IN modern carsmobiles in gasoline power plants the principle of operation of the power system is similar to that used on diesel engines. In these engines, it is divided into two - intake and injection. The first provides air supply, and the second provides fuel. But due to constructive and operational features the functioning of the injection is significantly different from that used on diesel engines.
Note that the difference between the injection systems of diesel and gasoline engines is increasingly erased. To receive best qualities designers borrow design solutions and apply them to different types power supply systems.
The device and principle of operation of the injection injection system
The second name for injection systems for gasoline engines is injection. Its main feature lies in the precise dosage of fuel. This is achieved by using injectors in the design. Device injection injection The engine includes two components - executive and control.
The task of the executive part includes the supply of gasoline and its spraying. It includes not so many building blocks:
- Pump (electric).
- Filter element (fine cleaning).
- Fuel lines.
- Ramp.
- Injectors.
But these are only the main components. The executive component may include a number of additional units and parts - a pressure regulator, a system for draining excess gasoline, an adsorber.
The task of these elements is to prepare fuel and ensure its supply to the nozzles, which are used to inject them.
The principle of operation of the executive component is simple. When turning the ignition key (on some models - when opening driver's door) an electric pump turns on, which pumps gasoline and fills the rest of the elements with it. The fuel is cleaned and enters the rail through the fuel lines, which connects the injectors. Due to the pump, the fuel in the entire system is under pressure. But its value is lower than on diesel engines.
The injectors are opened by electrical impulses supplied from the control part. This component of the fuel injection system consists of a control unit and a whole set of tracking devices - sensors.
These sensors track indicators and parameters of work - rotation speed crankshaft, amount of air supplied, coolant temperature, throttle position. The readings are sent to the control unit (ECU). He compares this information with the data stored in the memory, on the basis of which the length of the electrical impulses supplied to the injectors is determined.
The electronics used in the control part of the fuel injection system are needed to calculate the time for which the injector should open in a particular operating mode power unit.
Types of injectors
But note that this is the general design of the gasoline engine supply system. But several injectors have been developed, and each of them has its own design and operational features.
On cars, engine injection systems are used:
- central;
- distributed;
- direct.
The central injection is considered the first injector. Its peculiarity lies in the use of only one injector, which injected gasoline into intake manifold simultaneously for all cylinders. It was originally mechanical and no electronics were used in the design. If we consider the device of a mechanical injector, then it is similar to carburetor system, with the only difference that a mechanically driven injector was used instead of the carburetor. Over time, the central feed was made electronic.
Now this type is not used due to a number of disadvantages, the main of which is the uneven distribution of fuel over the cylinders.
Distributed injection is currently the most common system. The design of this type of injector is described above. Its peculiarity lies in the fact that the fuel for each cylinder is supplied by its own injector.
In this design, the injectors are installed in the intake manifold and are located next to the cylinder head. The distribution of fuel among the cylinders makes it possible to ensure accurate dosage of gasoline.
Direct injection is now the most advanced type of gasoline delivery. In the previous two types, gasoline was fed into the passing air stream, and mixture formation began to take place even in the intake manifold. The design of the same injector copies the diesel injection system.
In a direct injection injector, the injector nozzles are located in the combustion chamber. As a result, the components air-fuel mixture here they are launched into the cylinders separately, and already in the chamber itself they are mixed.
The peculiarity of this injector is that high fuel pressure is required to inject gasoline. And its creation is provided by another node added to the device of the executive part - the pump high pressure.
Diesel engine power systems
And diesel systems are being upgraded. If earlier it was mechanical, now diesel engines are equipped with electronic control... It uses the same sensors and control unit as the gasoline engine.
Three types of diesel injections are currently used on cars:
- With a distribution injection pump.
- Common rail.
- Pump injectors.
As in gasoline engines, the design of diesel injection consists of an executive and a control part.
Many elements of the executive part are the same as for the injectors - the tank, fuel lines, filter elements. But there are also nodes that are not found on gasoline engines - a fuel priming pump, a high-pressure fuel pump, high-pressure fuel lines.
IN mechanical systems diesel engines used in-line injection pumps, in which the fuel pressure for each nozzle created its own separate plunger pair. These pumps were highly reliable but cumbersome. The injection moment and the amount of injected diesel fuel were regulated by a pump.
In engines equipped with a distributor injection pump, only one plunger pair is used in the pump design, which pumps fuel for the injectors. This node is compact in size, but its resource is lower than in-line. Such a system is used only in light vehicles.
Common Rail is considered one of the most efficient diesel systems injection engine. Its general concept is largely borrowed from the split-feed injector.
In such a diesel engine, the moment of the beginning of the supply and the amount of fuel is controlled by the electronic component. The task of the high pressure pump is only to pump diesel fuel and create high pressure. Moreover, diesel fuel is not supplied immediately to the injectors, but to the ramp connecting the injectors.
Unit injectors are another type of diesel injection. In this design, the injection pump is absent, and the plunger pairs that create the pressure of the diesel fuel enter the injector device. This design solution allows you to create the highest fuel pressure values \u200b\u200bamong existing varieties injection on diesel units.
Finally, we note that information on the types of injection of engines is given here in general. To understand the design and features of these types, they are considered separately.
Video: Fuel injection system control
Every modern car has a fuel supply system. Its purpose is to supply fuel from the tank to the engine, filter it, as well as the formation of a combustible mixture with its subsequent flow into the internal combustion engine cylinders. What types of SPT are and what are their differences - we will talk about this below.
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General information
As a rule, most of the injection systems are similar to each other, the fundamental difference may be in the mixture formation.
The main elements of fuel systems, regardless of whether about gasoline or diesel engines goes speech:
- The tank in which the fuel is stored. The tank is a container equipped with a pumping device and a filter element for cleaning fuel from dirt.
- Fuel lines are a set of pipes and hoses designed to supply fuel from the tank to the engine.
- Mixing unit, designed for the formation of a combustible mixture, as well as its further transfer to the cylinders, in accordance with the stroke of the power unit.
- Control module. It is used in injection motors due to the need to control various sensors, valves and injectors.
- The pump itself. As a rule, submersible options are used in modern cars. Such a pump is a small in size and power electric motor connected to liquid pump... The device is lubricated with fuel. If there is less than five liters of fuel in the gas tank, this can lead to engine damage.
SPT on the ZMZ-40911.10 motor Features of fuel equipment
In order for the exhaust gases to pollute the environment less, cars are equipped with catalytic converters. But over time, it became clear that their use is advisable only if a high-quality combustible mixture is formed in the engine. That is, if there are deviations in the formation of the emulsion, then the efficiency of using the catalyst is significantly reduced, which is why, over time, car manufacturers switched from carburetors to injectors. However, their effectiveness was also not very high.
So that the system can automatic mode adjust indicators, subsequently a control module was added to it. If besides catalytic converter, as well as an oxygen sensor, a control unit is used, this gives quite good indicators.
What are the advantages of such systems:
- Possibility to increase performance characteristics power unit. When correct work the engine power can be higher than 5% of the declared by the manufacturer.
- Improving the dynamic characteristics of the car. Injection motors are sensitive enough to changing loads, so they can independently adjust the composition of the combustible mixture.
- Formed in the correct proportions, the combustible mixture can significantly reduce the volume as well as the toxicity of the exhaust gases.
- Injection motors, as practice has shown, run perfectly in all weather conditions, unlike carburetors. Of course, if we are not talking about a temperature of -40 degrees (video by Sergey Morozov).
Fuel injection system device
Now we suggest that you familiarize yourself with the device of the injection SCT. All modern power units are equipped with injectors, their number corresponds to the number of installed cylinders, and these parts are connected to each other using a ramp. The fuel itself is contained in them under low pressure, which is created thanks to the pumping device. The amount of fuel supplied depends on how long the injector is open, and this, in turn, is monitored by the control module.
To correct the unit, it receives readings from various controllers and sensors located in different parts of the car, we suggest that you familiarize yourself with the main devices:
- Flowmeter or DMRV. Its purpose is to determine the fullness of the engine cylinder with air. If there are problems in the system, the control unit ignores its readings, and uses the usual data from the table to form the mixture.
- ДПДЗ - throttle position. Its purpose is to reflect the load on the motor, which is due to the position throttle, engine speed, as well as cyclic filling.
- DTOZH. The antifreeze temperature controller in the system allows you to control the fan, as well as adjust the fuel supply and ignition. Of course, all this is adjusted by the control unit based on the readings of the DTOZH.
- DPKV - crankshaft position. Its purpose is to synchronize the work of the SPT as a whole. The device calculates not only the speed of the power unit, but also the position of the shaft at a certain moment. The device itself belongs to polar controllers, respectively, its breakdown will lead to the impossibility of operating the car.
- Lambda probe or oxygen sensor... It is used to determine the amount of oxygen in the exhaust gas. The data from this device is sent to the control module, which, based on them, makes adjustments to the combustible mixture (video author - Avto-Blogger.ru).
Types of injection systems on gasoline internal combustion engines
What is Jetronic, what are the types of SPT for gasoline engines?
We suggest that you familiarize yourself with the issue of varieties in more detail:
- SPT with central injection. In this case, the gasoline supply of gasoline is realized thanks to the injectors located in the intake manifold. Since only one injector is used, such SPTs are also called mo-injections. At present, such SPTs are not relevant, therefore, they are simply not provided for in more modern cars. The main advantages of such systems are ease of use and high reliability. As for the disadvantages, this is a reduced environmental friendliness of the motor, and also quite high consumption fuel.
- SPT with distributed injection or K-Jetronic.Such units provide for the supply of gasoline separately to each cylinder, which is equipped with a nozzle. The fuel mixture itself is formed in the intake manifold. To date, most of the power units are equipped with just such SPT. Their main advantages include a fairly high environmental friendliness, acceptable consumption of gasoline, as well as moderate requirements in relation to the quality of consumed gasoline.
- Direct injection. This option is considered one of the most progressive, as well as perfect. The principle of operation of this SPT is direct injection gasoline in the cylinder. As the results of numerous studies show, such FSPs make it possible to achieve the most optimal and high-quality composition of the air-fuel mixture. Moreover, at any stage of the operation of the power unit, which can significantly improve the combustion procedure of the mixture and largely increase efficiency iCE operation and its power. And, of course, reduce the amount of exhaust gases. But it should be borne in mind that such SPTs also have their drawbacks, in particular, a more complex design, as well as high requirements for the quality of the gasoline used.
- SPT with combined injection. This option is, in fact, the result of combining DCT with distributed and direct injection. As a rule, it is used in order to reduce the volume of toxic substances released into the atmosphere, as well as exhaust gases. Accordingly, it is used to improve the environmental performance of the engine.
- L-Jetronic system still used in gasoline engines... This is a twin fuel injection system.
Photo gallery "Varieties of gasoline systems"
Types of injection systems for diesel internal combustion engines
The main types of FPS in diesel engines:
- Pump injectors. Such FSCs are used for feeding and further injection of the formed emulsion under high pressure using pump nozzles. The main feature of such FPS is that the unit injectors perform the pressure generation options, as well as direct injection. Such FPS also have their disadvantages, in particular, we are talking about a pump equipped with a special drive permanent type from camshaft power unit. This unit is not disconnected, therefore, it contributes to increased wear of the structure as a whole.
- It is because of the latter drawback that most manufacturers prefer common rail or battery injection. This option is considered more perfect for many diesel units. SPT has this name as a result of the use of a fuel frame - the main structural element. One ramp is used for all injectors. In this case, the fuel is supplied to the injectors from the ramp itself, it can be called a battery high blood pressure.
Fuel supply is carried out in three stages - preliminary, main, and also additional. Such a distribution makes it possible to reduce noise and vibration during the operation of the power unit, to make its operation more efficient, in particular, we are talking about the process of ignition of the mixture. In addition, it also allows and reduces the amount of harmful emissions into the environment.
Regardless of the type of SPT, diesel units are also controlled by electronic or mechanical devices. In mechanical versions, the devices control the level of pressure and volume of the components of the mixture and the moment of injection. Concerning electronic options, then they allow for more efficient control of the power unit.
Direct injection (also used the term "direct injection", or GDI) began to appear on cars not so long ago. However, the technology is gaining popularity and is increasingly found on the engines of new cars. Today we are in in general terms we will try to answer what technology is direct injection and is it worth fearing?
To begin with, it should be noted that the main distinctive feature technology is the arrangement of injectors, which are located directly in the cylinder head, respectively, and the injection under huge pressure occurs directly into the cylinders, in contrast to the long-established better side fuel into the intake manifold.
Direct injection was first tested in series production by the Japanese automaker Mitsubishi. Operation has shown that among the advantages, the main advantages are efficiency - from 10% to 20%, power - plus 5% and environmental friendliness. The main disadvantage is that the injectors are extremely demanding on the quality of the fuel.
It is also worth noting that a similar system has been successfully installed on. However, it was on gasoline engines that the application of the technology was fraught with a number of difficulties that have not yet been finally resolved.
A video from the YouTube channel "Savagegeese" explains what direct injection is and what can go wrong when using a vehicle with this system. In addition to the main pros and cons, the video also explains the intricacies of preventive system maintenance. In addition, the video touches on the topic of intake injection systems, which can be observed in abundance on older engines, as well as those that use both methods of fuel injection. Using Bosch diagrams, the presenter explains how it all works.
To find out all the nuances, we suggest watching the video below (turning on the translation of subtitles will help you figure it out if you don't know English very well). For those who are not too interested in watching, you can read about the main pros and cons of direct petrol injection below, after the video:
So, environmental friendliness and economy are good goals, but this is what the use of modern technology in your car:
Minuses
1. A very complex design.
2. Hence the second important problem. Since the young gasoline technology implies the introduction of serious changes in the design of the engine cylinder heads, the design of the injectors themselves and the associated change in other engine parts, for example, the injection pump ( fuel pump high pressure), the cost of cars with direct fuel injection is higher.
3. The production of the parts of the power system themselves must also be extremely precise. The nozzles develop pressure from 50 to 200 atmospheres.
Add to this the work of the injector in close proximity to the combustible fuel and the pressure inside the cylinder and you have the need to produce very high strength components.
4. Since the nozzles of the injectors look into the combustion chamber, all the products of gasoline combustion also settle on them, gradually clogging or disabling the injector. This is perhaps the most serious disadvantage of using the GDI construction in Russian realities.
5. In addition, you must very carefully monitor the condition of the engine. If oil burns out in the cylinders, the products of its thermal decomposition will quickly disable the nozzle and clog intake valves, forming an indelible deposit on them. Do not forget that classic injection with nozzles located in the intake manifold cleans the intake valves well, washing them under pressure with fuel.
6. Expensive repairs and the need for preventive maintenance, which is also expensive.
In addition, it also explains that improper use on direct injection vehicles can cause valve clogging and performance degradation, especially on turbocharged engines.
Modern cars are equipped with different fuel injection systems. In gasoline engines, the mixture of fuel and air is forcibly ignited by a spark.
The fuel injection system is an integral part. The injector is the main working element of any injection system.
Gasoline engines are equipped with injection systems that differ from each other in the method of forming a mixture of fuel with air:
- central injection systems;
- multipoint injection systems;
- systems with direct injection.
Central injection, or otherwise it is called monojetronic injection, is carried out by a single central electromagnetic injector that injects fuel into the intake manifold. It is a bit like a carburetor. Now cars with such an injection system are not produced, since a car with such a system also has low environmental properties of the car.
The distributed injection system has been continuously improved over the years. The system started K-jetronic... The injection was mechanical, which gave him good reliabilitybut the fuel consumption was quite high. Fuel was supplied not impulsively, but constantly. This system was replaced by the system KE-jetronic.
She was not fundamentally different from K-jetronicbut appeared the electronic unit control unit (ECU), which made it possible to slightly reduce fuel consumption. But this system did not bring the expected results either. The system appeared L-jetronic.
In which the ECU received signals from sensors and sent an electromagnetic pulse to each injector. The system had good economic and environmental performance, but the designer did not stop there, and developed a completely new system Motronic.
The control unit began to control both fuel injection and the ignition system. Fuel burns better in the cylinder, engine power has increased, consumption has decreased and harmful emissions car. In all these systems presented above, the injection is carried out by a separate nozzle for each cylinder into the intake manifold, where a mixture of fuel and air is formed, which enters the cylinder.
The most promising system today is the direct injection system.
The essence of this system is that fuel is injected directly into the combustion chamber of each cylinder, and already there it mixes with air. The system determines and delivers the optimal mixture composition to the cylinder, which provides good power at various engine operating modes, good economy and high environmental properties of the engine.
But on the other hand, engines with this injection system have a higher price compared to their predecessors, due to the complexity of their design. Also, this system is very demanding on the quality of fuel.
Modern vehicles use various systems fuel injection. The injection system (another name - injection system, from injection - injection), as the name suggests, provides fuel injection.
The injection system is used on both gasoline and diesel engines. However, the design and operation of the injection systems of gasoline and diesel engines differ significantly.
In gasoline engines, a homogeneous fuel-air mixture is formed by injection, which is forcedly ignited by a spark. In diesel engines, fuel is injected at high pressure, a portion of the fuel is mixed with compressed (hot) air and ignites almost instantly. The injection pressure determines the amount of fuel injected and, accordingly, the engine power. Therefore, the higher the pressure, the higher the engine power.
The fuel injection system is part of fuel system of the car. The main working element of any injection system is the injector ( injector).
Petrol injection systems
Depending on the method of forming the fuel-air mixture, a distinction is made between the following central injection systems, multipoint injection and direct injection. Central and multipoint injection systems are pre-injection systems, i.e. injection into them is carried out before reaching the combustion chamber - in the intake manifold.
Diesel injection systems
Fuel injection in diesel engines can be done in two ways: into the preliminary chamber or directly into the combustion chamber.
Pre-chamber injection engines feature low level noise and smooth operation. But nowadays, direct injection systems are preferred. Despite the increased noise level, such systems are highly fuel efficient.
Defining structural element The injection system of a diesel engine is a high pressure fuel pump (injection pump).
On cars from diesel engine various designs of injection systems are installed: with in-line injection pump, with distribution injection pump, pump nozzles, Common Rail. Progressive injection systems - unit injectors and Common Rail system.
