Editing Fuel injection (section)

=== Manifold injection ===
{{main|Manifold injection}}

Manifold injection systems are common in petrol-fuelled engines such as the [[Otto engine]] and the [[Wankel engine]]. In a manifold injection system, air and fuel are mixed outside the combustion chamber so that a mixture of air and fuel is sucked into the engine. The main types of manifold injections systems are ''multi-point injection'' and ''single-point injection''. 

These systems use either a ''continuous injection'' or an ''intermittent injection'' design.<ref name="Reif_107" /> In a continuous injection system, fuel flows at all times from the fuel injectors, but at a variable flow rate. The most common automotive continuous injection system is the [[Jetronic#K|Bosch K-Jetronic]] system, introduced in 1974 and used until the mid-1990s by various car manufacturers. Intermittent injection systems can be ''sequential'', in which injection is timed to coincide with each cylinder's intake stroke; ''batched'', in which fuel is injected to the cylinders in groups, without precise synchronization to any particular cylinder's intake stroke; ''simultaneous'', in which fuel is injected at the same time to all the cylinders; or ''cylinder-individual'', in which the engine control unit can adjust the injection for each cylinder individually.<ref name="Reif_107">Konrad Reif (ed.): Ottomotor-Management, 4th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-8348-1416-6}}, p. 107</ref>

==== Multi-point injection ====
[[File:Marvel Fuel Injection System Cross Section.png|thumb|Schematic of a mechanical port injection system]]

Multi-point injection (also called 'port injection') injects fuel into the intake ports just upstream of each cylinder's [[intake valve]], rather than at a central point within an intake manifold.<ref>{{cite web |title=Multi Point Fuel Injection or MPFI System- Working, advantages |url=https://www.enggstudy.com/multi-point-fuel-injection-system-mpfi/#Disadvantages_of_MPFI_system |access-date=26 December 2022 |date=25 November 2019}}</ref> Typically, multi-point injected systems use multiple fuel injectors,<ref name="Lohner_64" /> but some systems, such as GM's central port injection system, use tubes with poppet valves fed by a central injector instead of multiple injectors.<ref>1997 Chevrolet Truck Service Manual, page 6A-24, drawing, item (3) Central Sequential Muliport injector.</ref>

==== Single-point injection ====
{{Anchor|TBI|EGI|CFI|SPI|Throttle body injection}}
Single-point injection (also called 'throttle-body injection')<ref>{{cite web |title=How Fuel Injection Systems Work |url=https://auto.howstuffworks.com/fuel-injection.htm |website=HowStuffWorks |access-date=26 December 2022 |language=en-us |date=4 January 2001}}</ref> uses one injector in a [[throttle body]] mounted similarly to a [[carburettor]] on an [[intake manifold]]. As in a carburetted induction system, the fuel is mixed with the air before entering the intake manifold.<ref name="Lohner_64">Kurt Lohner, Herbert Müller (auth): Gemischbildung und Verbrennung im Ottomotor, in Hans List (ed.): Die Verbrennungskraftmaschine, Band 6, Springer, Wien 1967, {{ISBN|978-3-7091-8180-5}}, p. 64</ref> Single-point injection was a relatively low-cost way for automakers to reduce [[Vehicle emissions control|exhaust emissions]] to comply with tightening regulations while providing better "driveability" (easy starting, smooth running, no engine stuttering) than could be obtained with a carburettor. Many of the carburettor's supporting components—such as the air filter, intake manifold, and fuel line routing—could be used with few or no changes. This postponed the redesign and tooling costs of these components. Single-point injection was used extensively on American-made passenger cars and light trucks during 1980–1995, and in some European cars in the early and mid-1990s.
In the US, the G10 engine in the 2000 Chevrolet Metro became the last engine available on an American-sold vehicle to use throttle body injection.