Who invented the installment loan more specifically the car payment.
All i would like to know is the inventor's name and then i can
research the rest my self.

Instalment loans likely were invented long before the automobile,
perhaps before the wheel. Likely the first instalment loan applied to
a car caught little attention as simular items had been sold that way
for thousands of years.   Neil

It is commonly believed that Ford's invention of mass production
techniques for the manufacture of automobiles created a new and large
market for consumer credit that led to the "invention" of finance
companies specializing in auto loans:


http://www.creditwebdeals.com/credit-education-history.htm