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Investigation and Analysis of Brake Factor Variation and its Relation with Brake Pulling
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 19, 2022 by SAE International in United States
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Vehicle pull during braking can be defined as the deviation of vehicle travel from intended path of the vehicle by a margin of half a wheel track or more. It is a dynamic phenomenon with very complex inter-dependencies among the combined functioning of various aggregates such as steering system, suspension system, axles, and brakes. The problem is aggravated with shorter wheelbase & higher CG (Centre of Gravity) height, where the instantaneous load transfers are sudden and of relatively high magnitude which can lead to a combination of forces that are responsible for vehicle drifting or pulling to anyone side of centre-line travel.
Vehicle with shorter wheelbases, high GVW and high CG heights are more prone to this unstable behaviour due to sudden change in dynamic forces acting on the tires while turning and braking. Although these vehicles have some disadvantages, they are required for important applications such as stage and intercity operations and hence cannot be stopped producing due to business needs.
We have approached to solve this problem in our subject LCV vehicle (GVW- 6.9T) by keeping the focus on brakes system in particular for Brake Factor Variation with respect to Coefficient of friction of Lining Material. During DOE it was observed that brake force variation between LH and RH Brake plays a vital role in causing unstable vehicle pull while braking. When analysed, we understood that brake force variation depends on brake factor variation and in turn on liner coefficient of friction. This phenomenon is further studied on the vehicle by testing various liners of known coefficient of friction. Out of these, two liners were selected for further study and the output of study is presented in this paper.
This paper deals with identifying components of a braking system which are responsible for vehicle pull, through a systematic method by conducting a comprehensive DoE and reducing the intensity of pull to acceptable levels by changing co-efficient of friction values of liners material. The solution was proven by implementing it on similar vehicles.
CitationPandey, P., Pujari, S., and Nagrikar, R., "Investigation and Analysis of Brake Factor Variation and its Relation with Brake Pulling," SAE Technical Paper 2022-01-1171, 2022, https://doi.org/10.4271/2022-01-1171.
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