Lego plus a touch of boldness (episode 2)

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Using its expertise in electric vehicles, its experience in Formula 1 and with the enthusiasm and passion of its engineering, development and control teams, #renault has developed the innovative hybrid E-TECH powertrain. What is less well known is that it was invented and developed in a way that is both unusual and highly inspiring. Ahmed Ketfi-Cherif, Renault's Mechatronics Synthesis Architect, recalls the period when the conceptual LEGO model had to be transformed into a real engine. 

Once the satisfaction was over, it was time for the challenge: to give shape and life to the future E-TECH hybrid motorization. Nicolas Fremau, the designer of the LEGO prototype model, then turned to several #people in his professional circle to check that the innovative clutchless system he had imagined would be suitable, in use, for what the customers were entitled to expect in terms of performance. And in particular, Ahmed Ketfi-Cherif, a control specialist, to check that the transitions between the different operating modes imagined (at the time 'city', 'road' and 'motorway') were possible with simple dog clutches. 

"Going from the LEGO adventure to reality was a massive challenge. On a human level, it taught me a lot."

Ahmed Ketfi-Cherif, Renault's Mechatronics Synthesis Architect

A NEED FOR SMOOTHING 

The dog clutch was therefore the focus of attention. This part replaces both a sprocket and a synchronising ring in a clutchless system. The dog clutch is a gearbox that has a very good efficiency thanks to the reduction of parts rubbing against each other inside. This technology is used in motorsport where its lack of smoothness is not detrimental. On the other hand, on production models, it is necessary to offer smooth gear changes or else customers will be driven away. 

"We're used to using dog clutches in Formula 1, for a racing engine. But it was something completely new for a 'general public' engine. We had to make this simple object usable by Mr. and Mrs. Toulemonde," explains Ahmed Ketfi-Cherif. 

Further information in the press release to download