A flywheel is one of the most important components of an automobile engine. It’s a mechanical device that is specifically designed for storing rotational energy (kinetic energy). It’s proportional to the square of its rotational speed and mass.
What is a flywheel?
A flywheel as a weighty wheel requires enough forces to rotate on its axis. It resists changes in rotational speed by their moment of inertia. Changing the stored energy on the flywheel, its rotational speed must be increased or decreased. That is, it keeps spinning until lots of force is applied.
A great amount of kinetic energy is preserved when the flywheel rotates. This energy is later used to power up the vehicle when starting the engine or speeding.
Today we’ll be looking at the definition, construction, functions, working principle, and symptoms of bad automobile flywheel.
Construction of a flywheel
Due to the toughness requirement of a flywheel, it is typically made of steel that rotates on conventional bearings. High energy density flywheels are made of carbon fibre composites and use magnetic bearings. Such flywheel revolves at speed up to 60,000 RPM (1 kHz).
Functions of Flywheel
Flywheels can be found in almost all type of automobile as they serve a variety of purposes will be discussed here. Below are the functions of the flywheel in an automobile engine:
Engine Balancing: because the pistons are offset from the centre of the crankshaft vibration and wobbles occur. This is also because of each piston fires at a different angle.
The function of a flywheel in this situation is to suppress the side-to-side motion. This is achieved because of the heavyweight of the flywheel. Flywheels reduce the vibration of the engine as a whole as the engine is stabilized and balance on the mounts.
Engine Start: the flywheel plays another role while starting the engine. The gear teeth on the flywheel are attached to a starter motor. This starter motor is controlled with the car key so when the car is started the starter motor turns the flywheel.
Immediately the engine spins, the combustion effect continues turning the engine. The Bendix gear in the started motor withdraws in order for the flywheel to freely spin.
Drivetrain stress reduction: is another function of a flywheel, achieved by stabilizing the engine’s movement. It also smooths out the engine’s speed and reduce wear and tear on the drivetrain components.
Flywheel also limits the wear between the transmission shaft and the driveshaft. This two are attached with a universal joint.
Engine speed soothing: The crankshaft converts the piston movement into rotary motion which is jerky as the power is generated. the rotational speed of the crankshaft is constant and the engine runs smoothly. This is because the mass of the flywheel applies inertia which kept the engine crankshaft spinning between each piston firings.
Weight manipulation: the weight of a flywheel determines the performance of an engine. The weight is designed base on the performance of the vehicles.
Heavier flywheels allow the engine to work under loads which may cause the engine to bog down. Big truck or trailer is good with the heavier flywheels while sports car and some commercial cars make good use of the lighter flywheels.
Read: Components of an automobile engine
The working principle of a flywheel is quite easy and interesting as it stores energy for the vehicle’s usage. Just the way mechanical battery stores energy in a chemical form, flywheels save the power in the form of kinetic energy.
More energy is produced is the flywheel spins at a higher speed. that’s a higher moment of inertia means bulkier. It is better to spin faster than increasing its mass. This is because lighter flywheels produce twice the energy than flywheels that weighs more or double. That’s, the lighter the flywheel the more the energy stored.
It is advisable to use a lighter, highspeed wheels rather than the one with massive weight. But for a heavier vehicle like trailers, truck, van etc. heavier one’s will be suitable. This is because they carry extra load and not important to run at higher speeds.
So, knowing how a flywheel work is that the higher the speed the higher the energy stored. However, if the speed kept increasing, the wheel material might not be able to handle the force. This may lead to breaking up.
The video below explains how a flywheel work:
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Symptoms of a bad flywheel
Below are the symptoms that occur when a flywheel is faulty:
Clutch slipping: this flywheel issue occurs when changing gears while driving. The gear may slip. The happens when no power is transferred to the wheels, resulting in a worn clutch.
Slipping clutch will eventually wear out the flywheel as well. Grinding noises may suddenly occur from the pressure plate and the other parts of the flywheel in the clutch assembly will overheat. This will lead to warp and even crack.
Clutch dragging: this flywheel dilemma is similar to that of clutch slipping. In its situation, the clutch won’t completely release. This will cause a various level of gear grinding when the gear is change.
In fact, it might lead to complete failure of putting the car into first gear when starting from a standstill. This issue is not directly from the flywheel but in the bearing or bushing in the flywheel or crankshaft assembly.
A burning smell: A burning smell is produced when the clutch works improperly. This is caused by a bad flywheel or an inexperience driver.
The facings of the clutches are designed with materials which intended to reduce the amount of noise the clutch makes while working.
This facing produce lot of heat due to friction if not properly operated. Thus, an acrid smell which is quite noticeable occurs.
Read: Working and effectiveness of a propeller shaft
Clutch pedal vibrates: you noticed vibrations coming from the clutch pedal or vehicle’s floor when the flywheel is faulty. This happens because the flywheel’s spring mounts have gone bad.
This is to let you know the spring mechanism normally reduces the vibrations generated from the clutch being used.
Clutch chatter: this problem occurs when finding it difficult engaging the clutch. It skips along with the flywheel as the clutch grabs and releases the flywheel repeatedly. It feels like a stutter or vibration when released.
Clutch chatter often happens in any gear, popularly when starting from a complete stop. A warped flywheel can sometimes be the cause.
This problem can be difficult to diagnose as the clutch disc, pressure plate or release bearing are at fault. These parts might be worn, broken, warped or even contaminated by oil. It shows the same symptoms as the clutch chatter.
That’s it for this article “Working principle of a flywheel”. I hope the knowledge is attained, if so, kindly comment and share this article to other technical students. Thanks!