CYLINDER HEAD [SKYACTIV-G 2.0]
2016 – MX-5 – Engine
CYLINDER HEAD [SKYACTIV-G 2.0]
Outline
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A rocker arm (built in needle roller bearing) has been adopted to reduce sliding resistance.
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An HLA that maintains a constant 0 mm valve clearance has been adopted to achieve a maintenance-free design.
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The contact point of the rocker arm and cam is lubricated by the engine oil injected from the oil shower pipe.
Purpose, Function
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The cylinder head forms the combustion chamber and intake and exhaust ports.
Construction
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The lightweight cylinder head is made of aluminum alloy with excellent thermal conductivity.
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Designing a compact pentroof combustion chamber and positioning the spark plug on the top of the combustion chamber has improved the combustion efficiency.
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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.
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The tumble ratio is improved by optimizing the intake port entry angle and valve included angle which suppress knocking by increasing the combustion speed.
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With the adoption of plastic region tightening* for the cylinder head bolts, axial force has been stabilized.
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- 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).