26.11.2003
New Astra – Lots of space thanks to intelligent packaging

The dimensions of the new Astra are among the largest in its segment – 4.25 meters long, 1.75 meters wide, 1.46 meters high and with a 2.61 meter wheelbase, it is 35 millimeters higher, 44 mm wider and 139 mm longer than the previous model.

There is a clearly noticeable increase in shoulder room in the front and rear and, in particular, in the amount of headroom in the rear. The already generous legroom for the Astra's rear passengers has been increased by another 17 mm.

The new Astra also has a lot of space for luggage with 350 liters cargo volume (VDA standard). The key reason for the generous amount of space in the Astra interior is, in addition to its long wheelbase, intelligent packaging.

What is packaging exactly? Frank Leopold, Manager, Vehicle Integration and Packaging at Opel's International Technical Development Center (ITDC), defines it as, "The challenge to optimally divide up the available space between the car's technical components, its passenger cell and its luggage compartment to provide the maximum benefit possible."

Opel goes against the trend in the compact segment by creating a dynamic compact car with a generous amount of space. This made it a particularly interesting task for Leopold and his 28-member team to find the best packaging solutions. The experts were able to use the 2614 mm long wheelbase as the basis for the Astra's large interior.

Packaging begins with the engines and builds up from there, explains Leopold. When planning, it is not only a matter of considering the space requirement of the engines and transmissions, but their movements in the event of a frontal collision are also taken into consideration. The front bulkhead – separating the engine compartment from the interior – in the Astra and other Opel models is not just a plain wall. It is a complex sheet-metal component with many contours, and thanks to this it can be installed far towards the front. The space gained frees up more room in the interior.

In the engine compartment, all components are very closely positioned; a key component in this jigsaw is the large brake booster. This is linked to the brake pedal and may push it only slightly into the interior in the event of a frontal collision. The position of the pedals, according to Leopold, is a central parameter for the packaging; "A man who is 1.90 m tall sits back in a low reclined position in the driver's seat while a 1.55 m woman sits right at the front in a medium to high position. We must ensure that she can also reach the clutch pedal without difficulty and that she can see at an angle of at least 6.7 degrees over the hood, so the area immediately in front of the vehicle is visible. From this range, we define the area in which we put the hip(H)-point, the pivot between the trunk of the body and the legs, for the front seats." The H-point describes the position of the person in the car as a starting point for all measurements, such as the distance to the gearshift lever or the pedals.

The so-called 50-percentile woman and the 98-percentile man are used as virtual car drivers in development work at Opel, as are more than 50 other individual people-templates. Their measurements are scanned and stored in a program called "Ramsis". Ramsis is a computer-aided anthropological/mathematical system for passenger simulation. With the help of this high-tech tool, Leopold's colleagues from the so-called 'seats group' are able to simulate all the measurements and operating forces inside the car's interior on a computer, long before the first prototype is built. Ramsis quickly finds the answer to questions like: "Does the décor strip in the door trim disturb the driver's knee?" and, therefore, saves on the time-consuming construction of models.

"The interior of the new Astra fits like a glove. It provides typical 'feel-good' dimensions," says Leopold. It boasts greater comfort than its predecessor, and not only because it is 30 mm wider. The comparatively upright side windows ensure a pleasant, spacious and airy feeling at eye level. And the slightly raised and greatly lengthened roof contributes to the increase in headroom. Compared to the previous model, there is an additional 10 mm in height and 40 mm more length. The passengers sitting in the rear seat of the new Astra now also have the comfort of two centimeters more shoulder distance.

The large rear doors with their special shape mean climbing into the car is simple and there is no risk of banging the back of the head on the C-pillar. They also facilitate the installation of children's seats. The long windowpanes improve the view for the rear passengers and also the driver's peripheral vision. The larger rear window and the slightly angled A- and C-pillars also have a positive effect here. On top of these measurable gains in the interior, there are also clever details: The rounded transitions from the cockpit into the door trims, the structure of the center console, the horizontal décor strips, the two optically integrated central ventilation ducts and the flat design of the door handles are all elements which enhance the perception of space.

With the dynamic design of the new Astra a significant increase in height was out of the question from the beginning of the packaging plans. "With Agila, Meriva and Zafira we already have three high-roofed vans in our portfolio," explains Leopold. "The Astra, however, is a particularly dynamic model. For its agile handling we needed a low center of gravity." The space-saving layout of the rear axle helped here. The improved torsion beam design is so compact that Leopold and his colleagues were able to position the fuel tank deep between the wheels and also place the rear seats in a correspondingly low position. This gives the passengers a feeling of security and lowers the vehicle's center of gravity further. Another advantage of the compact rear axle: The floor of the trunk is flat, even with a full-size spare wheel/tire (instead of the standard temporary spare).