The inline engine, also known as a straight engine, features all cylinders arranged in a single row along a common crankshaft. This design has been widely used in automobiles, motorcycles, and commercial vehicles for decades, thanks to its simplicity, efficiency, and balanced performance. Whether in small compact cars or large heavy-duty trucks, the inline engine remains a key player in automotive engineering.
One of the major advantages of an inline engine is its smooth operation and mechanical balance. The inline-four (I4) is the most common configuration, offering an excellent mix of fuel efficiency, power, and cost-effectiveness, making it the preferred choice for modern passenger cars. The inline-six (I6), on the other hand, is known for its perfect balance and smooth power delivery, making it a favorite in luxury and performance vehicles. Unlike V-shaped engines, inline engines often require fewer moving parts, resulting in lower manufacturing costs and easier maintenance.
Despite its benefits, the inline engine does have limitations. Larger straight engine, such as the I6 and I8, require more space, making them less practical for front-wheel-drive vehicles and compact engine bays. As a result, V-shaped engines have become more popular in many modern vehicles due to their shorter, more compact design. However, inline engines continue to be widely used in trucks, motorcycles, and industrial applications, where their durability, reliability, and smooth torque output are essential.
As the automotive industry shifts towards hybrid and electric technologies, the inline engine is evolving with turbocharging, direct fuel injection, and hybrid-electric integration to improve performance and efficiency. While alternative powertrains gain popularity, the inline engine’s legacy of reliability and balanced performance ensures that it will remain an integral part of the automotive world for years to come.