• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.166-174
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• 2008

Recently, the automotive industry has been developing rapidly. With the progress parts of the automobile components need high quality and the reliability. Among them, braking unit is essential device, and acquire the reliability through the performance test of brake. This study was aimed to design the performance-test-bench to measure the drag torque which has effect on caliper in braking unit. In this progressive technology, it is vital importance to use hydraulic and pneumatic, and to combine test bench with instrumentation engineering technology. This system to construct the design of hydraulic and pneumatic circuit, interface technique between sensors and personal computer, data acquisition and display design, and integrated control are very important technology. Moreover, reliable data are obtained through vacuum system and hydraulic and pneumatic system by using of booster and brake master cylinder which are actually applied to automobile. Then, data signal detector sensors for speed, pressure and torque is attached on this system. Therefore, in this study, we designed a performance-test-bench by and we also made an total control system using personal computer which is more progressive and flexible method than existing PLC control.

• Journal of Korea Foundry Society
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• v.29 no.3
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• pp.138-143
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• 2009

Vacuum suction is applied to the mold during pouring in the inclined gravity die casting to remove defects such as misrun and gas porosity in the brake master cylinder. Casting defects are observed after solidification and their cause is analyzed by using the calculated results with commercial solidification and flow analysis code(ZCAST). The optimum vacuum suction is -2 cmHg, and when the start time of vacuum suction is 3 seconds after pouring, better filled result is obtained by holding it for 15 seconds. Reproducibility test under the optimum conditions attained from the above pouring tests is performed, and it is confirmed that these pouring conditions can be applied to the mass production immediately.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.175-181
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• 2004

Analysis of brake characteristics has progressed rapidly in recent years, as computer techniques have developed. However, there are many problems in predicting braking characteristics, due to the numerous design variables of the brake system. Therefore, a synthetic braking performance analysis is required for all brake system parts such as master cylinder, booster, control valve and split system. In this paper, a program which can analyze braking performance such as force distribution, braking efficiency, pedal force and pedal travel, is presented. The preprocessor of the program helps users prepare input files through a dialog box. An additional postprocessor makes the graph presentation of solved results. Also, a simple example problem is applied to show the usefulness of the presented program.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.8
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• pp.582-588
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• 2008

An experimental investigation was conducted to investigate the effect of Bio-ethanol fuel on the engine performance and exhaust emission characteristics under various engine operating conditions. To investigate the effect of bio-ethanol fuel, the commercial 1.6L SI engine equipped with 4 cylinder was tested on EC dynamometer. The engine performance including brake torque, brake specific fuel consumption, and barke specific energy consumption of bio-ethanol fuel was compared to those obtained by pure gasoline. Furthermore, the exhaust emissions were analyzed in terms of regulated exhaust emissions such as unburned hydrocarbon, oxides of nitrogen, and carbon monoxide.Result of this work shows that the effect of blending of ethanol to gasoline caused drastic decrease of emissions under various operating conditions. Also, improved engine performance such as brake torque and brake power were indicated for bio-ethanol fuel.

• Tribology and Lubricants
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• v.19 no.5
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• pp.259-267
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• 2003

A brake device for the high-speed impacting object is designed using an axial crushing of thin-walled metal cylinder. Thickness of the cylinder is increased smoothly from the impacting end to the fixed end, resulting in the truncated cone shape. Truncated cone shape minimizes the imperfection-sensitivity of the structure and ensures that plastic hinges are formed sequentially from impacting end. This prevents the undesirable sudden rise in the first peak-crushing load. Several specimens with different conic angles, mean thickness of the wall, and materials were designed and quasi-static compression tests were performed on them. Results indicate that adoption of appropriate conic angle prevents simultaneous wrinkles generation and sudden rise of crushing load and that appropriate conic angle differs in each case, depending on the geometry and material property of the cylinder. Finite element analysis was performed for static compression of the cylinder and its accuracy was checked for the future application.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.767-772
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• 2023

In this study, combustion experiments were conducted at various engine speeds under full-load conditions using a single-cylinder diesel engine by blending butanol, pentanol, and octanol with diesel at a volume ratio of 10%. Experimental results revealed that higher alcohol-diesel blends resulted in lower brake torque and brake power than pure diesel due to the lower calorific value and the cooling effect during evaporation. An evident improvement in the brake thermal efficiency of the blended fuels was observed at engine speeds below 2,000 rpm, with the butanol blend exhibiting the highest thermal efficiency overall. Furthermore, the brake-specific fuel consumption of the higher alcohol-diesel blends was lower than that of pure diesel at speeds below 2,200 rpm. When using blended fuels, the exhaust gas temperature decreased under lean mixture conditions due to heat loss to the air and the cooling effect from fuel evaporation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1157-1162
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• 2011

The parking brake is an essential unit embedded in the track-driving motor of an excavator. The parking brake plays an important role in keeping the excavator in place not only when it is parked, but also during the digging operation. In fact, the load placed on the parking brake during the digging operation is significantly higher than the parking load, because the impact and rating loads caused by the bucket digging force cycle frequently and have very high load ranges. Therefore, the load conditions during the digging operation should be taken into account in the parking brake certification test. In this study, a series of experiments was carried out in which various operating pressures were applied to the parking brake, where repeated loads were reciprocally placed on the brake by locking the multifriction disc and releasing the hydraulic cylinder. The characteristics of the parking brake were investigated by comparing the obtained experimental results and the theoretical design specifications.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.82-88
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• 2011

Lean combustion and exhaust emission characteristics in a ethanol fueled spark-ignited engine according to ethanol-gasoline fuel blending ratio were investigated. The test engine was $1591cm^3$ and 10.5 of compression ratio SI engine with 4 cylinders. In addition, lambda sensor system was connected with universal ECU to control the lambda value which is varied from 1.0 to 1.5. The engine performance and lean combustion characteristics such as brake torque, cylinder pressure and rate of heat release were investigated according to ethanol-gasoline fuel blending ratio. Furthermore, the exhaust emissions such as carbon monoxide (CO), unburned hydrocarbon (HC), nitrogen oxides ($NO_x$) and carbon dioxide ($CO_2$) were measured by emission analyzers. The results showed that the brake torque, cylinder pressure and the stability of engine operation were increased as ethanol blending ratio is increased. Brake specific fuel consumption (BSFC) was increased in higher ethanol blending ratio while brake specific energy consumption (BSEC) was decreased in higher ethanol blending ratio. The exhaust emissions were decreased as ethanol blending ratio is increased under overall experimental conditions, however, some specific exhaust emission characteristics were mainly influenced by lambda value and ethanol-gasoline fuel blending ratio.

• Journal of Biosystems Engineering
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• v.7 no.1
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• pp.53-61
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• 1982

As an attempt to reduce the consumption of petroleum resources and to improve the performance of a kerosene engine, a series of experiments was conducted using several kinds of ethanol-kerosene blends under the various compression ratios. The engine used in this study was a single-cylinder, four-cycle kerosene engine having a compression ratio of 4.5. To investigate the feasibility of ethanol-kerosene blends in the original engine, kerosene and blends of 5-percent, 10-percent, and 20-percent-ethanol, by volume, with kerosene were used. And to investigate the feasibility of improving the performance of the kerosene engine, a portion of the cylinder head was cut off to increase the compression ratio up to 5.0 by reducing the combustion chamber volume. Kerosene and blends of 30-percent and 40-percent-ethanol, by volume, with kerosene were used for the modified engine with an increased compression ratio. Variable speed tests at wide-open throttle were also conducted at five speed levels in the range of 1000 to 2200 rpm for each compression ratio and fuel type. Volumetric efficiency, engine torque, and brake specific fuel consumption were determined, and brake thermal efficiency based on the lower heating values of kerosene and ethanol was calculated. The results obtained in the study are summarized as follows: A. Test with the original engine: (1) No abnormal conditions were found when burning ethanol-kerosene blends in the original engine. (2) Volumetric efficiency increased with ethanol concentration in blends. When burning blends of 5-percent, 10-percent, and 20-percent ethanol, by volume, with kerosene, average volumetric efficiency increased 1.6 percent, 2.6 percent, and 4.1 percent respectively, than when burning kerosene. (3) Mean engine torque increased 5.2 percent for 5-percent-ethanol blend, 9.3 percent for 10-percent-ethanol blend, and 11.5 percent for 20-percent-ethanol blend than for kerosene. Increase in engine torque when using ethanol-kerosene blends was due to the improved combustion characteristics of ethanol as well as an increase in volumetric efficiency. (4) Up to ethanol concentration of 20 percent, mean brake specific fuel consumption was nearly constant inspite of the difference in heating value between ethanol and kerosene. (5) Brake thermal efficiency increased 0.3 percent for 5-percent-ethanol blend, 3.8 percent for 10-percent-ethanol blend, and 6.8 percent for 20-percent-ethanol blend than for kerosene. B. Test with the modified engine with an increased compression ratio: (1) When burning kerosene, mean volumetric efficiency, engine torque, and brake thermal efficiency were somewhat lower than for the original engine. (2) Engine torque increased 15.1 percent for 30-percent-ethanol blend and 18.4 percent for 40-percent-ethanol blend than for kerosene. (3) There was no significant difference in brake specific fuel consumption regardless of ethanol concentration in blends. (4) Brake thermal efficiency increased 15.0 percent for 30-percent-ethanol blend and 19. 5 percent for 40-percent-ethanol blend than for kerosene.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.90-96
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• 1995

In general, natural gas engine converted from gasoline engine has disadvantage of power decrease. In order to increase power output in natural gas engine, the improvement of in-cylinder flow motion has been believed as the most effective method. In this study, the geometry of combustion chamber in 4 valve DOHC natural gas engine is modified, and in-cylinder flow patterns is analyized. Also engine performance is evaluated according to the modification of in-cylinder flow motion.