TBH I'd be more interested in his cyclonic diesel filter idea. Having to empty a container of soot every so often seems a better idea than having a metal filter flooded with extra diesel and burned at high temperature before clogging up with the remaining ash resulting in a massive repair bill and probably a dumped car after a while.
IT can be more eco to use what you've got for longer.
As for Dyson's EV, it seems more likely he'd us his expertise in electric motors to supply improved parts to existing ev manufacturers i.e. Dyson motors in a Tesla car. He might know a lot about motors but I guess he doesn't know as much as the car companies about suspension, economics or just fit and finish.