• Journal of the Korean Ceramic Society
• /
• v.35 no.2
• /
• pp.172-179
• /
• 1998

Valve lifter namely tappet is supported by lifter hole which is located upper side of camshaft in cylinder block transforms rotatic mvement of camshaft into linear movement and helps to open and shut the en-gine valve as an engine parts. The face of valve lifter which is continuously contacting with camshaft brings about abnormal wears such as unfair wear and early wear because it is severely loaded in the valve train system. These wears act as a defect like over-clearance and cause imperfect combustion of fuel during the valve lifting in the combustion chamber. Consequently this imperfect combustion makes the engine out-put decrease and has cause on air pollution. To prevent these wears therefore The valve lifter cast in me-tal developed into SiC ceramics valve lifter which has an excellence in wear and impact resistance As a results the optimum process conditions like injection condition mixture ratio and debonding process could be established. After sintering fine-sinered dual microstructure in which prior ${\alpha}$-SiC matches well with new SiC(${\beta}$-SiC) produced by reaction among the ${\alpha}$-SiC carbon and silicon was obtained. Based on the study it is verified that mechanical properties of SiC valve lifter are excellent in Vickers hardness 1100-1200 bending strength (300-350 Pa) fracture toughness(1.5-1.7 Mpa$.$m1/2) Through engine dynamo test-ing SiC valve lifter and metal valve lifter are examined and compared into abnormal phenomena such as early fracture unfair and early wear. It is hoped that this research will serve as an important springboard for the future study of heavy duty diesel engine parts developed by ceramics which has a good wear resis-tance relaibility and lightability.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.401-402
• /
• 2002

Diesel engines have many sliding parts with solid body contact. For example, a piston-ring and a cylinder bore, a valve and a valve-seat, a cam and a valve tappet. These parts have a severe wear problem. during engine life times. During these times, the valve tappet has abnormal wear such as scuffing and pitting due to a high hertzian contact stress between the cam and the tappet. Excessive wear problems frequently occur to both the cam and the tappet. To solve these problems, we developed an advanced wear resistant tappet. The developed tappet consisted of a hard-metal wear part and a steel body. To increase a bonding strength, those two parts, were directly bonded to each other. Also to decrease a bonding temperature, we developed the composition of Ni-binder materials in the hard metal. To estimate the wear characteristics of the newly developed tappet, we performed wear tests and engine dynamo tests in order to compare them with a conventional Fe-base tappet. As a result, the newly developed tappet has better wear characteristics than those of the conventional tappet. In addition, we performed a 100,000km field-test, and the newly developed tappet showed much improved wear resistance.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.2
• /
• pp.175-181
• /
• 2018

Electric pump system is new technology for next generation propulsion unit. The system has simple structure which dose not need gas generator, injector and turbine and might better pump for low cost and low payload rocket. Therefore, this paper suggests conceptual design of electric-pump Permanent-Magnet Synchronous Motor (PMSM) which has 50 kW & 50,000 RPM for rocket. To satisfy the system's requirement, electromagnetic analysis is conducted for suitable inner and outer diameter of stator and rotor which uses 4000 Gauss cylinder magnet and Inconel 718 can to fix whole rotor. Futhermore, to confirm rotational vibration, rotordynamics analysis is conducted. By this analysis, Campbell diagram is printed. From the diagram, natural frequency could be determined for the only motor and dynamo meter test bench.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.3
• /
• pp.326-335
• /
• 2015

In this paper, is a study that analyzed the fuel consumption of hybrid tractor. Testing and analysis in order to evaluate the fuel consumption was performed. Analysis model was developed by using the SimulationX that is a commercial software. Also, map of the analysis model was modeled on the basis of test data. Test was performed using a dynamo device. The engine was tested the fuel consumption in accordance with the conditions on the load and throttle opening. The battery was tested the discharge and charge in accordance with the current amount. We verified the reliability of the analysis model by comparing the analysis results with the rest results. After considering the reliability of each analysis model was extended to the entire hybrid tractor system. To evaluate the efficiency using the analysis model, compared the fuel consumption of general tractor with hybrid tractor in the same load conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.22 no.2
• /
• pp.391-398
• /
• 1998

The intake noise, a major source of vehicle noises, has rapidly become a noticeable, and has been studied to reduce the level. Traditionally, the intake system has been developed through the road test and the experiment using a engine dynamo, namely, the trial and error process. This approach require very high cost and long time consuming to develop the system. In this study, the simulator which had a speaker in the cylinder head was presented. It was easy to analyze the acoustic characteristic of the intake system in laboratory environment. This study presented a improvement to reduce the level of the intake noise using the Transfer Matrix Method and NIT/SYSNOISE, FE analysis commercial software. It was to select optimum position of a resonator and verified by the simulator. This simulator can be used early in the design stage of development of the intake system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.1
• /
• pp.19-25
• /
• 2011

A vehicle fuel economy is very important issue in view of fuel cost and environmental regulation. The technology development for the fuel economy improvement improved the engine, power train and many components of vehicle. So, the fuel economy is much improved, but up to now the measurement of it tests the given mode(LA-4, FTP-75, etc) within computer simulation program and engine dynamo. In this paper, to deduct the method of its improvement of real road, the test vehicle ran 213Km Youngdong real highway using 3 different algorithms in computer simulation. For this, I extracted the distance and altitude data from received GPS data and calculated the grade angle, road load and accomplished the velocity profiles according to algorithms in all 213Km distance. The vehicle runs in computer with AVL Cruise simulation program using velocity profile. I calculate the fuel economy using AVL Cruise simulation result and propose the Eco-driving method of them.

• Journal of the Korean Applied Science and Technology
• /
• v.37 no.5
• /
• pp.1330-1343
• /
• 2020

In this study, emulsion fuel which contained water of 10 ~ 20% was prepared mixed with water and MDO(Marine Diesel Oil) which largely used in near sea. Diffusion stability of emulsion fuel was measured. Diffusion stability was measured at 30℃, 45℃, and 60℃ for 10 days respectively. The stability of the emulsion fuel was stabilized in the order of MDO-10 > MDO-13 > MDO-16 > MDO-20 and it means that the stability of the emulsion fuel was found to be stable in the order of low water content. Meanwhile, an engine dynamo-meter was used to test whether the manufactured emulsion fuel was actually available in the engine. The emulsified MDO emulsion fuel could be used as fuel for ships. For samples with more than 16% water added emulsion fuel, smoke was reduced by more than 50% in the load area of more than 50%, and nitrogen oxides were reduced by 20%.

• Clean Technology
• /
• v.16 no.4
• /
• pp.265-271
• /
• 2010

The deactivated diesel oxidation catalyst(DOC) was remanufactured by ultrasonic wave treatment with various solutions, followed by active component re-impregnation. The catalytic performance and surface properties of remanufactured DOC were studied at various remanufacturing conditions. The proper ultrasonic-wave cleaning time at various solutions and optimal re-impregnation amounts of active component for the best catalytic performance were investigated. The catalytic performance tests on the conversions of CO and THC(total hydrocarbon) were also carried out at various temperatures by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the catalytic performance of DOC remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acidic/basic solutions and active component re-impregnation method was recovered to 90% level of its activity compared to that of the fresh DOC, which was caused by removing the deactivating materials from the surface of the DOC through the analyses of catalyst performance test and their characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.957-964
• /
• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.