That cranky sound in your vehicle, Understanding the crankshaft and its functions.

in #automobile8 years ago (edited)

This morning I woke up elated with the thought of returning back to school filling up my mind. I took my bath as I set out to Abeokuta. Few kilometers from Lagos, this public transport had not gone far before this irritating sound filled the air. I must confess it was irritating to the ear especially at any bend. I was still trying to get hold of what was going on as a mechanical engineer when someone next to me mentioned the crankshaft was the problem.
How could that be?. I know crankshaft to be in the middle of the engine and if the engine was faulty then this vehicle would not move. I picked up my phone to make this research just to cure my curiosity.

Do you think it is annoying?

According to the Cambridge dictionary,
Crank means annoying, unpleasant person. Hey!
We are not talking human here. Its a shaft we are talking about. Shaft from the same dictionary means a rod that that turns and passes power through an engine.
These are just dictionary meaning of a crank and a shaft although they are true and quite easy to understand.
But in engineering, a crankshaft is that mechanical ugly looking rod you find in your engine that convert reciprocating motion of the piston to rotational motion of the flywheel. If you were hoping its straight well sorry to break your heart, it isn't straight but a zigzag looking rod which is connected to the connecting rod with a bearing in between. The crankshaft helps in balancing of forces in the engine and through holes that have been carefully drilled on it distributes engine oil to some parts of the engine that really needs it. Therefore, the crankshaft is a very important aspect of your engine or more like the spine of your engine. Without it there can be no engine, except for some small engines that do not use crank shaft.
The crank shaft consists of throws which acts as a lever arm during its operation. It throws and pulls the piston front and back through the connecting rod. A four cylinder engine should have four crank throws.
The end of the crank shaft is usually connected to a flywheel of the engine.

What are crankshaft made of?

The crankshaft are made of strong materials that can withstand heat and pressure. These material is called steel, it is made by forging or casting of steel. Shafts have to be polished to make them smooth and work effectively.

what does your crank shaft do?

As said earlier the crankshafts importance cannot be forgotten or set aside in an engine.



The simple answer is it converts one motion to another i.e. Linear to rotation.

But, let's not forget that an engine is all about rotation. Connected to the crankshaft is the connecting rod and the fly wheel. The connecting rod is connected to a piston which goes inside the cylinder where combustion occurs. So without this annoying shaft your engine is dead. The crank shaft is usually heavy depending on the size of the shaft and the engine.

The crank shaft reduces vibration in an engine.

This is where the balancing i talked about comes into play. Since it carries the flywheel it is responsible for balancing of the engine which reduces shock vibration in the engine.

Oil distribution

The shaft has some holes which have been drilled on it. These holes are responsible for distribution of lubrication oil on bearings that hold the connecting rod to the shaft. This reduces heat and friction and also enable smooth rotation of engine parts.

Connection to other engine parts

Several gears are mounted on the flywheel connected to the crankshaft. This is also different from the connecting rod that helps the piston to distribute power through out the engine.

Care of the crankshaft

This annoying shaft from the above importance you see should be taken good care of when loosing or checking out your engine.

  • The crankshaft are quite expensive and should not be left lying around a workshop as a serious dent or scratch could lead to something else after coupling.
  • Ensure to tighten all bolts well enough.
    This is very important as it could lead to death. All bolts should be tightened well enough to prevent being loose when an engine is functioning.
  • Alignment of shaft and parts
    The shaft should be well aligned and other parts connected to the shaft to prevent damage to the crankshaft and the engine.

Conclusion

Well it wasn't the shaft that was the problem with the vehicle i boarded but something else. The guy was wrong, it was the gear that had issues this was confirmed after the mechanic came to do a check up on the vehicle.
But this person had made me learn so much about crankshaft and i really appreciate him so much for that word he uttered.
The crankshaft are heavy annoying steel metal which is the backbone of any engine. Although some little internal combustion engines have no crankshaft. Crankshaft helps in balancing of the engine and reduces vibration. A four cylinder engine has four throws this goes for other engine types. There are different types and sizes of crankshaft but all they do is convert liner motion of the piston to rotational motion of the flywheel. The care of this precious shaft. Thanks for reading.

References

Sort:  

It always interest me to read about engineering related post. Good Job sir. However, indulge me as I will like to contribute to your post.

The crankshaft like you have noted is the backbone of the engine. It is the link between the input and output of the engine. The crankshaft is housed in an enclosed casting called Crankcase. This crankcase protects the crankshaft from foreign substances like dust and other unwanted materials.

Aside shielding, the crankshaft needs rigidity i.e. Its motion must be constrained such that it gives only the required rotation and is not allowed to move in any other direction. This rigidity is afforded to the crankshaft by bearings. Together with the crankcase, these bearings called "Main Bearings" support the crankshaft, thus ensuring its balance.

The number of bearings which supports the crankshaft depends of its size, which in turn depends on the size of the engine. Usually all crankshaft will have bearings at each end and the crankshaft will rotate in them.

Aside from end bearings, crankshafts have oil seals at their ends to prevent the leakage and loss of lubricant.

This is great sir. You are very correct and i hope to see your post very very soon. I really wish i had more sp to upvote this comment. Thanks for the contribution

Enlighting post,welldone

I enjoyed your post knowing myself very little about car mechanic. Thanks!

Thank you for reading.. The crankshaft does not deal with car engine only but any internal combustion engine.