Engine system with egr over-pressure protection

A method of operating an engine having a first cylinder and a second cylinder, the method comprising:

• directing air into the first cylinder and into the second cylinder;
• directing exhaust from the first cylinder into a first exhaust manifold;
• directing exhaust from the second cylinder into a second exhaust manifold;
• restricting a flow of exhaust from the first exhaust manifold into the second exhaust manifold;
• directing exhaust from the first exhaust manifold to mix with air entering at least one of the first and second cylinders;
• and
• selectively relieving a pressure of exhaust in the first exhaust manifold.

An engine, comprising:

• an engine block at least partially defining a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder;
• a first intake manifold fluidly connected to the first and second cylinders;
• a first exhaust manifold fluidly connected to the first and second cylinders;
• a second intake manifold fluidly connected to the third and fourth cylinders;
• a second exhaust manifold fluidly connected to the third and fourth cylinders;
• a turbocharger fluidly connected to only the second exhaust manifold;
• at least one recirculation passage extending from the first and second exhaust manifolds to the first and second intake manifolds;
• a restricted orifice connecting the first exhaust manifold to the second exhaust manifold;
• a pressure relief passage extending from the first exhaust manifold to at least one of the second exhaust manifold and a location downstream of the turbocharger;
• and
• a valve disposed within the pressure relief passage and movable to selectively reduce a back pressure of the first exhaust manifold.