Editing Straight-five engine (section)

== Characteristics ==
[[File:Reihenmotor Fünf Zylinder.gif|thumb|right|Animation of the 1-2-4-5-3 firing order]]
[[Image:5S50MC.jpg|thumb|right|''MAN B&W 5S50MC'' 1,865 litre marine diesel engine]]

Straight-five engines are typically shorter than [[straight-six engine]]s, making them easier to fit [[transverse engine|transversely]] in an engine bay.<ref name="car throttle">{{cite web |title=The Advantages And Disadvantages Of The Inline Five-Cylinder Engine |url=https://www.carthrottle.com/post/the-advantages-and-disadvantages-of-the-inline-five-cylinder-engine/ |website=Car Throttle |date=9 February 2017 |access-date=20 August 2022 |language=en}}</ref> They are also smoother than [[straight-four]] engines,<ref name="car throttle" /> and are narrower than [[V engine]]s<ref>{{cite web |title=Inline vs V Engine - Why High End |url=http://www.whyhighend.com/inline-vs-v-engine.html |website=www.whyhighend.com |access-date=20 August 2022}}</ref> and [[flat engine]]s.

=== Engine balance and vibration ===
Five-cylinder engines have a [[Crankshaft#Internal combustion engines|crankshaft]] with 72 degree angles.<ref name="gimme">{{cite web |title=Gimme Five |url=https://www.hemmings.com/blog/article/gimme-five/ |website=www.hemmings.com |access-date=21 August 2022}}</ref> Amongst [[four-stroke engine]]s, an advantage of engines with five or more cylinders is that the power strokes are overlapping if the engine has an even [[firing order]].<ref name="car throttle" />

A disadvantage of the odd number of cylinders in a straight-five engine is it results in imperfect primary and secondary [[engine balance]], unlike a [[straight-six engine]] which has perfect primary and secondary balance. Counterweights on the crankshaft can be used to counteract some amount of these vibrations.  This method is also used in [[straight-four engine]]s.<ref name="BoschHandbook459_463">Robert Bosch GmbH, ''Bosch Automotive Handbook, 6th edition'' p. 459–463, Professional Engineering Publishing 2004, {{ISBN|1-86058-474-8}}.</ref><ref>Bednar, Fundamentals of Combustion, 1989</ref>

=== Firing order ===
Most [[four-stroke engine|four-stroke]] straight-five engines use a firing order of 1-2-4-5-3.{{Citation needed|date=May 2023}} This firing order results in the minimal primary (crank speed) [[rocking couple]], and is used by the [[Volvo Modular engine]], [[List of Volkswagen Group petrol engines#Five-cylinder petrols|VW/Audi straight-five engine]], [[General Motors Atlas engine]] and [[Honda G engine]]. Straight-five  engines typically have a 72 degree crankshaft design.<ref name="gimme"/>

All [[two-stroke engine|two stroke]] straight-five engines are limited in having a single firing order for a given crank configuration; because a complete cycle occurs every 360 degrees, there is no chance to share piston phases without having simultaneous ignitions, so the straight-five is at no disadvantage in this case. Some two-stroke [[outboard engine]]s, e.g. the ''Mercury Marine Force 150'' engine use a firing order of 1-5-2-3-4.<ref>{{cite web |url=http://www.boats.net/parts/search/Merc2/Force/150%20H.P.%20%281989-1992%29/1989-A%20THRU%201992-C/CRANKSHAFT%20-%20PISTON/parts.html |title=150 H.P. (1989-1992) Force Outboard 1989-A THRU 1992-C CRANKSHAFT - PISTON Diagram and Parts |access-date=2015-12-02 |url-status=dead |archive-url=https://web.archive.org/web/20151208050058/http://www.boats.net/parts/search/Merc2/Force/150%20H.P.%20%281989-1992%29/1989-A%20THRU%201992-C/CRANKSHAFT%20-%20PISTON/parts.html |archive-date=2015-12-08 }}</ref>

=== Carburettors and fuel injection ===
The use of straight-five [[petrol]] engines in mass production cars only became truly viable with the advent of reliable [[fuel injection]]. This is because of the unavoidable problems of a [[carburettor]] supplying an odd number of cylinders and the length of the inlet [[manifold]] between the carburetor varying greatly between cylinders at the ends of the engine and those nearer the carburetor. Unlike other engine layouts, these problems are not easily solved by using multiple carburettors.

[[Diesel engine]]s have always used fuel injection, therefore large displacement straight-five diesel engines were commonly seen decades before straight-five petrol engines.