Designed to achieve greater efficiency and less contamination, they have evolved to direct injection per cylinder, improving power and immediate response when accelerating.
In gasoline engines, it has always been sought to achieve the perfect stocheometric mixture between air and fuel, with 14 parts of air and one part of fuel in order to obtain the maximum possible efficiency , and incidentally reduce the emissions of polluting gases into the atmosphere. , mainly CO 2 . For almost a century, the carburetor was responsible for making this mixture , which consisted of a totally mechanical fuel injection system manipulated by levers, throats and "kites" and by physical principles of air flow .
However, being a low pressure system, every so often it required to be synchronized and when starting the vehicle it was highly polluting while the engine was warming up.
Thanks to the computer technologies, sensors and actuators that burst onto the market to replace the old carburettor and thus give way to electronic injection , a revolution that allowed an exact dosage of fuel, while varying the injection time of the fuel. It mixes depending on the engine revolutions , the load situation and the gases produced by combustion.
In the case of injectors per cylinder, a better mixture is obtained, while achieving a faster and more efficient regulation . Likewise, the elimination of the carburetor implied the modification of the pipes of the intake system to obtain more adequate air currents that optimize the flow of air towards the propeller. and in this way achieve a better filling of the cylinders.
Here we show you which are the types of Distribution of injection systems:
Indirect injection: fuel injection occurs at the fork of the intake manifold, or just before the intake valve. The valve can be open or closed.
Direct injection: fuel injection takes place directly into the combustion chamber. This system drastically reduces consumption and improves combustion by reducing the emission of polluting gases.
By number of injectors:
Single point (TBI): it is a single gasoline injector for all cylinders. It is usually arranged behind the intake throttle to feed the intake manifold.
Multipoint (MPI): uses one injector for each cylinder. Injection is carried out on the intake manifold or directly in the combustion chamber.
Mechanical control system : as its name implies, it is controlled with fully mechanical injectors. (Derived from aviation in the 1950s)
Electromechanical (Probe Plate): this is an evolution of the previous one, combining electronics with mechanics.
Electronic: the control of the system is done through a computer ECU and the injectors are actuated electronically.
Number of injections
Continuous injection: fuel is continuously injected into the intake manifold with a certain pressure and proportion, which can be constant or variable, depending on the different parameters of the system used.
Intermittent Injection: the electronic control unit (ECU) is responsible for sending pulses to the injectors in order to open them for a certain period of time. This system has three execution modes:
Sequential: The sequential intermittent injection, injects fuel into each cylinder separately , through exhaustive control by the Control Unit (ECU), thus appealing to pure efficiency
Semi-sequential: Like the sequential injection, the semi-sequential follows the same principle, but in this case it is done in pairs . That is, it is a four-cylinder engine, it supplies fuel first to cylinders one and two, followed by an injection in cylinders three and four (the combinations can be varied and almost infinite).
Simultaneous: This last intermittent system is used in the most powerful engines as a general rule. Using the advantages of the intermittent system, in this case, the injection is carried out on all the cylinders at the same time . They do not separate, but when the Control Unit (ECU) gives the order that the engine needs fuel, they simply spread the flow through all the cylinders.
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