Technology that Works Behind the Variable Valve Timing

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Technology that Works Behind the Variable Valve Timing

Cars that we drive today are built with innovative technologies that work in combination with each other to enhance your driving experience. While some technologies increase the performance level, others play their role in making your ride smoother and safer. The modern car engines work automatically making the necessary advancements and retardations in the ignition timing in commensuration to the load it has to carry, and the acceleration inputs the driver pushes in. It was always the aim of the automotive engineers to take more control in the intake and exhaust valves to maximize the utility of power, boost fuel economy and reduce emissions. What came out as a solution for this was the concept of Variable Valve Timing. It is a kind of transmission that issued more control on the engine and is continuing as a successful mechanism not only for automobile vehicles but also in aircraft engines.

To take a closer look at how the Variable Valve Timing works, we asked an expert who served at the Union Park Hyundai dealer, and here’s a small account of what we learned from him.

Variable Valve Timing (VVT) Systems

Since the decade of 1960s, automobile engineers were experimenting with different setups of variable valve timing, and since 1980 the market was already flooded with several types of VVT systems, that included the following systems:

Cam Switching

This was to actually effect the lift and duration of engine with a different cam profile. This system works with two separate camshafts according to the ratio of engine rpms.

Three-Dimensional Cam Lobe

It is a VVT system that is made to achieve the capability to move the camshaft both fore-and-aft in the cylinder head to ensure that the different areas of the cam lobes are connected with the rocker arms to make the necessary changes in its lift and duration.

Eccentric Cam Drive

This is yet another VVT system, in which the camshaft is slowed or sped up as and when required in order to match with the engine speed, Eccentric cam drive systems needs a separate eccentric drive is needed for the intake and exhaust camshafts.

Phased Camshaft

A phased camshaft setup is a system that uses a mechanical linkage to carry out the tasks of advancing or retarding the engine time in tune with the opening and closing of the valves.

Controlling the VVT System

All the VVT systems are controlled by the engine computer, that depends on the readings of the crankshaft position sensor and also thee angle of the cam sensor that send data to the computer about the engine rpms and the load it is carrying. The implementation of the VVT setup takes place irrespective of the VVT system that is installed. Rather it is done by the changes that takes place in the oil pressure through solenoids, small oil galleys and switches.


From our experience at the Union Park Hyundai, we could arrive at the conclusion that overall the VVT Systems are much more intricate and hence expensive, but one thing is evident that it pays off in return through better emission control, enhanced fuel economy and power.

Donald Phillips

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