Cylinder head of multi-cylinder engine

A multi-cylinder engine comprising:

• a cylinder head including a plurality of combustion chambers, a plurality of intake ports, a first coolant flow passage, and a second coolant flow passage, the first coolant flow passage and the second coolant flow passage being independent of each other in the cylinder head,
• wherein the plurality of combustion chambers are provided side by side in a longitudinal direction of the cylinder head,
• the plurality of intake ports are provided side by side in the longitudinal direction of the cylinder head and respectively communicate with the plurality of combustion chambers,
• the first coolant flow passage extends in the longitudinal direction of the cylinder head along upper surfaces of the intake ports and, in at least one of cross sections perpendicular to the longitudinal direction, is located between a flat plane and a central line plane, the flat plane including central axes of the plurality of combustion chambers and parallel to the longitudinal direction, the central line plane including central lines of the plurality of intake ports, and
• at least a portion of the second coolant flow passage is located between the combustion chamber and the first coolant flow passage in at least one of cross sections perpendicular to the longitudinal direction, and
• wherein a temperature of a coolant flowing in the first coolant flow passage is lower than a temperature of a coolant flowing in the second coolant flow passage.