VVT is variable? Valve? The abbreviation of timing (variable valve timing) is a technology that can change the engine valve timing.
What is timing?
When the engine is working, the valve should be opened and closed repeatedly. For example, during intake, the intake valve is opened and the exhaust valve is closed. The intake valve and exhaust valve are closed during compression and operation, and the exhaust valve is opened and the intake valve is closed during exhaust. Timing is simply to control the opening and closing of intake valve and exhaust valve reasonably.
The crankshaft of an automobile engine drives the camshaft through a timing chain or a timing belt, and the cams on the camshaft drive the valves to work in turn according to the preset positions. So that the engine can run normally.
What is variable timing?
The timing mechanism of ordinary engine is hard-connected, and the valve switch always corresponds to which position the crankshaft turns, so there is no way to change it.
However, the intake and exhaust characteristics of the engine at different speeds are quite different, so the ordinary timing mechanism can not take into account the intake and exhaust efficiency at all speeds. Therefore, the overall performance of the engine cannot be greatly broken. Variable valve timing system can adjust the timing of valve opening and closing, advance or delay valve opening and closing within a certain range, give consideration to intake and exhaust efficiency at high and low speeds, and improve engine performance.
Different manufacturers have different names for variable valve timing systems.
At present, most family car engines have variable timing systems, but each manufacturer has a different name.
Most variable timing systems are realized by installing a phase adjuster on the top of the camshaft. The outer ring of the phase adjuster is connected with a timing chain or a timing belt, and the inner ring is connected with a camshaft. There is a gap between the inner and outer rings, and the timing angle is adjusted by controlling the oil to enter the corresponding gap through the solenoid valve.
For engines without variable valve timing system, the camshaft driving wheel is a common pulley. Just like the picture above.
The camshaft driving wheel of the variable valve timing system engine is a phase adjuster, as shown in the above figure.
The entry-level variable valve timing system can only be adjusted on the intake side or the exhaust side. At present, the mainstream is adjustable intake and exhaust. In the past, the technology of VVT was owned by only a few manufacturers, and ordinary cars were rarely used. Now this technology is very mature and many manufacturers have mastered it. Coupled with strict emission requirements and fuel consumption indicators, it is difficult to meet the requirements without some technical means. Therefore, almost all cars produced now have VVT system.
The way to know whether your car has a variable valve timing system is simple. Just open the engine compartment and look at the side of the cylinder head near the pulley to see if there is a VVT solenoid valve. If there is a solenoid valve, the engine has a variable valve timing system. Of course, some cars are not controlled by the camshaft phase adjuster, so these cars can't find the VVT solenoid valve.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.