FLYWHEEL AND ITS TYPES

10 min readJun 19, 2022

While not often talked about, flywheels are extremely important components of automobiles. In essence, flywheels are relatively heavy disks of metal that are fitted to the crankshaft rear-end (ideally, between the transmission and the vehicle engine). These disks typically have high levels of rotational inertia, which helps in counteracting sudden speed changes/fluctuations. The additional rotational energy is stored for usage later, energy pulses are smoothened, and the pistons receive the requisite energy. In order to ensure that vehicular engines operate smoothly and at constant speeds, the top flywheel manufacturers in India and abroad offer different types of flywheels — each with its specific features and advantages.

What is flywheel?

A flywheel is a heavy steel wheel that is attached to the rear end of the crankshaft. The size of the flywheel is depended upon the number of cylinders and the construction of the engine.

The flow of power from the engine cylinders isn’t smooth. Although, the power impulses in a multi-cylinder engine overlap each other to provide an even flow of power. However, additional levelling off power impulses is required. This is done by a flywheel.

Functions of Flywheel:

The Flywheel can be found in almost all types of automobiles as they serve different purposes, which will be discussed here. The functions of a flywheel in an automobile engine are given below:

1. Engine Balance

Because the piston is offset from the centre of crankshaft vibration and wobble, this is also because each piston fires at a different angle.

The function of the Flywheel in this situation is to suppress the side-to-side motion. This is achieved due to the heavyweight of the Flywheel. The Flywheel reduces vibrations throughout the engine as the engine is stable and balances on the mounts.

2. Engine Start

The Flywheel plays another role when starting the engine. The gear teeth on the Flywheel are connected to the starter motor. This starter motor is controlled by the car key, so when the car starts, the starter motor spins the Flywheel. Immediately the engine spins, the combustion effect keeps the engine running. The Flywheel retracts the Bendix gear in the started motor to rotate freely.

3. Drivetrain Stress Reduction

Another function of a flywheel is achieved by stabilizing engine speed. It also smooths engine speed and reduces wear and tear on drivetrain components.

The Flywheel also limits the wear between the transmission shaft and the driveshaft. These two are connected by a universal joint.

4. Engine Speed Soothing

The crankshaft converts piston movement into rotary motion, which is jerky when power is generated. The rotational speed of the crankshaft is constants, & the engine runs smoothly. This is because the mass of the Flywheels applies inertia that keeps the engine crankshaft rotating between each piston firing.

5. Weight Manipulation

The weight of the Flywheel determines engine performance. The weight is designed based on the performance of the vehicles. The heavy Flywheel allows the engine to operate under loads that can cause engine failure. A larger truck or trailer does well with a heavy flywheel, while sports cars and some commercial cars make good use of a lighter flywheel.

Parts of Flywheel

Following are the parts of a flywheel:

1. Flywheel housing

2. Springs

3. Planetary wheel

4. Axial sliding bearing

5. Radial sliding bearing

6. Ring gear

7. Locking pinhole

8. Support disk

9. Flywheel sliding shoe

10. Flywheel cover

1. Flywheel Housing

The flywheel housing is solid and sits outside of the flywheel. The flywheel is the part of the engine that rotates and delivers power to the alternator.

2. Springs

The flywheel is consisting of two-phase bent springs in parallel. The outer arc is adjusted to raise the spring when the engine is operating. The soft outer arc spring only serves to improve the uncertain resonance frequency range.

3. Planetary Wheel

A planetary wheel consists of many planetary gears fixed on a flywheel bracket. When the flywheel bracket is operated by a screw and rotates, the meshing with the outer ring gear produces a compound motion composed of each planetary gear revolution and rotation.

4. Axial and Radial Sliding Bearing

While the axially acting bearing serves only for weight compensation, the imbalance or parasitic radial forces initiated by the motor or generator unit must be compensated by radial Bearings.

5. Ring Gear

A ring gear is fitted to the outer diameter of the flywheel. It is usually fixed to the flywheel with the help of an interference fit, which is produced by heating the ring gear. So, the thermal expansion enables it to be placed around the flywheel.

6. Support Disc

As the name suggests, the support disc is attached inside the flywheel to support the two-phase bent springs and other components of the flywheel.

7. Flywheel Sliding Shoe

Sliding shoes preferably have a convex radial outer portion bearing on the inner wall of the flywheel. In this area, they are preferably manufactured to promote slip and suffer minimal wear and tear.

8. Flywheel Cover

The flywheel cover is commonly made of chrome. This chrome-plated flywheel cover will prevent dust from getting into the internal functions of the flywheel, due to which it is running poorly.

Working Principle:

The working principle of the Flywheel is quite simple and interesting as it stores the energy for the use of the vehicle. Just as a mechanical battery stores energy in chemical form, the Flywheel saves power in the form of kinetic energy.

A flywheel is nothing more than a heavy mechanical device attached to the shaft to store surplus rotational energy. It acts as a rotating reservoir which store energy; when its available in abundance and release when most needed much like a battery. It has a significant weight in respect to the crankshaft assembly; and thus helps maintain torque resisting rotational speed. They are generally installed in system’s with varying load and fluctuating torque; as in internal combustion engine.

Due to its heavy weight a flywheel have very high inertia causing it to; remain at the same speed irrespective of the opposing forces. The energy stored to these flywheels are proportional to their square of rotating speed. A torque is applied to the flywheel to store rotational energy and when needed; energy is released from flywheel in the form of torque applied on the mechanical load. Thus, it increases its rotational speed while storing energy and loose while releasing it.

The more energy is produced, the more speed the Flywheel spins. It has a high moment of inertia which means heavy. It is better to spin faster than to increase its mass. This is because a lighter wheel generates twice as much energy like a flywheel that is more or twice as heavy.

That is, the lighter the Flywheel, the more energy is stored. It is advisable to use light, high-speed wheels instead of wheels with a large weight. But heavy vehicles will be suitable for heavy vehicles like trailers, trucks, vans, etc. This is because they carry extra weight and are not important for running at high speeds.

So, knowing how a flywheel works, the higher the speed, the higher the energy. However, if the speed continues to increase, the wheel may not be able to handle the material force. This can lead to a breakup.

Types of Flywheels

Following are the types of flywheels used in vehicle:

1. Solid disc flywheel

2. Rimmed flywheel

3. High-velocity flywheel

4. Low-velocity flywheel

1. Solid Disc Flywheel

The Solid disc flywheel is a type of flywheel. It is used in a single flywheel thresher is made of cast iron. The solid disc flywheel is equipped with a flywheel hub and disc.

In the design calculation of a solid disk flywheel, various parameters are used as inputs. This includes the dimensions of the solid disk flywheel. Also, resulting functional values are calculated.

2. Rimmed Flywheel

The rim-type flywheel will explode at a much lower rotary speed than a solid disc-type wheel of equal weight and diameter. For minimal weight and high energy-storage capacity, a flywheel can be formed of high-strength steel and produced as a tapered disk, which is thick in the centre.

3. High Velocity Flywheel

In these types of the flywheel, the high-velocity flywheel has a velocity between 30000 rpm to 80000 rpm. That can also be adjusted up to 100,000 rpm.

They have magnetic levitation bearings and require little maintenance. These are light in weight when compared to a low-velocity flywheel according to size/capacity. They are more expensive than a low-velocity flywheel.

4. Low Velocity Flywheel

In these types of the flywheel, the low-velocity flywheel has a velocity of 10000 rpm. They are heavier and bulky than the high-velocity flywheels.

They require time to time maintenance and do not use magnetic levitation bearings. Their installation requires special concrete construction to carry its weight. They are more affordable than high-velocity flywheels.

Materials Use to Make Flywheel

The flywheel is made from many different materials depending on their applications. Cast iron flywheel is used in older steam locomotives. The flywheels used in the car’s engine are usually built of cast or nodular iron, steel, or aluminium.

Flywheels also made of high-strength steel. The composite flywheel is meant for use in vehicle energy storage and braking systems. The power of a flywheel is determined by the maximum amount of energy that it can store per unit load.

Common Problems of Flywheel

Following are the faults that occur when a flywheel is defective:

1. Clutch dragging

2. Clutch slipping

3. Burning smell

4. Clutch chatter

5. Clutch pedal vibration

1. Clutch Dragging

In this case, the clutch will not release completely. This will cause different levels of gear grinding when changing gears.

Moreover, it can completely fail to put the car in first gear when it starts at a standstill. This problem is not only made in the flywheel but in the flywheel or crankshaft assembly bearing or bushing.

2. Clutch Slipping

This problem occurs when the gears automatically change while driving. Due to it, the gear may slip. This happens when power is not transferred to the wheels, resulting in a clutch failure.

The slipping clutch will eventually degrade the flywheel as well. The pressure plate may cause a sudden grinding sound. Other parts of the flywheel in the clutch assembly will heat up. This will lead to bends and even cracks.

3. Burning Smell

When the clutch goes bad, a burning smell will produce. This is caused by a faulty flywheel or an unskilled operator.

The face of the clutch is designed with materials proposed to decrease the amount of sound the clutch makes while working. This produces too much heat due to friction when the facing is not properly operated.

4. Clutch Chatter

This occurs when the clutch has difficulty engaging. As the clutch catches, it slips along the flywheel and leaves the flywheel repeatedly. On release, it seems like stutter or vibration.

Clutch chattering is often in any gear when starting with a full stop. This fault can be difficult to recognize because there is a defect in the clutch disc, pressure plate, or release bearings. These parts can also be broken, deformed, or contaminated with oil.

5. Clutch Pedal Vibration

You may have noticed that the clutch pedal or vehicle floor is vibrating when the flywheel is damaged. This is because the spring mounts of the flywheel have declined. Let us tell you that the spring mechanism reduces the vibration caused by the clutch being used.

Applications of Flywheel

● In wind turbines

● With motorized generator to store energy

● in automobile engine

● In electric cars, to increase speed (in the experimental phase)

● In advanced locomotive propulsion systems

● Advanced Technology in Transit Buses

● To control the direction in satellites.

● In large power grids for protection against interruptions

Advantages and Disadvantages of Flywheel

Advantages

1. The overall cost of the flywheel is less.

2. They have a greater lifespan.

3. By using flywheel can provide you greater storage capacity.

4. It requires less maintenance and has a lesser thermal loss.

5. Flywheel is safe, reliable, and energy efficient.

6. It is easy to operate and requires high energy density.

Advantages of Flywheel over General Battery

These types of flywheels are more efficient than general batteries (only if we neglect installation cost) and so they are given preference over general batteries. Here is a list of few advantages of Flywheel over General Battery:

1.Greater capability to store energy

2.More life span

3.Storage capability is not affected by charging / discharging cycle

4.Less Maintenance involved

5.Lesser thermal loss

6.More round-trip efficiency

7.More peak-load capability

8.Ease of operation

Disadvantages

1. The main drawback of the flywheel is that it requires a lot of space.

2. They are quite expensive to manufacture.

3. Building materials always have a limit for.