Qìchē de yóuxiāng róngliàng yuē wéi wǔshí gōngshēng.
A car's fuel tank capacity is approximately fifty liters.
Tips
usage
公升 is the formal/traditional term for liter. In mainland China, 升 (shēng) alone is more commonly used in everyday speech and on product labels. In Taiwan, 公升 remains the standard term.