Purpose, Function
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
The hydraulic variable valve timing actuator is installed to the exhaust camshaft.
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
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
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
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
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.
Refrigerant Pressure Check
NOTE:
Measure the refrigerant pressure after approx.10 min have elapsed
from engine start.
1. Install the manifold gauge..
2. Start the engine and warm it up.
3. Set the fan speed MAX HI.
4. Turn the A/C switch on.
5. Set to RECIRCULATE mode.
6. Set the temperature control ...
Wheel Hub, Steering Knuckle Inspection
Wheel Bearing Excessive Play Inspection
1. Install the magnetic base and dial gauge as shown in the figure and measure
the wheel bearing axial excessive play.
If it exceeds the maximum specification, replace the wheel hub bearing.
Front wheel bearing maximum play
0 ...
Engine Oil Level Inspection
1. Position the vehicle on level ground.
2. Warm up the engine.
3. Stop the engine and allow at least 5 min before continuing.
4. Remove the dipstick, wipe it cleanly, and reinstall it fully.
5. Remove the dipstick and verify that the oil level is between the F and L marks
on the dipstick. ...