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.
Hydraulic Variable Valve Timing Actuator Inspection
MechanicalRelay And Fuse Block Middle Cover Disassembly/Assembly
1. Insert a tape-wrapped flathead screwdriver into the service hole in the position
shown in the figure.
2. While pressing the relay and fuse block middle cover tab in the direction
of arrow (1) shown in the figure, pull out the bracket in the direction of arrow
(2) to detach the relay a ...
Front Suspension
Outline
A strut type front suspension has been adopted.
The connection area of the front crossmember and body is a 6-point rigid
mount type.
The cross-section on the center member of the front crossmember has been
expanded and the longitudinal offset of the ...
Cooling System Cap
Purpose, Function
The cooling system cap maintains appropriate pressure in the engine coolant
passage. In addition, cooling efficiency has been improved by increasing the
engine coolant boiling point.
Construction
The cooling system cap is installed to the upper part of the ...