JPS593151Y2 - Power transmission device in turbo compound engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power transmission device for a turbo compound engine.

Conventional turbo compound engines, which were designed to effectively recover the energy contained in the engine's exhaust gas by attaching a low-pressure turbine to a normally supercharged engine, had the following drawbacks at low loads and during acceleration.

When the engine is operating under high load, there is sufficient exhaust energy from the engine, and a low-pressure turbine can be used to extract energy from the exhaust gas.

This corresponds to the area marked ■ in Figure 1. When the engine is operated at low load, the energy contained in the engine's exhaust gas decreases, making it impossible to rotate the low-pressure turbine to a rotational speed commensurate with the engine rotational speed using exhaust energy alone.

In addition, the low-pressure turbine shaft and the engine output shaft are connected by a gear train, and if there is not enough energy in the exhaust gas to rotate the low-pressure turbine at a rotation speed higher than the rotation speed of the engine, the energy Not only can it not be extracted, but energy must be supplied from the engine to rotate the low-pressure turbine until the rotational speed matches the engine rotational speed, and this amount of energy is removed from the overall engine output, resulting in a reduction in engine output. It was declining.

This corresponds to area II in FIG.

Therefore, a comparison of engine output with respect to rotational speed between a conventional engine and a turbo compound engine is as shown in Figure 2.

In Figure 2, the solid line shows the engine output of the conventional engine, the dotted line shows the engine output of the turbo compound engine, the filled areas are the areas where the output increases compared to the conventional engine, and the shaded areas are the areas where the output decreases compared to the conventional engine. It is.

In a turbo compound engine, the low-pressure turbine shaft and the engine output shaft are connected using a gear train, so the inertia of the entire engine can increase several times compared to a conventional engine.

When accelerating the engine, the exhaust energy cannot be obtained from the engine side to obtain the rotational speed of the low-pressure turbine commensurate with the engine rotational speed, and the entire increase in inertia is applied to the engine's output shaft, adversely affecting the acceleration performance of the engine. was.

FIG. 3 shows engine rotational speed versus time for a conventional engine (solid line) and a turbo compound engine (dotted line).

The shaded area is the delay in acceleration time due to increase in inertia.

The present invention was developed in view of the above circumstances, and its purpose is to reduce pressure from the output shaft when the exhaust energy of the engine decreases and the low-pressure turbine is no longer able to rotate at a rotation speed commensurate with the engine rotation speed. By cutting off the transmission of power to the turbine shaft, the output is increased compared to conventional compound engines, and the acceleration is also improved.
The goal is to make it equivalent to an engine that is not compounded.

Hereinafter, the present invention will be explained with reference to FIGS. 4 and 5.

In the drawing, 1 is an engine, and 2 is a turbocharger.

The inlet side of a low pressure turbine 9 is connected to the outlet side of the high pressure turbine 11 of the turbocharger 2, and the turbine shaft 3 of this low pressure turbine 9 is connected to the engine output shaft 4 of the engine 1 via a gear train 10. .

The intermediate shaft 3 of the gear train 10 is divided into an input side shaft 6 and an output side shaft 7. The input side shaft 6 is connected to the input side of the one-way clutch 8, and the output side shaft 7 is connected to the input side of the one-way clutch 8. It is connected to the output side.

This one-way clutch 8 is disengaged when the low-pressure turbine shaft 3 can no longer be rotated at a rotational speed commensurate with the rotational speed of the engine 1.

However, when the output of the engine 1 becomes a low load and the exhaust energy of the engine 1 decreases, and the low-pressure turbine 9 cannot be rotated at a rotation speed commensurate with the rotation speed of the engine 1, the one-way clutch 8 is disengaged and the low-pressure turbine shaft 3 and the output shaft 4 are separated, the low-pressure turbine 9 is rotated only by exhaust energy without being constrained by the rotational speed of the engine 1, so that the engine output is not absorbed by the I-pressure turbine 9. This means that the output has increased compared to conventional turbo compound engines.

The shaded area shown in FIG. 5 is the increase in output.

The solid line is the output curve of the conventional turbo compound engine, and the dotted line is the output curve of the turbo compound engine equipped with the power transmission device according to the present invention.

Further, as described above, when the one-way clutch 8 is disengaged, the increase in inertia due to the gear train 10 does not become a load on the engine 1, and the acceleration performance becomes equal to that of an engine that is not made of a turbo compound.

As detailed above, the present invention connects the inlet side of the low pressure turbine 9 to the outlet side of the high pressure turbine 11 of the turbocharger, and connects the low pressure turbine shaft 3 of the low pressure turbine 9 and the output shaft 4 of the engine 1. Power transmission in a turbo compound engine characterized in that a one-way clutch 8 is provided in a connected gear train 10 to cut off power transmission when a low-pressure turbine 9 cannot be rotated at a rotation speed commensurate with the rotation speed of an engine 1. It is a device.

Therefore, when the output of the engine 1 becomes a low load, the exhaust energy of the engine 1 decreases, and the low-pressure turbine 9 cannot be rotated at a rotation speed commensurate with the rotation speed of the engine 1, the one-way clutch 8 is disengaged and power transmission is interrupted. Since the low pressure turbine 9 is shut off, the low pressure turbine 9 is not restricted by the rotational speed of the engine 1 and is rotated only by the exhaust energy, so that the engine output is not absorbed by the low pressure turbine 9, and the output is increased by that much compared to a conventional turbo compound engine. It is possible to increase the engine speed, and the acceleration can be made equal to that of an engine that is not made of a turbo compound.

That is, it is possible to improve the deterioration in fuel efficiency and reduce inertia during acceleration due to the low-pressure turbine 9 absorbing power under partial load of the engine.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of engine output versus engine rotational speed in a conventional engine. Figure 2 is a comparative diagram of engine output between a conventional engine and a turbo compound engine. Figure 3 is an illustration of a turbo compound engine and a conventional engine. Fig. 4 is a diagram illustrating the configuration of an embodiment of the present invention, and Fig. 5 is a diagram showing the engine output of a turbo compound engine and a turbo compound engine equipped with a power transmission device according to the present invention. FIG. 3 is a low pressure turbine shaft, 4 is an output shaft, 8 is a one-way clutch, 9 is a low pressure turbine, and 10 is a gear train.

Claims (1)

[Scope of utility model registration request] The inlet side of the low pressure turbine 9 is connected to the outlet side of the high pressure turbine 11 of the turbocharger 2, and the low pressure turbine 9 is connected to the gear train 10 that connects the low pressure turbine shaft 3 of the low pressure turbine 9 and the output shaft 4 of the engine. A power transmission device for a turbo compound engine, characterized in that it is provided with a one-way clutch 8 that cuts off power transmission when the engine cannot be rotated at a rotation speed commensurate with the rotation speed of the engine.