What arrangement is referred to when cylinders are aligned in a single row?

The arrangement of cylinders in a single row is known as an inline engine. This design features all the cylinders arranged in a straight line along the crankshaft, which helps keep the engine compact and aligns the weight centrally within the vehicle. This configuration is common in many four-cylinder engines and is appreciated for its simplicity, ease of maintenance, and efficiency in manufacturing.

In contrast, a V engine features cylinders arranged in two banks set at an angle to each other, resembling a "V" shape. A boxer engine has horizontally opposed cylinders, which are also laid out, but they lie flat to the ground rather than in a straight line. A radial engine has cylinders arranged in a circle around a central crankshaft, commonly used in aircraft engines. Each of these designs serves specific performance requirements and operational characteristics, making them distinct from the inline configuration.