CYLINDER HEAD [SKYACTIV-G 2.5T]
id0110q8000400
Outline
• A rocker arm (built in needle roller bearing) has been adopted to reduce sliding resistance.
• An HLA that maintains a constant 0 mm valve clearance has been adopted to achieve a maintenance-free design.
• The contact point of the rocker arm and cam is lubricated by the engine oil injected from the oil shower pipe.
• 4-3 type exhaust passages have been adopted in the cylinder head to improve the acceleration/environmental performance.
Purpose, Function
• The cylinder head forms the combustion chamber and intake and exhaust ports.
Construction
• The lightweight cylinder head is made of aluminum alloy with excellent thermal conductivity.
• Designing a compact pentroof combustion chamber and positioning the spark plug on the top of the combustion chamber has improved the combustion efficiency.
• There are two intake valves and two exhaust valves per cylinder for a total of four valves and the intake/exhaust type has been changed to a cross-flow type, improving intake and exhaust efficiency.
• The tumble ratio is improved by optimizing the intake port entry angle and valve included angle which suppress knocking by increasing the combustion speed.
• With the adoption of plastic region tightening
* for the cylinder head bolts, axial force has been stabilized.
* :Plastic region tightening is a method of controlling the tightening using the rotation angle of a bolt and suppressing the variations in the axial force by tightening the bolt until its deformation does not return to its original condition (plastic region).
• The exhaust passages have been shortened by building 4-3 type exhaust passages into the cylinder heads.
