i6

I6 refers to an inline-six engine, a type of internal combustion engine with six cylinders arranged in a straight line along the crankcase. The pistons in each cylinder connect to a single crankshaft, and the firing order is configured to deliver smooth and balanced power.

The inline-six configuration is known for its smooth operation because it offers inherent primary and secondary balance, reducing vibration more effectively than many V6 layouts. This natural balance can result in refined idle and lower overall vibration without the need for elaborate balancing shafts. The arrangement tends to deliver strong low- to mid-range torque and a broad usable torque band, which suits longitudinal, rear-wheel-drive platforms. However, the engine’s length can complicate packaging in smaller or front-wheel-drive vehicles and can impact under-hood space.

Historically, inline-sixes were widespread in early and mid-20th-century automobiles and remain in use in certain luxury, performance, and truck applications. Modern I6 engines are frequently turbocharged or equipped with direct injection to meet current efficiency and emissions standards while preserving the smoothness associated with the layout. Notable contemporary examples include BMW’s inline-six family (such as the B58) and various designs from Jaguar, Volvo, and other manufacturers that have employed the I6 configuration over the years.

In other contexts, I6 can appear as an abbreviation or model designation outside automotive engineering, but within mechanical engineering it most commonly denotes the inline-six engine arrangement.