• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.6
• /
• pp.391-399
• /
• 2021

In order to investigate force and cavitation characteristics for the flat & twisted rudders in the Large Cavitation Tunnel (LCT), the rudder dynamometer was designed and manufactured. The measuring capacities of lift, drag and moment are ±1000 N, ±2000 N, and ±150 N-m, respectively. The present dynamometer uses the actuator with a harmonic drive to control the rudder angle without backlash. As the target ship is a military ship with twin shaft, each dynamometer was installed above the port & starboard rudders. After the installation of the model ship with all appendages, the model test composed of rudder force measurement and cavitation observation was conducted for the existing flat rudder & the designed twisted rudder. While the flat rudder showed the big difference of lift & moment between port & starboard, the twisted rudder presented a similar trend. The cavitation of the twisted rudder showed better characteristics than that of the flat rudder. Another set of model tests were conducted to investigate rudder performance by the change of the design propeller. There was little difference in rudder performance for the design propellers with slight geometric change. Through the model test, the characteristics of the flat & twisted rudders were grasped. On the basis of the present study, it is thought that the rudder with better performance would be developed.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.548-552
• /
• 2003

In the braking system, the friction force is the most important factor of the design. For long time, many researchers have been strived for getting the exact friction coefficients. But the friction coefficients are affected by the road condition and changed by lots of parameters, such as normal force and characteristics between two contacted materials, temperature, etc. For the development of ABS of the aircraft, HILS(Hardware-In-the-Loop-Simulation) test and dynamometer test was carried out. For the calculation of the friction coefficients, the wheel moments were measured using the load cell mounted on the housing of the wheel. The test conditions were dry and greasy, as the 0.7 and 0.4 in friction coefficient, respectively. In this paper, the test results of the friction coefficients were represented and the improvement method was suggested.

• Journal of Mechanical Science and Technology
• /
• v.15 no.5
• /
• pp.569-579
• /
• 2001

This study investigates the effects of operating conditions on the chattering of an automotive disk brake by experimental and computational methods. Design factors, which cause chattering in automobiles, have attracted great attentions for long time; but they are not well understood yet. For this study, we construct a brake dynamometer for measuring the disk surface temperature during chattering, and propose an efficient hybrid algorithm (combining FFT-FEA and traditional FEA program) for analyzing the thermo-elastic behavior of three-dimensional brake system. We successfully measure the judder in a brake system via the dynamometer and efficiently simulate the contact pressure variation by the hybrid algorithm. The three-dimensional simulation of thermo-mechanical interactions on the automotive brake, showing the transient thermo-elastic instability phenomenon, is presented for the first time in this academic community. We also find from the experimental study that the disk bulk temperature strongly influences the brake chattering in the automotive disk brakes.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.5
• /
• pp.90-99
• /
• 1996

To keep up with the regulation of OBD II(on board diagnostics II), many detection methods for engine misfire have been developed. Among them, the method of using the crankshaft speed fluctuation is the most noticeable in the point of view of lower cost and easier installation than any others. On the basis of the results obtained from the previous engine-dynamometer test, the integrating torque index (ITI) has been introduced. In this research, the instrumental and the interfacing systems to engine control unit(ECU) are developed for the vehicle test. Therefore, the vehicle and chassis-dynamometer test can be carried out in addition to the rough road test. From this test, the previousproposed method proved that it can be applied to the real vehicle.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.10a
• /
• pp.220-224
• /
• 2001

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. To perform efficient high-speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force. To measure cutting force in high-speed machining, dynamometer has to have high natural frequency. In this paper, The dynamometer which has high natural frequency used to measure the cutting force in various cutting conditions. High-speed machining characteristics are evaluated by the cutting force, FFT analysis of the cutting force and chip formation.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.152-155
• /
• 2007

Fuel cell electric vehicles (FCEVs) using hydrogen gas are zero emission vehicles, thus emission measurement for combustion vehicles is not applicable. The hydrogen gas consumption for fuel economy will be measured by the stabilized pressure/temperature method, mass flow method and electrical current method, etc. In this research, weight method with a newly manufactured test equipment is applied to measure the hydrogen consumption because above 3-methods have a deviation. The hydrogen consumption is directly calculated by the weight differences of the external hydrogen tank before and after the chassis dynamometer test. Ultimately the fuel economy for FCEVs is obtained with a deviation less than 1% in all chassis dynamometer tests.

• Journal of the korean Society of Automotive Engineers
• /
• v.8 no.4
• /
• pp.56-65
• /
• 1986

This paper theoretically analyzed the relations between the out-put braking torque and the wheel cylinder pressure in the leading-trailing drum brake for heavy duty truck as the characteristics of friction in break lining, comparing with the results derived from full-scale inertial brake dynamometer test in actual braking condition to develop reliable brake system in extensive using conditions. The main results obtained are as follows; 1) The characteristic curve representing the relations between BEF (Brake Effectiveness Factor) and Friction coefficient derived from theoretical analysis are consistent with the experimental results of dynamometer test. 2) According to the results of dynamometer test, the friction coefficient of brake lining is subject to initial brake speed and the actual using temperature in brake system.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.6
• /
• pp.112-118
• /
• 2001

In this study the leakage current measurement method based on a porous ceramic is applied to check the conductive substance caused by the ionized particles. By using engine and chassis dynamometer and an experiment vehicle, in which the hydrocarbon sensor (HC sensor) was exposed to the exhaust gas to create the electrical signal, the HC sensor in the exhaust line checked the conductive ions in emission gas. Generally the output electrical signal of HC sensor is followed with amount of hydrocarbon in the experiments in cold start and operation. By combining the electrical signal, a measure of conductivity of exhaust gas with hydrocarbon can be provided by OBD (On Board Diagnosis) II and EMS (Engine Management System).

• KSTLE International Journal
• /
• v.1 no.1
• /
• pp.1-7
• /
• 2000

Eviction characteristics of two typical friction materials (non-asbestos organic and low-steel friction materials) for an automotive brake system were investigated using an inertial brake dynamometer. In particular, the effect of sliding speed on friction coefficient was carefully investigated employing various test modes. The two friction materials were developed for commercial applications and were different mainly in the type and the amount of metallic ingredients in the friction material. The dynamometer test showed that the low-steel friction material was sensitive to the sliding speed exhibiting a negative $\mu$-v relation. On the other hand, the non-asbestos organic friction material was less sensitive to the sliding speed. The low steel friction materials with a negative $\mu$-v relation also induced larger vibration amplitude during brake applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.1000-1003
• /
• 2014

The primary purpose of this study is to observe the dynamic behavior within a vehicle on chassis dynamometer throughout cleat impact testing with two different constraining setups (Tie-down strap and one point fixation). Throughout this empirical experiment, no outstanding dynamic behavior characteristics are observed between two setups and thus, the performance of the one point fixation device is validated. Neither the interior noise nor acceleration at driver seat rail and knuckle is heavily influenced by two different constraining methods. However, one point fixation is far more advantageous considering its shorter set up time and its capability of measuring traction force with its built in force sensor.