Onésiphore Pecqueur (1792–1852) was a French mechanical engineer who patented the modern-day differential gear, found on the axles that connect to the powertrain of all automobiles.
He was born in the Pas-de-Calais.
He invented the differential in 1827 (known in French as the différentiel mécanique). He invented it whilst at the Conservatoire des Arts et Métiers. It was derived from his work as a watchmaker, whereby cogs move at different rates. The differential allowed the adjustment of rotational ratios of two wheels turning on the same axle.
He died in Paris in 1852.