The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engines are often categorized by the number of rotors present. Gas turbine engines are often categorized into turbojets, turbofans, turboprops and turboshafts.

Piston engines

Piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

s are usually designed with the

cylinders A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infini ...

in lines parallel to the

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

. It is called a

straight engine The straight or inline engine is an internal combustion engine with all cylinders aligned in one row and having no offset. Usually found in four, six and eight cylinder configurations, they have been used in automobiles, locomotives and aircraft ...

(or 'inline engine') when the cylinders arranged in a single line. Where the cylinders are arranged in two or more lines (such as in

V engines A V engine, sometimes called a Vee engine, is a common engine configuration, configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common cranksh ...

or flat engines), each line of cylinders is referred to as a 'cylinder bank'. The angle between cylinder banks is called the 'bank angle'. Engines with multiple banks are shorter than straight engines and can be designed to cancel out the unbalanced forces from each bank, in order to reduce the vibration. Most engines with four or less cylinders use a

layout, and most engines with eight cylinders or more use a V engine layout. However, there are various exceptions to this, such as the

straight-eight engine The straight-eight engine (also referred to as an inline-eight engine; abbreviated I8 or L8) is a piston engine with eight cylinders arranged in a straight line along the crankshaft. The number of cylinders and perfect primary and secondary engi ...

s used by various luxury cars from 1919-1954, V4 engines used by some marine outboard motors, V-twin and flat-twin engines used by motorcycles and

flat-four engine A flat-four engine, also known as a horizontally opposed-four engine, is a four-cylinder piston engine with two banks of cylinders lying on opposite sides of a common crankshaft. The most common type of flat-four engine is the boxer-four engine, ...

s used by various cars.

Single cylinder bank

Straight engine The straight or inline engine is an internal combustion engine with all cylinders aligned in one row and having no offset. Usually found in four, six and eight cylinder configurations, they have been used in automobiles, locomotives and aircraft ...

s (also known as "inline engines") have all cylinders aligned in one row along the crankshaft with no offset. When a straight engine is mounted at an angle, it is sometimes called a "slant engine". Types of straight engines include: * Single cylinder * Straight-2, also known as "parallel twin" * Straight-3, also known as "inline-triple" *

Straight-4 A straight-four engine (also called an inline-four) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The vast majority of automotive four-cylinder engines use a straight-four layout (with the ...

, the most common engine for cars * Straight-5 *

Straight-6 The straight-six engine (also referred to as an inline-six engine; abbreviated I6 or L6) is a piston engine with six cylinders arranged in a straight line along the crankshaft. A straight-six engine has perfect primary and secondary engine bal ...

* Straight-8

Multiple cylinder banks

V engines

V engines (also known as "Vee engines") have the cylinders aligned in two separate planes or 'banks', so that they appear to be in a "V" when viewed along the axis of the crankshaft. Types of V engines include: * V2, commonly called "V-twin" * V3 * V4 * V6 * V8 *

V10 A V10 engine is a ten-cylinder piston engine where two banks of five cylinders are arranged in a V configuration around a common crankshaft. V10 engines are much less common than V8 and V12 engines. Several V10 diesel engines have been pr ...

* V12 * V14 * V16 * V18 VR5 and VR6 engines use a narrow V angle and a single cylinder head.

Flat engines

Douglas motorcycle engine, Abergavenny steam rally 2012

Flat engine A flat engine is a piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common opposed-piston engine design, ...

s (also known as "horizontally-opposed" or "boxer" engines) have the cylinders arranged in two banks on either side of a single crankshaft. Types of flat engines include: * Flat-two, commonly called "flat-twin" * Flat-four * Flat-six * Flat-eight * Flat-twelve

W engines

W engines have the cylinders in a configuration in which the cylinder banks resemble the letter W, in the same way those of a V engine resemble the letter V. Types of W engines include: * W8 * W12 * W16

Other layouts

Radial engines have cylinders mounted radially around a central crankcase. Rotary engines have a similar configuration, except that the crankshaft is fixed and the cylinders rotate around it. (This is different from the Wankel engine configuration described below.) Radial and rotary engine designs were widely used in early

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...

s. U engines consist of two separate straight engines (complete with separate crankshafts) joined by gears or chains. Most U engines have four cylinders (i.e. two straight-two engines combined), such as square four engines and tandem twin engines. Similar to U engines, H engines consist of two separate flat engines joined by gears or chains. H engines have been produced with between 4 and 24 cylinders. An

opposed-piston engine An opposed-piston engine is a piston engine in which each cylinder has a piston at both ends, and no cylinder head. Petrol and diesel opposed-piston engines have been used mostly in large-scale applications such as ships, military tanks, and ...

is similar to a flat engine in that pairs of pistons are co-axial but rather than sharing a crankshaft, instead share a single combustion chamber per pair of pistons. The crankshaft configuration varies amongst opposed-engine designs. One layout has a flat/boxer engine at its center and adds an additional opposed-piston to each end so there are two pistons per cylinder on each side. An X engine is essentially two V engines joined by a common crankshaft. A majority of these were existing V-12 engines converted into an X-24 configuration. The

Swashplate engine A cam engine is a reciprocating engine where, instead of the conventional crankshaft, the pistons deliver their force to a cam that is then caused to rotate. The output work of the engine is driven by this cam. Cam engines are deeply rooted in his ...

with the K-Cycle engine is where pairs of pistons are in an opposed configuration sharing a cylinder and combustion chamber. A Delta engine has three (or its multiple) cylinders having opposing pistons, aligned in three separate planes or 'banks', so that they appear to be in a Δ when viewed along the axis of the main-shaft. An example of this type of layout is the Napier Deltic.

Wankel (rotary) engines

Wankel engines (sometimes called 'rotary engines') can be classified based on the number of rotors present. Most production Wankel engines have two rotors, however engines with one, three and four rotors have also been produced. Wankel engines can also be classified based on whether they are

naturally aspirated Naturally may refer to: ;Albums * ''Naturally!'', an album by Nat Adderley * ''Naturally'' (Houston Person album) * ''Naturally'' (J. J. Cale album) * ''Naturally'' (John Pizzarelli album) * ''Naturally'' (Sharon Jones album) * ''Naturally'' ...

turbocharged In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...

. Most Wankel engines are fueled by petrol, however prototype engines running on diesel and hydrogen have been trialed.

Gas turbine engines

Gas turbine engines— mostly used for aircraft— are usually separated into the following categories: * Turbojet, gasses travel through a propelling nozzle * Turbofan, gasses travel through a ducted fan * Turboprop, gasses travel through an unducted propeller, usually with variable pitch * Turboshaft, a gas turbine optimised for producing mechanical torque instead of thrust

References

{{DEFAULTSORT:Configuration, Engine Internal combustion engine