• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.668-669
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• 2016

The retarder as a hydraulic brake system in order to assist a service brakes in commercial vehicle is operated by automatic and manual mode due to driver. Braking energy by retarder operation is transmitted to the engine radiator of vehicle cooling system, passing through the retarder oil heat exchanger. At this moment, the retarder ECU performs the function that is controlled a braking torque with consideration for automatic and manual mode, temperature of retarder oil/water, engine coolant temperature, vehicle speed, and etc. In this paper, it deals with the design of retarder control logic and the results of retarder braking performance test regarding a cooling system of retarder and vehicle.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.33-48
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• 1977

Transporting agricultural products and the other material by the two-wheel-tractor (power-tiler)and trailer system may be one of its most widely used farming functions.The safety and hitching load for all the previaling performing conditions may be the general concern over the operation of the tiller-trailer system. In this study, a mathematical model to determine the static and dynamic forces excerting on the hitch point were developed . Based on the analysis of the model and the field measurements. the limiting hitching load and critical slope were analyzed. The results of the study are summarized as follows ; 1) The limit angle of slope land for the safety steering that two-wheel tractor-single axle trailer system was able to transport agricultural products was the direct angle (${\gamma}$) = 8 ; the cross angle$\beta$) 15 ; and it was decreased in accordance with the increase of carrying load ($W_4). 2) The critical velocity for safe operation in case of running on downward hill road was about 1.08m/sec. 3) The limiting carrying load for the safe steering was W$_4$=600kg. The degree of the safe steering for different braking methods was given in order as follows ; Simulataneous braking the tractor and trailer , braking the trailer only, and braking tractor only. 4) Among the three components of impact loads excerting on the hitch point, the component in the lateral direction ($P_{Vy}$) was near zero in spite of increase of hitching load ($W_4) , while the components in the other two mutually perpedicular directions ($P_{Vx}$ and ($P_{Vz}$) ) had larger values in horizontal plane than those in the slope lands. 5) Moment of forces on the lateral direction (M$y$) had the largest value among the three components of impact moment acting on the hitch point, however all the components were sharply increased in accordance with the increase of hitching loads ($W_4. Three components of the moment were the negative values.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.545-551
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• 2016

In this study, we evaluate the braking performance of an urban railway vehicle to verify its basic safety condition. The braking performance evaluation methods, deceleration measurement and braked weight percentage, were compared for trains with different numbers of cars, in order to assess the advantages of each method and their compatibility. With a probabilistic braking model, the effect of the adhesion coefficient distribution was analyzed in accordance with the train composition. A train with many cars has a narrower deceleration distribution width than one with few cars. The braked weight percentage method is expected to be useful in the design of train signal systems, because it allows the braking distance to be calculated for various initial brake velocities. The deceleration distribution model and its results are expected to be useful as a basis for precise train signal design.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1461-1466
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• 2004

Recently Domestic EMU's on board signal systems are gradually changed form Cab signal(Fix Block) to Distance-to-go. Interfaces with on board signal system, TCMS Redundancy structure is mainly required. This paper suggest Manaul/Automatic Driving based on TCMS-ATC interface and design of backup system which is operated by Stan-by Computer when one of it's Local Interface Unit(LIU) is out of oder. For the purpose of Precision Train Stop, Distance-to-go signal system require accuracy speed. Free-axle structure is required for this system This paper suggest Free-axle braking system that lack of brake-force is compensated by the distributed brake-force using TCMS. And one of braking system has out of order, compensation of brake-force for Free-axle system. Then we prove our design to Complete Car Test

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.220-229
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• 2000

In the brake systems a proportioning valve which reduces the brake pressure at each wheel cylinder for anti-locking of rear wheels is closely related with the safety of vehicles. But, it is impossible for a present proportioning valve to exactly control brake pressure because mechanically it is an open loop control system. So, in this paper we describe a electronic brake pressure distribution system using a fuzzy controller in order to exactly control brake pressure using a close loop control system. The object of electronic brake pressure distribution system is to change an cut-in pressure and an valve slop of proportioning valve in order to obtain better good performance of brake system than with mechanical system.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.597-607
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• 2017

The general control method for Anti-lock Brake System(ABS) is that the wheel slip ratio is observed and the braking force is controlled in real time in order to keep the wheel slip ratio under the value of the best slip ratio. When a wheel runs on the state of the best slip ratio, the ground friction of the wheel approaches the highest value. The value of best slip ratio, theoretically, is known as the value between 10 and 20 % and it is dependant on the ground condition such as dry, wet and ice. It is an important parameter for the braking performance and affects the braking stability and efficiency. In this thesis, an experimental method is suggested, which is a reliable way to decide the best slip ratio through dynamo tests simulating aircraft taxiing conditions. The obtained best slip ratio is proved its validity by results of aircraft taxiing tests.

• Tribology and Lubricants
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• v.26 no.1
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• pp.31-36
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• 2010

The brake system is an important part of the automobile safety system. The disc brake system is divided into two parts: a rotating axi-symmetrical disc, and the stationary pads. The frictional heat, which is generated on the interface of the disc and pads, can cause high temperatures during the braking process. The frictional heat source (the pads) is moving on the disc and the location is time-dependent. Our study applies a moving heat source, which is defined by the time and space variable on the frictional surface, in order to simulate the frictional heat behavior accurately during the braking process. The object of the present work is the determination of the temperature distribution and thermal stress in the solid disc by non-axisymmetric 3D modeling for repeated braking.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2428-2434
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• 2012

This paper describes the control of a solenoid valve of ESC(Electronic Stability Control) with hydraulic modulator in braking system. ESC ECU(Electronic Control Unit) to control the high-frequency control and slope control method was applied, the surge pressure and EMI(electromagnetic interference) reduction characteristics were studied. The stage of ECU output was added the slope shaping function to reduce electromagnetic emission at higher frequencies. Measurements show that this high frequency ECU manages to reduce the surge pressure and electromagnetic emission by the control of solenoid valve. In conclusion, by using the results of this study for the high frequency ECU control, we could expect enhancement of braking system performance.

• Journal of the Korea Safety Management & Science
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• v.20 no.2
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• pp.1-8
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• 2018

This study aims to provide a real-time information to the driver by effectively operating the advanced safety device attached to the freight vehicle, thereby minimizing insecure behavior of the driver such as speeding, rapid acceleration, sudden braking, And improve driving habits to prevent accidents and save energy. Advanced safety equipment is a device that warns the driver that the vehicle leaves the driving lane regardless of the intention of the driver and reduces the risk of traffic accidents by mitigating or avoiding collision by detecting a frontal collision during driving.The main contents of this report are as follows: In case of installing a warning device on a lane departing vehicle (excluding a light vehicle) and a lorry or special vehicle with a total weight exceeding 3.5 tonnes, the driver must continue to operate unless the driver releases the function.In addition, when the automatic emergency braking system is installed, the structure should be such that the braking device is operated automatically after warning the driver when the risk of collision with the running or stopped vehicle in the same direction is detected in front of the driving lane.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.519-528
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• 2019

Current brake system changes the kinetic energy into heat energy by friction-type of brake that the braking action is diverging into the air. The system has a device called a retarder that generates braking force. High-tech research on the high-speed response characteristics of retarders utilizing part of the braking energy of the retarder to save electrical energy consumption is already underway in advanced countries. In this paper, we propose DC-DC converter which converts 3-phase voltage generated from retarder to 24V DC voltage for battery charging and verify its validity through experiments.