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REPAIR MAINTENANCE OPERATION OF MOTOR VEHICLES
Mazda 3 (2003 release)

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Mazda 3
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Mazda
3
Operation and maintenance of car
Engine
General description new engines models L8, LF, L3
The mechanical part of engines
Variable valve timing mechanism
Variable valve timing
The design of the variable valve timing mechanism
Main features of the mechanism of variable valve timing
The design of the variable valve timing mechanism
The oil control valve (OCV)
Lubrication system
Cooling system
Fuel system
Exhaust and Emission
Electric motors
The mechanical part of engines
Appendix 1
Annex 2
Appendix 3
Engine Z6 - mechanical part
Lubrication system
Cooling system
Intake system
Fuel system
Exhaust and Emission
Ignition system
Control system
Tables
Transmission
Chassis
Steering Gear
Brakes
Onboard electric
Body
 


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Variable valve timing



Variable valve timing is continuously modifies the phase of the actuator and the variable valve timing camshaft drive under the influence of the intake valves of the hydraulic pressure, which is controlled by the oil control valve (OCV) so that the phase of opening and closing valves optimally match the operating conditions of the engine. Work the oil control valve (OCV) based on the signals from the camshaft position sensor according to the conditions of the engine. It controls the hydraulic pressure acting on the actuator variable valve timing.

The operation according to traffic conditions: idle, small load
By reducing the overlap is less than the combustion products back into the cylinder. This stabilizes the idling speed, improving fuel efficiency, and ensures stable operation of the engine at low loads.

Average load
Overlapping increases, and the ratio of EGR in the cylinder - grows. This reduces the friction loss (pumping loss) is reduced and the combustion temperature reduces the amount of CO in the exhaust gases. Emissions of hydrocarbons are also reduced due to not re-ignited gas afterburning.

High load, low and average speed
The inlet valves are closed early, which ensures a high volume. N. D., Thereby improving the torque at low and medium speeds.

Most of the load, the range of high speeds
The intake valve closes later to the high volume. N. D. Provides maximum power.

At low temperatures
Overlapping minimized to prevent combustion in the cylinders and to reduce the amount of supplemental fuel injected into the cylinders. This improves fuel efficiency and stabilize higher idle speed.

When starting or stopping the engine
Startability is improved owing to reduction of overlap, since the products of combustion are not returned to the cylinder.




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