Examination of flexible hose on vehicles

Flexible hoses are widely used in the automotive sector. These hoses provide the absorpition of the engine movement, force and vibration while transferring hot compressed air or oil. Teflon hoses are reinforced steel braided known as PTFE hoses and generally preferred for high pressure and temperature resistance. The aim of the project is to find the optimum hose length without any failure. The main reason of failed PTFE hoses is mostly related with not being able to dampen the engine movement which can cause varying stress on hoses. In the context of this thesis, the effect of the length on a hose in the way of performance was investigated by examining with different lengths (233mm, 245mm, 273mm). For that reason, the study was supported with vehicle field tests, rig lifetime cycle test and computer assisted analyses to which were inserted all of the parametric data taken from the rig test such as 6 bar air pressure, 32 mm displacement and variable force data (according to vehicle conditions). At the end of the study, a decrease of strain forces and an increase of total lifetime were observed on the hose by extending the hose length. As a result, the lifetime of a 233mm hose length to 245mm, is increased 2.7 times and the absorbing force is reduced approximately by 12%. A 233mm hose length increased to 273mm has been extended lifetime 45.62 times and the absorbing force is reduced approximately by 20.56%. This study's outputs show that increasing the length of the hose reduces the stress on the hose and is effective in extending the part's service life.