Question from the forum “Behind the wheel” – we answer them from time to time.
What is alusil and why is it used in the automotive industry
Alusil is an aluminum alloy with a significant silicon content around 12 percent. The main appeal lies in the ease and cost savings of manufacturing cylinder blocks from this material compared with traditional cast iron liners. Aluminum blocks without liners contribute to a lighter engine, which improves overall efficiency and performance. In addition, aluminum offers superior thermal conductivity, meaning heat moves away from the combustion chamber more effectively, while the materials involved expand at similar rates, reducing the risk of fitment issues as temperatures change. The engine can deliver strong performance with this setup, though when a major overhaul is necessary, lining the cylinder block becomes a practical necessity.
The Alusil cylinder tread creates a smoother interaction with the piston and rings, which translates into lower friction and reduced fuel consumption overall. This resting layer is, however, extremely thin and vulnerable to damage from shocks and high temperatures, which makes engines using this technology particularly sensitive to detonation and overheating events.
Coated cylinders enable a closed block circuit with greater rigidity and durability in some designs. Yet the general geometry of aluminum blocks can be described as capable of a long life but prone to small deformations over time, especially as mileage climbs into the tens of thousands of kilometers.
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