Diesel engine. History In 1890, Rudolf Diesel developed the theory of the "economical thermal engine", which, thanks to strong compression in the cylinders. - presentation

Common types of power systems

In modern cars, the two most common types of fuel are diesel and gasoline.
Gas lags behind them a little, although it is also used quite often. The fuel used directly affects the design and operating principle of the fuel system. Initially, cars running on gasoline used a carburetor as the main element providing mixture formation. Now such a power system is considered obsolete and is not used in cars, but it has been replaced by an injector.

As for the diesel engine, it has its own system - diesel. It is noteworthy that the principle of its functioning in a diesel engine has remained unchanged since its creation, only the design has changed. In addition, the principle of this system in some way underlies the operation of the injector. Therefore, it is necessary to consider in more detail each of the types of power systems currently used.

Injector and its device

The operation of an internal combustion power plant is based on the process of converting the energy released during the combustion of a special mixture into mechanical action. But for this process to occur correctly, it requires careful preparation and feeding into the cylinders. And this is done by the fuel system in the power unit.

The task of this system is to supply fuel (one of the components of the mixture) and mix it with air, as a result of which a combustible mixture is formed, before it all enters the cylinder.

It is not for nothing that the internal combustion engine (hereinafter referred to as the ICE) is considered the heart of the car. It is the torque it produces that is the primary source of all mechanical and electrical processes occurring in the vehicle.

However, the motor cannot exist separately from the systems that serve it - lubrication, power, cooling and exhaust gases. The most significant role in the operation of the internal combustion engine is played by the engine power system (or fuel system).

Each car is characterized by such a concept as “power reserve”. It is determined by the distance that a car can travel on a full fuel tank without additional refills.

This indicator is influenced by a variety of factors: seasonal, weather and natural driving conditions, the nature of the road surface, the degree of vehicle load, the individual characteristics of the driver when driving, etc.).

However, the main role in determining the “appetite” of a car is played by the power system and its proper operation.

The power system performs the following functions:

1. fuel supply, cleaning and storage;
2. air purification;
3. preparing a special flammable mixture;
4. supplying the mixture to the internal combustion engine cylinders.

The classic car power system consists of the following structural elements:

• a fuel tank designed to store fuel;
• a fuel pump that performs the functions of creating pressure in the system and forcing fuel supply;
• fuel lines - special metal tubes and rubber hoses for transporting fuel from the fuel tank to the internal combustion engine (and excess fuel in the opposite direction);
• fuel purification filter (or filters);
• air filter (to clean the air from impurities);
• devices for preparing the fuel-air mixture.

The power supply system has a fairly simple principle of operation: under the influence of a special fuel pump, fuel from the tank, having previously undergone a cleaning procedure with a fuel filter, is supplied through fuel lines to a device intended for preparing the fuel-air mixture. And only then the mixture is supplied to the engine cylinders.

The main types of fuel for internal combustion engines are gasoline and diesel fuel (“diesel fuel”). Gas (methane) also belongs to the types of modern fuel, but, despite its widespread use, has not yet become relevant. The type of fuel is one of the criteria for classifying internal combustion engine power systems.

In this regard, power units are distinguished:

1. gasoline;
2. diesel;
3. based on gaseous fuel.

But the most recognized among experts is the typology of engine power systems based on the method of fuel supply and preparation of the fuel-air mixture. Following this classification principle, we distinguish, firstly, the power supply system of a carburetor engine, and secondly, the power supply system with fuel injection (or an injection engine).

Carburetor

The carburetor system is based on the operation of a technically complex device - a carburetor. A carburetor is a device that prepares a mixture of fuel and air in the required proportions. Despite the variety of types, in automotive practice the most widely used is the float suction carburetor, the circuit diagram of which includes:

• float chamber and float;
• atomizer, diffuser and mixing chamber;
• air and throttle valves;
• fuel and air channels with corresponding jets.

The preparation of the fuel-air mixture in the carburetor is carried out according to a passive scheme. The movement of the piston during the intake stroke (first stroke) creates a rarefied space in the cylinder, into which air rushes, passing through the air filter and through the carburetor.

It is here that the formation of a combustible mixture occurs: in the mixing chamber, in the diffuser, the fuel escaping from the atomizer is crushed by the air flow and mixed with it. Finally, through the intake manifold and intake valves, the combustible mixture is supplied to a specific engine cylinder, where at the required moment it is ignited by a spark from the spark plug.

Thus, the power system of a carburetor engine is a predominantly mechanical method of preparing the fuel-air mixture.

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Fuel injection

The era of the carburetor is being replaced by the era of the injection engine, the power system of which is based on fuel injection. Its main elements are: an electric fuel pump (located, as a rule, in the fuel tank), injectors (or nozzle), and an internal combustion engine control unit (the so-called “brains”).

The principle of operation of this power system is reduced to spraying fuel through nozzles under pressure created by the fuel pump.

The quality of the mixture varies depending on the operating mode of the engine and is controlled by the control unit. An important component of such a system is the injector.

1. with distributed injection;
2. with central injection.

The distributed injection system involves the use of injectors according to the number of engine cylinders, where each cylinder is served by its own injector, which is involved in preparing the combustible mixture. The central injection system has only one injector for all cylinders, located in the manifold.

The operating principle on which the diesel engine power system is based stands out as if apart.

Here, fuel is injected directly into the cylinders in atomized form, where the process of mixture formation (mixing with air) occurs, followed by ignition from compression of the combustible mixture by the piston.

Depending on the fuel injection method, the diesel power unit is available in three main options:

• with direct injection;
• with swirl chamber injection;
• with pre-chamber injection.

The swirl chamber and pre-chamber options involve injection of fuel into a special preliminary chamber of the cylinder, where it is partially ignited and then moved into the main chamber or the cylinder itself. Here the fuel mixes with air and finally burns out.

Direct injection involves delivering fuel immediately into the combustion chamber and then mixing it with air, etc.

Another feature that distinguishes the diesel engine power system is the principle of ignition of the combustible mixture.

This does not come from the spark plug (as in a gasoline engine), but from the pressure created by the cylinder piston, that is, by self-ignition. In other words, in this case there is no need to use spark plugs.

However, a cold engine will not be able to provide the proper temperature level required to ignite the mixture. And the use of glow plugs will allow for the necessary heating of the combustion chambers.

Depending on the goals and road conditions, the driver can use different driving modes. They also correspond to certain operating modes of the power supply system, each of which has a special quality fuel-air mixture.

1. The mixture will be rich when starting a cold engine. At the same time, air consumption is minimal. In this mode, the possibility of movement is categorically excluded. Otherwise, this will lead to increased fuel consumption and wear of power unit parts.
2. The composition of the mixture will be enriched when using the “idling” mode, which is used when coasting or running the engine in a warm state.
3. The mixture will be leaner when driving with partial loads (for example, on a flat road at medium speed in high gear).
4. The mixture composition will be enriched at full load when the vehicle is moving at high speed.
5. The mixture will be rich, close to rich, when driving under conditions of sharp acceleration (for example, when overtaking).

The choice of operating conditions for the power system, therefore, must be justified by the need to move in a certain mode.

During the operation of the vehicle, the vehicle's fuel system experiences loads that lead to its unstable operation or failure. The following faults are considered the most common.

Poor quality fuel, long service life, and environmental exposure lead to contamination and clogging of fuel lines, tank, filters (air and fuel) and technological openings of the combustible mixture preparation device, as well as breakdown of the fuel pump. The system will require repairs, which will consist of timely replacement of filter elements, periodic (every two to three years) cleaning of the fuel tank, carburetor or injector nozzles and replacement or repair of the pump.

Engine power loss

A malfunction of the fuel system in this case is determined by a violation of the regulation of the quality and quantity of the combustible mixture entering the cylinders. Troubleshooting involves the need to diagnose the combustible mixture preparation device.

Fuel leak

A fuel leak is a very dangerous phenomenon and is absolutely unacceptable. This malfunction is included in the “List of malfunctions...” with which the vehicle is prohibited from moving.

The causes of the problems lie in the loss of tightness of the components and assemblies of the fuel system.

Troubleshooting involves either replacing damaged system elements or tightening the fuel line fastenings.

The essence of the functioning of the injector is that fuel is forcibly injected into the passing air flow. In this case, gasoline is supplied under pressure, which ensures its atomization, thereby improving its mixing with air.

History of creation

Main article: History of internal combustion engines

From the moment of their appearance, heat engines (mainly steam engines) were distinguished by their large dimensions and weight due to the use of external combustion (boilers, condensers, evaporators, heat exchangers, tenders, pumps, water tanks, etc. were required), at the same time the main (functional) part of the steam engine (piston and cylinder) is relatively small[2]. Therefore, the inventors’ thoughts always returned to the possibility of combining fuel with the working fluid of the engine, which subsequently made it possible to significantly reduce the dimensions and weight and intensify the processes of intake and exhaust of the working fluid. These differences are especially important in transport.

Gas turbine internal combustion engine

The greatest contributions to the creation of various internal combustion engines were made by such engineers as John Barber (invention of the gas turbine in 1791), Robert Street (patent for a liquid fuel engine, 1794), Philippe Le Bon (discovery of lighting gas in 1799, the first gas engine in 1801), François Isaac de Rivaz (first piston engine, 1807), Jean Etienne Lenoir (Lenoir gas engine, 1860), Nikolaus Otto (spark ignition engine with mixture compression in 1861, four-stroke engine in 1876), Rudolf Diesel (Diesel engine on coal dust, 1897), Gottlieb Daimler and Wilhelm Maybach, Ogneslav Stepanovich Kostovich (gasoline engine with carburetor, 1880s), Gustav Vasilyevich Trinkler (diesel engines running on liquid fuel, 1899), Wernher von Braun (jet and turbojet engines, starting from the 1930s to the Lunar Program), and others. Thus, internal combustion engines developed behind steam engines (for example, a steam pump for pumping water was invented by Thomas Severi in 1698), due to the lack of suitable fuel. The very idea of ​​an internal combustion engine was proposed by Christiaan Huygens back in 1678; the Dutch scientist proposed using gunpowder as fuel[3]. The Englishman Etienne Barber tried to use a mixture of air and gas obtained by heating wood for this purpose[4]. The emergence of a whole galaxy of various powerful and lightweight engines made it possible to create new, previously non-existent types of transport (propeller and jet aircraft, helicopters, rockets, spacecraft, gas turbine ships, hovercrafts), and improve the efficiency and environmental friendliness of ship power plants and locomotives. Motorization also led to an acceleration of the pace of people's lives, the emergence of an entire automobile culture (USA); in military affairs it made it possible to create unusually destructive death machines (tank, fighter, bomber, missiles with conventional and nuclear warheads, submarine with torpedoes and others).

Rotary internal combustion engine

Power System Options

Carburetor

Thus, the power system of a carburetor engine is a predominantly mechanical method of cooking

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Fuel injection

The principle of operation of this power system is reduced to spraying fuel through nozzles under pressure created by the fuel pump. The quality of the mixture varies depending on the operating mode of the engine and is controlled by the control unit. An important component of such a system is the injector. The typology of injection engines is based precisely on the number of injectors used and their location.

Fuel system of diesel internal combustion engines: basic principles

The operating principle of a diesel fuel system differs from a gasoline one, which also affects the functioning of the fuel supply system.

We will only touch on the differences regarding the fuel component. The first of them is that a diesel engine has internal mixture formation. That is, the components of the mixture are fed into the cylinders separately and they are mixed there. And the second difference is that the mixture is ignited by compression, so the pressure in the diesel cylinders (compression) is almost twice as high as that of a gasoline unit. And both of these differences make their own adjustments to the design of the diesel fuel system.

As previously stated, the system consists of two main components - air and fuel. This also applies to diesel.

Regarding the air part, it differs little from the gasoline part. The only thing is that a diesel engine uses a better filter, since this engine is very sensitive to air purity.

The fuel component is also partly similar to the injection component, although there are some special elements. In total, the design includes:

• tank;
• lines (low and high pressure, supply and drain);
• two filter elements (coarse and fine);
• fuel priming pump (usually included in the injection pump design);
• high pressure fuel pump (HPFP);
• nozzles;

Diesel engine fuel system

Previously, the entire power system was completely mechanical, but now more and more electronic parts are appearing in the design. But to make it clearer, let's consider everything using the example of a mechanical system.

The fuel is located in the tank, from where, due to the operation of the fuel priming pump, it is supplied to the coarse filter element through the low-pressure supply line.

After this filter, it is fed through the same line into the second filter – fine filter. And only after this the fuel is supplied to the fuel injection pump.

The main working elements of this pump are plunger pairs consisting of a piston and sleeve. The pump itself operates from the crankshaft and has a cam shaft installed inside it. It is this shaft that drives the plunger pair, and due to their operation, the fuel pressure increases significantly.

After the injection pump, diesel fuel is supplied to the injectors through supply lines, but at high pressure.

The fuel system is the most important part of the car, which serves to supply fuel from the tank to the combustion chamber of the engine.

It consists of many elements designed for transportation, filtration, accounting, preparation and removal of fuel.

In the article, we will take a closer look at the fuel systems of gasoline and diesel engines, and also find out what a fuel return line (“return line”) is and why it is needed.

The main function of any fuel system is to supply the required amount of fuel from the tank to the combustion chamber at a certain point in time. Functionally, it is divided into two main systems:

• transportation of fuel, its filtration and creation of pressure in the system is carried out by mechanical and hydraulic devices;
• calculation of the quantity and timing of fuel injection, as well as its distribution among the cylinders, is carried out by electronic devices.

Vehicle fuel system

The fuel system includes the following elements:

• Tank is a sealed container for storing fuel.
• Pipelines (direct and return) - tubes and flexible hoses through which fuel is transported.
• Filters (coarse and fine) - perform cleaning from mechanical contaminants.
• Pressure regulator - necessary to ensure a given level of pressure.
• The pump is usually submersible, driven by an electric motor.
• Injection pump - for direct injection systems (diesel engines).
• Fuel injectors.

Depending on the type of gasoline engine, there are carburetor and injection fuel systems. They have differences in design and operating parameters.

The carburetor system operates according to the following principle:

• The pump sucks fuel from the tank. At the same time, it provides low pressure, sufficient only to supply fuel.
• Moving through the pipeline, the fuel undergoes filtration.
• In a special chamber (carburetor) fuel is mixed with air.
• The finished mixture is fed directly into the engine cylinders, where it burns.

The fuel system of an injection engine differs in that it has an injection system that forces fuel into the combustion chamber. The pump of such a fuel system creates a higher pressure, depending on the type of injection:

• With individual injectors for each cylinder (distributed injection). The pressure created by the pump in the fuel rail ranges from 2.5 bar to 4 bar.
• With one injector (mono-injection) supplying fuel to all engine cylinders. A simple scheme that is practically not used in the modern automotive industry due to low efficiency.
• Direct injection. The injectors are installed in the cylinder head, allowing direct injection of fuel into the cylinders. In this case, the operating pressure will be about 155 bar.

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Design features of a car fuel tank

Scheme of operation of the fuel system of an injection gasoline engine:

• The pump supplies gasoline to the fuel rail through filters.
• The regulator on the ramp provides a given level of fuel pressure.
• Injectors mounted on the ramp inject fuel into the cylinders.
• When gasoline is supplied to the cylinders, air is also supplied, forming an air-fuel mixture.

Common rail fuel system diagram

Diesel fuel supply systems have their own characteristics. There are three types of structures:

• Common rail (or battery);
• With pump injectors;
• Separated.

Level of development of internal combustion engines as a measure of technical progress

The emergence of a whole galaxy of various powerful and lightweight engines radically changed the way of life of mankind, made it possible to create new, previously non-existent types of transport - propeller and jet aircraft, helicopters, rockets, spaceships, gas turbine ships, hovercrafts), improve the efficiency and environmental friendliness of ship power plants and locomotives. Motorization also led to an acceleration of the pace of people's lives, the emergence of an entire automobile culture (USA); in military affairs it made it possible to create unusually destructive death machines (tank, fighter, bomber, missiles with conventional and nuclear warheads, submarine with torpedoes and others).

Rotary internal combustion engine

The development of an internal combustion engine is non-trivial, since there are many paths to the goal. Selecting the best (for a specific area and requirements) is an example of multifactor optimization. Intuition is not enough here; large expenses are required when developing options, and resource tests. Engine development trends provide many options for further development[23].

High requirements for internal combustion engine parts, technological complexity (materials, processing), production cycle (flow rate, possibility of defects), scale of production (millions of units), high level of competition and integration of the world economy, together allow us to judge the level of technology of the state based on the level of production ICE. Highly efficient engines not only make it possible to create economical and environmentally friendly transport, but also to conduct independent development in such areas as military affairs and rocket science (in particular, space programs). High-tech industries themselves serve as a center for the crystallization of engineering communities and the birth of new ideas. It is no coincidence that, for example, conveyor assembly was first introduced precisely in the assembly of cars equipped with internal combustion engines. In turn, maintaining and operating numerous vehicles also created many new professions, jobs, business methods and even lifestyles (traveling salesmen, travelers). It would not be an exaggeration to say that the advent of internal combustion engines revolutionized the entire world[24].