The main parameters of fuel injection of a gasoline engine. Fuel injection systems: differences and principles of operation. Features of fuel equipment

In modern cars in gasoline power plants The principle of operation of the power supply 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 - fuel. But due to the design and operational features, the operation of the injection differs significantly from that used on diesel engines.

Note that the difference in the injection systems of diesel and gasoline engines is increasingly being erased. For getting best qualities designers borrow design solutions and apply them to different types power 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 is the exact dosage of fuel. This is achieved by using nozzles in the design. The engine injection device includes two components - executive and control.

The task of the executive part is the supply of gasoline and its spraying. It includes not so many components:

1. Pump (electric).
2. Filter element (fine cleaning).
3. Fuel lines.
4. Ramp.
5. Nozzles.

But these are just the main components. The executive component may include a number of additional components and parts - a pressure regulator, a system for draining excess gasoline, an adsorber.

The task of these elements is to prepare the 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 the ignition key is turned (on some models, when the driver's door is opened), an electric pump is turned on, which pumps gasoline and fills the rest of the elements with it. The fuel undergoes cleaning and enters the rail through the fuel lines, which connects the nozzles. Due to the pump, the fuel in the entire system is under pressure. But its value is lower than on diesels.

The opening of the nozzles is carried out due to 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 monitor performance and operating parameters - crankshaft rotation speed, amount of air supplied, coolant temperature, throttle position. The readings are sent to the control unit (ECU). He compares this information with the data entered in the memory, on the basis of which the length of the electrical pulses supplied to the nozzles is determined.

The electronics used in the control part of the fuel injection system is needed to calculate the time for which the nozzle should open in a particular mode of operation of the 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 operating 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 nozzle, which injected gasoline into the intake manifold simultaneously for all cylinders. Initially, it was mechanical and no electronics were used in the design. If we consider the device of a mechanical injector, then it is similar to a carburetor system, with the only difference being that a mechanically driven nozzle was used instead of a carburetor. Over time, the central feed was made electronic.

Now this type is not used due to a number of shortcomings, 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 nozzle.

In the design of this type, the nozzles are installed in the intake manifold and are located next to the cylinder head. The distribution of fuel over the cylinders makes it possible to ensure an 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 same injector by design copies the diesel injection system.

In a direct feed injector, the nozzle nozzles are located in the combustion chamber. As a result, the components of the air-fuel mixture are launched into the cylinders separately here, and they are already mixed in the chamber itself.

The peculiarity of this injector is that high fuel pressure is required for gasoline injection. And its creation provides another node added to the device of the executive part - a high pressure pump.

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 in the gasoline engine.

Now cars use three types of diesel injection:

1. With distribution injection pump.
2. common rail.
3. Injector pump.

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 those of the injectors - a tank, fuel lines, filter elements. But there are also components that are not found on gasoline engines - a fuel priming pump, high-pressure fuel pump, lines for transporting high-pressure fuel.

In the mechanical systems of diesel engines, in-line injection pumps were used, in which the fuel pressure for each nozzle was created by its own separate plunger pair. Such pumps were highly reliable, but were bulky. The moment of injection and the amount of injected diesel fuel were regulated by a pump.

In engines equipped with a distribution 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 ones. This system is used only on passenger vehicles.

Common Rail is considered one of the most efficient diesel engine injection systems. Its general concept is largely borrowed from the injector with separate supply.

In such a diesel engine, the moment the supply starts and the amount of fuel is “managed” 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 nozzles, but to the ramp connecting the nozzles.

Pump injectors are another type of diesel injection. In this design, there is no high-pressure fuel pump, and plunger pairs that create diesel fuel pressure enter the injector device. This design solution allows you to create the highest fuel pressure among the existing types of injection on diesel units.

Finally, we note that here information is provided on the types of engine injection in general. To deal with the design and features of these types, they are considered separately.

Video: Fuel injection system control

The performance of any vehicle, first of all, is ensured by the proper operation of its "heart" - the engine. In turn, an integral part of the stable activity of this “organ” is the well-coordinated work of the injection system, with the help of which the fuel necessary for operation is supplied. Today, due to its many advantages, it has completely replaced carburetor system. The main positive aspect of its use is the presence of "smart electronics" that provide accurate dosage of the air-fuel mixture, which increases the power of the vehicle and significantly increases fuel efficiency. Besides, electronic system injection to a much greater extent helps to adhere to strict environmental standards, the issue of compliance with which, in recent years, is becoming increasingly important. Given the above, the choice of the topic of this article is more than appropriate, so let's look at the principle of operation of this system in more detail.

1. Working principle of electronic fuel injection

An electronic (or more well-known version of the name “injector”) fuel supply system can be installed on cars with both gasoline and gasoline engines. However, the design of the mechanism in each of these cases will have significant differences. All fuel systems can be divided according to the following classification features:

- according to the method of fuel supply, intermittent and continuous supply are distinguished;

Distributors, nozzles, pressure regulators, plunger pumps are distinguished by the type of dosing systems;

For the method of controlling the amount of supplied combustible mixture - mechanical, pneumatic and electronic;

The main parameters for adjusting the composition of the mixture are the vacuum in the intake system, at the throttle angle and air flow.

Modern fuel injection system gasoline engines has either electronic or mechanical control. Naturally, an electronic system is a more advanced option, since it can provide much better fuel economy, reduced emissions of harmful toxic substances, increased engine power, improved overall vehicle dynamics and facilitated cold start.

The first fully electronic system was a product released by an American company Bendix in 1950. 17 years later, a similar device was created by Bosch, after which it was installed on one of the models Volkswagen. It was this event that marked the beginning of the mass distribution of the electronic fuel injection (EFI - Electronic Fuel Injection) system, and not only on sports cars but also on luxury vehicles.

A fully electronic system uses for its work (fuel injectors), all activities of which are based on electromagnetic action. At certain points in the engine cycle, they open and remain in this position for the entire time required to supply a particular amount of fuel. That is, the time of the open state is directly proportional to the required amount of gasoline.

Among the fully electronic fuel injection systems, the following two types are distinguished, differing mainly only in the way the air flow is measured: system with indirect measurement of air pressure and with direct measurement of air flow. Such systems, to determine the level of vacuum in the manifold, use the appropriate sensor (MAP - manifold absolute pressure). Its signals are sent to the electronic control module (unit), where, taking into account similar signals from other sensors, they are processed and redirected to the electromagnetic nozzle (injector), which causes it to open at the right time for air to enter.

A good representative of a system with a pressure sensor is the system Bosch D-Jetronic(letter "D" - pressure). The operation of the electronically controlled injection system is based on some features. Now we will describe some of them, characteristic of the standard type of such a system (EFI). Let's start with the fact that it can be divided into three subsystems: the first is responsible for the fuel supply, the second is for air intake, and the third is an electronic control system.

The structural parts of the fuel supply system are the fuel tank, fuel pump, the fuel supply line (guide from the fuel distributor), the fuel injector, the fuel pressure regulator and the fuel return line. The principle of operation of the system is as follows: using an electric fuel pump (located inside or next to fuel tank), gasoline leaves the tank and is fed into the nozzle, and all contaminants are filtered out using a powerful built-in fuel filter. That part of the fuel that was not sent through the nozzle to the suction pipe is returned to the tank through the return fuel actuator. Maintaining a constant fuel pressure is provided by a special regulator responsible for the stability of this process.

The air intake system consists of a throttle valve, a suction manifold, an air purifier, inlet valve and air intake chamber. Its principle of operation is as follows: with the throttle valve open, air flows through the cleaner, then through the air flow meter (they are equipped with L-type systems), the throttle valve and a well-tuned inlet pipe, after which they enter the inlet valve. The function of directing air to the motor requires an actuator. As the throttle valve opens, a much larger amount of air enters the engine cylinders.

Some powertrains use two different ways to measure the amount of incoming air flow. So, for example, when using the EFI system (type D), the air flow is measured by monitoring the pressure in the intake manifold, that is, indirectly, while a similar system, but already type L, does this directly using a special device - an air flow meter.

The electronic control system includes the following types of sensors: engine, electronic control unit (ECU), fuel injector assembly and related wiring. With the help of this block, by monitoring the sensors of the power unit, the exact amount of fuel supplied to the nozzle is determined. In order to supply the engine with air / fuel in the appropriate proportions, the control unit starts the operation of the injectors for a specific period of time, which is called the “injection pulse width” or “injection duration”. If you describe the main mode of operation of the system electronic injection fuel, taking into account the already named subsystems, it will have the following form.

Getting into power unit through the air intake system, air flows are measured using a flow meter. When air enters the cylinder, it mixes with the fuel, not the least of which is the operation of the fuel injectors (located behind each intake manifold intake valve). These parts are a kind of solenoid valves that are controlled by an electronic unit (ECU). It sends certain pulses to the injector by turning its ground circuit on and off. When it is on, it opens and sprays fuel onto the back of the intake valve wall. When it enters the outside air, it mixes with it and evaporates due to the low pressure of the suction manifold.

The signals sent by the ECU ensure that the fuel supply is sufficient to achieve the ideal air/fuel ratio (14.7:1), also known as stoichiometry. It is the ECU, based on the measured air volume and engine speed, that determines the main injection volume. Depending on the operating conditions of the engine, this figure may vary. The control unit monitors such variable values ​​as engine speed, temperature of antifreeze (coolant), oxygen content in exhaust gases and throttle angle, in accordance with which it makes an injection adjustment that determines the final volume of injected fuel.

Undoubtedly, the power supply system with electronic fuel metering is superior carburetor power gasoline engines, so there is nothing surprising in its wide popularity. Gasoline injection systems, due to the presence of a huge number of electronic and moving precision elements, are more complex mechanisms, therefore, require a high level of responsibility in the approach to the issue of maintenance.

The existence of the injection system makes it possible to more accurately distribute fuel over the engine cylinders. This became possible due to the absence of additional resistance to the air flow, which was created at the inlet by the carburetor and diffusers. Accordingly, an increase in the filling ratio of the cylinders directly affects the increase in the engine power level. Let's now take a closer look at all the positive aspects of using an electronic fuel injection system.

2. Pros and cons of electronic fuel injection

The positive points include:

Possibility of a more even distribution of the fuel-air mixture. Each cylinder has its own injector that delivers fuel directly to the intake valve, eliminating the need to feed through the intake manifold. This helps to improve its distribution between the cylinders.

High-precision control of the proportions of air and fuel, regardless of the operating conditions of the engine. With the help of a standard electronic system, the exact ratio of fuel and air is supplied to the engine, which greatly improves the vehicle's drivability, fuel efficiency and emissions control. Improved throttle performance. By supplying fuel directly to the back of the intake valve, the intake manifold can be optimized, thereby increasing the airflow through the intake valve. Due to such actions, the torque and the working efficiency of the throttle are improved.

Improved fuel efficiency and improved emission control. In engines equipped with an EFI system, the richness of the fuel mixture at cold start and wide open throttle can be reduced, since fuel mixing is not a problematic action. Due to this, it becomes possible to save fuel and improve the control of exhaust gases.

Improving the performance of a cold engine (including starting). The ability to inject fuel directly to the intake valve, in combination with an improved spray formula, accordingly increases the starting and operating capabilities of a cold engine. Simplification of mechanics and reduction of sensitivity to adjustment. When cold starting or metering fuel, the EFI system is independent of the richness control. And since, from a mechanical point of view, it is simple, the requirements for its maintenance are reduced.

However, no mechanism can be exclusively positive qualities, therefore, in comparison with the same carbureted engines, engines with an electronic fuel injection system have some disadvantages. The main ones include: high cost; almost complete impossibility of repair actions; high requirements for the composition of the fuel; strong dependence on power sources and the need for constant voltage (a more modern version that is controlled by electronics). Also, in the event of a breakdown, it will not be possible to do without specialized equipment and highly qualified personnel, which translates into too expensive maintenance.

3. Diagnosis of the causes of malfunctions of the electronic fuel injection system

The occurrence of malfunctions in the injection system is not such a rare occurrence. This issue is especially relevant for owners of older car models, who have repeatedly had to deal with both the usual clogging of nozzles and more serious problems in terms of electronics. The causes of malfunctions that often occur in this system can be very many, but the most common among them are the following:

- defects ("marriage") of structural elements;

Limit service life of parts;

Systematic violation of the rules for operating a car (use of low-quality fuel, system pollution, etc.);

External negative impacts on structural elements (moisture ingress, mechanical damage, oxidation of contacts, etc.)

The most reliable way to determine them is computer diagnostics. This type of diagnostic procedure is based on automatic recording of deviations of the system parameters from the set norm values ​​(self-diagnosis mode). Detected errors (inconsistencies) remain in the memory of the electronic control unit in the form of so-called "fault codes". To carry out this research method, a special device is connected to the diagnostic connector of the unit ( Personal Computer with the program and cable or scanner), whose task is to read all the available fault codes. However, be aware that apart from special equipment, the accuracy of the results of the computer diagnostics, will depend on the knowledge and skills of the person who conducted it. Therefore, the procedure should be trusted only by qualified employees of special service centers.

Enter the computer check of the electronic components of the injection system t:

- diagnostics of fuel pressure;

Checking all mechanisms and components of the ignition system (module, high-voltage wires, candles);

Checking the tightness of the intake manifold;

The composition of the fuel mixture; assessment of toxicity of exhaust gases on the scales of CH and CO);

Diagnostics of the signals of each sensor (the method of reference oscillograms is used);

Cylindrical compression test; control of timing belt position marks and many other functions that depend on the model of the machine and the capabilities of the diagnostic tool itself.

Carrying out this procedure is necessary if you want to find out if there are any malfunctions in the electronic fuel supply (injection) system and, if so, which ones. The EFI electronic unit (computer) “remembers” all malfunctions only while the system is connected to battery, if the terminal is disconnected, all information will disappear. It will be so, exactly until the moment when the driver turns on the ignition again and the computer re-checks the operation of the entire system.

On some vehicles equipped with an electronic fuel injection (EFI) system, there is a box under the hood, on the lid of which you can see the inscription "DIAGNOSIS". A rather thick bundle of different wires is still connected to it. If the box is opened, then the terminal marking will be visible from the inside of the cover. Take any wire and use it to short the leads. "E1" and "TE1", then get behind the wheel, turn on the ignition and watch the reaction of the "CHECK" light (it shows the engine). Note! The air conditioner must be turned off.

As soon as you turn the key in the ignition lock, the indicated light will flash. If she "blinks" 11 times (or more), after an equal period of time, this will mean that in memory on-board computer there is no information and a trip to the full diagnostics of the system (in particular, electronic fuel injection) can be delayed. If the flashes are at least somehow different, then you should contact the specialists.

This method of "home" mini-diagnostics is not available to all owners vehicles(mostly only foreign cars), but those who have such a connector are lucky in this regard.

Modern vehicles use a variety of fuel injection systems. The injection system (another name is the injection system, from injection - injection), as the name implies, provides fuel injection.

The injection system is used on both petrol and diesel engines. At the same time, the design and operation of injection systems for gasoline and diesel engines differ significantly.

In gasoline engines, a homogeneous fuel-air mixture is formed by injection, which is forcibly ignited by a spark. In diesel engines, fuel is injected under high pressure, a portion of the fuel is mixed with compressed (hot) air and ignites almost instantly. The injection pressure determines the amount of injected fuel and, accordingly, the engine power. Therefore, the higher the pressure, the higher the engine power.

The fuel injection system is an integral part of the vehicle's fuel system. The main working body of any injection system is the nozzle ( injector).

Injection systems for petrol engines

Depending on the method of formation of the fuel-air mixture, the following systems of central injection, distributed injection and direct injection are distinguished. Central and port injection systems are pilot 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 pre-chamber or directly into the combustion chamber.

Pre-chamber injection engines feature low level noise and smooth operation. But at present, preference is given to direct injection systems. Despite the increased noise level, such systems have high fuel efficiency.

The defining structural element of the diesel engine injection system is the high pressure fuel pump (TNVD).

For cars with 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 - pump nozzles and Common Rail system.

Dear readers and subscribers, it's nice that you continue to study the structure of cars! And now to your attention is an electronic fuel injection system, the principle of which I will try to tell in this article.

Yes, it is about those devices that have replaced the time-tested power supplies from under the hoods of cars, and we will also find out how much in common modern gasoline and diesel engines have.

Perhaps we would not have discussed this technology with you if a couple of decades ago humanity had not seriously taken care of the environment, and toxic exhaust gases from cars turned out to be one of the most serious problems.

The main drawback of cars with engines equipped with carburetors was the incomplete combustion of fuel, and to solve this problem, systems were needed that could regulate the amount of fuel supplied to the cylinders depending on the mode of operation of the engine.

Thus, injection systems or, as they are also called, injection systems, appeared on the automotive arena. In addition to improving environmental friendliness, these technologies have improved the efficiency of engines and their power characteristics, becoming a real boon for engineers.

To date, fuel injection (injection) is used not only on diesel, but also on gasoline units, which undoubtedly unites them.

They are also united by the fact that the main working element of these systems, whatever type they are, is the nozzle. But due to differences in the method of burning fuel, the designs of the injection units for these two types of engines, of course, differ. Therefore, we will consider them in turn.

Injection systems and gasoline

Electronic fuel injection system. Let's start with gasoline engines. In their case, injection solves the problem of creating an air-fuel mixture, which is then ignited in the cylinder by a spark from a spark plug.

Depending on how this mixture and fuel is supplied to the cylinders, injection systems can have several varieties. The injection happens:

central injection

The main feature of the technology located first in the list is one single nozzle for the entire engine, which is located in the intake manifold. It should be noted that this type of injection system does not differ much from the carburetor system in its characteristics, therefore, today it is considered obsolete.

Distributed injection

More progressive is distributed injection. In this system, the fuel mixture is also formed in the intake manifold, but, unlike the previous one, each cylinder here boasts its own injector.

This variety allows you to experience all the advantages of injection technology, therefore it is most loved by automakers, and is actively used in modern engines.

But, as we know, there are no limits to perfection, and in pursuit of even higher efficiency, engineers have developed an electronic fuel injection system, namely the direct injection system.

Her main feature is the location of the nozzles, which, in this case, with their nozzles go into the combustion chambers of the cylinders.

The formation of an air-fuel mixture, as you might already guess, occurs directly in the cylinders, which has a beneficial effect on the operating parameters of the engines, although this option is not as environmentally friendly as that of distributed injection. Another tangible drawback of this technology is the high requirements for the quality of gasoline.

Combined injection

The most advanced in terms of emissions of harmful substances is a combined system. This is, in fact, a symbiosis of direct and distributed fuel injection.

How about diesels?

Let's move on to diesel units. Their fuel system is faced with the task of supplying fuel at very high pressure, which, mixing in a cylinder with compressed air, ignites itself.

A lot of options for solving this problem have been created - both direct injection into cylinders and with an intermediate link in the form of a preliminary chamber are used, in addition, there are various layouts of high pressure pumps (high pressure pumps), which also adds variety.

However, modern motorists prefer two types of systems that supply diesel fuel directly to the cylinders:

• with pump nozzles;
• common rail injection.

Pump nozzle

The pump-injector speaks for itself - it has an injector that injects fuel into the cylinder, and a high-pressure fuel pump are structurally combined into one unit. The main problem of such devices is increased wear, since the unit injectors are connected permanent drive with a camshaft and never disconnect from it.

common rail system

The Common Rail system takes a slightly different approach, making it the preferred choice. There is one common injection pump, which supplies diesel to the fuel rail, which distributes fuel to the cylinder nozzles.

This was just a brief overview. injection systems, therefore, friends, follow the links in the articles, and using the Engine section, you will find all injection systems for study modern cars. And subscribe to the newsletter so as not to miss new publications, in which you will find a lot of detailed information on the systems and mechanisms of the car.

Engines with fuel injection systems, or injection engines, are almost forced out of the market carbureted engines. To date, there are several types of injection systems that differ in design and principle of operation. Read about how various types and types of fuel injection systems are arranged and work in this article.

Device, principle of operation and types of fuel injection systems

Today, most new cars equipped with engines with a fuel injection system ( injection engines), which have better performance and are more reliable than traditional carbureted engines. We have already written about injection engines (article " Injection engine"), so here we will only consider the types and varieties of fuel injection systems.

There are two fundamental different types fuel injection systems:

Central injection (or single injection);
- Distributed injection (or multipoint injection).

These systems differ in the number of nozzles and their modes of operation, but their principle of operation is the same. In an injection engine, instead of a carburetor, one or more fuel injectors are installed, which spray gasoline into the intake manifold or directly into the cylinders (air is supplied to the manifold using a throttle assembly to form a fuel-air mixture). This solution makes it possible to achieve uniformity and High Quality combustible mixture, and most importantly - a simple setting of the engine operating mode depending on the load and other conditions.

The system is controlled by a special electronic unit (microcontroller), which collects information from several sensors and instantly changes the engine operating mode. In early systems, this function was performed by mechanical devices, but today the engine is completely controlled by electronics.

Fuel injection systems differ in the number, installation location and mode of operation of the injectors.

1 - engine cylinders;
2 - inlet pipeline;
3 - throttle valve;
4 - fuel supply;
5 - electric wire, through which a control signal is supplied to the nozzle;
6 - air flow;
7 - electromagnetic nozzle;
8 - fuel torch;
9 - combustible mixture

This solution was historically the first and simplest, therefore, at one time it became quite widespread. In principle, the system is very simple: it uses one nozzle, which constantly sprays gasoline into one intake manifold for all cylinders. Air is also supplied to the manifold, so a fuel-air mixture is formed here, which enters the cylinders through the intake valves.

The advantages of single injection are obvious: this system is very simple, to change the engine operating mode, you need to control only one nozzle, and the engine itself undergoes minor changes, because the nozzle is put in place of the carburetor.

However, mono-injection also has disadvantages, first of all - this system cannot meet the ever-increasing requirements for environmental safety. In addition, the failure of one injector actually disables the engine. Therefore, today engines with central injection are practically not produced.

Distributed injection

1 - engine cylinders;
2 - fuel torch;
3 - electrical wire;
4 - fuel supply;
5 - inlet pipeline;
6 - throttle valve;
7 - air flow;
8 - fuel rail;
9 - electromagnetic nozzle

In systems with distributed injection, nozzles are used according to the number of cylinders, that is, each cylinder has its own nozzle located in the intake manifold. All injectors are connected by a fuel rail through which fuel is supplied to them.

There are several types of systems with distributed injection, which differ in the mode of operation of the nozzles:

Simultaneous injection;
- Pair-parallel injection;
- Phased spray.

Simultaneous injection. Everything is simple here - the nozzles, although they are located in the intake manifold of “their” cylinder, open at the same time. We can say that this is an improved version of mono injection, since several nozzles work here, but the electronic unit manages them as one. Simultaneous injection, however, makes it possible to individually adjust the fuel injection for each cylinder. In general, systems with simultaneous injection are simple and reliable in operation, but are inferior in performance to more modern systems.

Pair-parallel injection. This is an improved version of simultaneous injection, it differs in that the nozzles open in turn in pairs. Typically, the operation of the injectors is configured in such a way that one of them opens before the intake stroke of its cylinder, and the second before the exhaust stroke. To date, this type of injection system is practically not used, however, on modern engines, emergency operation of the engine is provided in this mode. Typically, this solution is used in case of failure of the phase sensors (camshaft position sensors), in which phased injection is not possible.

phased injection. This is the most modern and best performing type of injection system. With phased injection, the number of nozzles is equal to the number of cylinders, and they all open and close depending on the stroke. Usually the injector opens just before the intake stroke - this is how the best engine performance and economy are achieved.

Distributed injection also includes systems with direct injection, however, the latter has fundamental design differences, so it can be distinguished into a separate type.

Direct injection systems are the most complex and expensive, but only they can provide best performance in terms of power and economy. Also, direct injection makes it possible to quickly change the engine operating mode, regulate the fuel supply to each cylinder as accurately as possible, etc.

In systems with direct fuel injection, the nozzles are installed directly in the head, spraying fuel directly into the cylinder, avoiding the "intermediaries" in the form of an intake manifold and an intake valve (or valves).

Such a solution is quite difficult in technical terms, since in the cylinder head, where the valves and the spark plug are already located, it is also necessary to place the nozzle. Therefore, direct injection can only be used in sufficiently powerful and therefore large engines. In addition, such a system cannot be installed on a serial engine - it has to be upgraded, which is associated with high costs. Therefore, direct injection is now used only on expensive cars.

Direct injection systems are demanding on fuel quality and require more frequent maintenance, however, they provide significant fuel savings and provide more reliable and high-quality engine operation. Now there is a tendency to reduce the price of cars with such engines, so in the future they can seriously push cars with injection engines of other systems.