This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Calculation of Drag Torque Losses by Component of a Transfer Case
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 22, 2019 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
In recent decades, fuel economy has become a key indicator of an automaker corporate social responsibility and a market differentiation factor, and ultimately it is regulated by government agencies such as EPA through CO2 emissions compliance tests. The light pick-up truck and SUV production share has been increasing in the last few years, being 4-wheel drive capability one of the main features that customers seek. Within the 4-Wheel Drive system, the transfer case has a significant impact to both torque transfer efficiency and parasitic losses. The scope of this paper is to better understand the parasitic losses of a transfer case by the quantification of its individual drag losses by component. At product development phases, one measurement of interest is the system level spin loss which has a target value defined by the automakers, and contribution by component is often neglected if the system has the expected performance. This study summarizes the tests performed on a 2-speed chain driven transfer case, where as a first step, a baseline spin loss measurement was taken, then the chain and sprockets, planetary carrier, and oil pump were removed at different points within the test to quantify their contribution by comparing the results to the initial baseline measurement. Lastly, the transfer case with all its components assembled was tested and spin loss was measured using different oil levels.
CitationRivera Rodriguez, R. and Martinez, C., "Calculation of Drag Torque Losses by Component of a Transfer Case," SAE Technical Paper 2019-01-2605, 2019, https://doi.org/10.4271/2019-01-2605.
Data Sets - Support Documents
|[Unnamed Dataset 1]|
- SAE International Surface Vehicle Recommended Practice , “Definition and Measurement of Transfer Case Speed-Dependent Parasitic Loss,” SAE Standard J2985, Feb. 2014.
- Zhou, S. and Williams, B. , “Transmission Output Chain Spin Loss Study,” SAE Int. J. Engines 10(3), 2017, doi:10.4271/2017-01-1135.
- Kirk, M., Ilyas, S., D'Anna, T., Perakes, A., and Ross, C. , “Development of a Standard Spin Loss Test Procedure for 4WD Transfer Cases,” SAE Technical Paper 2012-01-0306, Apr. 2012, doi:10.4271/2012-01-0306.
- Baglione, M., Duty, M., and Pannone, G. , “Vehicle System Energy Analysis Methodology and Tool for Determining Vehicle Subsystem Energy Supply and Demand,” SAE Technical Paper 2007-01-0398, Apr. 2017, doi:10.4271/2007-01-0398.
- Kirk, M., Ilyas, S., D'Anna, T., Perakes, A., and Ross, C. , “Development of a Standard Spin Loss Test Procedure for FWD-Based Power Transfer Units,” SAE Int. Apr. 2013, doi:10.4271/2013-01-0361.
- Miller, S.J. , “The Arithmetic and Geometric Mean Inequality,” 2003, http://www.williams.edu/go/math/sjmiller/public_html/OSUClasses/487/ArithMeanGeoMean.pdf.
- Törnqvist, L., Vartia, P., and Vartia, Y. , “How Should Relative Changes be Measured?” The American Statistician 43-46, 1985, doi:10.2307/2683905.