Technician A says that a vibration damper, also known as a harmonic balancer, is used to dampen harmful vibrations of the crankshaft. Technician B says that most engines are externally balanced. Which technician is correct? Group of answer choices
Technician A says that a vibration damper, also known as a harmonic balancer, is used to dampen harmful vibrations of the crankshaft. Technician B says that most engines are externally balanced. Which technician is correct? Group of answer choices
The Correct Answer and Explanation is:
Correct Answer: Technician A is correct.
Explanation
A vibration damper, commonly referred to as a harmonic balancer, is a crucial component attached to the front end of an engine’s crankshaft. Its main function is to absorb and dampen torsional vibrations—twisting forces that occur as the crankshaft rotates. These vibrations are a natural result of the power pulses from the engine’s combustion cycles, which can cause the crankshaft to flex and twist. Over time, this constant flexing can lead to metal fatigue and eventual failure of the crankshaft.
Technician A is correct because the harmonic balancer helps reduce these harmful vibrations, thereby prolonging engine life and improving smoothness. The typical harmonic balancer consists of two parts: an inner hub that is bolted to the crankshaft and an outer ring connected to the hub via a rubber layer. The rubber allows the outer ring to absorb the vibrations, preventing them from damaging the crankshaft.
Technician B, however, is incorrect in stating that “most engines are externally balanced.” While some engines are externally balanced, most modern engines are internally balanced.
- Internal balancing means that the counterweights are placed inside the engine (on the crankshaft itself), providing better balance and smoother operation.
- External balancing uses external components, such as the flywheel or harmonic balancer, to balance the engine. This is typically seen in older engine designs or specific high-performance applications where internal balancing alone is not sufficient.
Therefore, while external balancing does exist, it is not the norm in most modern engines. As such, Technician B’s statement is inaccurate, whereas Technician A correctly identifies the function of the harmonic balancer.
Conclusion: Technician A is correct.
