Automotive Engineer

The Zafira has been a huge success for Opel-Vauxhall. The company’s largest MPV has sold more than 2 million since it was launched in 1999. Buyers appreciated its practicality. The third-generation Zafira has been developed to meet increasingly demanding requirements, not just for practicality but also for driveability.

Consumers expect interior versatility so they can pack their families and belongings in the back of the vehicle. Drivers also want to be cocooned from the outside world as you’d expect in a sedan. So Opel-Vauxhall’s engineers benchmarked competitor MPVs and sedans when the Zafira Tourer development project began four years ago at the company’s Rüsselsheim facilities in Germany. Andreas Haefele, line director for the Tourer, says: “We wanted the car to drive more like a mid-sized sedan than a van, and to reach a new level of perceived quality inside the cabin. NVH was also an important target and one of the biggest challenges as the monobox design almost completely encapsulates the engine.”  

But the first challenge for the team was the increased size of the new vehicle compared to the second-generation Zafira. The wheelbase is 57mm longer at 2,760mm. The front track is 96mm wider at 1,584mm, and the rear track has increased in width by 78mm to 1,588mm. That has affected weight – at 1,571kg, the vehicle is 60kg heavier than the previous model. “We pushed the limits on dimensions while still being in the same vehicle segment, which made it very hard to compensate for the increase in weight,” says Haefele.

The Zafira’s size could have had a far bigger impact on weight, but the engineers minimised increases by making the A-pillar from hydroformed high-strength steel. The sheet metal for the body has been reduced in thickness too. “Simulation tools have helped us scrutinise the car to squeeze out each and every millimetre of sheet-metal thickness which is not required, helping to keep weight down,” says Haefele. Aluminium has been used too – for example in the front control arms. But Haefele admits that these are exceptions and that wider use of the material wouldn’t have been cost-effective in a series production vehicle like the Zafira. He says: “This isn’t a racing car where you can construct everything out of lightweight materials. The project had to be very efficient, both in weight and cost.”  

Weight is one of the reasons why the vehicle doesn’t have a sliding-door system, although the engineers did test different door technologies for the rear entry points. Rear hinged doors, as seen on the smaller Meriva, were deemed to be unworkable.

“The doors would have had to be much bigger than the Meriva’s to allow people into that third row. The spacing between the hinges would need to be further apart. That would have impacted on the belt line of the car, changing the overall design and affecting interior functionality,” he says.