Integrated exhaust manifold cooling jacket

An exhaust manifold integrated in a cylinder head of an engine, comprising:

• a plurality of exhaust runners coupling a plurality of cylinder exhaust gas outlet ports to an exhaust exit port, the plurality of exhaust runners forming a first exhaust passage, a second exhaust passage, and a third exhaust passage at the exhaust exit port;
• a passage terminating at a degas port;
• an upper cooling jacket positioned vertically above the first exhaust passage and the second exhaust passage;
• a lower cooling jacket positioned vertically below the third exhaust passage;
• and
• a central cooling jacket positioned vertically below the first exhaust passage and the second exhaust passage and vertically above the third exhaust passage, the central cooling jacket including a ridge extending upward from a top portion of the central cooling jacket, the ridge positioned intermediate the first exhaust passage and the second exhaust passage and fluidly coupled to the passage.

An exhaust manifold for an engine, comprising:

• a plurality of exhaust runners coupling a plurality of cylinder exhaust gas outlet ports to an exhaust exit port, the plurality of exhaust runners forming a first exhaust passage, a second exhaust passage, and a third exhaust passage at the exhaust exit port;
• an upper cooling jacket positioned vertically above the first exhaust passage and the second exhaust passage;
• a lower cooling jacket positioned vertically below the third exhaust passage;
• and
• a central cooling jacket positioned vertically below the first exhaust passage and the second exhaust passage and vertically above the third exhaust passage, the central cooling jacket fluidly coupled to the lower cooling jacket at a first fluidic coupling located at a first end of the central cooling jacket and fluidly coupled to the upper cooling jacket at a second fluidic coupling located at a second end of the central cooling jacket, the central cooling jacket maintained fluidly separate from the lower cooling jacket along an entirety of the central cooling jacket other than at the first fluidic coupling.