機(jī)械外文翻譯--一個(gè)使用四個(gè)液體系統(tǒng)分析盤式制動(dòng)器的制動(dòng)效率的實(shí)驗(yàn)（英文）

1、Research Journal of Applied Sciences, Engineering and Technology 5(4): 1302-1308, 2013 ISSN: 2040-7459; e-ISSN: 2040-7467 © Maxwell Scientific Organization, 2012 Submitted: July 02, 2012

2、 Accepted: August 08, 2012 Published: February 01, 2013 Corresponding Author: Seth Daniel Oduro, Department of Design and Technology Education, University of Education Winneba, Kumasi Campus. P.O. Box 1277, Kumasi, Gh

3、ana 1302 An Experimental Analysis of Brake Efficiency Using four Fluids in a Disc Brake System 1Seth Daniel Oduro, 2Prince Owusu Ansah and 3Agyei Agyamang 1Department of Design and Technology Education, University of Ed

4、ucation Winneba, Kumasi Campus. P.O. Box 1277, Kumasi, Ghana 2Department of Mechanical Engineering, Kumasi Polytechnic, P.O. Box 854, Kumasi, Ghana 3Department of Mechanical Engineering, Kwame Nkrumah University of Sc

5、ience and Technology, KNUST, Kumasi, Ghana Abstract: The paper studies disc brake failure in Mini-buses using an experimental analysis to test the maximum braking force when different brake fluids such as clean, less d

6、irty, dirty and soapy water solution were used in the braking system. The experimental results clearly showed that the soap solution appears to be the best fluid as far as low viscosity and stability of viscosity with

7、increase in temperature are concerned. However, the soap solution is not compatible with other fluid which makes it difficult to be substitute as a clean brake fluid. The result of the Thepra Universal Brake Testing Eq

8、uipment used for the braking efficiency test indicated that a pedal brake of 117 kN produce a brake force of 0.96 kN for clean brake fluid, 0.91 kN for the less dirty, 0.85 kN for dirty and 1.44 kN for soap solution. T

9、he value of 1.44 kN which was achieved when the soap solution was used indicated a positive braking force and the indicating that soap solution could be used to produce a high pedal force within a very short time (abou

10、t 10-30 min) and can therefore be used only in case of emergency. The brake efficiency test indicated that under hot conditions the braking efficiency is reduced and the presence of air in the system renders the braking

11、 ineffective because higher pedal force was needed to be able to produce a significant braking force which is noted for causing brake failure. Keywords: Brake fade, brake failure, disc brake, efficiency, pedal force I

12、NTRODUCTION When a vehicle is accelerated, energy supplied by the engine causes the vehicle’s speed to increase. Part of this energy is instantly used up in overcoming frictional and tractive resistance but a large am

13、ount of it remains stored in the vehicle. According to Heinz (1999) this energy of motion is called the kinetic energy and the existence of kinetic energy is observed when a vehicle is moving and neutral gear is sele

14、cted. The vehicle does not immediately come to rest; instead it travels for a considerable distance before it becomes stationary. In this case the stored energy is used to drive the vehicle against the resistances th

15、at oppose the vehicle’s motion. Relying on these resistances to slow down a vehicle could cause many problems, so an additional resistance called a brake is needed to convert the kinetic energy to heat energy at a fa

16、ster rate in order to reduce the speed of the vehicle Mcphee and Johnson (2007). This reduces the speed of the vehicle at a faster rate and brings the vehicle to rest within the shortest possible time when the brakes

17、 are applied. From the point of view of Johnson et al. (2003) most automotive systems in use today utilize front disc brakes, but four-wheel disc systems are also common In disc brakes, the rotor rotates with the whe

18、el and the pads move out to rub the rotor when the brakes are applied. Most disc brakes use floating calipers. The caliper slides in and out as the brakes are applied and released. The piston moves the inside pad out

19、 and pushes the outside pad into the rotor by sliding the caliper back toward the rotor. The use of disc brakes to reduce speed or bring the vehicle to rest when in motion cannot be over emphasized if the safety of

20、 the occupant is to be guaranteed Heinz (1999). To bring a vehicle to a stop, the disc brakes have to absorb all the energy given to the vehicle by the engine and that due to the momentum of the vehicle. This energy

21、must then be dissipated. In most vehicle disc brakes, the energy is absorbed by friction, converted into heat and the heat dissipated to the surrounding air (Thoms, 1988). As the energy is absorbed, the vehicle is sl

22、owed down; in other words, its motion is retarded. The brakes must also pull up the vehicle smoothly and in a straight line to bring the vehicle to a stop position. It is therefore very important that the disc brake

23、s of vehicles operate with the highest efficiency. This could Res. J. Appl. Sci. Eng. Technol., 5(4): 1302-1308, 2013 1304 Ghanaian drivers sometimes used other fluid such as dirty brake fluid, less dirty fluid and e

24、ven soapy water sometimes as a substituted to the original brake fluid. This study among other things will also investigate which of these brake fluid, clean, dirty, less dirty and soapy water will have the best visc

25、osity, high boiling point and less braking force. MATERIALS AND METHODS The design used for this study was experiment which employed the used of viscometer and Thepra Universal Automotive Brake Testing machine to chec

26、k the efficiency of the four fluids in the transmission of braking forces. Laboratory analysis: The viscosity tests on the four different liquids were carried out at the Kwame Nkrumah University of Science and Techno

27、logy (KNUST) Thermodynamics laboratory. The liquids were clean brake fluid, less dirty brake fluid, dirty brake fluid and soap solution. It was necessary to find out how the viscosity of different qualities of brake

28、 fluid affected braking efficiency and to find out whether there was any correlation between these and the occurrence of brake failure. Viscosity test on the various fluids used: The viscosity test was carried out on

29、 a Redwood Viscometer in Fig. 2 on the four different kinds of fluids to determine their viscosities. The apparatus consists of a vertical cylinder containing the fluid under test which was allowed to flow through a

30、calibrated orifice situated at the centre of the cylinder base. The orifice is closed by a ball valve when it is not being used. The oil cylinder is surrounded by a water jacket which maintains the lubricant under te

31、st at a required temperature by means of a Bunsen burner flame applied to the heating tube. The thermometer for the water in the jacket is mounted in a paddle-type stirrer which can be rotated by hand, using the hand

32、le (Zammit, 1987). Procedure for testing various viscosities of the fluids: To test the viscosity of a fluid, the water jacket was filled with water with the orifice ball valve in position. Fluid was poured into the c

33、ylinder to the level of the pointer. A 50 mL measuring flask was placed centrally under the orifice. The water was stirred gently until the water and fluid thermometers were the same (room temperature, 30ºC). Th

34、e temperature was recorded. The ball valve was then raised and a stop- watch used to record the time (in seconds) for a 50 mL of fluid to flow into the measuring flask. The test was repeated with the fluid temperature