. The engine is characterized by driving an exhaust turbine and adding its output directly to the output shaft of the engine.

Next, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, an exhaust turbine 3 is installed in the exhaust pipe 2 of the engine 1.
A rotor of a charge air compressor 4 is attached to the rotating shaft of the turbine 3 to form a supercharger 13.

5 is a cooler for cooling air supply, and 6 is an air supply pipe.

Although the above structure is no different from a conventional supercharged engine, in the present invention, a branch pipe 7 is provided at the exhaust gas introduction port 14 of the exhaust turbine 3 of the exhaust pipe 2.

The branch pipe 7 has an on-off valve 8. small exhaust turbine 9
are set up consecutively.

The output of the exhaust turbine 9 is controlled by a reduction gear mechanism 10. It is linked to the output shaft 12 of the engine 1 via a centrifugal clutch 11.

Regarding the operation, first, the operation of the conventional device will be explained with reference to FIG. 2 (the dotted line in FIG. 2 indicates the operation of the conventional device).
As the output is increased at a compression ratio that ensures combustion performance at low output, the maximum in-cylinder output Pcmax increases, and when it reaches the maximum pressure PM that is the limit for engine strength (at 100% output) There are no words that can increase the output more than this.

Even at this 100% output, the excess air ratio λ is generally about 2.0 to 2.2, which is about 1 to 1 of the fuel at the same output.
．． Surplus air remains in the cylinder that can burn twice as much.

Even though this air remains, Pcmax is PM
The disadvantage of the conventional device is that it is not possible to obtain a higher output to reach .

On the other hand, the operation of the device of the present invention is as follows (Second
The solid line in the figure indicates the operation of the device of the present invention).

That is, for example, if the on-off valve 8 is opened from 50% of the engine output to allow a portion of the exhaust gas to flow out to the small exhaust turbine 9, the engine output will increase slightly thereafter.

Therefore, the fuel consumption rate at constant output is improved by the increased output.

Since part of the exhaust gas flows out to the small exhaust turbine 9, the work given to the supercharger turbine 3 decreases.
The fresh air intake amount decreases by that amount, causing a slight decrease in the air supply pipe pressure Pa, and as a result, the cylinder maximum pressure Pcmax decreases.

When the output is further increased after that, the work of the small exhaust turbine 9 increases, and as the exhaust gas work of the exhaust turbine supercharger increases, the supply air pressure Pa also increases, making it possible to increase the output. .

And the minimum excess air ratio λ that can burn the fuel at maximum output
Pcmax is possible even at this maximum output.
・will be kept below PM.

The output of the small exhaust turbine 9 is automatically connected to the engine output shaft 12 by the centrifugal clutch 11.
This will result in lower fuel consumption.

As the output increases further, λmin or Pcmax
It can be understood from the graph shown in FIG. 2 that it is possible to increase the output up to = p M (for example, 120% output).

Thus, the present invention extracts a portion of the exhaust gas upstream of the exhaust inlet of the exhaust turbine of the supercharger, and uses it to drive a small exhaust turbine separately from the turbine of the supercharger. Since the output is directly added to the engine's output shaft, the engine's power is increased compared to the conventional system where exhaust gas at high output could only be used to increase the supercharger discharge pressure. A part of the exhaust gas can be effectively used as a fuel source, and therefore the engine output can be increased without increasing the maximum cylinder pressure of the engine.Therefore, its practical effect is remarkable. .

Further, according to the present invention, since the energy contained in the exhaust gas can be recovered as immediate engine output, the energy loss is extremely small, and therefore the fuel consumption rate can be sufficiently increased.

Furthermore, according to the present invention, the engine output can be increased without increasing the maximum pressure in the cylinder of the engine, so there is no need to lower the compression ratio, so poor combustion does not occur during low output operation.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operating state of the engine, where the solid line shows the case of the present invention and the dotted line shows the case of the conventional example. 1... Engine, 2... Exhaust pipe, 3...
... Exhaust gas turbine, 4... Air supply compressor,
6... Air supply pipe, 7... Branch pipe, 8...
...Opening/closing valve, 9...Small exhaust gas turbine, 10...Reduction gear mechanism, 11...
centrifugal clutch.

Claims (1)

[Scope of utility model registration request] A branch pipe 7 is provided at the exhaust gas inlet 14 of the exhaust turbine 3 of the supercharger 13, and a small exhaust turbine 9 is connected to the branch pipe 7 via an on-off valve 8, so that the opening/closing is performed when the engine 1 has a high output. Valve 8
A part of the exhaust gas introduced into the exhaust turbine 3 of the supercharger 13 is extracted, the extracted exhaust gas drives the small exhaust turbine 9, and its output is sent to the output shaft 12 of the engine 1. Internal combustion engine with a supercharger designed for direct addition.