Multi-cylinder engine

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For multiple-cylinder steam engines, see Compound steam engine and Triple-expansion steam engine

A cutaway illustration of a V6, 24-valve, DOHC engine, an example of a Vee-configured six-cylinder engine.
An Fiat AS.6 engine for a Macchi-Castoldi M.C.72 racing seaplane. While it is often considered a "V24 engine", it is actually two V12 engines bolted together in tandem, driving separate crankshafts.

A multi-cylinder engine is a reciprocating internal combustion engine with multiple cylinders. It can be either a 2-stroke or 4-stroke engine, and can be either Diesel or spark-ignition. The cylinders and the crankshaft which is driven by and co-ordinates the motion of the pistons can be configured in a wide variety of ways. Multi-cylinder engines offer a number of advantages over single-cylinder engines, chiefly with their ability to neutralize imbalances by having corresponding mechanisms moving in opposing directions during the operation of the engine.[1] A multiple-cylinder engine is also capable of delivering higher revolutions per minute (RPM) than a single-cylinder engine of equal displacement, because the stroke of the pistons is reduced, decreasing the distance necessary for a piston to travel back and forth per each rotation of the crankshaft, and thus limiting the piston speed for a given RPM. Typically, the more cylinders an engine has, the higher the RPM's it can attain for a given displacement and technology level, at a cost of increased friction losses and complexity. Peak torque is also reduced, but the total horsepower is increased due to the higher RPM's attained.

Although there are 1, 3 and 5-cylinder engines, almost all other inline engines are built with even numbers of cylinders, as it's easier to balance out the mechanical vibrations. Another form of multiple-cylinder internal combustion engine is the radial engine, with cylinders arranged in a star pattern around a central crankshaft. Radial engines are most commonly used as aircraft engines, and in basic single-row configuration are typically built with odd numbers of cylinders (from 3 to 9), as odd numbers are easier to balance in this configuration. "Twin-row" or "multi-row" radials are also built, which is basically two or more single-row radials connected front-to-back and driving a common crankshaft. In this "twin row", or "multi-row" configuration, the total number of cylinders will be an even number, although each row still has an odd number. For example, a typical single row radial such as the Wright Cyclone has 9 cylinders. The twin row Wright Twin Cyclone is based on this engine and thus has two banks of 9 cylinders, for a total of 18, an even number.

Common configurations[edit]

Two-cylinder engines[edit]

Configurations of two-cylinder engines include:

Three-cylinder engines[edit]

Configurations of three-cylinder engines include:

Four-cylinder engines[edit]

Configurations of four-cylinder engines include: the most common 4-cylinder engine

Five-cylinder engines[edit]

Configurations of five-cylinder engines include:

  • Straight-five engine, an engine with 5 cylinders in a straight line.
  • VR5 engine, an engine with 5 cylinders staggered slightly, allowing cylinder bore centerlines to be closer together, reducing overall engine length.

Six-cylinder engines[edit]

Configurations of six-cylinder engines include:

Eight-cylinder engines[edit]

Configurations of eight-cylinder engines include:

Ten-cylinder engines[edit]

Configurations of ten-cylinder engines include:

Twelve-cylinder engines[edit]

Configurations of twelve-cylinder engines include:

Larger configurations[edit]

References[edit]

  1. ^ Victor Albert Walter Hillier, Peter Coombes, Hillier's Fundamentals of Motor Vehicle Technology, Book 1 (2004), p. 47.