understanding flywheels smf dmf and planetary dmf

after some research i have found some information on flywheels some of which is in video's

3D image of a dual mass flywheel


and an explanation of one type of dual mass flywheel


and here we have an explanation of smf dmf and planetery dmf

What is a Standard Flywheel

The flywheel is effectively a weight which is fastened to the end of the crankshaft of the engine. The power from the pistons tends to be created in "pulses" and the weight of the flywheel smoothes out these pulses by providing inertia to the rotating engine, (smoother on tick over), As well as providing a weight the flywheel has a gear around its circumference on which the starter motor operates and is a convenient means of attaching the clutch which provides a variable connection to the transmission. Taking your foot away from the clutch between gear changes makes the clutch last longer, hovering on the pedal is the single most cause of premature clutch wear.

Then what is Dual Mass flywheel

Modern diesel engines generate high torque and as a result they need extra smoothing out or "damping". To help with this process a DMF (Dual Mass Flywheel) is fitted. This is effectively two flywheels that transmit the drive through a number of springs which cushion the drive to the transmission In modern light-diesel technology we are seeing much greater horsepower and torque gains sometimes coupled to better fuel economy.

Dual Mass Flywheels have been used in many light-duty diesel trucks since 1987 that are fitted with a standard manual transmission. Along with their continued use in such applications, Dual Mass Flywheels are now also being fitted to high proportion of standard passenger vehicles (Cars MPV's etc) their primary purpose being to provide a vibration dampening action in the drive train at lower speeds.

The benefits of the Dual Mass Flywheel. ( the technical bit) To eliminate excessive transmission gear rattle, making driving comfortable at any speed, reduce gear change/shift effort, and Increased fuel economy. Mass Flywheel's are designed to provide maximum isolation of the frequency below the engine's operating RPM, usually between 200-400 RPM. The time that the DMF works hardest is during engine start-up and shutdown.

There are two basic types of Dual Mass Flywheel The first type of dual mass flywheel, or DMF as it is more commonly known, is made up of a primary and secondary flywheel with a series of torsion springs and cushions. There is a friction ring located between the inner and outer flywheel that allows the inner and outer flywheel to slip. This feature is designed to alleviate any damage to the transmission when torque loads exceed the vehicle rating of the transmission. The friction ring is the weak spot in the system and can wear out if excessive engine torque loads are applied through it. The system also has a center support bearing that carries the load between the inner and outer flywheel. The system is also fitted with damper springs to absorb shocks

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The second is designed with planetary gearing (planetary DMF) is designed especially for engines with stronger vibrations in the lower rpm range. Although these are primarily diesel engines, this type of DMF provides a smooth engine output comparable to that of petrol engines. This type provides in addition to greater driving and shifting comfort, benefits for drivers include lower fuel consumption because the idling rpm is lower.

the above taken from a document here here http://www.aceautose...k/flywheel.html