IJR International Journal of Railway

Vol. 8, No. 1 / March 2015, pp. 30-34

Vol. 8, No. 1 / March 2015 − 30 −

The Korean Society for Railway

Maglev(UTM-02) Brake System Change from

Pneumatic Bake System to Hydraulic Brake System

Kinam Kim†, Sungwoon Hwang* and Heekwon Jeon*

Abstract

The Maglev(UTM-02) project is leading by Korea Institute of Machinery & Materials and financially supported from the

ministry of Commerce, Industry and Energy. The early development stagy of Maglev(UTM-02) was adopted the general

urban railway pneumatic brake system due to the Korea domestic industrial environment. Currently there is two com-

mercial operation Light Railway Train(LRT) system in Korea. One is U-Line in Uijungbu, and the other is Everline in

Yongin. Both LRT systems are adopting high performance light weight hydraulic brake system. But those design and

manufacturing core technology of the brake system is came from a major brake system companies located from aboard.

Currently various studies have been continued to increase practical application and to improve competitiveness on per-

formance for each sub-system of Maglev. Also in case of brake system, developing competitive hydraulic brake system

is required. In this study, we have introduced the development process and performance evaluation of the new hydraulic

brake system of Maglev.

Keywords: Pneumatic brake system, Hydraulic brake system, Brake system

1. Introduction

UTM-02 was developed in 2005 based on previous

UTM-01 technology. Beginning stage of hydraulic brake

system development, LINIMO system in Japan or LRT

system in Europe was considered in application, but

finally the optimized conventional pneumatic brake sys-

tem was adopted due to Korea domestic environment.

However, recently most of LRT system is adopting a

hydraulic brake system due to benefit of high perfor-

mance, light weight and compact optimized design. To

improve performance and competitiveness of the previ-

ous maglev brake system, we have studied to change the

pneumatic brake system to new developed hydraulic

brake system in UTM-02. It is the first time to intro-

duce a hydraulic brake system in train by domestic com-

pany in Korea. There was partially applied semi-

hydraulic brake system which used pneumatic-hydrau-

lic converter.

2. Configuration of theNew Hydraulic Brake System

2.1 System modification review

A review of previous installed hardware of UTM-02

brake system had to be conducted to modify from the pneu-

matic brake system to the new hydraulic brake system.

Fig. 1 (a) shows the schematic diagram of the previous

pneumatic-hydraulic converter, and Fig. 1(b) shows the

schematic diagram of the developed Electric Hydraulic

Power Unit(EHPU).

Also new developed EHPU and brake control unit

should be installed in UTM-02 instead of previous pneu-

matic pipe line, bake system, brake controller and pneu-

matic-hydraulic converter. Fig. 2 shows the eliminated

components in the previous pneumatic brake system. Fig.

3 shows the new components of hydraulic brake system by

using EHPU.

Table 1. shows the expected improving performance by

modification from previous pneumatic brake system to

†

*

Corresponding author: Yujin Machinery Ltd, R&D Center, Korea

E-mail : knkim@yujinltd.co.kr

Yujin Machinery Ltd, R&D Center, Korea

ⓒThe Korean Society for Railway 2015

http://dx.doi.org/10.7782/IJR.2015.8.1.030

− 31 −

Kinam Kim, Sungwoon Hwang and Heekwon Jeon / IJR, 8(1), 00-00, 2015

new hydraulic brake system.

2.2 New Hydraulic brake system design

Fig. 4 shows the manifold block 3D drawing of EHPU

installed in UTM-02. EHPU performs exactly same func-

tion and better performance comparing to previous pneu-

matic brake system.

Fig. 5 shows the external picture of EHPU prototype.

Table 2 shows the general specification of EHPU

Table 3 shows the part list and description of EHPU

Table 2, Table 3 and Fig. 6 can be diversely applied and

designed according to system requirement.

3. Verification in UTM-02

3.1 Installation of EHPU

Developed EHPU is installed in UTM-02 instead of pre-

Fig. 1 Brake system comparison

Fig. 2 Eliminated components from previous brake system

Fig. 3 New hydraulic brake system diagram by using EHPU

Table 1. System comparison

Clasification Pneumatic system Hydraulic system

Weight Approx. 76 kg Approx. 47 kg

Idle time 3.0 Sec 2.0 Sec

Res. time 0.4 Sec 0.2 Sec

Power

consumption

Current control

700 mA, 120 WVoltage control

Temp. -25oC -35oC

Fig. 4 EHPU 3D Drawing

Maglev(UTM-02) brake system change from pneumatic bake system to hydraulic brake system

− 32 −

vious pneumatic brake system as shown in Fig. 7

Brake control unit which control EHPU is installed in

the switchboard as shown in Fig. 8

3.2 Verification for system modification

EHPU uses hydraulic motor to generate hydraulic brake

force, and separated power supplier is required to control

hydraulic motor. Fig. 9 shows the separated control circuit

Fig. 5 Prototype of EHPU

Table 2. Specification of EHPU

Classification Specification

Max. Discharge pressure 162 bar

Max. System Supply pressure 140 bar

Pump delivery 1.89 L/min at 3000 RPM

Motor Capacity 3000 RPM, 500 W

Viscosity range 20 ... 80 cst

Hydraulic Fluid Univis HVI 26

Supply power DC 24 V

Control power DC 24 V

Ambient temperature -35oC ~ 50oC

Construction Manifold type

Size(HxVxZ) 435 × 350 × 180 mm

Table 3. Part list about the EHPU

Classification Component name Description

a Pump Transfer mechanical energy of motor to hydraulic energy and supply

bc Motor Transfer electric energy to mechanical energy and operate pump

c Supply filter Protect hydraulic device from impurity

d Check valve Prevent counter current of Main line

i By pass valveBypass valve will dump for monitoring when pressure transducer(supply port)in main

line is in fault condition such as supply filter fault, obstruction and malfunction

mb Pressure limiting valve Pressure setting for system pressure of main line

n Hand valve Manual dump in main line hydraulic pressure

raControl valve for brake

application(Charge)Charge or discharge hydraulic energy in main line

rbControl valve for brake

application(Dump)WSP (Wheel slide protection) function apply by dumping oil in Control line

maPressure limiting valve for security

brake pressurePressure setting for Security brake pressure

sa Security brake valve On/Off control for output mode of ma (B11) in ra (B9)

sb Brake release valve Charge or discharge brake pressure

ea Pressure transducer(Supply) Monitoring main line pressure

eb Pressure transducer(Control) Monitoring control line pressure

p Pressure switch for brake pressure System protection by sensing the over pressure value in control line

u Tank Oil storage

fa Test fitting(Supply) Flushing and pressure checking in main line

fb Test fitting(Control) Flushing and pressure checking in control line

M Main line Main line is connected to Accumulator

C Control line Control line is connected to Actuator

− 33 −

Kinam Kim, Sungwoon Hwang and Heekwon Jeon / IJR, 8(1), 00-00, 2015

installed in UTM-02 (ref. Fig. 7).

4. Test Results

4.1 Static test in UTM-02

4.1.1 Interface I/O test results

Before conducting dynamic test in main test line, static

test is required in advance. In this study, interface I/O test

and brake function test were conducted to check the basic

static function. Fig. 10 shows the function test equipment

connected to UTM-02 in depot.

Table 4 shows the interface I/O test result for brake sig-

nal line. It shows that main brake system signal related to

UTM-02 operation is in normal operation state. This

results show that all brake system component is installed

correctly and ready to conduct the static brake perfor-

mance test.

Fig. 6 Hydraulic circuit diagram of the EHPU

Fig. 7 EHPU installed in UTM-02

Fig. 8 Brake control unit for EHPU

Fig. 9 Control logic for verification

Fig. 10 Static function test equipment

Maglev(UTM-02) brake system change from pneumatic bake system to hydraulic brake system

− 34 −

4.1.2 Static brake performance test results

Various brake mode tests, such as general brake mode

(B1~B6), Full Service Brake (B7) and Emergency brake

mode, were conducted to check the actual brake operation

performance. Fig. 11 shows the brake force & response

time comparison between previous pneumatic-hydraulic

converter system and new hydraulic brake system (B2

mode). It shows that the response time of new hydraulic

brake system is improved 0.2 second, and brake force is

same as designed value. The 0.2 second delay is the char-

acteristics of previous pneumatic-hydraulic converter. The

delay phenomenon is disappeared by using new hydraulic

brake system, and it shows that the brake performance is

improved comparing to previous system.

5. Conclusion

In this study, we have developed the new hydraulic

brake system for UTM-02 instead of previous pneumatic-

hydraulic converting brake system. We have studied to

modify previous pneumatic brake system to new hydrau-

lic brake system applying UTM-02. It is the first time to

apply hydraulic brake system in train by own domestic

technology.

The study results show that new developed hydraulic

system is successfully installed instead of previous pneu-

matic brake system as shown in interface I/O test results.

Also it shows the improved response time comparing to

previous pneumatic-hydraulic convert method.

In future, dynamic performance test in test line will be

conducted to secure total brake performance based on

brake performance specification.

Acknowledgement

This research was supported by a grant(14RTRP-

A069839-02) from Railroad Technology Research Pro-

gram funded by Korean Ministry of Land, Infrastructure

and Transport of Korean government

References

1. W.D. Lee and G.D. Kim and J.R. Shin (2004). “A study on

the application method for hydraulic brake system of urban

transit system”.

2. N.J. Lee and K.H. Kang and W.S. Lee and C.G. Kang

(2012). “Design and manufacturing of bogie system for Low

Floor Tram”, KSR2012S138.

Table 4. Interface I/O test result for the brake signal line of

UTM-02

Divide Brake signal name Result

1 MCV(Eddy current valid signal) Operating state

2 PWMH(Brake input signal) Operating state

3 LWS(Stress load signal for traction) Operating state

4 EB2(Emergency brake input signal) Operating state

5 FSB(Full service brake input signal) Operating state

7 BMODE(Brake mode) Operating state

8 FO(Regenerative braking termination signal) Operating state

9 DC(Door close) Operating state

10 EO(EO mode) Operating state

11BEAH(Regenerative braking achieve

signal, PWM signal) Operating state

12BEDS(Regenerative braking demand

signal, PWM signal) Operating state

13 PS(Powering signal) Operating state

14 Air spring pressure signal Operating state

Fig. 11 Brake force & response time comparison between

previous pneumatic hydraulic converter system and new

hydraulic system.