ENGINEERING NEWS IN BRIEF

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                  ENGINEERING NEWS IN BRIEF
                        E-Mail Newsletter

                               No.72
             Issued by the Asian TOP Panel, December 2007

           The Chinese Mechanical Engineering Society (CMES)
           The Institution of Engineers, Indonesia (PII)
           The Japan Society of Mechanical Engineers (JSME)
           The Korean Society of Mechanical Engineers (KSME)

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    According to the agreement made in the 2nd Asian TOP Panel Meeting,
the ENGINEERING NEWS IN BRIEF (E-mail newsletter) has now been edited
by the CMES for the year 2007.

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[Contents]
(1) Morphology and Microhardness of Ni-W Alloy Nanocrystalline Coatings Prepared
     by Electrodeposition (Source: CMES)
(2) Investigation on Flow Direction of a Point in Axisymmetric Plastic Deformation      (Source: CMES)
(3) Precipitation-Hardening And Toughness Of Precipitation- Hardening Stainless Steel      Fv520(B) (Source: CMES)
(4) Development of Application Technology of Aluminum Roof for SUV (Source: JSME)
(5) Advancement of Element Parts of Fuel Injection System for Motorcycles
     (Source: JSME)
(6) Plasma Actuator: Flow Control without Visible Actuation (Source: JSME)
(7) NOx Reduction Catalysts on Diesel Engines (Source: JSME)
(8) Microturbine Using Humid Air Turbine Cycle (Source: JSME)

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(1) Morphology and Microhardness of Ni-W Alloy Nanocrystalline Coatings Prepared by      Electrodeposition

     WU Yucheng SHU Xia
     School of Material Science and Engineering, Hefei University of Technology

Ni-W alloy coatings prepared by electrodeposition have been studied by means of X-ray diffraction, transmission electron microscopy, energy dispersive spectrometer and scanning electron microscope. The results showed that the sizes of Ni-W alloys' crystal grains are determined within 30 nm and they are recognized as the nanocrystalline coatings. During electrodeposition, the coating grows at the nicks or corrosive holes firstly. Surfaces close cyst-form and uniform of Ni-W alloy coatings under the optimum process condition, and the microstructures are compact and well-distributed. The microhardness of Ni-W alloy electrodeposited coatings comes to more than 600HV and can attain to 1 132.88HV after heat treatment at 550 ℃. When the concentration of Na2WO4・2H2O is 30~50 g/L, the current density is 15 A/dm2, the pH value is 7 and the temperature is about 60~70 ℃, then optimum Ni-W alloy coatings of electrodeposition will be obtained.

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(2) Investigation on Flow Direction of a Point in Axisymmetric Plastic Deformation

    ZHANG Ji HE Zhubin YUAN Shijian
    School of Materials Science and Engineering, Harbin Institute of Technology

In order to investigate the relationship between the flow direction of a point and local stress field in plastic deformation, an approximate solve algorithm is carried out to calculate the maximum mean stress gradient direction of local stress field. The algorithm is applied to calculate the maximum mean stress gradient directions in stress fields of typical axisymmetric problems, such as cylinder compression, ring compression and extrusion. Then the maximum mean stress gradient directions and the flow directions of points are visualized and compared. Good similarity is found between the movement direction and the maximum mean stress gradient direction of the related local mean stress field in the deforming bodies. Furthermore, the motion of a point in plastic deformation is decomposed into two components：the motion of rigid body and the relative motion. The motion of rigid body is mainly determined by tool motion, while the relative motion is consistent with the maximum mean stress gradient direction.

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(3) Precipitation-Hardening and Toughness Of Precipitation- Hardening Stainless Steel      Fv520(B)

     NIU Jing DONG Junming XUE Jin
     School of Material Science＆Engineering, Xi' an Jiaotong University, Xi' an 710049

By transmission electron microscope, hardenss test and instrumented impact test, the effect of aging process on microstructure and properties of precipitation-hardening stainless steel FV520(B) is investigated. The results show that the most precipitate of FV520(B) steel is copper-rich phase ε-Cu. The maximum hardness is reached after FV520(B) ages at 420 ℃, due to the coherent precipitation of fine copper particles. However, the hardness of FV520(B) aged at higher than 420 ℃ gradually decreases , due to the ε-Cu precipitating and coarsening, the matrix recrystallizing. Toughness of FV520(B) at different aging temperatures is dependent on the crack propagation energy. The effect of aging microstructure on impact crack initiation energy is less, but the effect of that on crack propagation energy is great. As FV520(B) aged at 420 ℃ and 600 ℃, its toughness is the worst and best respectively. The fracture appearance of the impact specimens aged at 420 ℃ and 470 ℃ mostly is in form of cleavage, which of the specimens aged at other temperature mostly in form of dimple, but the dimples have nice difference.

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(4) Development of Application Technology of Aluminum Roof for SUV

     Yoshinobu MATSUMURA, Mitsubishi Heavy Industries, Ltd,

To maximize the beneficial effect of weight reduction on drive performance, an aluminum roof panel was adopted for LANCER EVOLUTION Ⅷ MR- the first Japanese-made steel body with aluminum roof vehicle. Subsequently, a development project was carried out to achieve high drive performance comparable with that of sedan models for the tall SUV (Sports Utility Vehicle) by introducing an aluminum roof panel into OUTLANDER. As a result, the accuracy of the thermal deformation analysis method developed for LANCER EVOLUTION could be upgraded, and the SPR (Self-Piercing Rivet) joining mechanism was elucidated.

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(5) Advancement of Element Parts of Fuel Injection System for Motorcycles

     Yoshikatsu NAKANO, Tohoku University

With the increasing requirements of environmental conservation in recent years, reduced exhaust emissions and increased fuel-efficiency are in high demand for smaller size motorcycles. In order to meet such demand, the optimum design of the fuel injection sysytem is the most effective method. Due to extensive application of fuel injection system to small motorcycles, the system has to be compact size, low energy consuming, low cost, and general versatility in function. For the fuel injector, the spray form was optimized using fuel spray simulation techniques. For the fuel pump, efficiency was improved by the optimization of pump rotor shape. As a result of these activities, system components to constitute a fuel injection system easily installed in and suitable for the wide range of engine frames and engine characteristics of small size engines have been developed.

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(6) Plasma Actuator: Flow Control without Visible Actuation

     Akihiko SASOH, Nagoya University

Plasma actuator is a flow control device which utilizes dielectric barrier discharge (DBD). On both side of a dielectric plate, a pair of film electrodes are fabricated so that DBD occurs over the inter-electrode region. Due to unsteady motions of charged particles, an effective blowing force is generated from the electric potential. The induced flow is highly functional to modify boundary layer velocity profile, and can delay separation. This device has potential applications to automobiles, aircrafts and other industrial devices.

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(7) NOx Reduction Catalysts on Diesel Engines

     Teruo NAKADA, ISUZU Motors Limited

Current status and future prospects on the NOx reduction catalysts technologies used in automobile are discussed with focusing the systems to be used for tougher emission regulations scheduled in 2009-10. Currently DPF (Diesel Particulate Filter) or NOx catalysts are used with the combination of engine emissions reduction technologies, since the exhaust emissions on diesel engines have some NOx-PM trade-off relations in general. And for the next regulation, both DPF and NOx catalysts are required to be installed together on vehicle for fulfilling the requirements of reducing both NOx and PM to 1/3 from the current level. Two major NOx catalysts technologies, the urea-SCR catalyst and the NOx storage catalyst, are discussed in detail with a view of problems to be solved in a combination with DPF, such as durability and reliability, cost, fuel consumption, serviceability and so on.

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(8) Microturbine Using Humid Air Turbine Cycle

     Susumu NAKANO,
     Hitachi, Ltd. Power and Industrial Systems R & D Laboratory

A prototype machine for a next generation microturbine system incorporating a simplified humid air turbine cycle has been developed for laboratory evaluation. Design targets of electric output were 150 kW and of electrical efficiency, 35 % LHV. A low NOx combustor which applied a lean-lean zone combustion concept and water lubricated bearings were developed for the prototype machine, and power conversion system was integrated with water cooling Insulated Gate Bipolar Transistor. The main feature of this microturbine system is utilization of water for improved electric output and lubrication of bearings. Full speed test with no load, and rated load test without water atomizing inlet air cooling (WAC) and humid air turbine (HAT) were done successfully. Electrical output of 135 kW with an efficiency of more than 33 % was obtained in the rated load test. Operation tests for WAC and HAT which were carried out under the condition of 63 % load as preliminary tests showed significant effects on the electrical efficiency with an increase of 3.0 point % and electric output with an increase of 20 % by supplying just 2.4 weight % water as the inlet air flow rate of the compressor.

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Editor : Tian Ruizhu
           The Dept. of Internationa Affairs
           Chinese Mechanical Engineering Society