HYDRAULIC VARIABLE VALVE TIMING ACTUATOR [SKYACTIV-G 1.3, SKYACTIV-G 1.5]

id0110q3001700

Without coolant control valve (4-1 exhaust system)

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

•  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.

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Advance mode

•  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.

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•  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.

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Retard mode

•  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.

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Hold mode

•  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.

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