Diesel engine.
Diesel cycle

Endothermic engine
Gearbox

Compression

History of the diesel engine

History of the diesel engine

The diesel engine was invented by Rudolf Diesel, in the year 1893. Rudolf Diese was a German engineer, employed by the firm MAN.

Rudolf Diesel studied high thermal efficiency engines, with the use of alternative fuels in internal combustion engines. Diese's goal was to replace the old steam engines that were inefficient, very heavy and expensive.

First steps before reaching the diesel engine

In 1806, brothers Claude and Nicéphore Niépce developed the first known internal combustion engine and the first fuel injection system. The two brothers tested systems…

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Differences between the Otto engine and the diesel engine

Differences between the Otto engine and the diesel engine

The Otto engine and the diesel engine are two types of thermal engines. These are two types of endothermic engines that, through thermodynamic reactions, convert the internal energy of the fuel into mechanical work. However, there are certain differences between them.

The most important difference is found in its theoretical cycle. The Otto engine operates according to the Otto cycle by spark ignition while the diesel engine is controlled according to the diesel cycle by compression ignition.

The other important difference is in the ignition of the fuel. In the Otto engine the ignition…

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Otto cycle

Otto cycle

The theoretical Otto cycle is the ideal cycle of the Otto engine. The Otto engine is also known as a spark ignition engine because the ignition of the fuel is done through a spark caused by a spark plug. It is also known as a gasoline engine because of the type of fuel it uses.

One way to study the performance of this engine is by analyzing its theoretical cycle. The theoretical cycle is an approximation to the real cycle with many simplifications. In practice, there are so many variables that affect the performance of the engine that calculating the actual cycle is practically impossible.…

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Advantages of the diesel engine

Advantages of the diesel engine

Diesel engines have several advantages over other internal combustion engines:

Advantages related to diesel engine fuel

The fuel of a diesel engine has a higher energy density and a smaller volume of fuel is required to perform a specific amount of work.

Diesel engines inject fuel directly into the combustion chamber, have no air intake restrictions other than air filters and intake pipes and have no vacuum in the intake manifold to add parasitic load and pump losses to push the pistons down against the vacuum of the intake system. Cylinder filling is aided by atmospheric…

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I cycle indicated provided

It is necessary to know the cycle, not only to check if the thermal engine operation is correct, but also to determine the value of the forces acting on the engine components. When in the design phase is to establish the dimensions of the engine components, proceed to the calculation of stresses based on an expected cycle. This similarity can be drawn by motor cycles parangonables with that study, but also obtained a simple and fast way, ore than with a sufficient approximation, using the following method is set forth by way of example and recommend as applicable to the case engine 4-stroke…

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Atkinson cycle

Atkinson cycle

The Atkinson cycle engine is a type of reciprocating internal combustion engine invented by James Atkinson in 1882. It is practically a common Otto cycle engine, but with a crank modified crank to obtain greater efficiency at the expense of a reduction in the power. The objective was to compete with the Otto cycle without infringing any patent.

In its original version, the Atkinson cycle requires a single rotation of the crankshaft to complete a cycle of operation, keeping the phases of the Otto cycle engine intact: intake, compression, expansion (useful phase) and discharge. However,…

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Theoretical diesel cycle

Theoretical diesel cycle

The theoretical diesel cycle is the theoretical cycle of a diesel engine, also known as a compression ignition engine.

The theoretical cycle of a thermal engine is a theoretical approximation of its operation to calculate its performance.

The cycle of an internal combustion engine is constituted by the physical and chemical transformations suffered by the fuel during its passage inside the engine.

The study of a real cycle taking into account all the numerous variables, represents a very complex problem. For this reason, it is usually simplified by resorting to theoretical…

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Compression ignition

Compression ignition

The compression ignition engine is the diesel or diesel cycle engine. This qualification refers to the way fuel combustion starts inside the piston.

In this type of motor, what enters the chamber initially is only air; the diesel is injected more or less near top dead center. The fuel enters the liquid state, but it is dense. The dense fuel must be vaporized, mixed with the air and reach the conditions of pressure and temperature appropriate to ignite. The time that this process takes is the self-ignition delay and limits the speed at which the engine can turn and, therefore, its maximum…

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Stirling Cycle

Stirling Cycle

The Stirling cycle is a thermodynamic cycle that describes the operation of a class of equipment (generating or operating machines). The cycle describes the original Stirling engine that was invented and patented in 1816 by the Reverend Robert Stirling, helped substantially by his brother engineer.

The Stirling engine is an external combustion engine. This characteristic differentiates it from other types of engines such as the otto engine or the diesel engine which are internal combustion engines. Both engines operate according to the otto cycle and the diesel cycle respectively.

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Alternative engine

Alternative engine

The reciprocating engine uses the reciprocating motion of one or more pistons to convert the pressure into a working fluid. Generally this work is in the form of rotation movement, that is, we obtain mechanical energy. In the opposite direction we find ourselves with the rotating machines in which the movement of the parts of the machine is already rotating like the turbines or the Wankel engine.

The reciprocating engine is also known as a piston engine. The most common alternative engines are internal combustion engines. These thermal engines are widely used in motor vehicles.

The…

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4-stroke engine

4-stroke engine

A four-stroke engine is a type internal combustion engine, an alternative engine. It can work both in diesel cycle and Otto cycle (gasoline engine). It is therefore a thermodynamic and combustion motorcycle.

The most important feature is that you need to perform four strokes of the piston or plunger to complete the cycle. During these 4 races the crankshaft makes two full turns. These four times are: admission, compression, combustion or explosion and escape.

In 1861, the German Otto experimented with his first 4-stroke gas engine. Otto had to abandon the project due to technical…

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Comparison between the three theoretical cycles

To compare cycle just discussed, it is necessary to refer some of the factors whose value depends on the shape and surface, such as: the compression ratio, the maximum pressure, the amount of heat supplied and the heat subtracted useful work.

The following figure are plotted the curves of the ideal thermal performance variations by varying the ratio of co

RINTING for three cycles: Otto, Diesel and Sabathé. For Diesel cycles and Sabathé has chosen a constant pressure…

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Difference between real and theoretical Otto cycles

Difference between real and theoretical Otto cycles

Between the Otto real cycle and the corresponding theoretical Otto there are substantial differences. Some of these differences can be observed when comparing the diagram of the real cycle with the theoretical cycle diagram. The other differences that we are going to analyze refer to the differences between the temperature and pressure values of the two Otto engine cycles.

Differences in the form of the diagram

The difference in shape of the diagram between a real Otto cycle and a theoretical Otto cycle consists of a different profile in the expansion and compression curves, in…

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Pressure diagram for a 4-stroke engine

Pressure diagram for a 4-stroke engine

Next we analyze the diagram of the pressures of a real cycle as a function of the angular displacement of the axis for a 4-stroke engine.

Knowing the indicated cycle, the immediate thing is to draw the diagram of the pressures in the cylinder of the thermal engine as a function of the angular displacement of the crank, instead of depending on the volumes or the reciprocating movements of the piston. In doing so, we take into account the kinematic relationship that links the latter with the axis rotation.

The diagram related to a 4-stroke engine is shown in the figure. In the real…

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Otto Motor

Otto Motor

The Otto engine is a type of alternative thermal engine that works through the Otto cycle. It is an alternative engine capable of converting the chemical energy of fuel into mechanical energy through a thermodynamic reaction.

Due to the characteristics of this type of thermal engine it can receive several names.

  • Gasoline engine. Due to the fuel used.
  • Otto Engine. Because it works through the otto cycle.
  • Spark ignition engine. Due to the way to start the ignition of the fuel. The ignition starts through a guspira generated by a spark plug.
Use…

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Parts and components of a heat engine

Parts and components of a heat engine

In this section we describe the different parts of a thermal engine. Of thermal engines have many types, however we will focus on the diesel engine and the gasoline engine (otto cycle).

Despite being different engines share many parts in common, so the scheme presented will serve to indicate the nomenclature of each element.

The most important elements of internal combustion engines, common to diesel and explosion engines, we classify them in two large groups:

  • Fixed elements of a heat engine: block, cylinder head, crankcase.
  • Moving parts of a heat engine:…

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Differences between the real and theoretical diesel cycle

Differences between the real and theoretical diesel cycle

Between real and theoretical diesel cycles there are differences and similarities in the form and in the values of pressures and temperatures. Differences that also appear in the otto cycle. Some of these similarities correspond to those of the otto cycle; for example, the similarities due to the variation of the specific heats, to the loss of heat and to the opening time of the exhaust valve.

Others differ in part and are caused by dissociation and loss by pumping. Finally, one is peculiar to the diesel engine, namely; the one concerning that the combustion is not verified at constant…

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Real cycles of thermal engines

Real cycles of thermal engines

The actual cycle of a thermal engine is the one that reflects the effective conditions of its operation. These conditions are identified with the diagram of average pressures in the cylinder in correspondence to the different positions of the piston. The pressure shown in a mean pressure diagram is the so-called average pressure indicated.

The indicated diagram is the graph that represents this cycle.

Simplified operation of the indicator

The indicator is a device used to obtain the indicated diagram of a thermal engine cycle.

In the indicator of the indicated diagram,…

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Diesel engine

Diesel engine

Diesel engines are also known as compression ignition engines. The diesel engine is a type of internal combustion engine that uses gas oil as fuel for the diesel thermodynamic cycle.

The actual performance of diesel cylinder thermal engines is between 35% and 40% and is widely used to propel vehicles.

Diesel engines can operate with 4-cycle and 2-cycle cycles. 2-stroke engines do not consume more fuel than engines with 4-stroke cycles, because the cylinder is swept with pure air and not with the fuel mixture. This is the reason why there is no loss of fuel through the exhaust.

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