Continental has presented a driverless and fully electric test vehicle developed to measure the braking performance of passenger car tires. The objective of the fully automated test is to reduce the braking distance of tires further to ensure greater road safety.
The AVA – "Analytic Vehicle AIBA" – enables precise monitoring of the frictional properties of tires during braking manoeuvres on dry and wet roads. Continental AVA combines the advantages of a test method which is independent of the vehicle model with the controlled and reproducible test environment of the Automated Indoor Braking Analyzer (AIBA). Continental's tire testing experts can therefore perform tests regardless of vehicle-specific characteristics. With this, Continental says it has one of the world's most advanced and precise tire braking test methods. The test vehicle is used on the company's proving ground Contidrom near Hanover, Germany.
"Our analytic vehicle AVA helps us analyse our premium tires' performance in even greater detail and systematically develop them," explains Dr Boris Mergell, Head of Research and Development of Continental's Tires group sector. The transmission of forces between the tire and the road surface is decisive for tire braking performance. It is equally important for cornering characteristics or when changing direction. "The performance of the tire during braking is essential for the vehicle's safety. For this reason, we make great efforts to analyse our tires as precisely as possible," emphasises Dr Mergell.
For the tire braking tests, the AVA is accelerated to a test speed of 65 km/h with an electromagnetic linear drive, which is derived from modern roller coaster technology. Then, several fully automated braking tests are carried out. The AVA drive system is equipped with two electrically driven axles, powered by a high-performance battery. The high maximum torque ensures that a constant speed can be maintained, while the test tires on the third axle can be systematically braked. The integrated braking system is equipped with Brake-by-Wire technology from Continental's Automotive business sector. Unlike conventional hydraulic braking systems, the braking signal is transferred electronically. As a result, the brake response is swift and precise, essential for accurate testing or measuring.
Meletis Xigakis is responsible for global tire testing at Continental.
"Our AVA determines the transmission of forces between the tire and the road surface, while various slipping states, so-called "µ-slip curves", are precisely reproducible. With state-of-the-art measuring technology, we measure all of the forces which act between the tire and the road surface during braking. As a result, we can compare our tires and their various compound compositions even more precisely and optimise them for their special uses," explains Meletis Xigakis, who is responsible for global tire testing at Continental. The AVA is used in the Automated Indoor Braking Analyzer, which has started operation in 2012. Brake tests on road surfaces are performed on the 75 meter test track. The air-conditioned area of the test hall has up to five road surfaces which can be exchanged hydraulically. In the weather-independent facility, up to 100,000 braking tests can be performed annually on dry, wet or even icy roads. The system is integrated into a 350 meter long and 30 meter wide hall.
New Continental tire models are run for the equivalent of 25 million kilometres per year on testbeds and test tracks. This corresponds to 625 times around the world. This extraordinary effort is fully justified. It is the basis of the premium quality of Continental tires. Together with the company test tracks in Uvalde, Texas (USA), and in Arvidsjaur, Sweden, the Contidrom in Jeversen, near Hannover, Germany, is one of the most modern proving grounds in the world. The test track near Hanover was opened in 1967 and since then has been continuously modernised to meet the increasing requirements on tire tests.
On a total area of 160 hectares, the proving ground provides every possible option for tire testing. On a ten kilometre track with a large variety of partly water-covered road surfaces and the legendary circuit with banked turns, speeds of more than 250 km/h are achieved. In addition, there are also tracks for testing chassis elements. In 2022, an innovative, dynamic driving simulator that can calculate the tires' exact dynamic parameters and the test vehicle involved will be commissioned at the Contidrom. This provides the professional Continental test drivers with the same subjective driving feel as tire tests on the test track.
Comments