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The Effect of Application Air Pressure on Brake Stroke Measurements from 70 to 125 psi
Technical Paper
2015-01-2833
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Brake chamber construction allows for a finite stroke for pushrods during brake application. As such, the Federal Motor Carrier Safety Regulations (FMCSRs) mandate maximum allowable strokes for the various chamber types and sizing. Brake strokes are often measured during compliance inspections and post-accident investigations in order to assess vehicle braking performance and/or capability. A number of studies have been performed, and their results published, regarding the effect of brake stroke and function on braking force and heavy truck stopping performance [1] through [4]. All of the studies have relied on a brake supply pressure of 100 pounds per square inch (psi). When brake strokes are measured in the field, following the Commercial Vehicle Safety Alliance (CVSA) procedure, the application pressure is prescribed to be maintained between 90 and 100 psi. However, circumstances that are difficult for investigators to control in the field often result in brake stroke measurements being taken with the application pressure outside of the CVSA-prescribed range. Although opinions have been offered regarding suitable correction factors, the authors could not locate any published test data on the topic. The authors conducted an experiment with an in-service vehicle to quantify a relationship between measured brake stroke and system air pressure in the range after the linings have made complete contact with the drums (70 to 125 psi). This paper describes the experiment, results, and theoretical implications, including effects of the varying stiffness of different brake components.
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Citation
Dunn, A., Boggess, B., Eiselstein, N., Dorohoff, M. et al., "The Effect of Application Air Pressure on Brake Stroke Measurements from 70 to 125 psi," SAE Technical Paper 2015-01-2833, 2015, https://doi.org/10.4271/2015-01-2833.Also In
References
- Heusser , R. Heavy Truck Deceleration Rates as a Function of Brake Adjustment SAE Technical Paper 910126 1991 10.4271/910126
- Flick M.A. The Effect of Brake Adjustment on Braking Performance Report DOT HS 807 287 National Highway Traffic Safety Administration Washington D.C. April 1988
- Dunn , A. , Guenther , D. , and Radlinski , R. Application of Air Brake Performance Relationships in Accident Reconstruction and Their Correlation to Real Vehicle Performance SAE Int. J. Commer. Veh. 5 1 251 270 2012 10.4271/2012-01-0609
- Dunn , A. , Tanner , C. , Morr , D. , Bayan , F. et al. The Influence of Disablement of Various Brakes on the Dry Stopping Performance and Stability of a Tractor-Semitrailer SAE Int. J. Commer. Veh. 2 1 1 16 2009 10.4271/2009-01-0099
- Training Bulletin: Pushrod stroke measurement procedure described in the CVSA North American Standard Level I Inspection Procedure and North American Standard Out-of-Service Criteria Federal Motor Carrier Safety Administration March 2013
- Highway-Railroad Grad Crossing Collision, US Highway 95, Miriam, Nevada, June 24, 2011 NTSB/HAR-12/03, PB2013-103891, National Transportation Safety Board December 11 2012
- Manitoba Public Insurance Air Brake Manual DVL0025/0337-18-B3 August 2014
- Fancher , P. , Bareket , D. , and Campbell , K. Statistical and Mechanical Analyses of Brake Adjustment Criteria for Heavy Trucks University of Michigan Transportation Research Institute USA
- National Transportation Safety Board Safety Study PB92-917003, NTSB/SS-92/01 April 29 1992
- Radlinski , R. and Williams , S. NHTSA Heavy Duty Vehicle Brake Research Program - Report 2: The Effect of Adjustment on Air Brake Performance DOT HS 806 740 April 1985
- Flick , M. The Effect of Brake Adjustment on Braking Performance DOT HS 807 287 April 1988
- Seiff , H. Heavy Truck Brake Adjustment - Problems and Solutions ATA Foundation, Trucking Research Institute USA
- Fancher , P. , Bareket , Z. , Blower , D. , Mink , C. , and Campbell , K. Evaluation of Brake Adjustment Criteria for Heavy Trucks - Final Report August 1993 The University of Michigan Transportation Research Institute