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Article by: Fabio Squadrani, Senior Manager, Braking Systems in Applus IDIADA
This research focuses on reducing the mileage of open-road brake tests by simulating brake patterns on dynamometers. This involves analyzing durability test data to define target wear values, designing an “ideal lap” for the dynamometer that correlates with vehicle testing, and determining a scaling factor between dynamometer and full-vehicle testing. The scaling factor has to be as simple as possible. Multiple simulated dynamometer laps are defined based on temperature, energy, or power profiles. The results show reasonable correlation between dynamometer and vehicle testing, validated across different conditions. Robust, repeatable, and reliable dynamometer simulation methodologies are crucial for optimizing vehicle testing and reducing development costs.
Many studies have been produced in order to improve the testing time for development and validation tests for brake and friction materials in particular. There is a constant effort by brake industry for reducing vehicle prototype phase, moving testing activities to brake dynamometer reducing the testing time. Many studies have been recently presented (Sierra C. [4] has presented an innovative method for correlation between physical vehicle testing and dynamometer testing, which was used as an inspiration for this work).
See also: Applus IDIADA’s Advanced Brake Testing Solution
Mojácar Testing
Why Testing in Mojacar?
Applus+ IDIADA has conducted extensive research to correlate global public road brake durability standards across various markets and driving conditions. The scope of these studies was to establish comprehensive equivalence ratios between different test locations worldwide, encompassing city traffic and mountain road patterns in Europe, America, and China.
However, Mojacar has been chosen for this study, due to its unique driving conditions, combining high adherence asphalt, with demanding driving conditions and favourable weather conditions.
The research involved a thorough objective parametrization of each route, including detailed analysis of driving profiles, brake applications, speeds, deceleration ranges and component wear.
The primary focus of this study was on brake wear, as it is a critical factor in optimizing brake durability testing. The findings enable Applus+ IDIADA to offer clients robust, globally harmonized methodologies for evaluating brake performance and reducing development costs through more efficient testing procedures.
Standard Mojacar Route Description
A standard route of around 200 km is performed in Mojacar surroundings. The route is combining very humid climate in the seashore with very dry conditions in the interior part of the route, where the mountains are hit by the winds coming from north Africa.
The reasons behind choosing Mojacar as the reference patterns are as follows:
- Very well known industry standard, used by many different OEMs in their validation programmes.
- If we consider brake load factor and energy load factors
It is clear that Mojacar is very well representative of a sever usage of brakes in real conditions.
- As mentioned in [1] by Ferrer, it is clear that Mojacar is showing an higher wear rate with respect to other industry standards in the automotive world:
For the sake of completeness, some other characteristics of Mojacar routes are as follows for standard B/C segment vehicles:
- Average vehicle speed between 58 and 65 km/h
- Average brake temperature between 120 and 150 ºC
- Brake ratio between 3 and 3.6 brakes app / km
- 80% country road
Standard Mojacar Wear Results
In order to set the reference for the testing procedure validation, two vehicles have been considered for the sake of correlation. The wear results on front pads are as follows:
In both cases we are dealing with standard C segment vehicles equipped with ICE which were in the market in 2020-21. This data has been collected through internal testing activities performed by Applus IDIADA in the frame of internal innovation projects.
About Applus IDIADA
With over 25 years’ experience and 2,450 engineers specializing in vehicle development, Applus IDIADA is a leading engineering company providing design, testing, engineering, and homologation services to the automotive industry worldwide.
Applus IDIADA is located in California and Michigan, with further presence in 25 other countries, mainly in Europe and Asia.
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