Achievements List

Achievements List
(only English paper)

1. STIRLING POWER SYSTEM FOR UNDERWATER APPLICATION
TSUKAHARA, S., KUWABARA, M., HIRATA, K., KUMAKURA, T., ISSHIKI, N.
Proceedings of 6th International Stirling Engine Conference, p. 421-426, 1993.

2. DESIGN OF APPLICATIVE 100 W STIRLING ENGINE
KAGAWA, N., HIRATA, K., TAKEUCHI, M., YAMASHITA, I., ARAOKA, K., HAMAGUCHI, K., ISSHIKI, N., MATSUO, M., MATSUSHITA, M., MIYABE, H., MORIYA, S.
Proceedings of the 30th. Intersociety Energy Conversion Engineering Conference, Book No. 10384C, p. 341-346, 1995.

A small 100 W displacer type Stirling engine is being developed under a project of a JSME committee, RC127. The project consists of sixteen Japanese academic researchers of universities and governmental laboratories and eleven enterprise members related to the Stirling field. The engine has very unique features. Its expansion cylinder is heated by combustion gas or solar energy directly, and a simple cooling system rejects heat from the working fluid. A regenerator is built in the displacer piston with heating and cooling tubes in which the working fluid flows from/to outer tubes. The outer tubes for heating were located at the top of the expansion cylinder and the tubes for cooling are in the middle of the cylinder.
The target performance is a 100 W output with 20 % thermal efficiency at the operating conditions of 923 K expansion space temperature, 343 K compression space temperature, and 1000 rpm. The 100 W displacer engine was designed based on a design manual established by a related JSME committee, RC110. It contains several guides to design for cycle, heat exchanger system, and mechanism of most Stirling cycle machines. The engine was designed by using the fundamental method, the second- and third-order analyses accomplished with the newly arranged knowledge about each component. This paper presents the engine specifications and the theoretical analysis results. The design method is also introduced briefly.

3. DESIGN OF A 100 W STIRLING ENGINE
KAGAWA, N., HIRATA, K., TAKEUCHI, M., YAMASHITA, I., ARAOKA, K., HAMAGUCHI, K., ISSHIKI, N., MATSUO, M., MATSUSHITA, M., MIYABE, H., MORIYA, S.
Proceedings of 7th International Conference on Stirling Cycle Machines, p. 211-216, 1995.

A small 100 W displacer type Stirling engine named "Ecoboy-SCM81" is being developed under a project of a JSME committee, RC127. The engine has very unique features. Its expansion cylinder is heated by combustion gas or solar energy directly, and a simple cooling system rejects heat from the working fluid. A regenerator is built in the displacer piston with heating and cooling tubes in which the working fluid flows from/to outer tubes. The outer tubes for heating were located at the top of the expansion cylinder and the tubes for cooling are in the middle of the cylinder.
The 100 W displacer engine was designed based on a design manual established by a related JSME committee, RC110. It contains several guides to design for the cycle, heat exchanger system, and mechanism of most Stirling machines. The engine was designed by using the fundamental method, the second- and third-order analyses combined with the newly arranged knowledge about each components.
This paper presents the engine specifications and its unique components and features.

4. MODEL STIRLING ENGINE WITH VARIABLE PHASE ANGLE MECHANISM
HIRATA, K., TSUKAHARA, S., KUWABARA, M.
Proceedings of 7th International Conference on Stirling Cycle Machines, p. 507-512, 1995.

5. THE STIRLING ENGINES FOR TEACHING AND DEVELOP AND PROGRESS OF EDUCATION IN JAPAN
MATSUO, M., HIRATA, K., IWAMOTO, S., TODA, F., ISSHIKI, N.
Proceedings of 7th International Conference on Stirling Cycle Machines, p. 41-46, 1995 .

6. STUDIES ON REGENERATIVE ROTARY DISPLACER STIRLING ENGINE
ISSHIKI, N., RAGGI, L., ISSHIKI, S., IWAMOTO, S., MATSUO, M., HIRATA, H.
Proceedings of 7th International Conference on Stirling Cycle Machines, p. 185-190, 1995.

7. INVERTED T STIRLING ENGINE (ITSE-1)
TSUKAHARA, S., KUWABARA, M., HIRATA, K., ISSHIKI, N., OHTOMO, M.
Proceedings of 7th International Conference on Stirling Cycle Machines, p. 431-436, 1995.

8. TEST RESULTS OF APPLICATIVE 100 W STIRLING ENGINE
HIRATA, K., KAGAWA, N., TAKEUCHI, M., YAMASHITA, I., ISSHIKI, N., HAMAGUCHI, K.
Proceedings of the 31st Intersociety Energy Conversion Engineering Conference, Book No. vol. 2, p. 1259-1264, 1996.

A small 100 W displacer-type Stirling engine, 'Ecoboy-SCM81' has being developed by a committee of the Japan Society of Mechanical Engineers (JSME). The engine contains unique features, including an expansion cylinder which is heated by either combustion gas or direct solar energy. Also, a simple cooling system rejects heat from the working fluid. A displacer piston has both heating and cooling inner tubes for the working fluid which flows to and from outer tubes. The outer tubes for heating were located at the top of the expansion cylinder and the outer tubes for cooling were located in the middle of the cylinder. A regenerator is located in the displacer piston.
The components of the engine adopted some new technologies. For instance, a porous type matrix consisting of pressed zigzag stainless steel wires was adopted for the regenerator. The matrix is practical for Stirling engines because it can be made at low cost and the assembling process is simplified.

9. REGENERATIVE ROTARY DISPLACER STIRLING ENGINE
ISSHIKI, N., RAGGI, L., ISSHIKI, S., HIRATA, K., WATANABE, H.
Proceedings of the 31st Intersociety Energy Conversion Engineering Conference, Book No. vol. 2, p. 1249-1254, 1996.

10. PERFORMANCE EVALUATION FOR A 100 W STIRLING ENGINE
HIRATA, K., IWAMOTO, S., TODA, F., HAMAGUCHI, K.
Proceedings of 8th International Stirling Engine Conference, p. 19-28, 1997.

A small 100 W displacer-type Stirling engine, Ecoboy-SCM81 has being developed by a committee of the Japan Society of Mechanical Engineers. The engine contains unique features, including an expansion cylinder which is heated by either combustion gas or direct solar energy. Also, a simple cooling system rejects heat from the working gas. A displacer piston has both heating and cooling inner tubes for the working gas which flows to and from outer tubes. A regenerator is located in the displacer piston.
To improve the engine performance efficiently, an analysis model for the prototype engine was developed. The analysis model is based an isothermal method considered a pressure loss in the regenerator, a buffer space loss caused by a leakage of the working gas, and a mechanical loss. In the case of a calculation for the pressure loss, the analysis model adopts a new suggestion that considers effects of entrance and exit area on the velocity distribution in the regenerator. The buffer loss is calculated with three kinds of methods, an isothermal, an adiabatic and a heat transfer model to consider a suitable method for the buffer space model. Some improvement methods for the prototype engine are discussed after the effectiveness of the analysis model is evaluated.

11. COMPARISON OF LOW- AND HIGH TEMPERATURE DIFFERENTIAL STIRLING ENGINES
IWAMOTO, S., TODA, F., HIRATA, K., TAKEUCHI, M., YAMAMOTO, T.
Proceedings of 8th International Stirling Engine Conference, p. 29-38, 1997.

Stirling engines can be operated with various heat sources. We have developed several Stirling engines, included a low temperature differential Stirling engine using hot spring heat and a high temperature differential Stirling engine using a combustion gas as the fuel. These engines have different features and characteristics, and have different thermal performance.
In this paper, the performances of these difference types of Stirling engines were measured, were compared using the normalized values.

12. BASIC CHARACTERISTICS AND APPLIED TESTS OF 'SPRING MESH' AS A NEW REGENERATOR MATRIX FOR STIRLING ENGINE
HAMAGUCHI, K., HIRATA, K., TAMURA, T., ISSHIKI, N.
Proceedings of 8th International Stirling Engine Conference, p. 51-58, 1997.

13. EFFECTS OF SUDDEN EXPANSION AND CONTRACTION FLOW ON PRESSURE DROPS IN STIRLING ENGINE REGENERATOR
HAMAGUCHI, K., YAMASHITA, I., HIRATA, K.
Proceedings of the 33rd Intersociety Energy Conversion Engineering Conference, 1998.

The flow losses in the regenerators greatly influence the performance of the Stirling engine. The losses mainly depend on fluid friction through the regenerator matrix, but are also generated in sudden expansion and contraction flow at the regenerator ends. The latter losses can't be neglected in the case of small area ratio (entrance area/cross-sectional area in regenerator). The pressure drops in regenerators are usually estimated assuming a uniform velocity distribution of working gas in the matrices. The estimation results, however, are generally smaller than practical data. The cross-sectional flow areas of the heater and cooler of typical Stirling engines are smaller than the cross-sectional area of the regenerator. So, it is necessary to understand the quantitative effects of the sudden change in flow area at the regenerator ends on the velocity distribution and pressure drop. In this paper, the effects of the regenerator ends are examined using stacked wire gauzes in the matrix by a steady single blow experiment and presented using the empirical equation defined by effective flow area ratio. The results show that the effective flow area ratio which is an index of the uniformity of the velocity distribution is independent of the mesh number and the Reynolds number but dependent on the entrance and exit areas and the stack thickness. Additionally, the effects of regenerator ends on the pressure drop in an actual engine are studied theoretically and experimentally.

14. Study on Design and Performance Prediction Methods for Miniaturized Stirling Engine
HIRATA, K., IWAMOTO, S.
The 6th Small Engine Technology Conference & Exposion, SAE, p.444-449, Sept. 1999.

This paper shows a design and performance prediction methods for a miniaturized Stirling engine, in order to develop a small portable generator set. First, a 100 W class Stirling engine is designed and manufactured. In order to miniaturize the engine, unique type heat exchangers were applied. A regenerator was located in a displacer piston. For a piston drive mechanism, a Scotch-yoke mechanism which was useful to realize the small-size engine without any lubricating device, was adopted.
Next, an analysis model for the miniaturized engine is developed to improve the engine performance efficiently. The pressure in the working space is analyzed by an isothermal analysis which takes into account a gas leakage through a piston ring and pressure loss in the heat exchangers. To estimate a shaft power, the mechanical loss and the buffer loss, which is caused by a pressure change in a crank case are considered on the analysis model. The calculated results were compared with the experimental data carefully. Then we suggest how to develop practical Stirling engines as a next step.

15. Study on Turning Performance of a Fish Robot
HIRATA, K., TAKIMOTO, T. and TAMURA, K.
First International Symposium on Aqua Bio-Mechanisms, p.287-292, Aug. 2000.

The aim of this study is to develop a fish mimetic underwater robot with good dynamics performance. At first, we discussed turning modes for the fish robot that uses tail swing. Based on the discussion, the prototype fish robot, which has 340 mm body length, was developed. Just after manufacturing, swimming speed at straight propulsion was measured. Next, we measured turning performance with the suggested turning modes. As the result, it was confirmed that frequency, amplitude and leaning of the tail affect the turning performance. Still more, we made sure that the prototype fish robot turned quickly from straight propulsion and stationary state.

16. Development of a Small 50W Class Stirling Engine
HIRATA, K.
Sixth International Symposium On Marine Engineering, p.235-240, Oct. 2000.

In order to develop a compact and low cost Stirling engine, a gamma type Stirling engine with simple moving-tube-type heat exchangers and a Rhombic mechanism was developed. Its target shaft power is 50 W at engine speed of 4000 rpm and mean pressure of 0.8 MPa using helium as working gas. This paper describes the outline of the engine design and the performance test. The test was done without load, using air in atmospheric condition. Also, a mechanical loss measurement was done in highly pressurized condition, in which the engine was driven by a motor compulsory. Then, methods to get higher performance were considered based on the comparison of experimental and calculated results. The results indicate that a higher performance heat exchanger and decreasing of mechanical loss are needed for the attainment of the target performance.

17. Development of Experimental Fish Robot
HIRATA, K.
Sixth International Symposium On Marine Engineering, p.711-714, Oct. 2000.

Underwater robots are widely used in the fields of ocean development, ocean investigation and marine environmental protection. They need higher efficient of propulsive performance. In order to get an underwater robot with high propulsion efficiency, we have studied on a fishlike swimming mechanism and developed a prototype fish robot. It has about 600 mm body length, and three joints of a tail moved by two servomotors with an original link mechanism. It can simulate various moving patterns optionally. In this paper, experimental results of swimming speed measurements using two types of a tail fin are reported. Also, research areas needed for getting higher performance fish robots are discussed.

18. Performance of Stirling Engines(Arranging Method of Experimental Results and Performance Prediction Method)
IWAMOTO, S., HIRATA, K., TODA, F.
JSME International Journal, Series B, Vol. 44, No. 1, p. 140-147, Feb. 2001.

We have developed five kinds of high- and low-temperature differential Stirling engines and their engine performance was investigated experimentally. In order to determine the parameters that affect engine performance, experimental results were discussed and compared with results calculated using analytical methods. We show an arranging method for the experimental results, and consider the performance of general Stirling engines. After using the arranging method with nondimensional numbers obtained by a dimensional analysis, a prediction method, which is used at the early design stage, is formulated. One of the nondimensional numbers in this prediction method is calculated based on engine specifications, including the properties of the working gas. The prediction method can predict engine speed, output power, the effect of working gas and operating conditions.

19. Acts Toward an Accessible Passenger Boat and Barrier-free Design in Japan
KAMATA, M., MIYAZAKI, K., HIRATA, K., IMASATO, M.
9th International Conference on Mobility and Transport for Elderly and Disabled People, p.598-601, July 2001.

20. A Semi Free Piston Stirling Engine for a Fish Robot HIRATA, K. Proceedings of 10th International Stirling Engine Conference, p.146-151, Sept. 2001.	In this paper, the author examined to adopt a semi-free-piston Stirling engine (SFPSE) for the power source of a fish robot. One of characteristics of the SFPSE is that the output power can be obtained directly from the reciprocating motion of a power piston. Typical thermal engines convert the reciprocating motion of the piston to rotary motion through a crank mechanism. The rotary motion is suitable for applications such as a screw propeller of a ship. However, in the case of a fish robot, it is the best way that the reciprocating piston drives the oscillating tail fin directly. A great deal of mechanical frictional loss can thus be reduced. This mechanism should result in high potential for efficiency. Two types of experiments were done in this paper. First, the performance of a simple experimental SFPSE - tail fin system was examined experimentally, and it is compared with calculated results based on a simple simulation model. Second, a model boat with a fish-like swimming mechanism driven by a SFPSE was developed. The ship performance was investigated and the adaptability of SFPSE for fish robots was discussed.
21. On aerodynamic characteristics of a hybrid-sail with square soft sail Toshifumi Fujiwara, Koichi Hirata, Michio Ueno, Tadashi Nimura. Proceedings of ISOPE 2003.
22. On development of high performance sails for a oceangoing sailing ship Toshifumi Fujiwara, Koichi Hirata, Michio Ueno, Tadashi Nimura. Proceedings of MARSIM '03.
23. On the Characteristics of Walking and Moving by Wheelchair on the Passage of Oscillating Ships Junko Hayashi, Kuniaki Shoji, Keiko Miyazaki, Koichi Hirata, Aiko Suzuki Proceedings of 11th Japan Group Meeting on Human Response to Vibration 2003, July 2003.
24. Mechanical Loss Reduction of a 100 W Class Stirling Engine HIRATA, K. Proceedings of 11th International Stirling Engine Conference, p.338-343, Nov. 2003.	We have developed a 100 W class displacer-type Stirling engine named 'Ecoboy-SCM81' since 1995. The original engine has a mechanical seal as an external seal device. On the other hand, a hermetic Stirling engine, which has a generator in a pressurized crankcase, is suitable for an application of a generator set. Because the hermetic engine does not have any external seal device between the working space and the atmosphere, and it expects to have small mechanical loss. Then we remodel the original Stirling engine to the hermetic structure. Also, in order to reduce the mechanical loss, the shot peening of molybdenum-disulfuride, which is one of the surface treatments, is applied to the cylinder wall, a surface of the displacer rod and other mechanical parts. And, the performance of the engine is measured for a comparison with that of the original engine. As the result, it is confirmed that the hermetic engine has higher shaft power and generator power than that of the original engine.
25. Evacuation Simulation for Disabled People in Passenger Ship Keiko Miyazaki, Mitujiro Katsuhara, Hiroshi Matsukura, Koichi Hirata, TRANSED 2004, May 2004.
26. Development of a Multi-cylinder Stirling Engine Koichi Hirata, Masakuni Kawada Proceedings of 12th International Stirling Engine Conference, p.315-324, Sept. 2005.	We have researched a multi-cylinder Stirling engine for a waste heat recovery system. The multi-cylinder Stirling engine has a possibility to achieve higher efficiency than a single-cylinder engine. In this paper, we discuss a simple thermal analysis for the multi-cylinder engine. And based on the analyzed result, a prototype engine is designed and built in our laboratory. The prototype engine consists of three engine units that have different piston stroke for each unit to getting the optimal thermal condition. Also it has unique components, such as a heater made from a block of aluminum alloy and an assembling cooler. As the result of the previous operating test, it is confirmed that the shaft power of the prototype engine is bigger than the sum of shaft power of each engine units.
27. Discussion of Applicative Marine Stirling Engine Systems Koichi Hirata, Masakuni Kawada 7th International Symposium On Marine Engineering, Oct. 2005.	Many kinds of internal combustion engines are used as a prime mover of traffic systems. Also the electric power systems, such as fuel cells, an electric propulsive ship and an electric automobile, are developed for the environmental preservation. On the other hand, a Stirling engine, which is an external engine, has excellent characteristics, which are a high thermal efficiency, multi-fuel capability and low pollution. In this paper, we discuss about marine applications using the Stirling engine. They are a prime mover for a large ship, a hybrid system for a small vehicle and waste heat recovery systems with a marine Diesel engine. We also consider the technical problems of the marine Stirling engine systems.
28. Design of an Experimental Manta-like Underwater Robot Kazuhisa Hishinuma, Akihisa Konno, Akisato Mizuno, Koichi Hirata, Masakuni Kawada 7th International Symposium On Marine Engineering, Oct. 2005.
29. Development of Turtle-like Submergence Vehicle Akihisa Konno,Takuro Furuya, Kazuhisa Hishinuma, Akisato Mizuno, Koichi Hirata, Masakuni Kawada 7th International Symposium On Marine Engineering, Oct. 2005.
30. A Support System for Flexible Arrangements of Escape Routes on Passenger Ships Keiko Miyazaki, Koichi Hirata 7th International Symposium On Marine Engineering, Oct. 2005.
31. Development and performance estimation of flapping fin propulsion system Akihisa Konno, Koichi Hirata, Masakuni Kawada ISABMEC, July 2006
32. Development of Turtle-like Submersible Vehicle KONNO, A., FURUYA, T., MIZUNO, A., HISHINUMA, K, .HIRATA, K, .KAWADA, M. Journal of The Japan Institution of Marine Engineering, Vol.41, Special Issue, p.158-163, Sept. 2006.

Koichi Hirata, Dr.
Shinkawa 6-38-1, Mitaka Tokyo 181-0004, Japan
Environment and Energy Department
National Maritime Research Institute
Tel&Fax.: +81-422-41-3607
E-mail: khirata@nmri.go.jp

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