Patent ID: 8893667

Claim:
An internal combustion engine comprising: a deactivatable cylinder group including at least one deactivatable cylinder to be selectively operated and deactivated according to a state of the internal combustion engine during operation of the internal combustion engine; a constantly operating cylinder group including a constantly operating cylinder to constantly operate during operation of the internal combustion engine; a first water passage provided around the deactivatable cylinder group; a second water passage provided around the constantly operating cylinder group; an upstream integrated water passage that communicates on an upstream side with a pump and communicates on a downstream side with upstream sides of the first water passage and the second water passage; a downstream integrated water passage that is connected on an upstream side to downstream sides of the first water passage and the second water passage, the downstream integrated water passage includes a junction at which passages respectively connected to the downstream sides of the first water passage and the second water passage join together, the downstream integrated water passage communicating on a downstream side thereof with a radiator; a connecting passage that connects the radiator and the pump; a third water passage that connects to the downstream integrated water passage at a location upstream of the junction; and a device provided adjacent to at least a part of the third water passage to exchange heat with water flowing in the third water passage.