HYDRAULIC VARIABLE VALVE TIMING ACTUATOR [SKYACTIV-G 1.3, SKYACTIV-G 1.5 (WITH 4-1 EXHAUST SYSTEM)]
id0110q30017q4
Purpose, Function
• The hydraulic variable valve timing actuator operates using the engine oil supplied by the OCV, and changes the phases of the intake camshaft (valve timing).
• The hydraulic variable valve timing actuator cannot be disassembled because it is a precision unit.
Construction
• The hydraulic variable valve timing actuator consists of the following parts:
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― The intake camshaft sprocket is integrated with the housing.
― The rotor and the intake camshaft are engaged and they rotate together.
― There are two types of hydraulic chambers; advance chamber and retard chamber, between the housing and the rotor.
― When the rotor (intake camshaft) is in the maximum retard position, the stopper pin is engaged with the rotor depression.
Operation
Fixed mode
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• The stopper pin inside the variable valve timing actuator is engaged with the depression of the rotor positioned in the maximum retard position by the spring force.
• The intake camshaft sprocket and the intake camshaft rotate as a single unit.
Advance mode
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• Engine oil is led to the oil passage by the OCV, and the oil pressure is applied to the stopper pin. As a result, stopper pin is released.
• When the stopper pin is released, oil pressure is applied to the advance chamber. As a result, the rotor rotates in the advance direction relative to the intake camshaft sprocket, and the valve timing is advanced.
Retard mode
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• The oil passage is switched by the OCV and the oil pressure is applied to the retard chamber. As a result, the rotor rotates in the retard direction relative to the intake camshaft sprocket, and the valve timing is retarded.
Hold mode
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• The oil pressure is applied from the OCV to both the advance and retard chambers. As a result, the relative angle of the rotor and the intake camshaft sprocket is not changed and the valve timing is held.
