What is Inline-four engine?
[[Image:BlocoMotor4CilindrosAluminio.PNG|thumb|4-cylinder engine block made of [[aluminum]]]] [[File:Reihenmotor Vier Zylinder 1-2-4-3.gif|thumb|Animation of an Inline-four engine]] The '''Inline-four engine''' or '''Straight-four''' is an [[internal combustion engine]] with four [[Cylinder (engine)|cylinder]]s. All four cylinders are mounted in a straight line along one [[crankshaft]]. It can be powered by different types of fuels, including [[gasoline]], [[Diesel fuel|diesel]] and [[natural gas]]. The single bank of cylinders may be in a vertical direction (straight up), or at an angle. When the cylinders are mounted at an angle, it is sometimes called a '''slant-four'''. When listed as an abbreviation, an inline-four engine is listed either as '''I4''' or '''L4''' (for ''longitudinal''). L4 is often used to avoid confusion between the digit 1 and the letter I. The inline-four layout is a mechanically simple engine. It has a natural basic engine balance. It is smoother than one, two, and three cylinder engines. This makes it popular for economy [[cars]].<ref>Nunney, ''Light and Heavy Vehicle Technology'', page 12</ref> It does have a problem with secondary engine balance. This causes minor vibrations in smaller engines. These vibrations become worse as engine size and power increase. The more powerful engines used in larger cars use a different engine layout to avoid this problem. == Displacement == This inline-four gasoline configuration is the most common in cars with a displacement (engine size) up to 2.4&nbsp;[[Litre|L]]. [[Porsche]] used a 3.0&nbsp;L four in its 944 S2 and 968 sports cars. Antique vehicles tended to have larger displacements to develop [[horsepower]] and [[torque]]. The Model A Ford was built with a 3.3&nbsp;L inline-four engine. Four-cylinder diesel engines are lower revving than gasoline engines. They often exceed 3.0&nbsp;L. [[Toyota]] made a 4.1&nbsp;L diesel engine that was used in the Toyota Mega Cruiser. Larger four-cylinder engines are used in [[Industry|industrial]] applicati