Vauxhall/Opel‘s International Technical Development Centre (ITDC) reproduces conditions comparable to the Sahara desert. In Rüsselsheim, Germany in the middle of winter, the mercury is at 60 degrees Celsius and the sweat is pouring. In the middle of it all, the new Astra Sports Tourer defies the adverse conditions.
One day later, same place, same time, but the observer is confronted with a completely different scenario: the Astra Sports Tourer is all wrapped up in a white outfit that is covered with a thin layer of ice. The vehicle’s spacious interior is not visible from the outside, as the windows are completely frozen over. The temperature is -40 degrees, and without warm winter clothing no one can last in here.
“We want to see how the materials in the Sports Tourer react to extreme conditions. We also check if its appearance changes and if extreme heat or cold have an effect on, for example, gap width,” explains Otto Hemmelmann, Lead Engineer Test Methods. With his interdisciplinary team from various specialist areas, he is responsible for this foray into scorching and freezing conditions.
The heat and cold test bench, also called thermal cycling testing, is part of the compulsory program in Vauxhall vehicle development, just like the acoustic and electronic lab tests. “After all, our customers around the world drive the Astra in all different climate zones,” says Hemmelmann. A complete production series Astra Sports Tourer is tested. This ensures that the exact materials used in customer vehicles are put to the test.
During the two-week phase, temperatures change daily. “Sealing, bonding, plastic parts and materials, rubber, all this has to work properly, meaning constant elastic constricting and stretching like a rubber band, without bearing any traces of it,” explains the Chief Engineer.
Even direct sunlight can be simulated in the climatic chamber. “If the Sports Tourer is parked outside in the summer, interior temperatures can reach 90 degrees,” says Hemmelmann. With the help of the sun simulation, the team tests the interior materials’ stress tolerance. “But we also test how long the air conditioner has to be on until the temperature is bearable again.” In addition, the so-called four-post test bench moves the Sports Tourer up and down under its wheels. This enables testers to ensure that comfort in the car is not compromised even under extreme conditions and that the interior materials make no irritating noises during driving despite high strain and stress.
The Astra Sports Tourer does not need to be specially prepared for the heat/cold test bench. It is fitted with commercial tyres and belts secure the car on the four-post test bench. Nevertheless, the vehicle is thoroughly checked before the test. Because after the hot/cold treatment, Vauxhall engineers look at the Sports Tourer through the customer’s eyes and identify differences. “We look at what impression the car makes on us and take measurements to determine if anything has become distorted or misaligned,” says Hemmelmann.