What is the typical style of most modern crankshaft seals?

Most modern crankshaft seals are typically designed in a circular style. This design is particularly effective because the circular shape allows for a uniform sealing surface around the crankshaft, minimizing the risk of leaks. Circular seals can properly conform to the circular motion of the crankshaft, providing a tight fit that effectively contains oil and prevents contamination from entering the engine.

The circular design also allows the seal to maintain a consistent pressure against the crankshaft, accommodating variations that may arise during operation such as thermal expansion. This ensures durability and reliability in sealing performance over time. Additionally, circular seals can be manufactured with different materials and lip configurations to enhance their sealing capabilities and longevity, which is essential in high-performance diesel engines.

Other shapes like square, rectangular, and oval do not provide the same level of effectiveness for sealing in applications related to crankshafts due to their inability to properly conform to the rotating part's geometry, potentially leading to failures or leaks in the engine.