Rüsselsheim. The new Opel Astra will celebrate its world premiere at the 2019 Frankfurt Motor Show (public days from 12. To 22. September) – and shines with top values in fuel efficiency and aerodynamics. What's more, it goes straight to the top, joining the legendary aerodynamics champion Opel Calibra and Opel's flagship Insignia, the most streamlined models the automaker from Rüsselsheim has built to date. With a drag coefficient of 0.26, both the new Astra five-door and the Sports Tourer are among the vehicles with the lowest drag coefficient in the compact class. This will make the new Astra one of the best vehicles on the market -. At the same time to the most efficient Astra ever. In addition to state-of-the-art engine technology, aerodynamics play a key role in reducing fuel consumption and CO2 emissions.
The throne as aerodynamics champion has been held for almost 30 years by the Opel Calibra. The coupé, which at first glance appears to be particularly streamlined, achieved a drag coefficient of cW 0.26, making it the aerodynamics world champion. The engineers have now achieved the same outstanding result with the compact Astra model – but with solutions that can only be seen at second glance. Even the current Astra, which premiered at the 2015 IAA and was voted "European Car of the Year" the following year, shines with a low cW value of 0.29. But the engineers did not stop there. They wanted more – and gave themselves the ambitious goal of making both the new five-door and the new Sports Tourer best-in-class aerodynamics. As with all new Opel models, the developers at the Stuttgart Research Institute for Automotive Engineering and Vehicle Engines (FKFS) used the wind tunnel at the University of Stuttgart to further improve the already excellent wind resistance of the Astra.
Opel engineers paid special attention to the underbody, wheels and wheel arches of the Astra, as these are precisely the areas responsible for around 40 to 50 percent of a vehicle's aerodynamic drag. They also formed a task force specifically focused on developing a new active full-surface aero shutter.
Active full-surface aero shutter: Improves aerodynamics and thermal management
This state-of-the-art radiator shutter helps to further reduce fuel consumption and ensures the greatest possible efficiency in everyday operation. An intelligent control system combines thermal, electrical and aerodynamic parameters and automatically opens and closes the upper and lower parts of the radiator grille independently of each other. A ten percent reduction in drag makes a difference of around two percent in fuel consumption according to the NEDC (New European Driving Cycle); at a speed of 130 km/h, up to five percent of fuel can be saved. In the Astra, the airflow optimized by the active full-surface aero shutter alone reduces CO2 emissions by up to two grams per kilometer.
The full-surface aero shutter also brings thermal benefits: After switching off, the engine cools down more slowly, while the warm-up phase is accelerated during cold starts. This has a positive effect on fuel consumption and comfort, especially in winter, as the engine, transmission and heating system warm up more quickly.
The solution of an active full-surface radiator shutter presents designers and engineers with a challenging task, as they have to take numerous factors into account. It is not only a question of appearance, packaging or pedestrian protection requirements, but also of hull classifications, engine and transmission variants and the corresponding thermal management and, of course, engine cooling requirements. Air flow under the vehicle is improved by covers under the engine. Transmission as well as in the front floor area. In addition, there is an enlarged heat shield for the tank, which also serves as an air deflector, up to ten millimeters less ground clearance depending on the model variant, and aerodynamically shaped control arms on the rear axle.
Thanks to all the aerodynamic improvements, the new Astra emits 4.5 grams less CO2 per kilometer according to WLTP – a decisive saving, especially in view of the increasingly stringent regulations. For example, according to EU emissions standards from 2021, the average CO2 emissions of the new car fleet must not exceed 95 grams per kilometer. In conjunction with the completely new generation of engines, CO2 emissions from the new Opel Astra are reduced by up to 21 percent.
IAA Star 1989: World premiere for the aerodynamics champion Opel Calibra
The new Astra celebrates its world premiere at the IAA exactly 30 years after the Calibra. Since the start of production in 1990, the two-door coupé from Rüsselsheim, with its drag coefficient of 0.26, was regarded for ten years as the world's most streamlined production vehicle. The Calibra owes this to its elongated, low body and numerous aerodynamic tricks. This includes the optimum depth of the front spoiler as well as the inwardly tapering rear end. Sills between the front and rear wheels ensure that the air flowing under the vehicle does not escape to the outside, thus further reducing air resistance.
The Opel Calibra became the most successful sports coupé of the 1990s – more than 238.600 vehicles rolled off the production line between 1989 and 1997 alone. The Calibra was available in five performance levels. The spectrum ranged from a two-liter engine with 85 kW/115 hp to a 150 kW/204 hp turbocharged power unit. The absolute highlight in the Calibra's motorsport career was its victory in the 1996 International Touring Car Championship.