Short Answer:

The flywheel effect refers to the ability of a flywheel to resist sudden changes in the speed of a rotating system by storing and releasing rotational energy. It helps maintain a steady speed of the engine crankshaft during different strokes by balancing energy differences between the power stroke and other strokes.

In simple terms, the flywheel effect keeps the engine running smoothly by storing extra energy when power is produced and releasing it when energy demand increases. This ensures uniform motion and prevents speed fluctuations in machines and engines.

Detailed Explanation :

Flywheel Effect

The flywheel effect is the phenomenon in which a rotating flywheel stores kinetic energy when the speed of the engine increases and releases it when the speed decreases. This effect helps to maintain a nearly constant rotational speed of the crankshaft or machine shaft, even when the torque applied on it varies.

In an internal combustion engine, power is generated only during the power stroke, while the suction, compression, and exhaust strokes consume energy. Hence, the crankshaft tends to speed up during the power stroke and slow down during the other strokes. The flywheel, mounted on the crankshaft, reduces this speed variation by its inertia. The energy stored in the flywheel during the power stroke is used to drive the other strokes. This behavior is known as the flywheel effect.

Principle of Flywheel Effect

The working principle of the flywheel effect is based on the law of conservation of energy. The flywheel stores energy when the supply is more than the demand and releases it when the demand exceeds the supply. The energy stored in a flywheel depends on its moment of inertia and the square of its rotational speed.

Mathematically,

where,
= Energy stored (Joules)
= Moment of inertia of the flywheel (kg·m²)
= Angular speed (rad/s)

When the speed of rotation increases, the flywheel stores kinetic energy; when the speed decreases, it releases the stored energy. This process keeps the rotation uniform and minimizes the variation in angular velocity.

Function of Flywheel Effect in Engines

1. Maintains Constant Speed:
   During engine operation, torque is not uniform. The flywheel stores energy during high torque and releases it during low torque, keeping the engine speed almost constant.
2. Balances Power Output:
   In multi-cylinder engines, the flywheel helps smooth out torque variations between cylinders.
3. Reduces Vibration:
   The flywheel effect minimizes sudden jerks and vibrations by evenly distributing energy throughout the rotation.
4. Assists During Load Change:
   When load increases suddenly, the flywheel supplies additional energy, and when load decreases, it absorbs excess energy, preventing damage to engine components.
5. Energy Storage Device:
   Flywheels are used as temporary energy storage devices in various mechanical systems like electric power systems, vehicles, and industrial machines.

Importance of Flywheel Effect

The flywheel effect is essential for achieving smooth and stable operation in mechanical systems. In engines, it prevents irregular rotation caused by varying torque during different strokes. In electrical machines, it ensures steady motion even with load fluctuations.

• In Single-Cylinder Engines:
  The torque produced is highly fluctuating, so a large flywheel is necessary to maintain uniform speed.
• In Multi-Cylinder Engines:
  Since torque variations are less, smaller flywheels are sufficient.
• In Power Presses or Punching Machines:
  These machines require a high torque for a short duration. The flywheel stores energy during the idle period and releases it during the working stroke.

Thus, the flywheel effect plays a crucial role in mechanical systems by maintaining energy balance and preventing speed variation.

Factors Affecting Flywheel Effect

1. Moment of Inertia:
   The energy stored depends directly on the moment of inertia. A heavier flywheel or one with mass distributed farther from the axis can store more energy.
2. Speed of Rotation:
   The energy stored increases with the square of the rotational speed. Hence, higher speed results in a greater flywheel effect.
3. Fluctuation of Energy:
   The greater the difference between energy supplied and consumed per cycle, the larger the flywheel effect required to maintain uniform speed.
4. Coefficient of Speed Fluctuation:
   It is the ratio of speed variation to the mean speed. The flywheel effect increases as the allowable fluctuation decreases.

Applications of Flywheel Effect

1. Internal Combustion Engines:
   Maintains smooth operation by storing and releasing energy between power strokes.
2. Industrial Machines:
   Used in rolling mills, presses, and punching machines to balance energy during high load periods.
3. Hybrid and Electric Vehicles:
   Used as energy recovery devices to store braking energy and improve fuel efficiency.
4. Power Plants:
   Helps maintain generator speed during load variation in power generation systems.
5. Energy Storage Systems:
   Modern flywheels are used for short-term energy storage in renewable energy systems like wind or solar plants.

Advantages of Flywheel Effect

• Ensures steady engine speed
• Reduces vibration and noise
• Provides energy during peak load
• Improves mechanical efficiency
• Increases life of machine components by minimizing shock loads

Limitations of Flywheel Effect

• Adds extra weight to the system
• Requires more space
• May cause balancing problems at high speeds
• Inefficient for long-term energy storage

Conclusion:

The flywheel effect is a very important concept in mechanical engineering, especially in engines and rotating machines. It helps to maintain uniform speed by storing excess energy during high torque periods and releasing it during low torque periods. This ensures smooth and stable operation, reduces vibration, and enhances the life of mechanical components. Therefore, the flywheel effect is vital for achieving consistent performance and energy balance in mechanical systems.