JP2006299905A - Turbo compound engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbo compound engine reducing a motive power loss by driving a power turbine from the engine body side in a low load. <P>SOLUTION: This turbo compound engine has a turbocharger for recovering motive power from exhaust gas, and the power turbine for further recovering the motive power from the exhaust gas passing through a turbine of the turbocharger; and transmits the motive power recovered by the power turbine to a crankshaft via a hydraulic coupling 9. A transmission efficiency restraining means for reducing motive power transmission efficiency of the hydraulic coupling 9 in the low load, comprises a normally opening control valve 17 arranged in the middle of a supply line 16 for supplying engine oil 15 as a working fluid to the hydraulic coupling 9, and a control device 18 for throttling the oil volume by controlling opening of the control valve 17 by an opening command signal 17a so as to become small in the low load. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbo compound engine.

  Conventionally, a turbocharger that recovers power from exhaust gas and a power turbine that recovers power from exhaust gas that has passed through the turbine of the turbocharger are provided, and the power recovered by the turbocharger is used as supercharging power for pressurizing the intake air. A turbo compound engine is known in which power recovered by a power turbine can be effectively used as engine driving force.

  FIG. 3 shows an example of a general turbo compound engine. In the example shown here, the energy of the exhaust gas 2 discharged from the engine body 1 is recovered as power by the turbine 4 of the turbocharger 3, While the compressor 6 driven by the turbine 4 pressurizes the intake air 6 entering the engine body 1, the power turbine 7 further recovers energy from the exhaust gas 2 passing through the turbine 4 as power, and the recovered power is used as the first gear. This is transmitted to the crankshaft 11 of the engine body 1 through the train 8, the fluid coupling 9, and the second gear train 10.

  Here, the reason why the fluid coupling 9 is included in the power transmission system from the power turbine 7 to the crankshaft 11 is to prevent rapid rotation fluctuations such as torsional vibration and engine stall of the engine body 1 from being transmitted. .

  In FIG. 3, reference numeral 12 denotes an input gear of the fluid coupling 9 constituting one element of the first gear train 8, 13 denotes an output gear of the fluid coupling 9 constituting one element of the second gear train 10, and 14 denotes a flywheel. .

As prior art document information related to this type of turbo compound engine, there is the following Patent Document 1 and the like.
JP-A-9-2222026

  However, in such a conventional turbocompound engine, if the energy of the exhaust gas 2 decreases at a low load, not only the power turbine 7 cannot recover the power, but the power turbine 7 is conversely the engine main body 1. However, there is a problem that the power turbine 7 becomes a load viewed from the engine body 1 side and power loss occurs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a turbo compound engine capable of reducing power loss due to the power turbine being driven from the engine body side at a low load.

  The present invention includes a turbocharger that recovers power from exhaust gas, and a power turbine that further recovers power from exhaust gas that has passed through the turbine of the turbocharger. The power recovered by the power turbine is transferred to a crankshaft through a fluid coupling. The turbo compound engine configured to transmit is characterized by comprising transmission efficiency suppressing means for reducing the power transmission efficiency of the fluid coupling at a low load.

  In this way, when the exhaust gas energy is large and medium and high, the power is recovered by the power turbine from the exhaust gas that has passed through the turbine of the turbocharger, and the recovered power is recovered from the engine body by the fluid coupling. While being transmitted to the crankshaft and effectively utilized, at low loads, the power transmission efficiency of the fluid coupling is reduced by the transmission efficiency suppression means, so the power from the engine body side is transferred to the power turbine side by the fluid coupling. As a result, it is difficult to transmit the power turbine, and the power turbine is not required to have a very large load when viewed from the engine body side, so that power loss is remarkably reduced.

  Further, in the present invention, the amount of oil is controlled by controlling a normally-open control valve provided in the middle of a supply line for supplying engine oil to the fluid coupling and the opening degree of the control valve so as to become small at low load. It is possible to configure the transmission efficiency suppressing means by the control device for narrowing down.

  In this way, the opening of the control valve in the middle of the supply line is reduced by the control device when the load is low, and the amount of oil to the fluid coupling is reduced, so the engine in the fluid coupling is rotated while being rotated from the engine body side. The oil becomes insufficient, thereby reducing the power transmission efficiency of the fluid coupling and making it difficult for the power from the engine body side to be transmitted to the power turbine side.

  Furthermore, when configuring the transmission efficiency suppressing means, an air introduction line that is connected in the middle of a supply line that supplies engine oil to the fluid coupling and guides pressurized air from a pressurized air source, and in the middle of the air introduction line The transmission efficiency suppressing means can be constituted by the normally closed control valve provided and the control device that opens the control valve at low load.

  In this way, the control device opens the normally closed control valve in the middle of the air introduction line when the load is low, and pressurized air is mixed from the pressurized air source into the engine oil supplied to the fluid coupling. Therefore, the power transmission efficiency of the fluid coupling is reduced, and the power from the engine body side is hardly transmitted to the power turbine side.

  According to the turbo compound engine of the present invention described above, the power transmission efficiency of the fluid coupling at the time of low load can be reduced and the power transmission from the engine body side to the power turbine side can be greatly suppressed. It is possible to achieve an excellent effect that power loss due to the power turbine being driven from the engine body side can be remarkably reduced.

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

  FIG. 1 shows an example of an embodiment for carrying out the present invention. In the following description, an overall configuration not shown in FIG. 1 will be described with reference to FIG. 3 used in the description of the prior art. And

  The present embodiment is characterized in that a turbo compound engine having substantially the same configuration as that of FIG. 3 described above is provided with a transmission efficiency suppressing means for reducing the power transmission efficiency of the fluid coupling 9 at a low load. In the illustrated example, a normally open control valve 17 provided in the middle of a supply line 16 for supplying engine oil 15 as a working fluid to the fluid coupling 9 and the opening of the control valve 17 are reduced at low loads. In addition, a transmission efficiency suppression means is configured by the control device 18 that controls the amount of oil by controlling the opening command signal 17a.

  Further, the control device 18 includes an accelerator opening signal 19a from an accelerator sensor 19 (load sensor) that detects the accelerator opening as a load of the engine body 1, and a rotation sensor 20 that detects the engine speed of the engine body 1. Is input, and the current operating state is a low load state in which the opening degree of the control valve 17 should be reduced based on the accelerator opening signal 19a and the rotation speed signal 20a. It is determined whether or not there is.

  The low load state in which the opening degree of the control valve 17 should be reduced is that the energy of the exhaust gas 2 is so small that the power turbine 7 (see FIG. 3) cannot recover the power, and the power turbine 7 is closer to the engine body 1 It is in a state where it is in an operating region where it is driven from.

  Here, the details of the fluid coupling 9 will be described with reference to FIG. 1. In this fluid coupling 9, a turbine impeller 22 having a large number of turbine blades 21 in an annular shape and a large number of impeller blades 23 are provided. An impeller impeller 24 provided in an annular shape is disposed oppositely in the casing 25, and the turbine chamber 26 is formed on the turbine impeller 22 side of the space defined between the opposed impeller impeller 24. An impeller chamber 27 is formed on the side.

  The turbine impeller 22 is attached to an output shaft 28 that rotates integrally with an output gear 13 that is an element of the second gear train 10 (see FIG. 3), and the impeller impeller 24 is connected to the output shaft 28. It is attached to an input shaft 29 that is rotatably fitted to the end opposite to the output gear 13, and this input shaft 29 is an input that constitutes one element of the first gear train 8 (see FIG. 3). A gear 12 is integrally provided.

  Between the turbine impeller 22 and the impeller impeller 24, the engine oil 15 from the supply line 16 passes through an oil passage 30 formed at the end opposite to the output gear 13 of the output shaft. About half of this engine oil 15 is stored even when the engine is stopped by a cover 31 attached to the outer periphery of the impeller impeller 24 so as to enclose the turbine impeller 22. It has become so.

  Thus, when the fluid coupling 9 is configured in this way, power is recovered by the power turbine 7 from the exhaust gas 2 that has passed through the turbine 4 of the turbocharger 3 when the energy of the exhaust gas 2 is large, and the recovery is performed. The transmitted power is transmitted to the crankshaft 11 of the engine body 1 by the fluid coupling 9 and is effectively used. On the other hand, at the time of low load, the control valve 17 in the middle of the supply line 16 by the opening command signal 17a of the control device 18 is used. And the amount of oil to the fluid coupling 9 is reduced, and the engine oil 15 in the fluid coupling 9 becomes insufficient while being rotated from the engine body 1 side. Therefore, the power from the engine body 1 side is hardly transmitted to the power turbine 7 side by the fluid coupling 9, and the power turbine 7 So that the power loss is significantly reduced when viewed from the body 1 side has been completed by the not become too heavy load.

  Therefore, according to the above embodiment, the power transmission efficiency of the fluid coupling 9 at the time of low load can be reduced and the power transmission from the engine body 1 side to the power turbine 7 side can be significantly suppressed. Power loss due to the power turbine 7 being driven from the engine body 1 side can be significantly reduced.

  FIG. 2 shows another embodiment of the present invention. In the example shown here, an air tank 32 (pressurized air) is connected in the middle of a supply line 16 for supplying engine oil 15 to the fluid coupling 9. The air introduction line 34 for introducing the pressurized air 33 from the source), the normally closed control valve 35 provided in the middle of the air introduction line 34, and the control valve 35 controlled by the opening command signal 35a to reduce the load. A transmission efficiency suppressing means is constituted by the control device 18 that is sometimes opened.

  In this way, the normally closed control valve 35 in the middle of the air introduction line 34 is opened by the opening command signal 35a from the control device 18 at low load, and the engine oil 15 supplied to the fluid coupling 9 is added to the engine oil 15 from the air tank 32. Since the compressed air 33 is mixed, the density of the engine oil 15 as a working fluid is reduced, thereby reducing the power transmission efficiency of the fluid coupling 9 and transmitting the power from the engine body 1 side to the power turbine 7 side. It becomes difficult.

  That is, the force that rotates the impeller wheel 24 from the turbine wheel 22 side can be expressed as the density of the working fluid multiplied by the flow velocity, so that the pressurized air 33 from the air tank 32 is mixed into the engine oil 15. If the density decreases, the power transmission force in the fluid coupling 9 decreases and the power transmission efficiency is reduced.

  Therefore, even in such a configuration, the power transmission efficiency of the fluid coupling 9 at the time of low load can be reduced and power transmission from the engine body 1 side to the power turbine 7 side can be greatly suppressed. Sometimes, the power loss due to the power turbine 7 being driven from the engine body 1 side can be significantly reduced.

  Note that the turbo compound engine of the present invention is not limited to the above-described embodiment. The transmission efficiency suppressing means may adopt a configuration other than the illustrated example, and otherwise depart from the gist of the present invention. Of course, various modifications can be made within the range not to be performed.

It is sectional drawing which shows an example of the form which implements this invention. It is sectional drawing which shows another example of a form of this invention. It is the schematic which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Exhaust gas 3 Turbocharger 4 Turbine 7 Power turbine 9 Fluid coupling 11 Crankshaft 15 Engine oil 16 Supply line 17 Control valve (transmission efficiency suppression means)
18 Control device (transmission efficiency suppression means)
32 Air tank (Pressurized air source: Transmission efficiency suppression means)
33 Pressurized air 34 Air introduction line (Transmission efficiency suppression means)
35 Control valve (means for suppressing transmission efficiency)

Claims (3)

  A turbocharger that recovers power from exhaust gas and a power turbine that recovers power from exhaust gas that has passed through the turbine of the turbocharger are provided, and the power recovered by the power turbine is transmitted to the crankshaft through a fluid coupling. A turbo compound engine comprising: a transmission efficiency suppressing means for reducing the power transmission efficiency of the fluid coupling at a low load.   Transmission efficiency with a normally-open control valve provided in the middle of the supply line for supplying engine oil to the fluid coupling, and a control device for controlling the opening of the control valve so as to be reduced at low loads to reduce the amount of oil The turbo compound engine according to claim 1, wherein suppression means is configured.   An air introduction line connected to the supply line for supplying engine oil to the fluid coupling and leading the pressurized air from a pressurized air source; a normally closed control valve provided in the middle of the air introduction line; and the control The turbo compound engine according to claim 1, wherein the transmission efficiency suppressing means is configured by a control device that opens the valve at a low load.

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