Home Salon The structure and principle of operation of the fuel injection system. Fuel injection system - schemes and principle of operation What are there any injection systems in auto

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The structure and principle of operation of the fuel injection system. Fuel injection system - schemes and principle of operation What are there any injection systems in auto

In each modern car there is a fuel supply system. Its purpose is to supply fuel from the tank to the engine, its filtration, as well as the formation of a combustible mixture, followed by its admission to cylinders in DVS. What are the views of the SPT and what is their differences - we will tell about this below.

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General

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 the gasoline or diesel engines in question:

The tank in which fuel is stored. The tank is a container equipped with a pumping device, as well as a filtering element for cleaning fuel from dirt.
Fuel highways are a set of nozzles and hoses designed to supply fuel from the tank into the engine.
The mixing assembly unit intended for the formation of a combustible mixture, as well as its further transmission to the cylinders, in accordance with the tact of the operation of the power unit.
Managing module. It is used in injection engines, it is due to the need to control different sensors, valves and nozzles.
Pump itself. As a rule, in modern cars Submersible options are used. Such a pump is a small in size and power of an electric motor connected to a liquid pump. The lubricant of the device is implemented by fuel. If there will be less than five liters of fuel in the gas tank, it can lead to a motor breakage.

SPT on the motor ZMZ-40911.10

Features of fuel equipment

In order for the exhaust gases less contaminated the surrounding among, cars are equipped with catalytic neutralizers. But over time, it became clear that their use is appropriate only if a high-quality combustible mixture is formed in the engine. That is, if there are deviations in the formation of the emulsion, the efficiency of using the catalyst is significantly reduced, that is why over time, car manufacturers switched from carburetors to injectors. Nevertheless, their effectiveness was also not particularly high.

In order for the system to automatically adjust the indicators, the control module was subsequently added to it. If, in addition to the catalytic neutralizer, as well as the oxygen sensor, the control unit is used, it issues quite well indicators.

What advantages are characteristic of such systems:

Ability to increase performance characteristics Power unit. In proper operation, the engine power may be higher than 5% of the manufacturer.
Improving the dynamic characteristics of the car. Injector motors are sufficiently sensitive in relation to the change in loads, so they can independently adjust the composition of the combustible mixture.
The combustible mixture formed in the correct proportions will be able to significantly reduce the volume, as well as the toxicity of exhaust gases.
Injector motors, as practice showed, are perfectly launched under all weather conditions, unlike carburetors. Of course, if it comes to the temperature of -40 degrees (the author of the video is Sergey Morozov).

Device injector fuel supply system

Now we suggest familiarizing yourself with the Injector SPT device. All modern power units are equipped with nozzles, their number corresponds to the number of cylinders installed, and together these parts are connected using the ramp. The fuel itself is contained under low pressure, which is created through a pumping device. The volume of incoming fuel depends on how long the nozzle is open, and this, in turn, is controlled by the control module.

To adjust the block receives readings from various controllers and sensors located in different parts of the car, we suggest familiarizing with the main devices:

Flow meter or DMRV. Its purpose is to determine the source of the engine cylinder with air. If there are problems in the system, its readings of the control unit ignores, and the usual data from the table uses to form a mixture.
DPDZ - throttle positions. Its purpose is to reflect the load on the motor, which is due to the position of the throttle, motor turnover, as well as cycular filling.
Duck. The antifreeze temperature controller in the system allows you to implement the fan control, as well as adjust the fuel and ignition. Of course, all this adjusts the control unit based on the Dzhtniki.
DPKV - the position of the crankshaft. His appointment is to synchronize the operation of the GTT as a whole. The device calculates not only the revolutions of the power unit, but also the position of the shaft at a certain point. In itself, the device refers to the polar controllers, respectively, its breakdown will lead to the impossibility of the operation of the car.
Lambda probe or. It is used to determine the volume of oxygen in exhaust gases. The data from this device comes to the control module, which, based on them, adjusts the combustible mixture (by video author - avto-blogger.ru).

Types of injection systems on gasoline engine

What is a jetronics, what kind of spt gasoline engines?

We offer to familiarize yourself with the question of varieties:

SPT with central injection. IN this case Gasoline gas supply is realized thanks to the inlet reservoirs. Since the nozzle is used only one, such SPTs are also called the Moomprosis. Currently, such SPTs are not relevant, therefore, in more modern cars, they simply are simply provided. The main advantages of such systems include simplicity of operation, as well as high reliability. As for minuses, this is a reduced motor environment, as well as a rather high fuel consumption.
SPT with distributed injection or k-jetronics.In such nodes, gasoline is provided separately to each cylinder, which is equipped with a nozzle. The combustible mixture itself is formed in the intake manifold. To date, most of the power units are equipped with such a SPT. Their main advantages include fairly high ecology, an acceptable consumption of gasoline, as well as moderate requirements in relation to the quality of gasoline consumed.
With immediate injection. This option is considered one of the most progressive as well as perfect. The principle of operation of this PT is in direct gasoline injection into the cylinder. As the results of numerous studies show, such PTA make it possible to achieve the most optimal and qualitative composition of the fuel and air mixture. Moreover, at any stage of the operation of the power unit, which makes it possible to significantly improve the combustion procedure of the mixture and increase the efficiency of the engine and its power in many respects. Well, of course, reduce the amount of exhaust gases. But it must 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 gasoline used.
SPT with combined injection. This option is, in fact, the result of the combination of SPT with distributed and direct injection. As a rule, it is used to reduce the amount of toxic substances dropped into the atmosphere, as well as exhaust gases. Accordingly, it is used to increase engine environmental readings.
L-jetronics system still used in gasoline engines. This is a paired fuel injection system.

Photo gallery "Varieties of gasoline systems"

Types of diesel engine injection systems

The main types of SPT in diesel engines:

Pump-nozzle. Such SPTs are used to feed, as well as the further injection of the formed emulsion under high pressure using pump-nozzles. The main feature of such PT is that the pump-nozzles perform the options for pressure formation, as well as directly injection. Such PTTs also have their drawbacks, in particular, we are talking about a pump equipped with a special drive of a constant type from the distribution shaft of the power unit. This node is not turned off, respectively, it contributes to increased wear of the structure as a whole.
It is because of the last disadvantage that most producers prefer SPT type COMMON RAIL. or rechargeable injection. This option is considered more perfect for many diesel units. SPT has such a name as a result of using the fuel frame - the main element of the structure. The ramp is used one for all nozzles. In this case, the fuel supply is carried out to the nozzles from the ramp itself, it can be referred to as an increased pressure battery.
Fuel supply is carried out in three stages - preliminary, main, as well as additional. Such a distribution makes it possible to reduce the noise and vibration during the operation of the power unit, to make it work more efficient, in particular, we are talking about the process of igniting the mixture. In addition, it also allows and reduce the amount of malicious emissions into the environment.

Regardless of the type of SPT, diesel units are also controlled using electronic or mechanical devices. In mechanical versions of the device control the level of pressure and volume of the components of the mixture and the moment of injection. Concerning electronic optionsThey allow you to provide more efficient management of the power unit.

System direct injection Fuel in gasoline engines today is the most advanced and modern solution. The main feature of the immediate injection can be considered that fuel is supplied to the cylinders directly.

For this reason, this system is also often called direct fuel injection. In this article, we will look at how the engine with the immediate injection of fuel works, as well as what advantages and disadvantages have such a scheme.

Read in this article

Direct fuel injection: direct injection system

As mentioned above, fuel in such fed directly into the engine combustion chamber. This means that the nozzles spray gasoline is not in, after which the fuel and air mixture enters through into the cylinder, and inject the fuel into the combustion chamber directly.

The first gasoline engines with the immediate injection of steel. In the future, the scheme was widespread, with the result that today with such a fuel supply system can be found in the line of many well-known automakers.

For example, concern Vag. presented a number audi models and Volkswagen with atmospheric and turbocharged, which received the direct fuel injection. Also, direct injection engines manufactures BMW, Ford, GM, Mercedes and many others.

Such a wide distribution of the direct fuel injection was obtained due to the high economy of the system (about 10-15% compared with the distributed injection), as well as a more complete combustion of the working mixture in cylinders and a decrease in the level of toxicity of exhaust gases.

Direct injection system: design features

So, let's take the FSI engine as an example with its so-called "layer-by-layer" injection. The system includes the following items:

high pressure circuit;
gasoline;
pressure regulator;
fuel ramp;
high pressure sensor;
injector nozzles;

Let's start with the fuel pump. The specified pump creates high pressure under which the fuel is fed to the fuel ramp, as well as on the nozzles. Pump has plungers (plungers can be both several and one in the pumps rotor type) and drives from the camshaft of the inlet valves.

RDT (fuel pressure regulator) is integrated into the pump and is responsible for the dosage of fuel supply, which corresponds to the injection of the nozzle. Fuel rail (fuel ramp) is needed in order to distribute fuel on the nozzles. Also, the presence of this element allows you to avoid jumps of pressure (pulsation) fuel in the circuit.

By the way, the scheme uses a special fuse valve that stands in a rake. The specified valve is needed in order to avoid too high fuel pressure and thereby protect individual system elements. Pressure growth may arise due to the fact that fuel has the property to expand when heated.

The high pressure sensor is a device that measures the pressure in the fuel rail. Signals from the sensor are transmitted to, which, in turn, can change the pressure in the fuel rail.

As for the injection injector, the element provides timely feed and spray fuels in the combustion chamber to create the necessary fuel mixture. Note that the processes described flow under control. The system has a group of various sensors, an electronic control unit, as well as actuators.

If we talk about the direct injection system, together with the high-pressure sensor, the fuel is involved:, DPRV, air temperature sensor in the intake manifold, the temperature sensor, etc.

Thanks to the operation of these sensors, the necessary information is received on the computer, after which the block sends signals to actuators. This allows you to achieve a coherent and accurate operation of electromagnetic valves, nozzles, safety valve and a number of other elements.

How does the direct fuel injection system work

The main advantage of direct injection is the ability to achieve various types of mixing formation. In other words, such a power system is able to flexibly change the composition of the working fuel mixture, taking into account the mode of operation of the engine, its temperature, the load on the engine, etc.

Layered mixture formation, stoichiometric, as well as homogeneous. It is such a mixing formation that makes it ultimately the fuel to consume the most effectively. The mixture is always obtained high-quality independently of the mode of operation of the engine, gasoline burns full, the engine becomes more powerful, while the exhaust toxicity is reduced at the same time.

The layer-by-layer mixing is activated when the load on the engine is low or medium, and the crankshaft turns are small. If simply, in such modes the mixture is somewhat shifted in order to save. Stoichiometric blending involves the preparation of such a mixture, which is easily flammable, is not too enriched.
Homogeneous mixing allows you to get the so-called "powerful" mixture, which is needed at large loads on the engine. At the depleted homogeneous mixture, in order to further savage, the power unit operates in transient modes.
When the layer laying mode is activated, throttle valve Widely open, while intake dampers are in a closed state. In the combustion chamber, air is fed at high speed, air flow swirls occur. Fuel is injected closer to the end of the compression tact, injection is produced in the area of \u200b\u200bthe spark plug.

In a short time, before the spark appears on the candle, the fuel and air mixture is formed, in which the excess air coefficient is 1.5-3. Next, the mixture is flammified from the spark, while there is a sufficient amount of air around the ignition zone. Specified air performs the function of the temperature "insulator".

If you consider homogeneous stoichiometric mixture formation, such a process occurs when the intake flaps are open, while the throttle valve is also open to one or another angle (depends on the degree of pressing the accelerator pedal).

In this case, fuel is injected on the intake tact, resulting in a homogeneous mixture. Excess air has a coefficient close to one. Such a mixture is easily flammable and fully burns throughout the volume of the combustion chamber.

The depleted homogeneous mixture is created when the throttle is fully open, and intake dampers are closed. In this case, the air is actively moving in the cylinder, and the fuel injection falls on the intake tact. ECD maintains an excess air at 1.5.

Additionally, spent gases can be added to clean air. This is due to the work. As a result, the exhaust is re-"trades" in the cylinders without prejudice to the motor. This reduces the level of emissions of harmful substances into the atmosphere.

That in the end

As can be seen, a direct injection allows you to achieve not only fuel economy, but also a good return from the engine both in modes of low and medium and high loads. In other words, the presence of direct injection means that the optimal composition of the mixture will be maintained in all modes of operation of the OI.

As for the shortcomings, the consumption of direct injection can be attributed unless the increased complexity during the repair and price of spare parts, as well as the high sensitivity of the system to the quality of fuel and the state of fuel and air filters.

Types of injection systems on gasoline engine

On gasoline engines, the following fuel supply systems are used - central injection (mono injection), distributed injection (multipoint), combined injection and direct injection.

Central injection

Fuel supply in the central injection system occurs due to the fuel injector, which is located in the intake manifold. Since the nozzle is only one, then this system of injection is called still - MonovPrash.

The systems of this species today have lost their relevance, so in the new models of cars they are not envisaged, however, in some old models of some automotive brands you can meet.

The advantages of mono injection include reliability and ease of use. The disadvantages of such a system are the low level of engine environmental friendliness and high fuel consumption.

Distributed injection

The multipoint injection system provides for the supply of fuel separately to each cylinder equipped with its own fuel inlet. In this case, the fuel retox is formed only in the intake manifold.

Currently, most gasoline engines are equipped with a distributed fuel supply system. The advantages of such a system are high ecology, optimal fuel consumption, moderate requirements for the quality of fuel consumed.

Direct injection

One of the most advanced and progressive injection systems. The principle of operation of such a system is the direct feed (injection) of fuel into the combustion chamber of cylinders.

The system of direct fuel supply allows you to obtain the qualitative composition of the fuel assembly at all stages of the engine work in order to improve the combustion process of combustible mixture, increasing engine operating power, reducing the level of exhaust gases.

The disadvantages of this injection system include complex design and high quality fuel quality.

Combined injection

The system of this type combined two systems - direct and distributed injection. It is often used to reduce emissions of toxic elements and spent gases, due to which high engine environmental performance is achieved.

All fuel supply systems replaced on gasoline engine can be equipped with mechanical or electronic control devices, of which the latter is most perfect, since it provides the best engineering and engine environmental performance.

Fuel supply in such systems can be carried out continuously or discretely (pulse). According to experts, the impulse fuel supply is the most appropriate and effective and today applied in all modern engines.

Types of diesel engine injection systems

In modern diesel engines, injection systems are used as a system pump system, Common Rail system, a row system or distribution pump (high pressure fuel pump).

The most popular and are considered the most progressive systems: Common Rail and the pumps-nozzles, about which we will talk below with a little more detail.

TNVD is a central element of any diesel engine fuel system.

In diesel engines, the supply of combustible mixture can be carried out both in the pre-chamber, and directly into the combustion chamber (immediate injection).

To date, preference is given to the direct injection system, which is distinguished by an elevated noise level and less smooth operation of the engine, compared with injection in the preliminary chamber, but it provides a much more important indicator - efficiency.

Injection system pump-nozzle

Such a system is used to supply and injected the fuel mixture under high pressure by a central device - nozzles pump.

By title, you can guess that the key feature of this system is that two functions are combined in a single device (pump-nozzle): the creation of pressure and injection.

The constructive disadvantage of this system is that the pump is equipped with a constant type drive from the engine camshaft (not turned off), which leads to a rapid wear of the structure. Because of this, manufacturers increasingly make a choice in favor of the Common Rail injection system.

Common Rail injection system (rechargeable injection)

This is a more advanced TC system for most diesel engines. Its name went from the main structural element - the fuel ramp, common to all injectors. Common Rail in English just means - the overall ramp.

In such a system, fuel is fed to fuel injectors From the ramp, which is also called a high-pressure battery, because of which the system has a second name - the battery injection system.

The Common Rail system provides for the three stages of injection - preliminary, main and additional. This allows you to reduce the noise and vibration of the engine, make a more effective fuel ignition process, reduce the amount of harmful emissions into the atmosphere.

To control injection systems on dieselms, the presence of mechanical and electronic devices. Systems on mechanics allow you to control the operating pressure, the volume and moment of fuel injection. Electronic systems provide more efficient control of diesel engine in general.

The first injection systems were mechanical (Fig. 2.61), not electronic, and some of them (for example, a highly efficient Bosch system) were extremely witty and worked well. For the first time, the mechanical fuel injection system was developed on Daimler Benz, and the first serial car With the injection of gasoline was reulted in 1954. The main advantages of the injection system compared to carbure systems are the following:

The absence of additional resistance to the air flow on the inlet having a place in the carburetor, which ensures an increase in the filling of cylinders and a liter engine power;

More accurate distribution of fuel in separate cylinders;

A significantly higher degree of optimization of the composition of the combustible mixture on all modes of engine operation, taking into account its condition, which leads to an improvement in the fuel eco and reduce the toxicity of exhaust gases.

Although in the end it turned out that it is better to use electronics for this purpose, which makes it possible to make the system compact, more reliable and more adaptable to the requirements of various engines. Some of the first electronic injection systems were a carburetor, from which all the "passive" removed fuel systems And installed one or two nozzles. Such systems were called "Central (single-point) injection" (Fig. 2.62 and 2.64).

Fig. 2.62. Central (single-point) injection unit

Fig. 2.64. Scheme of the central fuel injection system: 1 - fuel supply;

Fig. 2.63. The electronic unit control 2 - air intake; 3 - throttle four-cylinder damper; 4 - intake pipeline; Valvetronic BMW 5 - nozzle; 6 - Engine

Currently, the largest distribution systems (multipoint) electronic injection were obtained. On the study of these power systems, it is necessary to stop more detail.

Power system with electronic distributed gasoline injection (type Motronic)

In the central injection system, the mixture supply and its distribution over the cylinders is carried out inside the intake manifold (Fig. 2.64).

The most modern fuel injection system is characterized by the fact that a separate nozzle is installed in the intake path of each cylinder, which in the defined moment is injected into the dosage portion of gasoline on inlet valve The corresponding cylinder. Gasoline arrived

In the cylinder, evaporates and stirred with air, forming a combustible mixture. Motor teli with such power systems have better fuel efficiency and pony in the premium content of harmful substances in the exhaust gases compared to the car by bureau engines.

The operation of the nozzles controls the electronic control unit (ECU) (Fig. 2.63), which is a special computer, which receives and processes electrical signals from the sensor system, compares their readings with values,

stored in the memory of the computer, and the controls of the electrical signals on the electromagnetic valves of the injectors and other actuators are issued. In addition, the ECU is constantly diagnosed

Fig. 2.65. Scheme of the Motronic Fuel Injection System: 1 - Feed Top Liva; 2 - air intake; 3 - Packing village damper; 4 - inlet pipe water; 5 - nozzles; 6 - Engine

Fuel injection systems and with troubleshooting in operation warns the driver using a control lamp installed in the instrument panel. Series are recorded in the memory of BLO control and can be read when conducting diagnostics.

The system with a distributed injection has the following components:

Fuel supply and cleaning system;

Air supply and air purification system;

Sailing and burning system of gasoline vapor;

Electronic part with a set of sensors;

The system of release and afterburning spent gases.

Fuel supply systemit consists of a straight tank, electric fuel pump, fuel filter, pipelines, and top area ramps on which nozzles and a fuel pressure regulator are installed.

Fig. 2.66. Submersible electric fuel pump; a - fuel collector with the NASO som; b - the appearance of the pump and the pump section of the rotary type of the fuel pump with an electrical drive; in - gear; r - roller; d - lamellar; E - Scheme of operation of the pump section of the rotor type: 1 - body; 2 - suction zone; 3 - rotor; 4 - discharge zone; 5 - direction of rotation

Fig. 2.67. Fuel rap five-cylinder engine with nozzles installed on it, pressure regulator and pressure control unit

ElectricalSonasos(usually roller) can be installed both inside the gas tank (Fig. 2.66) and outside. Petrol pump is included with the electromagnetic relay. Ben Zin sucks with a pump from the tank and at the same time is washes and cools the pump electric motor. At the outlet of the pump, there is a check valve that does not allow the fuel from the pressure from the head line when the fuel pump is turned off. A safety valve is served to limit pressure.

Coming from fuel pump fuel, under pressure at least 280 kPa passes through fuel filter Fine cleaning and enters the fuel ramp. The filter has a metal housing filled with a paper filtering element.

Ramp(Fig.2.67) is a hollow structure to which the nozzles and pressure regulator are attached. Rampa is mounted bolted to the engine inlet pipe. The ramp also establishes a fitting, which serves to control the pressure of fuel. The fitting is closed by a threaded plug for pollution protection.

Nozzle(Fig. 2.68) has a metal casing, inside which is located solenoid valveconsisting of electrical winding, steel of gray dehkin, springs and a shut-off needle. In the upper part of the nozzle is not a large strainer, the prevention sprayer nozzle (having very small holes) from pollution. Rubber rings provide non-needed seal between ramp, nozzle and landing place in the inlet pipeline. Fixation of the nozzle

rampa is carried out using a special clamp. On the housing of the nozzle there are electrical contacts for

Fig. 2.68. Electromagnetic gasoline engine nozzles: Left - GM, right - Bosch

Fig. 2.69. Fuel pressure control:1 - body; 2 - cover; 3 - nozzle for vacuum hose; 4 - membrane; 5 - KLAN; A - fuel cavity; B - Vacuum cavity

Fig. 2.70. Plastic intake trumpets with a receiver and throttle

keeping electrical connector. Adjusting the amount of fuel injected by the nozzle is carried out by changing the length of the electrical pulse supplied to the contacts of the nozzle.

Pressure regulatorfuel (Fig. 2.69) is used to change the pressure in the ramp, in dependence on vacuum in the inlet pipeline. In the steel chassis of the regulator, a spring-loaded needle valve is false, connected to a diaphragm. On the diaphragm, the pressure of the fuel in the ramp is affected with one side, and with another vacuum in the inlet pipeline. With an increase in the vacuum, during the cover of the throttle, the valve opens, the excess of fuel merge along the drain pipe back into the tank, and the pressure in the ramp decreases.

Recently, injection systems appeared in which there is no fuel pressure regulator. For example, on the Ramp of the V8 car NEW Range Rover There is no pressure regulator, and the composition of the combustible mixture is provided only by the operation of the nozzles receiving signals from the electronic unit.

Air supply and cleaning systemconsists of a air filter with replaceable filter element, throttle with damper and regulator idle move, Review faith and exhaust pipeline (Fig. 2.70).

Receivermust have a sufficiently large volume in order to smooth the pulsation of the air engine entering the cylinders.

Throttle pipefastened at the receiver and serves to change the amount of WHO Spirit in the engine cylinders. The change in the amount of air is carried out using a throttle blade rotated in the housing using the cable lead from the "Gas" pedal. The throttle position sensor is installed on the throttle position sensor and the idle regulator. In the throttle nozzle there are holes for the occasion of the RA RAB, which is used by the gasoline vapor capture system.

Recently, the injection system designers begin to apply the electric drive, when there is no mechanical connection between the gas pedal and the throttle (Fig. 2.71). In such structures on the "Gas" pedals, the sensors of its position are established, and the throttle is rotated by a stepper electric motor with a gearbox. The electric spring rotates the damper along the signals of the computer, managing the work of the engine. In such designs, not only a clear execution of the driver teams is not only ensured, but it is possible to influence the engine, correcting the driver's errors, to act the electronic system for maintaining the stability of the car and other modern electronic security systems.

Fig. 2.71. Throttle with electronicFig. 2.72. Inductive sensors with a positional drive ensures the age of crankshaft and the distribution capacity of the engine control by proof

Water

Throttle position sensorit is a potentiometer whose slider is connected to the axis of the throttle. When turning the throttle, the electric resistance of the sensor and the voltage of its power supply is changed, which is the output of the spasband for the ECU. In the throttle control electric drive systems, no less than two sensors are used to make the computer to determine the direction of movement of the damper.

Idling regulatorit serves to adjust the rotor of the crankshaft engine at idle by changing the amount of air passing into the closed throttle. The regulator consists of a stepping motor, controlled by the ECU, and the conical valve. In modern systems with more powerful engine operation computers, cost no idle regulators. The computer, analyzing the signals from many numerical sensors, controls the length of the electric current of electric currents entering the injectors and the engine operation in all modes, including at idle.

Between the air filter and the inlet pipe nozzle sets dat Chik mass flow Fuel.The sensor changes the frequency of the electrical signal, posting to the ECU, depending on the amount of air passing through the nozzle. This sensor comes to the ECU and an electrical signal corresponding to the temperature of flowing air. In the first electronic injection systems, sensors were used, evaluating the volume of incoming air. In the inlet nozzle, the damper was established, which deviated to different values \u200b\u200bdepending on the head of the incoming air. A potentiometer has been associated with a barrier, which changed resistance depending on the valve rotation value. Modern air mass flow sensors work using the principle of changing the electrical resistance of heated wire or conductive film when cooled by its incoming air flow. The control computer, which also receives signals from the temperature of the incoming air temperature, can determine the mass of the air entered the air.

For the correct management of the operation of the distributed injection system, the electronic BLU is required signals from other sensors. Latest: Cooling fluid temperature sensor, Crankshaft position sensor, Crankshaft speed sensor, Mobile velocity sensor, detonation sensor, oxygen concentration sensor (installed in the receiving pipe of the exhaust gas release system in the injection system feedback).

As temperature sensors, the mixture of nicknames are mainly used, which change the electrical resistance when the temperature changes. The sensors of the position and the speed of rotation of the crankshaft are usually carried out inductive type (Fig. 2.72). They produce electric current pulses when turning the flywheel with marks on it.

Fig.2.73. Adsorber work scheme:1 - suction air; 2 - throttle; 3 - engine intake manifold; 4 is a valve blowing vessel with activated carbon; 5 - signal from ECU; 6 - vessel with activated carbon; 7 - surrounding air; 8 - Top straightened pairs in the fuel tank

The power supply system with a distributed injection may be sequential or parallel. In a parallel injection system, depending on the number of engine cylinders, several injectors are triggered at the same time. In the system with a serial injection at the right point in time, only one, particular nozzle, is triggered. In the second case, the ECU should receive information about the moment of finding each piston near the VMT in the intake tact. This requires not only the crankshaft position sensor, but also dat chick position of the camshaft.On modern cars, as a rule, the engines with a sequential injection are putty.

For trample of gasoline vaporwhich evaporates from the fuel tank, in all system themes of injection uses special adsorbers with activated carbon (Fig. 2.73). Activated coal located in a special container connected by pipelines with fuel tank, well absorbs gasoline pairs. To remove gasoline from the adsorber, the latter is blowing with air and is connected to the engine inlet pipe, in order

In order for the operation of the engine at the same time, the purge is performed only on the definition of the engine operation modes, with the help of special valves that are opened and closed at the command of the ECU.

In feedback injection systems, use oxygen concentration sensorsin the exhaust gases, which are installed in the exhaust system with a catalytic neutralizer of exhaust gases.

Catalytic neutralizer(Fig. 2.74;

Fig. 2.74. Two-layer three-component catalytic neutralizer Floor Gaza:1 - oxygen concentration sensor for closed contour management; 2 - monolithic block carrier; 3 - MON HELF Element in the form of a wire mesh; 4 - Double-wing thermal insulation Nate Roller

2.75) is installed in the exhaust system to reduce the content of harmful substances in the exhaust gases. Neutral, the plot contains one recovery (rhodium) and two oxidative (platinum and palia) catalyst. Oxidative kata Lisauses contribute to the oxidation of non-fermentation hydrocarbons (CH) in water vapor,

Fig. 2.75. Appearance Neutralizer

and carbon monoxide (CO) in carbon dioxide. The VOS Family Catalyst restores the harmful nitrogen oxides NOX in harmless nitrogen. Since these neutralizers reduce in the exhaust gases, the content of three harms, they are called three-component.

The operation of the automotive engine on eaten gasoline leads to the failure of an expensive catalytic neutralizer. Therefore, in most countries, the use of eatented benzina is prohibited.

A three-component catalytic nithelifier works most effectively if a mixture of stoichiometric composition is supplied, i.e., with a ratio of air and fuel as 14.7: 1 or the coefficient of excess air equal to one. If the air in the mixture is too small (that is, little oxygen), then CH and CO not completely oxidize (burned) to a secure by-product. If the air is too much, then the decomposition of N0x can be provided for oxygen and nitrogen. Therefore, a new generation of engines appeared, in which the mixture was adjusted constantly to obtain accurate compliance of the coefficient of excess aircraft SS \u003d 1 using the dates of the oxygen concentration (lambda zones yes) (Fig. 2.77) embedded in the exhaust system.

Fig. 2.76. Dependence of the effectiveness of the neutralizer from the coefficient of an excess air

Fig. 2.77. Oxygen concentration sensor device:1 - Sealing KO; 2 - metal case with thread and hexagon "turnkey"; 3 - Ceramic cue insulator; 4 - wires; 5 - sealing cuff wires; 6 - Current contact of the power supply of the heater; 7 - external protective screen with holes for atmospheric air; 8 - Toko puller electrical signal; 9 - electronic heater; 10 - ceramic tip; 11 - Protective screen with brass for exhaust gases

This sensor determines the amount of oxygen in the exhaust gases, and its electrical signal uses the computer, which correspondively changes the amount of the top Liva. The principle of operation of the sensor lies in the ability to pass through themselves the ki slurry. If the oxygen content on the active surfaces of the sensor (one of which is in contact with the atmosphere, and the other with the exhaust gases) is significantly different, a sharp change in voltage on the sensor outputs occurs. Sometimes there are two dates of the oxygen concentration of oxygen: one - to the neutralizer, and the other after.

In order for the catalyst and the oxygen concentration sensor to work effectively, they should be labels to a certain temperature. The minimum temperature, with which 90% of harmful substances are delayed, is about 300 "C. It is also necessary to avoid overheating of the neutralizer, since this may damage the body and partially block the passage for gases. If the engine begins to work with interruption, then unburned fuel tramples in the catalyst, sharply increasing its temperature. Ino, the gda can be enough a few minutes of engine operation with interruptions to completely damage the neutralizer. That's why electronic systems Modern engines must identify passages in work and prevent them, as well as warn the driver about seriously the same problem. Sometimes to accelerate the warm-up of the catalytic neutralizer after the PU SKA of the Cold Engine uses electrical heaters. Circular concentration sensors, currently used, almost all have heating elements. In modern engines, in order to limit emissions of harmful substances in the atmosphere

the RU during the engine warming up the preliminary catalytic locomotives are set as close as possible to the exhaust collector (Fig. 2.78) to ensure the rapid heating of the neutralizer to the operating temperature. Oxygen sensors Installed before and after the neutralizer.

To improve the environmental performance of the engine, it is necessary not only with the ledge of the exhaust gas neutralizers, but also to improve the processes that proceed in the engine. The content of hydrocarbons was possible to reduce due to the reduction

"Slit volumes", such as the gap between the piston and the cylinder wall above the top compendent ring and cavities around the valve saddle.

A thorough study of the fluxe of a combustible mixture inside the cylinder using a computer of the Ternoye technique made it possible to provide a more complete combustion and low levels of CO. The NOX level was reduced using the exhaust gas recycling system by boron of the gas part graduation system And feeding it into the air flow on the inlet. These measures and fast, accurate control of the operation of the engine in transient modes can be reduced harmful emissions to a minimum even before the catalyst. To accelerate the warm-up of the catalytic neutralizer and the output of it on the operating mode, the method is also used to secondary in the exhaust manifold using a special electric pump.

Another effective and proper way to neutralize harmful products in the exhaust gases is flame afterburning, which is based on the ability of combustible components of the exhaust gases (CH, CH, Aldehydes) to oxide at high temperatures. The exhaust gases enter the chamber of the shocking agent, having an ejector, through which the heated air from the heat of the lobemnik. The burning occurs in the chamber,

Fig. 2.78. Engine exhaust manifoldand for ignition is the fastener

with preliminary neutralizercandle.

Direct gasoline injection

The first gasoline injection systems directly into the engine cylinders appeared in the first half of the XX century. and used on aircraft engines. Attempts to apply direct injection in gasoline engines of cars were discontinued in the 40s of the XIX century, because such engines were obtained expensive, uneconomical and highly smoked at high power modes. Injecting gasoline directly into cylinders is associated with certain difficulties. Injectors for direct gasoline injection work in more complex conditions than those installed in the inlet pipeline. The head of the block into which such nozzles should be attached, it turns out more complex and expensive. The time allocated to the mixing process during direct injection is significantly reduced, and therefore, for good mixture, it is necessary to supply gasoline to PWM pain.

With all these difficulties managed to cope with Mitsubishi specialists, to Toraya for the first time applied the system of direct gasoline injection on automotive engines. First serial car Mitsubishi. Galant with a 1.8 GDI engine (Gasoline Direct Injection - direct gasoline injection) appeared in 1996 (Fig. 2.81). Now the magnets with direct injection of gasoline produce Peugeot-Citroen, Renault, Toyota, Daimlerchrysler and other manufacturers (Fig. 2.79; 2.80; 2.84).

The advantages of the direct injection system are mainly in improving fuel efficiency, as well as some increase in capacity. The first is explained by the engine ability with the direct injection system to work

Fig. 2.79. Volkswagen FSI engine circuit with direct gasoline injection

Fig.2.80. In 2000, PSA Peugeot-Citroen presented its two-liter-cylinder HPI engine with direct gasoline injection, which could work on poor blends

on very poor blends. The increase in power is due to the fact that the organization of the fuel supply process into the engine cylinders makes it possible to increase the degree of compression to 12.5 (in conventional gasoline engines, it is rarely able to establish a compression ratio over 10 due to the onset of detonation).

In the engine GDI, the fuel pump provides a pressure of 5 MPa. Electro magnetic nozzle installed in trick of the cylinder block injected benzin directly into the engine cylinder and can operate in two modes. Due to the simplicity of the supplied electrical signal, it can inject the fuel or a powerful conical torch, or a compact jet (Fig. 2.82). The bottom of the piston has a special form in the form of a spherical excavation (Fig. 2.83). This form allows you to spin the incoming air, to send the injected fuses in to the ignition candle installed in the center of the combustion chamber. Inlet pipe wire is not located on the side, and the vertical

Fig. 2.81. Engine Mitsubishi GDI - Per serial Engine With a system not mediocre gasoline injection

but on top. It does not have sharp bends, and therefore air comes with high speed.

Fig.2.82. GDI engine nozzle can operate in two modes, providing a power (a) or compact (b) sprayed gasoline torch

In the operation of the engine with a direct injection system, three different modes can be distinguished:

1) mode of operation on ultra-walled mixtures;

2) mode of operation on the stoichiometric mixture;

3) the mode of sharp accelerations from small revolutions;

First modeit is used in the case when the car moves without sharp usskini at a speed of about 100-120 km / h. In this mode, a very poor combustible mixture is used with an excess air coefficient of more than 2.7. Under normal conditions, such a mixture cannot ignite from the spark, so the nozzle is injected by the fuel to the package at the end of the compression tact (as in the diesel). The spherical excavation in the piston on the rustles the fuel stream to the spark plug electrodes, where the high concentration of gasoline vapor provides the possibility of mixing the mixture.

Second modeused when moving a car with high speed and with sharp accelerations when you need to get high power. Such mode of movement requires the stoichiometric composition of the mixture. A mixture of such a composition is easily flammable, but the engine GDI has increased degree

Compression, and in order not to be taken de Tonation, the nozzle injects fuel with a powerful torch. The finely sprayed then fuel fills the cylinder and, evaporating, ox the cylinder surface, reducing the likelihood of detonation.

Third modewe are necessary to obtain a large torque with a sharp press of the pedal "Gas" when the engine is

bottles on small turns. This engine mode is different in that during one cycle, the nozzle works twice. During the intake tact in the cylinder for

Fig. 2.83. The engine piston with the direct injection of gasoline has a special form (combustion process over the piston)

4. Order No. 1031. 97

Fig. 2.84. Constructive features Engine with direct injection Ben Zina Audi 2.0 FSI

its cooling with a powerful torch is injected by an ultra-walled mixture (A \u003d 4.1). At the end of the tact of compression nozzle once again injects fuel, but compact torch. At the same time, the mixture in the cylinder is enriched and detonation does not occur.

Compared with ordinary engine With a power system with a gasoline distributed, the engine with a GDI system is about 10% more economical and discarded 20% less carbon dioxide into the atmosphere. Increased engine power reaches 10%. However, as shown by the operation of cars with such type engines, they are very sensitive to the content of sulfur in gasoline.

The original gasoline injection process was developed by ORBITAL. In this process, gasoline is injected into the engine cylinders, in advance mixed with air with a special nozzle. Orbital nozzle consists of two jaws, fuel and air.

Fig. 2.85. Orbital nozzle work

Air to air jackets comes in a compressed form from a special compressor at a pressure of 0.65 MPa. The fuel pressure is 0.8 MPa. First, the top listed fat is triggered, and then at the right moment and air, therefore the fuel-air mixture in the form of an aerosol (Fig. 2.85) is injected into the cylinder.

The nozzle installed in the cylinder head next to the spark plug fueling the fuel and air jet directly to the spark plug electrodes, which ensures its good ignition.

In modern cars in gasoline power plants The principle of operation of the system is similar to that applied on diesel engines. In these motors, it is divided into two - inlet and injection. The first provides air supply, and the second fuel. But due to the constructive and operational features, the operation of the injection is significantly different from the diesels used.

Note that the difference in the injection systems of diesel and gasoline engines is increasingly erased. To obtain the best qualities, designers borrow constructive solutions and apply them to different types Power systems.

Device and principle of operation of the injection injection system

The second name of gasoline engines injection systems is an injection. Its main feature is the exact dosage of fuel. This is achieved by using injectors in the design. The engine injection injection device includes two components - executive and control.

The task of the executive part includes the supply of gasoline and its spraying. It includes not so much composite elements:

Pump (electric).
Filtering element (fine cleaning).
Fuel supply.
Ramp.
Nozzle.

But these are only the main components. The executive component may include another number of additional components and parts - the pressure regulator, the drain system of gasoline surplus, adsorber.

The task of these elements includes the preparation of fuel and ensuring its receipt to the nozzles that their injection is carried out.

The principle of operation of the executive component is simple. When turning the ignition key (on some models - when opening a driver's door), an electric pump is included, which pumps gasoline and fills them with the other elements. The fuel is cleaned and the fuel lines enters the ramp, which connects the nozzles. Due to the pump fuel throughout the system is under pressure. But its value is lower than on diesels.

Opening the nozzles is carried out due to the electrical pulses 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 the indicators and operation parameters - the rotation speed of the crankshaft, the amount of air supplied, the temperature of the coal, the position of the throttle. Indications come to the control unit (ECU). It compares this information with the data listed in 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 to open the nozzle at a time or another mode of operation of the power unit.

Types of injectors

But note that this is the overall design of the gasoline motor supply system. But the injectors have developed several, and each of them has its constructive and work features.

Engine injection systems are used on cars:

central;
distributed;
direct.

The central injection is considered the first injector. Its peculiarity is to use only one nozzle, which injected gasoline in the intake manifold at the same time for all cylinders. Initially, it was mechanical and no electronics in the design was not used. If we consider the device of the mechanical injector, it is similar to a carburetor system, with a single difference that instead of the carburetor, a mechanical drive nozzle was used. Over time, the central filing was made electronic.

Now this type is not used due to a number of shortcomings, the main of which is the uneven fuel distribution over the cylinders.

Distributed injection at the moment is the most common system. The design of this type of the injector is described above. Its feature is that the fuel for each cylinder gives its own nozzle.

In the design of this type of nozzles are installed in the intake manifold and are located next to the GBC. The distribution of fuel in the cylinders makes it possible to ensure accurate dosage of gasoline.

The immediate injection is now the most advanced type of gasoline. In the previous two types, gasoline was supplied to the passing air flow, and the mixture began to be carried out still in the intake manifold. The same design injector copies the diesel injection system.

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

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

Diesel engines power systems

And diesel systems are upgraded. If the earlier it was mechanical, now the diesel engine is equipped with electronic control. It uses the same sensors and control unit as in a gasoline motor.

Now there are three types of diesel injections on cars:

With distribution pump.
COMMON RAIL.
Pump-nozzle.

As in gasoline engines, design diesel injection Consists of executive and control units.

Many elements of the executive part are the same as injectors - tank, fueling, filtering elements. But there are also nodes that are not found on gasoline engines - fuel pumping pump, TNVD, high-pressure fuel for transportation.

In mechanical systems of diesel engines, rowed TNVDs were used, in which the fuel pressure for each nozzle created its own separate plunger pair. Such pumps differed high reliability, but were bulky. The moment of injection and the amount of diesel fuel injected was regulated by the pump.

In engines equipped with distribution pump, in the pump design, only one plunger pair is used, which shakes fuel for nozzles. This node is characterized by compact sizes, but its resource is lower than in the row. This system is used only on passenger vehicles.

COMMON RAIL is considered one of the most effective diesel engine injection systems. The overall concept is largely borrowed from the injector with separate feed.

In such a diesel, the moment of the feed and the amount of fuel "Heads" the electronic component. The task of the high pressure pump is only the discharge of diesel fuel and the creation of high pressure. Moreover, diesel fuel is not immediately applied to the nozzles, but in the ramp connecting the nozzles.

Pump-nozzles - another type of diesel injection. There is no TNVD in this design, and plunger pairs that create a pressure of diesel fuel are included in the injectors. Such a constructive solution allows you to create the highest fuel pressure values \u200b\u200bamong existing injection species on diesel units.

Finally, we note that information is given here on the types of engine injection generalizable. To deal with the design and features of the specified types, they are considered separately.