Automotive Engineer

Ford expects its B-Max vehicle to achieve the maximum Euro NCAP rating. The mini-MPV's body-in-white has no B-pillars so the door system and surrounding structure have been engineered for greater stiffness to compensate.

The door system design – conventional front doors and sliding rear doors – offers an opening more than 1.5m wide for easy access to the passenger compartment. Greater use of ultra-high strength, hot-stamped boron steel together with a patented locking system restore the stiffness lost when deleting conventional B-pillars from the body.

Ford's product development quality director, Darren Palmer, said: “One of the key things that we needed to do was manage the side impact. With this vehicle we integrated the B-pillar into the two doors, and together with specially-designed latches we get the same crash performance. We're targeting a five star Euro NCPAP rating, to the new rating measurements.”

The steels Ford has used in the B-Max doors and structural reinforcement rings surrounding the 1550mm-wide apertures are even stronger than the grades of boron steel typically used by the OEM in body engineering.

And instead of latching half way up the door, as with a conventional design, the B-Max has latches located in the floor and roof sections. Palmer said that they were designed in such as way that in a side impact the crash forces would push the latches further into position, rather than tending to pull them apart.

Optimisation of the doors and the body mean that the B-Max is as stiff as the Fiesta hatchback, to ensure that ride and handling attributes met Ford's targets. Weight has also been optimised to ensure good fuel consumption and emissions.

The rear sliding doors open manually – there's no powered option in this application – but Palmer added that the concept was scaleable and could be used in other segments in future.