The purpose of the injector (or injector) in the engine is dosing fuel, its atomization, the formation of a mixture of air and gasoline (or diesel fuel). Modern engines are equipped with injectorswith electronic control fuel injection. There are 3 types of injectors, different methods of injection.

Electromagnetic



Injectors with electromagnetic action method is equipped with petrol engines, including engines with direct injection. Nozzle design is simple; that is, a nozzle, an electromagnetic valve connected to the needle. The work of the atomizer is in accordance with the work control block. At a certain time, the voltage on the valve - occurring electromagnetic field, overcoming resistance of a spring, pulls the needle, freeing the nozzle. The result is a gasoline injection. When the electronic control unit stops applying the voltage, the electromagnetic field disappears, the needle returns to the original place, thanks to the elasticity of the spring.


Electro-hydraulic



Works in conjunction with diesel engines. Construction includes draining, the intake throttle chamber control valve (solenoid). The essence of the work lies in the application of pressure. When submitting a block of a corresponding voltage to the valve, immediately open the drain throttle - diesel fuel goes in the trunk.

The task of the intake throttle – preventing equalization of pressure, the control chamber. As a result, the piston pressure is reduced, but the needle on the fuel pressure still, because of what she is lifted and fuel is injected. When the electronic control unit de-energizes the valve needle of the injector is pressed against the seat by the force of pressure of diesel fuel on the piston in the control chamber. Injection does not occur, because the fuel pressure on the needle smaller than the plunger.

Piezoelectric



Is considered most advanced and is installed on diesels. Its main advantage is high response speed (more than solenoid injectors 4 times). The consequence of this is the several opportunities to perform fuel injection for only one cycle, plus the exact dosage. The design of the piezo injector includes a switching valve, a needle, a piezoelectric element, a pusher.

The principle of operation of this injector is also based on hydraulics. Starting position: the needle is located on the saddle because of the higher fuel pressure. When the piezo voltage falls, its length increases, due to which is passed the force on the pushrod. Due to this, the switching valve opens, fuel goes in the trunk. Further rises and the needle is injected.