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Adapting On-vehicle Brake Drag Testing to a Bench Dynamometer
Technical Paper
2011-01-2376
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Fuel economy can be increased by reducing running resistance or mechanical drag. Since modern disk brake systems produce mechanical drag, a component-level test method was developed to measure and understand this effect.
Measuring brake drag typically requires a vehicle test on a chassis dynamometer, and an engineer must distinguish brake drag from other sources of drag (e.g., tire, wheel bearing, transmission, and others). This method often generates brake drag data that lacks in resolution, accuracy, and repeatability. Alternatively, a new method of measuring drag on a traditional brake dynamometer has been developed that yields statistically relevant and repeatable results.
To accurately measure brake drag on a brake dynamometer, pad temperature, wheel bearing temperature, and caliper experience pressure need to be controlled. Also, depending on the type of wheel bearing used, a correction factor for bearing drag may be needed. Finally, the method by which the brake pads are conditioned, using burnish stops or a specified test mode, and the amount of pad taper wear generated needs to be understood to attain reliable results. With these items in mind, a process was developed to more precisely measure component level drag on a traditional brake dynamometer.
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Authors
Citation
Krough, B., Dyar, L., and Bray, P., "Adapting On-vehicle Brake Drag Testing to a Bench Dynamometer," SAE Technical Paper 2011-01-2376, 2011, https://doi.org/10.4271/2011-01-2376.Also In
References
- Hoffman, C. Beurmann, D. “Measurement and Reduction of On-Road Brake Drag,” SAE Technical Paper 790723 1979 10.4271/790723
- Code of Federal Regulation Fuel Economy and Carbon-Related Exhaust Emission Regulations for 1978 and Later Year Automobiles - Test Procedures
- Super, R. Bonawit, D. Dyer, D. Goepfrich, R. et al. “Construction and Operation of Brake Testing Dynamometers,” SAE Technical Paper 530130 1953 10.4271/530130
- Code of Federal Regulation Mileage Accumulation Requirement for Test Vehicles
- King, M. Wang, N. “New Generation Foundation Brake Developments,” SAE Technical Paper 871247 1987 10.4271/871247