chief purpose fuel system car are fuel supply from the tank, filtration, formation combustible mixture and feeding it into the cylinders. There are several types of fuel systems for. The most common in the 20th century was carburetor system fuel mixture supply. The next step was the development of fuel injection using a single nozzle, the so-called mono injection. The use of this system has reduced fuel consumption. Currently, a third fuel supply system is used - injection. In this system, fuel under pressure is supplied directly to intake manifold. The number of injectors is equal to the number of cylinders.

injection andcarburetor option

Fuel system device

All engine power systems are similar, differ only in the methods of mixing. The composition of the fuel system includes the following elements:

1. Fuel tank, designed to store fuel and is a compact container with a fuel intake device (pump) and, in some cases, coarse filtration elements.
2. Fuel lines are a complex fuel pipes, hoses and are designed to transport fuel to the mixture formation device.
3. Mixing devices ( carburetor, single injection, injector) is a mechanism in which fuel and air (emulsion) are combined for further supply to the cylinders at (intake stroke).
4. The control unit for the operation of the mixture formation device (injection power systems) - complex electronic device to control the operation of fuel injectors, shut-off valves, control sensors.
5. Fuel pump, usually submersible, designed to pump fuel into the fuel line. It is an electric motor connected to a liquid pump in a sealed housing. Lubricated directly by fuel and long-term operation with a minimum amount of fuel, leads to engine failure. In some engines, the fuel pump was attached directly to the engine and was driven by the rotation of an intermediate shaft, or camshaft.
6. Additional coarse filters and fine cleaning . Installed filter elements in the fuel supply chain.

The principle of operation of the fuel system

Consider the operation of the entire system as a whole. The fuel is sucked from the tank by the pump and fed through the fuel line through the cleaning filters to the mixing device. Fuel enters the carburetor float chamber, where it is then fed through calibrated jets into the mixture formation chamber. Mixed with air, the mixture enters the intake manifold through the throttle valve. After the intake valve opens, it enters the cylinder. IN mono injection system fuel is supplied to the nozzle, which is controlled by an electronic unit. At the right time, the nozzle opens, and the fuel enters the mixture formation chamber, where, as in the carburetor system, it mixes with air. Further, the process is the same as in the carburetor.

IN injection system fuel is supplied to the nozzles, which are opened by control signals from the control unit. The injectors are interconnected by a fuel line, which always contains fuel. All fuel systems have a fuel return line that drains excess fuel into the tank.

The power supply system of a diesel engine is similar to that of a gasoline engine. True, fuel is injected directly into the combustion chamber of the cylinder, under high pressure. Mixing takes place in the cylinder. To supply fuel under high pressure, a high pressure pump (TNVD) is used.

For everyone modern cars mobile phones with gasoline engines a fuel injection system is used, since it is more advanced than a carburetor, despite the fact that it is structurally more complex.

The injection engine is not new, but it became widespread only after the development of electronic technologies. This is because it was very difficult to mechanically organize the control of a system with high accuracy. But with the advent of microprocessors, this became quite possible.

injection system differs in that gasoline is supplied in strictly specified portions forcibly into the manifold (cylinder).

The main advantage that the injection power system has is the observance of the optimal proportions of the constituent elements of the combustible mixture in different operating modes. power plant. This results in better power output and economical petrol consumption.

System device

The fuel injection system consists of electronic and mechanical components. The first controls the parameters of work power unit and on their basis gives signals for actuation of the executive (mechanical) part.

The electronic component includes a microcontroller (electronic control unit) and a large number of tracking sensors:

• crankshaft position;
• mass air flow;
• provisions throttle valve;
• detonation;
• coolant temperature;
• air pressure in the intake manifold.

Injector system sensors

Some cars may have a few more additional sensors. All of them have one task - to determine the parameters of the power unit and transfer them to the computer

As for the mechanical part, it includes the following elements:

• electric fuel pump;
• fuel lines;
• filter;
• pressure regulator;
• fuel rail;
• nozzles.

Simple fuel injection system

How it all works

Now consider the principle of operation of the injection engine separately for each component. With the electronic part, in general, everything is simple. Sensors collect information about the speed of rotation of the crankshaft, air (entered the cylinders, as well as its residual part in the exhaust gases), throttle position (associated with the accelerator pedal), coolant temperature. These data are constantly transmitted by the sensors to the electronic unit, due to which a high accuracy of gasoline dosing is achieved.

The ECU compares the information coming from the sensors with the data entered in the cards, and already on the basis of this comparison and a number of calculations, it controls the executive part. The so-called cards with optimal parameters the operation of the power plant (for example, for such conditions it is necessary to apply so much gasoline, for others - so much).

First injection Toyota engine 1973

To make it clearer, let's consider in more detail the algorithm of work electronic block, but according to a simplified scheme, since in reality a very large amount of data is used in the calculation. In general, all this is aimed at calculating the temporal length of the electrical pulse that is applied to the injectors.

Since the circuit is simplified, we assume that the electronic unit only calculates according to several parameters, namely the base time pulse length and two coefficients - the coolant temperature and the oxygen level in the exhaust gases. To obtain the result, the ECU uses a formula in which all available data are multiplied.

To obtain the basic pulse length, the microcontroller takes two parameters - the speed of rotation of the crankshaft and the load, which can be calculated from the pressure in the manifold.

For example, the engine speed is 3000, and the load is 4. The microcontroller takes this data and compares it with the table entered on the map. In this case, we get a base time pulse length of 12 milliseconds.

But for calculations, it is also necessary to take into account the coefficients, for which readings are taken from the coolant temperature sensors and the lambda probe. For example, the temperature is 100 degrees, and the oxygen level in the exhaust gases is 3. The ECU takes this data and compares it with several more tables. Assume that the temperature coefficient is 0.8 and the oxygen coefficient is 1.0.

Having received all the necessary data, the electronic unit performs the calculation. In our case, 12 is multiplied by 0.8 and by 1.0. As a result, we get that the impulse should be 9.6 milliseconds.

The described algorithm is very simplified, but in fact, more than a dozen parameters and indicators can be taken into account in the calculations.

Since the data is constantly sent to the electronic unit, the system almost instantly responds to changes in the parameters of the engine and adjusts to them, ensuring optimal mixture formation.

It should be noted that the electronic unit controls not only the fuel supply, its task also includes adjusting the ignition angle to ensure optimal performance motor.

Now about the mechanical part. Everything is very simple here: a pump installed in the tank pumps gasoline into the system, and under pressure to ensure forced supply. The pressure must be certain, so a regulator is included in the circuit.

On the highways, gasoline is supplied to the ramp, which connects all the nozzles. An electrical impulse supplied from the computer leads to the opening of the nozzles, and since gasoline is under pressure, it is simply injected through the opened channel.

Types and types of injectors

There are two types of injectors:

1. With single injection. Such a system is obsolete and is no longer used on cars. Its essence is that there is only one nozzle installed in the intake manifold. This design did not provide an even distribution of fuel over the cylinders, so its operation was similar to carburetor system.
2. Multi-point injection. On modern cars, this type is used. Here, each cylinder has its own nozzle, so this system is characterized by high dosing accuracy. Nozzles can be installed both in the intake manifold and in the cylinder itself ( injector).

On a multi-point fuel injection system, several types of injection can be used:

1. Simultaneous. In this type, the impulse from the ECU goes to all the injectors at once, and they open together. Now such an injection is not used.
2. Paired, he is pairwise-parallel. In this type, the nozzles work in pairs. It is interesting that only one of them supplies fuel directly in the intake stroke, while the second cycle does not match. But since the engine is 4-stroke, with a valve gas distribution system, the injection mismatch in cycle does not affect the performance of the engine.
3. Phased. In this type, the ECU sends open signals for each injector separately, so the injection occurs with the same stroke.

It is noteworthy that a modern fuel injection system can use several types of injection. So, in normal mode, phased injection is used, but in the event of a transition to emergency operation (for example, one of the sensors failed), injection engine switches to twin injection.

Sensor feedback

One of the main sensors, on the basis of which the ECU regulates the opening time of the injectors, is a lambda probe installed in the exhaust system. This sensor determines the residual (not burned) amount of air in the gases.

The evolution of the lambda probe from Bosch

Thanks to this sensor, the so-called "feedback" is provided. Its essence is this: the ECU did all the calculations and gave an impulse to the injectors. Fuel entered, mixed with air and burned. The resulting exhaust gases with unburned particles of the mixture are removed from the cylinders through the exhaust system exhaust gases in which the lambda probe is installed. Based on his readings, the ECU determines whether all calculations were carried out correctly and, if necessary, makes adjustments to obtain the optimal composition. That is, on the basis of the already completed stage of fuel supply and combustion, the microcontroller makes calculations for the next one.

It should be noted that during the operation of the power plant there are certain modes in which the readings oxygen sensor will be incorrect, which may disrupt the operation of the motor or a mixture with a certain composition is required. In such modes, the ECU ignores information from the lambda probe, and it sends signals for the supply of gasoline based on the information stored in the maps.

In different modes, the feedback works like this:

• Starting the motor. In order for the engine to be able to start, an enriched combustible mixture with an increased percentage of fuel is needed. And the electronic unit provides this, and for this it uses the given data, and it does not use information from the oxygen sensor;
• Warming up To make the injection engine gain faster operating temperature ECU sets increased speed motor. At the same time, he constantly monitors its temperature, and as it warms up, it adjusts the composition of the combustible mixture, gradually depleting it until its composition becomes optimal. In this mode, the electronic unit continues to use the data specified in the cards, still not using the readings of the lambda probe;
• Idling. In this mode, the engine is already fully warmed up, and the exhaust gas temperature is high, so the conditions for the correct operation of the lambda probe are met. The ECU is already starting to use the readings of the oxygen sensor, which allows you to set the stoichiometric composition of the mixture. With this composition, the greatest power output of the power plant is provided;
• Movement with a smooth change in engine speed. To achieve economical fuel consumption at maximum power output, a mixture with a stoichiometric composition is needed, therefore, in this mode, the ECU regulates the supply of gasoline based on the readings of the lambda probe;
• A sharp increase in turnover. In order for the injection engine to respond normally to such an action, a slightly enriched mixture is needed. To provide it, the ECU uses card data, and not lambda probe readings;
• Motor braking. Since this mode does not require power output from the motor, it is enough that the mixture simply does not allow the power plant to stop, and a lean mixture is also suitable for this. For its manifestation, the readings of the lambda probe are not needed, so the ECU does not use them.

As you can see, although the lambda probe is very important for the operation of the system, the information from it is not always used.

Finally, we note that the injector, although a structurally complex system and includes many elements, the failure of which immediately affects the operation of the power plant, but it provides a more rational consumption of gasoline, and also increases the environmental friendliness of the car. Therefore, there is no alternative to this power system yet.

Autoleek

The main elements, which are nozzles.

Into the power system carburetor engine are included: fuel tank, sediment filter, fuel lines, fuel pump, fuel fine filter, air cleaner, inlet pipeline, exhaust pipeline, exhaust pipes, muffler, fuel gauges.

Work power system

When the engine is running the fuel pump sucks fuel from the fuel tank and delivers it through filters to the carburetor float chamber. During the intake stroke, a vacuum is created in the engine cylinder and air, having passed through the air cleaner, enters the carburetor, where it mixes with fuel vapors and is fed into the cylinder in the form of a combustible mixture, and there, mixing with the rest of the exhaust gases, a working mixture is formed. After the stroke is completed, the exhaust gases are pushed out by the piston into the exhaust pipeline and through the exhaust pipes through the muffler into the environment.

High pressure fuel pump device YaMZ

Power supply and exhaust gas systems of a car engine:

1 - air supply channel to the air filter; 2 - air filter; 3 - carburetor; 4 - handle manual control air damper; 5 - handle for manual control of throttle valves; 6 - throttle control pedal; 7 - fuel wires; 8 - filter-sump; 9 - silencer; 10 - receiving pipes; 11 - exhaust pipeline; 12 - fuel fine filter; 13 - fuel pump; 14 - fuel gauge; 15 - fuel gauge sensor; 16 - fuel tank; 17— fuel tank cap; 18 - crane; 19 - muffler exhaust pipe.

Fuel. As a fuel in carburetor engines, gasoline is usually used, which is obtained as a result of oil refining.

Automobile gasolines, depending on the number of easily evaporating fractions, are divided into summer and winter.

For automotive carburetor engines, gasoline A-76, AI-92, AI-98, etc. are produced. The letter “A” indicates that gasoline is automobile, the number is the lowest octane number that characterizes the detonation resistance of gasoline. Isooctane has the highest detonation resistance (its resistance is taken as 100), the smallest is n-heptane (its resistance is 0). The octane number characterizing the knock resistance of gasoline is the percentage of isooctane in such a mixture with n-heptane, which is equivalent in knock resistance to the tested fuel. For example, the test fuel detonates in the same way as a mixture of 76% iso-octane and 24% n-heptane. The octane number of this fuel is 76. The octane number is determined by two methods: motor and research. When determining the octane number by the second method, the letter “I” is added to the marking of gasoline. The octane number determines the allowable compression ratio.

Fuel tank. The car is equipped with one or more fuel tanks. The volume of the fuel tank should provide 400-600 km of car run without refueling. The fuel tank consists of two welded halves made of stamped leaded steel. Inside the tank there are baffles that give rigidity to the structure and prevent the formation of waves in the fuel. In the upper part of the tank, a filler neck is welded, which is closed with a stopper. Sometimes, for the convenience of refueling the tank with fuel, a retractable neck with strainer. A fuel gauge sensor and a fuel intake tube with a strainer are mounted on the upper wall of the tank. At the bottom of the tank there is a threaded hole for draining sludge and removing mechanical impurities, which is closed with a stopper. The filler neck of the tank is tightly closed with a stopper, in the body of which there are two valves - steam and air. The steam valve opens when the pressure in the tank rises and releases the steam into the environment. The air valve opens when fuel is flowing and a vacuum is created.

Fuel filters. Coarse and fine filters are used to clean the fuel from mechanical impurities. The coarse filter-sump separates the fuel from water and large mechanical impurities. The filter-sump consists of a housing, a sump and a filter element, which is assembled from plates 0.14 mm thick. The plates have holes and protrusions 0.05 mm high. The plate package is mounted on a rod and is pressed against the body by a spring. In the assembled state, there are slots between the plates through which fuel passes. Large mechanical impurities and water are collected at the bottom of the sump and are periodically removed through a plug hole in the bottom.

Fuel tank (a) and operation of the exhaust (b) and intake (c) valves: 1—filter-sump; 2 - tank mounting bracket; 3 — a collar of fastening of a tank; 4 - sensor of the fuel level indicator in the tank; 5 - fuel tank; 6 - crane; 7 - tank cap; 8 - neck; 9 - cork lining; 10 - rubber gasket; P - cork body; 12 - exhaust valve; 13 - exhaust valve spring; 14 - inlet valve; 15 - tank plug lever; 16 - intake valve spring.

Settling filter: 1 - fuel wire to the fuel pump; 2 - body gasket; 3 - body-cover; 4 - fuel wire from the fuel tank; 5 - filter element gasket; 6 - filter element; 7— stand; 8 - sump; nine- drain plug; 10 - filter element rod; 11 - spring; 12 - filter element plate; 13 - hole in the plate for the passage of purified fuel; 14 - protrusions on the plate; 15 - hole in the plate for racks; 16 - plug; 17 — a bolt of fastening of the case cover.

Fine fuel filters with filter elements: a - mesh; b - ceramic; 1 - body; 2 - inlet; 3— gasket; 4— filter element; 5 - removable glass-sump; 6 - spring; 7— screw fastening the glass; 8— channel for fuel removal.

Fine filter. To purify fuel from small mechanical impurities, fine filters are used, which consist of a housing, a sump cup and a filter mesh or ceramic element. The ceramic filter element is a porous material that provides labyrinthine fuel movement. The filter is held in place by a bracket and screw.
Fuel wires connect fuel system devices and are made of copper, brass and steel tubes.

Fuel pump supply system

The fuel pump is used to supply fuel through the filters from the tank to the carburetor float chamber. Eccentric-driven diaphragm pumps are used camshaft. The pump consists of a housing in which the drive is mounted - a two-arm lever with a spring, a head where inlet and discharge valves with springs are located, and covers. The edges of the diaphragm are clamped between the body and the head. The diaphragm rod is pivotally attached to the drive lever, which allows the diaphragm to work with a variable stroke.
When the two-arm lever (rocker) lowers the diaphragm down, a vacuum is created in the cavity above the diaphragm, due to which the inlet valve opens and the supra-diaphragmatic cavity is filled with fuel. When the lever (pusher) escapes from the eccentric, the diaphragm rises under the action of a return spring. Above the diaphragm, the fuel pressure rises, the inlet valve closes, the discharge valve opens and the fuel enters through the fine filter into the carburetor float chamber. When changing filters, the float chamber is filled with fuel using a manual pumping device. In the event of a diaphragm failure (crack, break, etc.), fuel enters the lower part of the housing and flows out through the control hole.

Air filter serves to clean the air entering the carburetor from dust. Dust contains the smallest crystals of quartz, which, settling on the lubricated surfaces of parts, causes wear.

Carburetor device K-126B

Filter requirements:

. efficiency of air purification from dust;
. low hydraulic resistance;
. sufficient dust capacity:
. reliability;
. ease of maintenance;
. design manufacturability.

According to the method of air purification, filters are divided into inertial oil and dry.
Inertial oil filter consists of an oil bath housing, a cover, an air intake and a filter element made of synthetic material.
When the engine is running, air passing through the annular slot inside the housing and, in contact with the oil surface, sharply changes the direction of movement. As a result, large dust particles in the air adhere to the surface of the oil. Then the air passes through the filter element, is cleaned of small dust particles and enters the carburetor. Thus, the air undergoes a two-stage purification. When clogged, the filter is washed.
Dry Type Air Filter consists of a body, a cover, an air intake and a filter element made of porous cardboard. Change the filter element if necessary.

in a carbureted engine gasoline is used as fuel. Gasoline is a flammable liquid that is obtained from petroleum by direct distillation, or cracking. Gasoline is one of the main components of the combustible mixture. Under normal conditions of combustion of the working mixture, there is a gradual increase in pressure in the engine cylinders. When using fuel of lower quality than required technical specifications car engine, the speed of combustion of the working mixture can increase by 100 times and be 2000 m / s, such a rapid combustion of the mixture is called detonation. The propensity of gasoline to detonation is conditionally characterized by an octane number, the higher the octane number of gasoline, the less prone it is to detonation. Gasoline with a higher octane rating is used in automobile engines with a higher compression ratio. To reduce detonation, ethyl liquid is added to gasoline.

In the cylinders of an automobile engine, the working process proceeds quite quickly. For example, if crankshaft rotates at a speed of 2000 rpm, then each cycle takes 0.015 s. To do this, it is necessary that the speed of combustion of the fuel is 25-30 m/s. However, the combustion of fuel in the combustion chamber is slower. In order to increase the rate of combustion, the fuel is crushed into tiny particles and mixed with air. It has been established that for normal combustion 1 kg of fuel needs 15 kg of air, a mixture with this ratio (1:15) is called normal. However, at this ratio, complete combustion of the fuel does not occur. For complete combustion of fuel, more air is needed and the ratio of fuel to air should be 1:18. Such a mixture is called lean. With an increase in the ratio, the combustion rate decreases sharply, and at a ratio of 1:20, ignition does not occur at all. But highest power engine is achieved at a ratio of 1:13, in which case the combustion rate is close to optimal. Such a mixture is called enriched. With this composition of the mixture, complete combustion of the fuel does not occur, therefore, with an increase in power, fuel consumption increases.

When the engine is running, the following modes are distinguished:
1) cold engine start;
2) operation at a low crankshaft speed (idling);
3) work at partial (average) loads;
4) work at full loads;
5) work with a sharp increase in load or crankshaft speed (acceleration).

In each individual mode, the composition of the combustible mixture must be different.
The engine power system is designed to prepare and supply a combustible mixture to the combustion chambers, in addition, the power system regulates the amount and composition of the working mixture.

Carburetor engine power system includes the following elements:
1) fuel tank;
2) fuel lines;
3) fuel filters;
4) fuel pump;
5) carburetor;
6) air filter;
7) exhaust manifold:
8) intake manifold;
9) exhaust silencer.

On the modern cars instead of carburetor power systems are increasingly used fuel injection systems. On engines cars a port fuel injection system or a central single point fuel injection system can be installed.

Fuel injection systems have a number of advantages over carburetor power systems:
1) the absence of additional resistance to air flow in the form of a carburetor diffuser, which contributes to better filling of the combustion chambers of the cylinders and obtaining higher power;
2) improved cylinder scavenging by using the possibility of a longer period of valve overlap (with both intake and exhaust valves open);
3) improving the quality of the preparation of the working mixture by purging the combustion chambers with clean air without the admixture of fuel vapors;
4) more accurate distribution of fuel over the cylinders, which makes it possible to use gasoline with a lower octane number;
5) more accurate selection of the composition of the working mixture at all stages of engine operation, taking into account its technical condition.

In addition to the advantages, the injection system has one significant disadvantage. The injection fuel injection system has a higher degree of complexity in manufacturing parts, and this system also includes many electronic components, which leads to an increase in the cost of the car and the complexity of its maintenance.

Distributor fuel injection system is the most modern and perfect. The main functional element of this system is the electronic control unit (ECU). The ECU is essentially on-board computer car. The ECU provides optimal control of engine mechanisms and systems, ensures the most economical and efficient operation of the engine with maximum environmental protection in all modes.

The fuel injection system consists of:
1) air supply subsystems with throttle;
2) fuel supply subsystems with injectors, one for each cylinder;
3) afterburning systems for modified gases;
4) systems for capturing and liquefying gasoline vapors.

In addition to the control functions, the ECU has self-learning functions, diagnostic and self-diagnosis functions, and it also stores the previous parameters and characteristics of the engine, and changes in its technical condition.

Central single point fuel injection system differs from the distributor injection system in that it does not have a separate (distributive) gasoline injection for each cylinder. The fuel supply in this system is carried out using a central injection module with one electromagnetic nozzle. The air-fuel mixture is controlled by a throttle valve. The distribution of the working mixture over the cylinders is carried out, as in the carburetor power system. The remaining elements and functions of this power supply system are the same as in the distribution injection system.

Power supply systems for gasoline and diesel engines differ significantly, so we will consider them separately. So, what is a car power system?

Gasoline engine power system

There are two types of power systems for gasoline engines - carburetor and injection (injection). Since the carburetor system is no longer used on modern cars, we will only consider the basic principles of its operation below. If necessary, you can easily find Additional information on it in numerous special editions.

Supply system gasoline engine , regardless of engine type internal combustion, designed to store fuel, clean fuel and air from impurities, as well as supply air and fuel to the engine cylinders.

The fuel tank is used to store fuel in the vehicle. Modern cars use metal or plastic fuel tanks, which in most cases are located under the bottom of the body at the rear.

The power supply system of a gasoline engine can be divided into two subsystems - air supply and fuel supply. Whatever happens, in any situation, our field assistance specialists on the roads of Moscow will come and provide the necessary assistance.

The power supply system of a carburetor-type gasoline engine

In a carburetor engine, the fuel supply system works as follows.

The fuel pump (petrol pump) supplies fuel from the tank to the float chamber of the carburetor. The fuel pump, usually a diaphragm pump, is located directly on the engine. The pump is driven by an eccentric on the camshaft using a pusher rod.

Purification of fuel from contaminants is carried out in several stages. The roughest cleaning takes place with a mesh on the intake in the fuel tank. Then the fuel is filtered by a mesh at the inlet to the fuel pump. Also, a strainer-sump is installed on the carburetor inlet pipe.

In the carburetor, purified air from air filter and gasoline from the tank are mixed and fed into the engine intake pipe.

The carburetor is designed in such a way as to ensure the optimal ratio of air and gasoline in the mixture. This ratio (by mass) is approximately 15 to 1. An air-fuel mixture with this ratio of air to gasoline is called normal.

A normal mixture is necessary for the engine to operate in steady state. In other modes, the engine may require air-fuel mixtures with a different ratio of components.

A lean mixture (15-16.5 parts of air to one part of gasoline) has a lower combustion rate compared to an enriched one, but complete combustion of the fuel occurs. The lean mixture is used at medium loads and provides high efficiency, as well as a minimum emission of harmful substances.

A lean mixture (more than 16.5 parts air to one part gasoline) burns very slowly. A lean mixture can cause engine misfiring.

An enriched mixture (13-15 parts of air to one part of gasoline) has the highest combustion rate and is used with a sharp increase in load.

rich mixture(less than 13 parts of air to one part of gasoline) burns slowly. A rich mixture is needed when starting a cold engine and then idling.

To create a mixture other than normal, the carburetor is equipped with special devices - an economizer, accelerator pump(enriched mixture), air damper(rich mixture).

In carburetors of different systems, these devices are implemented in different ways, so we will not consider them in more detail here. The point is simply that carburetor type gasoline engine power supply system contains such constructs.

A throttle valve is used to change the amount of air-fuel mixture and, consequently, the engine speed. It is she who controls the driver, pressing or releasing the gas pedal.

Injection type gasoline engine power supply system

On a car with a fuel injection system, the driver also controls the engine through the throttle, but this is the analogy with the carburetor gasoline engine power system ends.

The fuel pump is located directly in the tank and has an electric drive.

The electric fuel pump is usually combined with a fuel level sensor and a strainer into a unit called the fuel module.

On most injection vehicles, the fuel from the fuel tank is pressurized into the replaceable fuel filter.

The fuel filter can be installed under the bottom of the body or in the engine compartment.

Fuel pipelines are connected to the filter with threaded or quick-detachable connections. The connections are sealed with petrol-resistant rubber rings or metal washers.

Recently, many automakers have begun to abandon the use of such filters. Fuel cleaning is carried out only by a filter installed in the fuel module.

The replacement of such a filter is not covered by the maintenance plan.

There are two main types of fuel injection systems - central fuel injection (single injection) and distributed injection, or, as it is also called, multipoint.

For automakers, central injection has become a transitional stage from a carburetor to a distributed injection and is not used on modern cars. This is due to the fact that the central fuel injection system does not allow meeting the requirements of modern environmental standards.

The central injection unit is similar to a carburetor, but instead of a mixing chamber and jets, an electromagnetic nozzle is installed inside, which opens at the command of an electronic engine control unit. Fuel injection occurs at the inlet of the intake manifold.

In a multiport injection system, the number of nozzles is equal to the number of cylinders.

The injectors are installed between the intake manifold and the fuel rail. IN fuel rail a constant pressure is maintained, which is usually about three bar (1 bar is equal to about 1 atm). To limit the pressure in the fuel rail, a regulator is used, which bleeds excess fuel back into the tank.

Previously, the pressure regulator was installed directly on the fuel rail, and to connect the regulator to fuel tank a fuel return line was used. IN modern systems the power supply of the gasoline engine, the regulator is located in the fuel module and the need for a return line is eliminated.

The fuel injectors open at the command of the electronic control unit, and fuel is injected from the rail into the intake pipe, where the fuel mixes with air and enters the cylinder as a mixture.

Injector opening commands are calculated based on signals from sensors electronic system engine control. This ensures the synchronization of the fuel supply system and the ignition system.

Injection type gasoline engine power supply system provides greater performance and the ability to meet higher environmental standards than carbureted.