interest is charged up front, lumped into a total payoff and then you pay as it goes and there's no real value in paying it off early.

If a bank/car company is offering that at the dealership and calling it a car loan then run away.

In a traditional car loan, any extra payment should go towards the principle and slow down the accrual of interest which allows you to pay it off sooner for less money (like a house). However, some banks, as was said above, might need to be told that's what you want the extra payments to do. I know with AFCU, they'll take 3 months of payment in advance---so one needs to tell them to specifically apply this money to the principle.