What is another name for an in-line engine?

An in-line engine is commonly referred to as a straight line engine due to its configuration. In this type of engine, all the cylinders are arranged in a single row or straight line, which allows for a straightforward design and simplicity in construction. The term "straight line" emphasizes the linear alignment of the cylinders, which is a key characteristic of this engine type. This arrangement contributes to easier manufacturing and can also lead to smoother operation compared to more complex engine configurations.

V-type engines have cylinders arranged in a V-shaped formation, creating a different balance and compactness. Boxer engines, also known as flat engines, feature horizontally opposed cylinders that lie flat, which differs from the straight alignment of in-line engines. Rotary engines utilize a completely different mechanism involving a rotary motion rather than linear cylinder arrangement, making them distinct from in-line engines.

Therefore, the term "straight line engine" accurately captures the essence of how an in-line engine is designed and functions, confirming why it's the correct answer in this context.