These theses that change life: Contributions to improving permanent magnet, direct current, motors for high-power automobile propulsion applications

All and any solu­tions that help low­er fuel con­sump­tion are wel­come. Switch­ing off a com­bus­tion engine at a red traf­fic lights (even if only for a minute) is good for your purse and for the plan­et in terms of green­house gas effects. To avoid tire­some man­u­al switch­ing on/off moves with the starter motor, we saw the advent a few years back of “stop-and-go” systems. 

“If you equip high qual­i­ty urban cars with a stop and go sys­tem, the com­bus­tion engine can be restart­ed via the alter­na­tor”, explains Aurélien Vauquelin. This offered a first tech­no­log­i­cal break­through, poten­tial­ly allow­ing 100 000 re-starts (com­pared with pre­vi­ous stan­dard 10 000 starts). “But this choice of using the alter­na­tor to pro­vide the start torque calls for the use of expen­sive elec­tron­ic com­po­nents”. For auto­mo­bile equip­ment mak­ers, the chal­lenge there­fore con­sist­ed of attain­ing the same per­for­mance lev­el using a less expen­sive technique. 

Aurélien Vauquelin grad­u­at­ed from UTC with the major Mechan­i­cal Engi­neer­ing and then did a CIFRE the­sis with the equip­ment com­pa­ny Valeo, on hav­ing the starter used rather than the alter­na­tor. “This sys­tem, called Restart, will enable 300 000 restart sequences in the life expectan­cy of a car, which comes down to once per kilo­me­tre”. Anoth­er con­straint is that you must be able to restart the engine is less than ½ sec­ond. “Tech­ni­cal­ly speak­ing, we were seek­ing a high pow­er impulse”. In short, this implies emp­ty­ing the bat­tery in a min­i­mum time lapse with­out see­ing the starter burst into flames! 

With the help of UTC-LEC (Lab­o­ra­toire Elec­tromé­canique de Com­pieg­ne) where the first stop-and-go® sys­tem was devel­oped, Aurélien Vauquelin has added improve­ments to the sys­tem in the course of his PhD work. This starter is now in ser­vice and costs 5 times less that the alter­na­tor solu­tion and leads to fuel-sav­ing off between 10–15% per urban trip. 

“The tech­nolo­gies devel­oped round the con­cept of high pow­er impuls­es could be used for elec­tric vehicles”. 

Le magazine

Avril 2024 - N°62

Faire face aux enjeux environnementaux

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