Few have seen the film of the transformation that the automobile is going through so closely. Philippe Brunet started at Renault in 1989 to fine-tune the settings of the legendary V10 engine which allowed the diamond to cover itself with glory on the Formula 1 circuits before creating the current four-cylinder which has surfed the diesel wave for decades. 2000 and 2010. Today, at age 57, Renault’s director of mechanical engineering is responsible for sounding the death knell for heat engines by orchestrating the forced transition to all-electric. A mission capable of exciting the imagination of an engineer but which, by erasing more than a century of automotive tradition, is not immune to blues.
Originally from Cannes, Philippe Brunet was preparing to follow in his father’s footsteps, working in the space industry, before being overtaken by his childhood passion for cars. ” My father thought it was much more intellectually stimulating to run satellites than to power cars, but when I finished my engineering studies I quickly got bored in Aerospace. »In 2000, at the end of Renault’s F1 epic, he did not have the impression of declining by agreeing to pilot the creation of a new diesel engine, a fuel which was to experience great popularity. After supervising the renewal of high-end vehicles (Espace, Talisman, Koléos) from Renault – “It was not the simplest nor the easiest”, He concedes – and provided technical coordination for the development of engines within the Renault-Nissan alliance, Philippe Brunet has been responsible for mechanical engineering for three years.
Switch from connecting rod and piston to wound rotor and permanent magnet
Going from the connecting rod and the piston to the wound rotor and the permanent magnet represents a genuine technological breakthrough. “Thermo-mechanics, combustion problems are no longer at the heart of the subject. Engineers of my generation must question everything they have learned ”, notes Philippe Brunet. The efficiency of a heat engine (ratio between the energy consumed and the energy returned to the wheels) does not exceed 42-43% while that of an electric motor exceeds 90%.
The main room for improvement has shifted to other ground than the engine itself. “For an electric vehicle, nothing could be easier than to develop strong powers; the difficulty lies in maintaining this performance over the long term in order to preserve the autonomy of the car ”, he continues. Hence the obligation to focus on the development of sophisticated power electronics. This component, which makes the difference, absorbs two-thirds of the cost of developing an electric motor block.
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