JPS63183225A - How to operate a diesel engine with a power turbine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an operating method for cut-off operation of an appropriate number of superchargers in a power turbine-equipped diesel engine equipped with two or more superchargers. It is.

[Prior art] A diesel engine with a power turbine equipped with two or more superchargers is used on a ship when the speed of the ship is not required or when one supercharger breaks down. In such cases, the number of turbochargers used is reduced. - As an example, to explain a diesel engine with a power turbine equipped with two superchargers, as shown in FIG. Two superchargers 1 and 2 equipped with a compressor C that compresses intake air by rotating a blade wheel are attached to a diesel engine 3 equipped with a power turbine 4, and when the load of the diesel engine 3 is 50% or more, the diesel A part of the exhaust gas sent from the engine to the turbine T of each supercharger 1, 2 is bypassed to operate the power turbine 4, and the power turbine 4 recovers it as power and returns it to the main shaft of the diesel engine. It's Nishide. Reference numeral 5 denotes a valve provided in the bypass line on the inlet side of the power turbine 4.

The amount of part of the exhaust gas sent from the diesel engine 3 to the superchargers 1 and 2 to the power turbine 4 and bypassed is the total amount of exhaust gas sent from the diesel engine 3 to the supercharger 1.2. Approximately 10 to 20% is said to be the best. If the amount of bypass is too small, the impeller of the power turbine 4 cannot be rotated sufficiently, making it impossible to recover sufficient power. If the amount of bypass is too large, the performance of the power turbine 4 improves, but the power to the supercharger is This is because the amount of exhaust gas decreases and sufficient output cannot be obtained, which deteriorates the performance of the diesel engine.

[Problems to be Solved by the Invention] However, in the conventional diesel engine with a power turbine described above, since the exhaust gas inlet casing of the power turbine 4 has a first structure, the two superchargers 1 and 2 home,
When one turbocharger 2 is operated from 1 to 1, the ratio of the exhaust gas bypassed to the power turbine to the total exhaust gas increases, and the amount of exhaust gas supplied to the turbocharger becomes relative. will decrease. Therefore, the amount of exhaust gas to be bypassed for the total exhaust gas a is set to 10 as described above.
When it is assumed that the best value is ~20%, in the conventional method, the bypass ratio increases during turbocharger cut operation and cannot be maintained at the above 10 to 20%, resulting in the exhaust gas flow to the turbocharger 1. There is a danger that the performance of the diesel engine 3 will be deteriorated due to the decrease in output and the output cannot be obtained.

Therefore, the present invention aims to change the ratio of exhaust gas that is bypassed in the exhaust gas from the diesel engine when performing supercharger cut operation in a diesel engine with a power turbine equipped with two or more superchargers. Supercharging is an attempt to prevent deterioration of diesel engine performance without reducing exhaust gas emissions.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that when an appropriate number of superchargers of two or more turbochargers are cut-off, a portion of exhaust gas from a diesel engine is When the exhaust gas is bypassed and recovered as motive power by a power turbine, the amount of the bypassed exhaust gas is changed to be reduced according to the number of superchargers to be cut, and the operation is performed without changing the bypass ratio. .

[Function] When operating a diesel engine by cutting one or a suitable number of superchargers to reduce the number of superchargers in operation, reducing the amount of bypass exhaust gas sent to the power turbine will reduce the bypass ratio. can be set at or close to the appropriate bypass ratio when all superchargers are in operation, and sufficient output can be obtained from the operating supercharger without degrading the performance of the diesel engine. .

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

FIG. 1 shows an embodiment of the present invention, and shows, as an example, a diesel engine with a power turbine equipped with two superchargers 1 and 2.

The two superchargers 1 and 2 and the diesel engine 3 are arranged so that the exhaust gas discharged from the diesel engine 3 is guided to each turbine T, and the air discharged from each compressor C is sent to the diesel engine 3. A bypass line 6 is provided for bypassing part of the exhaust gas led from the diesel engine 3 to the superchargers 1 and 2, and a power turbine 4 is installed in the bypass line 6. , the gas inlet casing of the power turbine 4,
For example, the configuration is as shown in FIG. That is, gas ports 8 and 9 having a required cross-sectional area are provided in the gas-filled casing of the power turbine 4 in correspondence with the number of superchargers 1 and 2, and two gas ports 8 and 9 are provided inside the casing 7 with a partition wall 10. The gas entering from each gas population 8 and 9 passes through the casing 7 and rotates a turbine wheel (not shown). Each gas population 8, 9 in the gas-filled location casing of the power turbine 4 configured as described above
are connected to the exhaust gas pipe 13 via exhaust gas bypass pipes 11.12, respectively, and valves 14 and 15 are installed in the middle of each bypass pipe 11.12. The exhaust gas bypass amount can be changed by appropriately opening and closing the valves, and when one valve 14 or 15 is closed, only half of the exhaust gas acts on the power turbine 4.

When the operating method of the present invention is implemented in a diesel engine with a power turbine having the above-described configuration, it is carried out as follows. First, operate the two superchargers 1 and 2 together,
Further, when the energy of the exhaust gas is to be recovered as motive power by the power turbine 4, the valves 14 and 15 are both opened.

The air compressed by the two superchargers 1.2 is sent to the diesel engine 3, and part of the exhaust gas from the diesel engine 3 is bypassed, but the amount of bypass is adjusted so that the bypass ratio is appropriate. Since the gas inlet is regulated at 8°9, a predetermined amount is sent to the power turbine 4. In the power turbine 4, the exhaust gas is converted into a motion that rotates a turbine wheel, and is recovered as motive power.

Next, when using the power turbine 4 during a cut operation in which one supercharger 2 is not used, either one of the valves 14 or 15, for example, the valve 15, is closed, and the valve 1 is closed.
Drive with only 4 in between.

As a result, the amount of bypass during supercharger cut operation can be changed to half, and the bypass ratio of exhaust gas can be maintained appropriately, and while the performance of the power turbine 4 is maintained, the performance of the diesel engine 3 is also deteriorated. I have nothing to do.

Note that the operating method of the present invention is not limited to the above-described embodiments; for example, two gas ports 8 and 9 are provided in the gas-filled casing of the power turbine 4, and the bypass pipes 11 and 12 are also provided with two gas ports 8 and 9. Although we have shown the case in this book, it is natural that the number of gas inlets and bypass pipes will increase or decrease depending on the number of turbochargers installed, and it is also possible to divide multiple gas inlets into the gas-filled casing a. Instead of providing a variable displacement nozzle, a variable displacement nozzle may be used to adjust the bypass amount of exhaust gas during supercharger cut operation.

[Effects of the Invention] As described above, according to the method of operating a diesel engine with a power turbine of the present invention, when operating with one of two or more superchargers cut, the diesel engine When the exhaust gas from the building engine is bypassed through the power turbine, the bypass amount of the exhaust gas is changed to maintain the optimal bypass ratio, so the performance of the power turbine is maintained well and the supercharging An excellent effect can be achieved in that sufficient output can be obtained and the performance of the diesel engine can be maintained well.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an example of implementing the operating method of the present invention, FIG. 2 is a perspective view showing an example of a gas inlet casing of a power turbine, and FIG. 3 is a schematic view showing a conventional example. 1.2...Supercharger, 3...Diesel engine, 4...
- Power turbine, 7... Gas inlet casing, 11
゜12...Bypass pipe.

Claims (1)

[Claims] 1) In a diesel engine equipped with a power turbine equipped with two or more superchargers, when an appropriate number of superchargers are cut-off, a portion of the exhaust gas from the diesel engine is bypassed and recovered as power by the power turbine. A method of operating a diesel engine with a power turbine, characterized in that the amount of exhaust gas to be bypassed is reduced in accordance with the number of superchargers to be cut, and the operation is performed without changing the bypass ratio.