Infinitely Variable Valve Lifting (IVVL)

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The main work of an INLET CAMSHAFT is to operate the valves for fluid flow into the combustion chamber. The camshaft consists of Cams with high and/or low lifts for valves on top of engine cylinder (i.e., OHCS). Now in IVVL, the regular cams (2-Dimensional) are replaced with Camoids (3-Dimensional). Camoids have two different types of motions i.e., Rotation & Translation. The rotation gives the lift and the translation gives the change in amount of lift.

The mechanism mainly consists of five parts: Camoid, Governor, Spring, Solid & Hollow Shafts. Camoids are mounted/attached to hollow-shaft. The governor and hollow-shaft will mount on top of solid-shaft. Also the governor has two sleeves, one is fixed to solid-shaft and the other which can slide over solid-shaft is connected to hallow-shaft. A compressed spring is place b/w two sleeves of governor. Then the total assembly will be connected to crankshaft with help of chain/belt/gear drives.

When the assembly is rotating, camod will open the valves at minimum lift. And the governor helps the camoid to translate it to maximum condition (max. lift). This happens when there is an equilibrium b/w centrifugal force of governor and compressive load of spring on sliding sleeve.

So, when camoid starts to translate, the air-fuel mixture entering into combustion chamber increases for every increase in rpm. This allows to produce more power &hence more output.

And the spring helps to control the translation of camoid in increasing and decreasing conditions.

The main advantage is that the vehicle pick-up time deceases. That is, vehicle starts to get more power/speed even at low rpm of crankshaft.

In general, ECU helps to swap b/w max. & min. cams with the help of rocker arms and other. But the IVVL is purely mechanically operated. There is no involvement of ECU. So, if we want, we can control camoid electronically.

The other main point is Length of camoid. Because the camoid comes with a Spherical follower, which will give point contact b/w them. So, if the length of camoid is more, the more number of lifts can possible. That explains the word “INFINITELY” in title.


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  • Name:
    K Srinoothan Reddy
  • Type of entry:
  • Profession:
    completed Masters (2018)
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  • K Srinoothan is inspired by:
    Of-course, this is new generation of electric vehicles.But I respect my academics in my life. I am able to design this mechanism based upon what i have gone through in my studies. I hope this may work with design procedure and calculations that I have.
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