Internal combustion engine

An internal combustion engine comprising:

• a turbocharger with a compressor that has an impeller arranged in an intake passage and is driven by energy of exhaust gas;
• a blow-by gas recirculation passage, through which blow-by gas flows back to an upstream section, which is upstream of the impeller in the intake passage;
• a first passage, which branches off from a downstream section, which is downstream of the impeller in the intake passage;
• a second passage, which connects the first passage and the upstream section to each other and forms part of the blow-by gas recirculation passage;
• a third passage, which connects the first passage and the upstream section to each other, wherein the third passage is provided separately from the second passage;
• and
• a change mechanism that changes in different manners the flow rate of compressed gas to flow back from the downstream section to the upstream section through the first and second passages and the flow rate of compressed gas to flow back from the downstream section to the upstream section through the first and third passages.