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A cutaway design of a fuel direct injected engine Fuel injection is the introduction of fuel in an internal combustion engine, many commonly automobile engines, by the ways of an injector. This article concentrates on fuel injection in reciprocating piston and rotary piston engines. All Diesel (compression-ignition) engines usage fuel injection, and many Otto (spark-ignition) engines use fuel injection of one kind or another.


In guest car gas engines, fuel injection was presented in the early 1950s, and gradually gained prevalence till it had largely replaced carburetors by the early 1990s. The primary difference between carburetion and fuel injection is that fuel injection atomizes the fuel through a small nozzle under high pressure, while a carburetor relies on suction produced by consumption air accelerated through a Venturi tube to draw the fuel into the airstream.


Normally, the only thing in common all fuel injection systems have is the lack of carburetion. There are 2 primary functional principles of mixture formation systems for internal combustion engines: internal mixture formation, and external mixture formation. fuel injectors. A fuel injection system that utilizes external mix formation is called a manifold injection system; there exist 2 kinds of manifold injection systems: multi-point injection (port injection), and single-point injection (throttle-body injection).


There exist a number of various varieties of both direct and indirect injection systems, the most common internal mixture development fuel injection system is the common-rail injection system, a direct injection system. The term electronic fuel injection refers to any fuel injection system having an engine control unit. A perfect fuel injection system can precisely supply exactly the correct amount of fuel under a all engine operating conditions.


In practice an ideal fuel injection system does not exist, but there is a substantial range of various fuel injection systems with specific benefits and disdvantages. Many of these systems were rendered obsolete by the common-rail direct injection system that is nowadays (2020) utilized in lots of automobile. Common-rail injection permits petrol direct injection, and is even much better fit for diesel motor fuel direct injection.


When developing a fuel injection system, a range of elements has to be thought about, including: All fuel injection systems make up 3 fundamental elements: they have at least one fuel injector (in some cases called an injection valve), a gadget that produces sufficient injection pressure, and a device that meters the correct quantity of fuel (fuel injectors).

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Early mechanical injection systems (except air-blast injection) generally utilized injection valves (with needle nozzles) in mix with a relatively sophisticated helix-controlled injection pump that both metered the fuel, and created the injection pressure. They were appropriate for intermittently injecting multi-point injection systems in addition to all sorts of traditional direct injection systems, and chamber-injected systems.




In modern-day engines, the fuel metering and injection valve actuation is normally done by the engine control unit. For that reason, the fuel injection pump does not need to meter the fuel or actuate the injection valves; it just needs to supply injection pressure. These modern systems are used in multi-point-injected engines, and common-rail-injected engines.




The summary below shows the most common kinds of mixture development systems in internal combustion engines. There are a number of various methods of characterising, grouping and webpage explaining fuel injection systems, the clade is based upon a differentiation between internal and external mix development systems. Mix development systems Internal mix formation Indirect injection Direct injection Hydraulic injection Walldistributed injection Airdistributed injection Pumpe-Dse system Pump-rail-nozzle system Air-guided injection Wall-guided injection Spray-guided injection Standard helixcontrolled injection pump systems Lanova direct injection Afterchamber injection G-System (sphere combustion chamber) Gardner system (hemisphere combustion chamber) Saurer system (torus combustion chamber) Flat piston (combustion chamber between piston and head) External mix formation Constant vacuum carburettor Multistage carburettor Multi-barrel carburettor Float-chamber-less membrane carburettor BMW M88 engine with multi-point injection In an engine with external mix formation, air and fuel are blended outside the combustion chamber, so that a premixed mix of air and fuel is drawn into the engine.




There exist 2 primary external mix development systems in internal combustion engines: carburettors, and manifold injection. The following description concentrates on the latter. Manifold injection systems can likewise be considered indirect injection, however this post mainly uses the term indirect injection to describe internal mix formation systems that are not direct injection.


They can utilize several different injection plans. Single-point injection uses one injector in a throttle body installed likewise to a carburetor on an consumption manifold. As in a carbureted induction system, the fuel is blended read here with the air before the inlet of the intake manifold. Single-point injection was a reasonably low-cost method for automakers to minimize exhaust emissions to adhere to tightening up policies while supplying better "driveability" (easy beginning, smooth running, freedom from hesitation) than could be gotten with a carburetor.


This delayed the redesign and tooling costs of these parts. Single-point injection was article used thoroughly on American-made passenger automobiles and light trucks throughout 19801995, and in some European cars in the early and mid-1990s. Multi-point injection injects fuel into the intake ports just upstream of each cylinder's intake valve, instead of at a central point within a consumption manifold.

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Manifold injected engines can use a number of injection schemes: constant, and intermittent (synchronised, batched, sequential, and cylinder-individual). In a constant injection system, fuel flows at all times from the fuel injectors, however at a variable circulation rate. The most common vehicle constant injection system is the Bosch K-Jetronic, introduced in 1974, and utilized till the mid-1990s by various cars and truck makers.


In an engine with an internal mixture formation system, air and fuel are mixed only inside the combustion chamber - fuel injectors. Therefore, only air is drawn into the engine during the consumption stroke. The injection scheme is always intermittent (either sequential or cylinder-individual). There are two different kinds of internal mix development systems: indirect injection, and direct injection.