The hybrid system in the Prius c comprises a SULEV (Tier 2 Bin 3)- rated 1.5 - liter in - line, four - cylinder gasoline engine (INZ - FXE) that utilizes an Atkinson cycle to increase efficiency, a new hybrid transaxle (P510), an air - cooled, high - output 144V, 6.5 Ah NiMH battery and a
variable -
voltage system in which a boost
converter boosts the operating
voltage of the system to a maximum of 520 V DC.