[Math] Subsystems of Peano arithmetic and incompleteness theorem

foundationslo.logicset-theory

I think everyone is familiar with Goedel's incompleteness theorems. In particular they imply that PA (Peano arithmetic) can not prove its own consistency. Now my question is what is the largest subsystem of PA that "can" prove its own consistency? You definitely can't have the induction axiom but is that enough?