Cylinder head of an internal combustion engine comprising a cooling circuit

1. A cylinder head of an internal combustion engine in which a cooling circuit is arranged, suited for a coolant circulation, the cylinder head comprising:

an exhaust duct opening out on a circular exhaust cavity comprising on its periphery an annular peripheral groove;

an exhaust valve seat assembled in said circular exhaust cavity, said exhaust valve seat comprising an annular peripheral groove arranged on its periphery, said annular peripheral groove of the circular exhaust cavity and said annular peripheral groove of said exhaust valve seat constituting a peripheral duct suited for the circulation of said coolant around said exhaust valve seat by the assembly of said exhaust valve seat in said circular exhaust cavity;

an inlet duct opening out on a circular inlet cavity comprising on its periphery an annular peripheral groove;

an inlet valve seat assembled in said circular inlet cavity, said inlet valve seat comprising an annular peripheral groove arranged on its periphery, said annular peripheral groove of the circular inlet cavity and said annular peripheral groove of said inlet valve seat constituting a peripheral duct suited for the circulation of said coolant around said inlet valve seat by the assembly of said inlet valve seat in said circular inlet cavity;

wherein said peripheral duct surrounding said exhaust valve seat and said peripheral duct surrounding said inlet valve seat communicate with each other using a connecting duct, wherein said peripheral duct surrounding said exhaust valve seat has a cross-sectional area perpendicular to a direction of flow of said coolant in said duct that is variable along said peripheral duct around said exhaust valve seat, and

wherein said cylinder head comprises a first coolant inlet, a second coolant inlet, and an outlet for heated coolant, said second inlet communicating with said connecting duct.

2. The cylinder head of an internal combustion engine according to claim 1 , wherein said annular peripheral groove surrounding said exhaust valve seat comprises a section of undulating shape formed by a first recess, a boss and a second recess.

3. The cylinder head of an internal combustion engine according to claim 1 , wherein said annular peripheral groove of said circular exhaust cavity has a section of hemicircular shape or of undulating shape formed by the alternating of a first recess, a boss and a second recess.

4. The cylinder head of an internal combustion engine according to claim 1 , wherein said cross-sectional area of said peripheral duct surrounding said exhaust valve seat varies between 24 mm 2 and 36 mm 2 around said exhaust valve seat.

5. The cylinder head of an internal combustion engine according to claim 1 , wherein said annular peripheral groove surrounding said inlet valve seat comprises a section of undulating shape suited for the passage of said coolant, said section being formed by a first recess, a boss and a second recess.

6. The cylinder head of an internal combustion engine according to claim 1 , wherein said annular peripheral groove of said circular inlet cavity has a section of hemicircular shape or of undulating shape formed by the alternating of a first recess, a boss and a second recess.

7. The cylinder head of an internal combustion engine according to claim 1 , wherein said peripheral duct surrounding said inlet valve seat has a variable section around said inlet valve seat.

8. The cylinder head of an internal combustion engine according to claim 7 , said section of said peripheral duct surrounding said inlet valve seat varies between 6 mm 2 and 21 mm 2 around said inlet valve seat.