Mazda CX-5 Service & Repair Manual: Hydraulic Variable Valve Timing Actuator
Purpose, Function
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The hydraulic variable valve timing actuator operates according to the hydraulic pressure and changes the phases of the exhaust camshaft. As a result, the open/close period of the exhaust valve is changed, optimized valve timing in accordance with driving conditions is realized, and the output and combustion efficiency is improved.
Construction
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The hydraulic variable valve timing actuator is installed to the exhaust camshaft.
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The hydraulic variable valve timing actuator has an assist spring to move the rotor in the advance direction while the engine is stopped.
Operation
At engine start
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Because the stopper pin in the hydraulic variable valve timing actuator is engaged with the rotor at the maximum advance position by the spring force, the camshaft sprocket and camshaft are rotated as a single unit.
Retarding valve timing
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Engine oil is lead to the retard oil passage by the OCV to apply oil pressure to the stopper pin and retard chamber. As a result, the engagement of the stopper pin is released, the rotor connected to the camshaft rotates in the retard direction against the camshaft sprocket driven by the crankshaft, and the valve timing is retarded.
Advancing valve timing
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Engine oil is lead to the advance oil passage by the OCV to apply oil pressure to the advance chamber. As a result, the rotor connected to the camshaft rotates in the advance direction against the camshaft sprocket driven by the crankshaft, and the valve timing is advanced.
Maintaining intermediate valve timing
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The retard and advance oil passages is closed by the OCV. As a result, the relative angle of the rotor and camshaft sprocket is maintained at a constant to hold the valve timing.
Hydraulic Variable Valve Timing Actuator Inspection
WARNING:
A hot engine can cause severe burns. Turn off the engine and wait until it
is cool before servicing.
CAUTION:
Do not disassemble the hydraulic variable valve timing a ...
Mechanical
Outline
The sliding resistance*1 has been reduced by:
the adoption of a rocker arm (built into needle roller bearing)
reducing load on the valve spring
narrow ...
Other materials:
Starting the Engine
WARNING
Radio waves from the key may affect medical devices such as pacemakers: Before
using the key near people who use medical devices, ask the medical device manufacturer
or your physician if radio waves from the key will affect the device.
NOTE
• The key must be carried because the
ke ...
D Pillar Speaker Inspection
D-pillar speaker
1. Disconnect the negative battery cable..
2. Remove the following parts:
a. Trunk board.
b. Trunk end trim.
c. Rear scuff plate.
d. Trunk side trim.
e. D-pillar trim.
3. Disconnect the D-pillar speaker connector..
4. Verify that the resistance between the D-pillar ...
Purge Control
Outline
An appropriate amount of evaporative gas is fed into the intake manifold
by the purge solenoid valve operation according to the engine operation conditions.
This ensures driveability and prevents release of evaporative gas into the atmosphere.
The PCM drives the purge so ...
