PSA Peugeot Citroën’s EMP2 platform sits underneath the Peugeot 308, Citroën C4 and Grand C4 Picasso and has been designed to form the basis of other new cars yet to come.

Stéphane Alibert was the chief engineer in charge of the project and also for the Citroën C4 Picasso. Flexibility as well as reduced weight and dimensions were the objectives of the project from the start, as Mr Alibert told IFW.

'We needed to make sure that this platform was flexible without major development to build cars from the C-segment and the D-segment – light CVs, SUVs, MPVs. The second objective was to reduce weight and dimensions to give more efficient fuel consumption and give more efficiency for styling the car – putting the wheels in the right position and giving more potential for the designers.’

Reducing weight is central to cutting fuel consumption and emissions. The C4 Grand Picasso uses a range of materials to cut weight including high strength steel, aluminium and composite materials.

‘We used aluminium for the steering wheel and seats. We used composite materials for the rear of the car – the rear floor for example is a synthetic material to reduce weight and the tailgate is made in a synthetic material too.’

Reducing size is another strategy and reducing the use of material where possible.

'We have made a floor that is lower, the position of the engine is lower so the centre of gravity is lower and so for stiffness and behaviour it’s more efficient than having to add some reinforcement at the end.’

Reducing cost was also a key consideration for the EMP2 platform for the current and future generations of models. Adopting a similar strategy to Volkswagen with its MQB platform has been part of the thinking, as Mr Alibert explains. ‘Using the same elements in the same place is the only way to reduce cost and it’s classical for the best construction.

‘We have taken into account different kinds of cars – SUV, MPV etc, different kinds of technologies – Euro 6 with selective catalytic reduction (SCR), hybrid systems, Hybrid4 or traditional hybrid. We have made a big matrix and asked, "What is strategic for PSA." We have said it’s OK for hybrid, for traditional engines, for three-cylinder engines and for SCR catalytic reduction. But, for example, in the first phase we said four-wheel drive is not a priority, so we will take it into account in the second phase.

‘So this platform will be OK for the traditional C-segment, for the Peugeot 308 now, with the sedan in China too. This platform will also go to South America.

‘We spent a year and a half just to think about the platform. We made some possible designs of cars based on it, then stopped. After that we decided to launch the C4 Picasso and the 308 for Peugeot, but it was very important to have this first reflection beforehand. For the previous generation – EMPT1 – we launched the car, the Peugeot 307, at the same time as the platform. It was fine for that car but for the previous C4 Picasso, or the Berlingo, it was too difficult so we had to manage a lot of modifications, with the accompanying costs.’

For the Grand C4 Picasso, the platform was given both a wider track and a longer wheelbase to increase interior space without making the car any bigger.

‘If you don’t reduce your weight, you don’t have the right fuel consumption – if you are at 140g/km CO­­2 now and it’s a beautiful car, you can’t sell it, it’s impossible,’ concludes Mr Alibert.