Arrangement of a direct-injection and spark-ignition 4-stroke internal-combustion engine

A direct-injection and spark-ignition 4-stroke internal-combustion engine comprising:

• a cylinder, a piston within the cylinder and having an upper face, and a cylinder head on the cylinder and having a lower face, the piston, cylinder, and cylinder head cooperating to define a combustion chamber having at least one intake port and an exhaust port, the at least one intake port adapted for connection to an intake line for introduction of air into the combustion chamber, the exhaust port adapted for connection to an exhaust line for exhaust of combustion gases from the combustion chamber;
• at least one intake valve having a longitudinal axis close to the longitudinal axis of the cylinder, for controlling flow of air through the at least one intake port;
• an exhaust valve for controlling flow of combustion gases through the exhaust port;
• an ignition element in the vicinity of the at least one intake port;
• and
• a fuel injection element in the vicinity of the ignition element,
• the piston upper face having a profile close to the profile of the cylinder head lower face, but with a recess in the vicinity of the ignition element.