Principle of the injector. Mechanical injector: the principle of operation

This article will consider the principle of workinjector and all its main components. This is a fairly promising system, which is currently used on all cars, regardless of their price group. But do not forget that for the first time such designs began to be used massively in the 70's and 80's. And at first the injectors were without the use of electronic components. Of course, they could be present, but in the minimum amount. It is also worthwhile to compare the injector and carburetor fuel injection systems.

Carburetor against injector

principle of operation of the injector

Perhaps among fans of the carburetor remainOnly those who like to start with a traffic light. The reason is that the carburetor allows a large torque and power to be developed at the bottom. The injection system of injection, even ideally tuned, is not close by. The simplicity of the carburetor and the cost of maintenance also give a small advantage. But that's what concerns the power and torque at high speeds, then the injector wins here, and with a large margin. In other words, if you overtake, your car will be more responsive if injection injection is installed. It is also possible to increase power by installing a turbine - a device capable of injecting excess air pressure into the injection system. Due to this, the engine power is increased many times. Of course, the resource suffers, but what you will not sacrifice for the sake of a spectacular ride?

Stages of development of injection injection

operating principle of the VAZ injector

On the famous "cigars" "Audi 100" was usedmechanical injector. The principle of its operation can be compared with the fuel supply system in diesel engines. With the help of a mechanical pump and the same drive of the injectors, the fuel-air mixture was fed into the combustion chambers. Of course, we can not fail to mention the transitional link - carburetors with electronic control. They were used on a small number of cars, and exclusively of Japanese production. Residents of the Land of the Rising Sun very much like a variety of electronic gadgets to this day. But electronic carburetors were not very popular, in the late 80's began their era and immediately ended. By the way, on cars VAZ-2110, for example, carburettors without a rope "suction" were established. Adjustment of air supply was carried out automatically, by means of a special damper, which changed its position as the engine warmed up. But today the injectors became very popular, the designs of which have already become classic. Here they are and should be considered in more detail, to disassemble by parts.

Fuel pump

mechanical injector principle of operation

This is the heart of the entire fuel system, as it helps to circulate gasoline. It consists of the following elements:

  1. The filter (in the people it is called "pampers", since it has an enviable similarity).
  2. The electric motor of a direct current.
  3. Pump driven by the engine.
  4. Level sensor (structurally it is integrated with the fuel pump).

The pump is located directly in the tank,fastened with nuts. Access to it can be obtained by raising the rear seat. In all cars, whether it's an old "ten" or a new "Japanese", there is a gasoline pump just under the seat. Of course, the removal and installation will be done on all machines in different ways. A fuel line is laid from the pump to the ramp. It must withstand a lot of pressure, so always keep an eye on her condition. In parallel to this highway a pipe is laid, which returns excess gasoline back to the tank. Quite simply the principle of the gasoline pump. The injector functions due to the excessive pressure created by the pump.

Fuel rail

injector engine operation principle

It is mounted directly on the engine. Its mission is to keep a mixture of gasoline and air under a certain pressure. It is in it that the process of combining the two components of a combustible mixture - gasoline and air - takes place. And the proportion should always be the same - 14 parts of air per gasoline. Only in this case the engine will work as stably as possible, stably, economically. To the ramp, connections have been made to mechanisms such as a throttle, electromagnetic injectors, a relief valve. By the way, it is in the fuel rail that the fuel pressure sensor is installed. But about him and all other electronic components will be told further. It should be noted that the Venturi injector, the principle of operation of which is similar to the system considered in the article, has a very wide application, and not only in automobiles.


operating principle of the VAZ 2110 injector

With the help of these devices, the feedair-fuel mixture into the combustion chambers of all cylinders. What are these mechanisms? If you know the carburetor design tolerably well, then remember the solenoid valve. That's it, the design is very similar to the one you can see at the nozzles. They have a winding, which is supplied with a constant voltage. The needle valve, when energized, opens the way for the passage of fuel. All this mixture under pressure is sprayed into the combustion chambers. Note that the injectors must spray the fuel in such a way that it fills as much as possible the combustion chamber. Easy to understand the principle of the injector injector, with its help is spraying. Fuel-air mixture at this point is similar to fog, in a certain volume of air, gasoline is in suspension. Consequently, the ignition occurs much faster and better than in the case of the carburetor system.

Throttle Body

principle of injector injector

Open the hood of the car and carefullyLook what's under it. You will see an air filter, which is usually screwed to the "TV" - the front of the car. From it there is a small branch pipe connected to a piece of plastic pipe, to which wires are connected. This is a sensor that measures the flow of an air motor. But after it is a damper. With its help, the air supply to the fuel rail is regulated. But here you need to look at the principle of the injector. After all, it should be noted that with a completely closed flap, a small part of the air still flows into the fuel system to ensure the optimum value of the engine speed. And this happens with the help of one specific actuator - the idle speed regulator (it is wrong to call it a sensor, since it is a stepper motor, it does not produce any measurements). This mechanism opens and closes, if necessary, a channel through which air enters the fuel rail.

Electronic control unit

Venturi injector principle of operation

Without this element of the injection system of injectionthe engine can not work. However, sometimes, even if it's worth it, it does not mean that the engine will start and work fine. And the whole point is that the electronic control unit is built on a microprocessor. And it is specially programmed to work as a control module for all actuators based on data received from sensors. Consequently, the electronic control unit must have a program written according to a certain algorithm. Moreover, this algorithm should be clear, so that the microcontroller knows exactly what it needs to do if, for example, there is a signal from the knock sensor, without which no modern injector can exist. The principle of the engine as with the injector, and with the carburetor remains unchanged.

Sensors in the car

operating principle of petrol injector injector

To properly and timely provide fuel inall cylinders, as well as pulses to the electrodes of spark plugs, it is necessary to accurately read all the parameters of the engine. In particular, it is important to know which speed is at the crankshaft. Also do not interfere with the data on what pressure is in the fuel rail. If it is necessary to stop the engine in automatic mode with insufficient lubrication, the oil pressure sensor is connected. In this case, it is necessary to prescribe its functions in the algorithm of the control unit, of course, the principle of the injector in this case will change slightly. You should also know about detonation, because it can tell a lot about how correctly the internal combustion engine functions. In modern cars, even the composition of gas in the exhaust system is controlled. This is done using two oxygen sensors. And the most important thing is, of course, the air flow. Without knowledge of this parameter, it is simply impossible to carry out the correct mixture formation.


Despite the apparent complexity of the design,the principle of the VAZ-2110 injector, like any other car, is very simple. You can even draw an analogy with a conventional compressor equipped with a spray gun. Of course, this will be a simplified version of the system, the injector is only one, the control unit is not complicated. But the essence is about the same. It is easier to understand the processes taking place in the engine with the injector injection system, rather than investigating the various turbulence and pressure differences in the carburettor. And if you thoroughly study the design, then you will not be afraid of any failure of the sensors of the entire control system.