Balancing in Multi-Cylinder In-line Internal Combustion Engine

In a multi-cylinder in-line internal combustion engine, balancing is an essential aspect to ensure smooth running and reduce vibrations. The even number of cylinders is chosen so that the secondary forces are balanced. Let's understand this in detail.

Primary and Secondary Forces

When the piston moves up and down in the cylinder, it generates forces that act on the crankshaft. These forces are of two types:

1. Primary Forces: These forces are generated due to the combustion process and the reciprocating motion of the piston. They act along the line of the piston and are balanced by the counterweights on the crankshaft.

2. Secondary Forces: These forces are generated due to the angularity of the connecting rod and the offset between the crankpin and the center of the cylinder. They act in a direction perpendicular to the line of the piston and cause vibrations in the engine.

Balancing of Secondary Forces

To balance the secondary forces, an even number of cylinders is chosen. The cylinders are arranged in a straight line, and the firing order is chosen such that the combustion in each cylinder occurs at equal intervals. This ensures that the forces generated by each cylinder are equal and opposite, and hence they cancel out each other.

For example, in a four-cylinder engine, the firing order can be 1-3-4-2. In this firing order, the combustion in cylinder 1 occurs, followed by cylinder 3, then cylinder 4, and finally cylinder 2. This firing order ensures that the forces generated by each cylinder are balanced, and hence the engine runs smoothly.

Advantages of Balancing

Balancing the secondary forces in a multi-cylinder in-line engine has the following advantages:

1. Reduced vibrations: Balancing the forces reduces the vibrations in the engine, which improves the overall performance and reduces wear and tear.

2. Smooth running: A balanced engine runs smoothly, and this enhances the driving experience.

3. Improved fuel efficiency: A balanced engine operates efficiently, which improves the fuel efficiency and reduces emissions.

Conclusion

Thus, choosing an even number of cylinders and balancing the secondary forces is crucial in a multi-cylinder in-line internal combustion engine. It ensures smooth running, reduces vibrations, and improves fuel efficiency.

Correct answer is - to balance coulpe. In 4 stroke 4 cylinder in line engine, secondary force is unbalanced