The heat engines can be classified in many different ways. Then classify heat engines, taking into account six different aspects:
Types of heat engines depending on where combustion takes place
- They Depending on where is combustion.
- Depending on the fuel used and the type of lighting.
- Depending on the movement of moving parts.
- Depending on how realizes the cycle.
- Depending on the number of cylinders
- Depending on the arrangement of the cylinders
Depending on where combustion takes place two types:
The applications where the value machine has been used have been changing with the passage of time.
Initially, since the beginning of the eighteenth century, steam engines have been used to power a multitude of uses. At first the steam engine was used as piston pumps. Subsequently, from the years 1780 began to appear alternative engines. With the alternative engines, the steam engines also served to give power to the factories and the industrial one. At the beginning of the 19th century, steam engines began to be used in transport by land and sea.
Steam engines were of great importance…
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.…
A motor or motor is a machine designed to convert a form of energy into mechanical energy . An engine can be classified into a category according to two criteria: the form of energy it accepts to create movement and the type of movement it produces.
As a general rule, engines have an axle, which in rotary offset and through mechanical devices such as drive gears. The exceptions are rocket motors and linear motors . Nowadays, combustion engines…
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…
Heat engines are a type of alternative engines. Actually, they are the most popular alternative engines.
This type of engine uses the thermal energy caused by the combustion of a fuel (usually gasoil or gasoline) to convert it into mechanical energy. Heat Machines
The concept of a thermal engine is often confused with that of a thermal engine. These terms are related but not exactly the same. A thermal machine is a device or system that works by establishing exchanges of heat and work with its environment. To achieve this, the machine transforms a substance through a cyclic…
Since the first developments of the alternative engine with the steam engine, its use has been growing exponentially. The appearance of internal combustion thermal engines has helped to accelerate its popularity.
However, the characteristics of the alternative engine entails a series of advantages and disadvantages that we intend to study.
From the first alternative engines such as the steam engine or the stirling engine to the current thermal engines the characteristics of this engine have varied a lot. Although the operating principle for the generation of mechanical energy is…
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…
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.
The Stirling engine applications can be divided into three main categories:
- Mechanical propulsion
- Heating and cooling
- Power generation systems
A Stirling engine is a thermal engine that works by cyclic compression and expansion of air or other gas, the working fluid. During the Stirling cycle there is a net conversion of heat to mechanical work. The Stirling cycle engine also operates in reverse, using a mechanical energy input to drive the heat transfer in a reverse direction (ie, a heat pump or refrigerator). Generation of electrical energy…
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.
In this website we try to explain the operation of the main types of engines from a theoretical point of view. We present schematically the parts, operating cycles and characteristics of the following types of engines:
- The thermal engine or internal combustion engine. Inside the thermal engines we explain the gasoline engine (or otto engine) and the diesel engine).
- The electric motor. This engine has undergone a great evolution throughout history and right now is one of the most used types of engines and with more projection of the future. We will analyze direct current…
A steam engine is a device that produces mechanical energy through the use of water vapor. In particular, thermal energy is transformed into mechanical energy by means of steam. Heat is typically produced by burning fossil fuels, particularly coal, but it can also come from wood, hydrocarbons or nuclear reactions. Description of steam engines
An essential part of the system that includes the steam engine is the steam generator, or the boiler. In the boiler water vapor is obtained by the administration of heat to liquid water. The steam is then sent to the engine, which can be…
Steam engines are mechanical devices capable of transforming heat energy into mechanical energy in a rotating axis. This heat energy takes advantage of the energy contained in water vapor at high pressure and temperature.
We consider steam engines all those machines that transform the thermal energy of a fluid into mechanical energy. In general, the fluid must be pre-heated and at the outlet of the steam machine it must be cooled to repeat the process.
Steam machines can be classified into these two types:
- Plunger steam engine
- Turbine steam engine
The development of the Stirling engine started with the aim of being an alternative to the machine of value due to certain advantages that it had with respect to the then popular steam engine.
Over time, certain disadvantages compared to internal combustion engines have left the Stirling engine in the background. Advantages of the Stirling engine compared to internal combustion engines
The main advantages of a Stirling engine compared to an otto engine, a diesel engine or a steam engine are:
- The maintenance facility
- They are quieter engines
The operating system of the thermal engines is based on a cycle that is constantly repeated. In the case of internal combustion engines this cycle consists of the fuel input (admission), combustion of the fuel, expansion of the cylinder and expulsion of the gases produced. This cycle generates a mechanical movement, if the cycle repeats we will have a constant mechanical movement.
A thermal engine can work through many different cycles. In this section we will explain the different operating cycles that an internal combustion engine can have, the real cycles and the theoretical cycles.…
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…
The endothermic engine, also known as internal combustion engine. The main characteristic of this type of alternative engines is that through the laws of thermodynamics it is able to take advantage of the energy contained in the fuel to obtain a mechanical work.
The endothermic engine is a type of alternative engine by the way of converting chemical energy into mechanical energy. The most popular endothermic engines are the Otto engine or gasoline engine that operates according to the Otto cycle and the diesel engine, which operates according to the diesel cycle. Meaning of the…
A first example of the history of the known from rotary to alternative movement is the crank mechanism. The oldest manual cranks appeared in China during the Han Dynasty (202 BC-220 AD). Several sawmills in Roman Asia and Byzantine Syria during the III-VI centuries AD had a connecting rod mechanism that converted the rotary motion of a water wheel into the linear movement of the saw blades. In 1206, the Arab engineer Al-Jazari invented a crankshaft. Piston motor
A free piston engine is a linear internal combustion engine, in which the movement of the piston is not controlled…
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…
Diesel fuel is a mixture of liquid hydrocarbons, obtained by fractional distillation of crude oil and used as fuel for diesel engines, for heating or for the production of electricity.
It is often inappropriately called naphtha, which is distinguished by a process of better refining and for different uses.
Diesel fuel finds its first applications in the mechanical field between 1893 and 1897, when in the workshops MAN (Maschinenfabrik Augsburg Nuremberg) of Augusta, Rudolf Diesel made the first investigations that led to the invention of the diesel engine. Its name derives from…
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:…
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…
The engine is a machine capable of transforming a source of energy, which can be in chemical form (in the presence of a fuel), electrical or thermal, into a mechanical energy or mechanically continuous work, typically used in the field application purposes. with the propulsion of various types of vehicles.
In a philosophical sense, an engine is the organism that causes movement or change in other affiliated institutions: Aristotle spoke of motionless motor, a term also picked up by other philosophers, to indicate the cause of the universe, that is, the object or subject which (according…
The crank shaft is the force that makes the whole rod-crank crank. Its function is to transform rotational movements in alternative movements (combustion engines, for example) or vice versa (Eccentric mechanical presses).
In the heat engine crankshaft collects forces originated during the explosion and turns through the rod, linear motion into rotary motion of the piston alternative. Transmits the movement and the driving force transmission elements that are coupled. Is subjected to bending and torsion efforts, and has a strong structure and very resistant. The crankshafts, which can…
The route of the Stirling engine throughout history begins in the early 1800s, in England. The hot air engines competed with the steam engine to provide mechanical power to the industrial machinery (in factories and mines) of the first industrial revolution.
Although steam engines had better characteristics than air machines, the air motor had the advantage of being less dangerous. This was due to the first realizations of steam engines suffered devastating boiler explosions. These explosions were due to the use of materials available at the time that were technologically poor.
The Stirling engine is an external combustion thermal engine. Originally it was conceived as an industrial main engine to compete with the steam engine, but in practice, for more than a century it was only used for domestic applications and for low power engines.
The Stirling engine was invented in 1816 by Robert Stirling, a Scottish priest. One of the concerns of the time was the safety of steam engines. Stirling's goal was to get a less dangerous engine than the steam engine.
The operation of the Stirling engine is based on the expansion and contraction of a gas that can be…
Traditionally, when we talk about motors, we usually refer to internal combustion engines or electric motors. However, there are other types of motor. Among these types of motor there are the physical power motors.
The so-called physical power motors are motors that take advantage of the kinetic energy or the potential energy of some element.
An example of power motors is found in hydro power plants. In this type of installation the potential energy of the water is used, which, when it falls, becomes kinetic energy and activates a turbine. In this way, a motor,…
By operating cycle of a thermal engine we understand the succession of operations that the active fluid executes in the cylinder and repeats periodically. The duration of the operating cycle is measured by the number of strokes made by the piston to perform it.
In this sense, there are two types of thermal engines:
- 4-stroke engine. In the four-stroke engine the cycle is carried out in 4 strokes of the piston. This engine makes a cycle every two revolutions of the motor shaft.
- 2-stroke engine. The two-stroke cycle is carried out only in 2 strokes of the piston. Two-stroke…
Gasoline (or essence and gasoline popularly) is a mixture of hydrocarbons derived from petroleum used as fuel in internal combustion engines. It has a very high calorific value of about 46 MJ / kg.
Gasoline is flammable liquid, colorless, not so dense as water (specific gravity: 0.70 to 0.75). Gasoline obtained from petroleum distillation, between 60 ° and 200 ° C, or by cracking of heavy fractions.
From a chemical point of view, gasoline is a mixture of alkanes, cycloalkanes and aromatic compounds from 4 to 10 carbon atoms and at times of alkenes. Gasoline is mainly used…
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.…
Safety in steam engines is an important issue that needs to be studied and prevented due to the characteristics of this type of machine.
The composition of the steam machines formed by boilers and other components under pressure causes fluids with a very high potential energy to be stored. Due to the high pressure and temperature with which you work any steam or explosion leaks can be very harmful for the safety of people.
Throughout the history of steam engines there have been very serious accidents that have involved considerable material damage and even the loss of human lives.…
Thermodynamics is the part of physics that deals with the relationship between heat and work. It studies the effects of the variation of pressure, temperature and volume of a physical system (we understand by physical system a liquid, a material, a set of bodies, etc.), at a macroscopic level, that is to say, that can be observed.
The term thermodynamics comes from the stem therm, which means heat and dynamics that refers to movement. The movement of heat in a body.
Matter is composed of different particles that move in a disordered way (what is called entropy). Thermodynamics…
A direct current motor (DC motor), or simply a continuous motor or direct current motor, is a rotating electric malternating currenthine that transforms electrical energy in the form of direct current into mechanical energy through electromagnetic interalternating currenttions.
Virtually all electric motors are reversible, that is, they can transform mechanical energy into electrical energy functioning as dynamos. direct current motors base their operation on the Lorentz law, also called Laplalternating currente's law when it is applied to a conductor, as is the case of motors. Applications…
Cycles theoretical endothermic engines
For theoretical cycles, commonly used approaches aproximacióna by the real conditions are three:
- real cycle
- air cycle
- air-fuel cycle.
A theoretical these cycles are compared in practice the actual cycles, which are obtained experimentally by means of the indicators, for this reason, the actual cycle also indicated cycle is called.
Although the theoretical cycles do not correspond to actual cycles, provide a useful reference for the thermodynamic study of internal combustion engines,…
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,…
We call it by spark to the one of the forms in which it ignites a thermal engine. The engines starting with spark ignition are Otto cycle gasoline engines.
In this type of engines there is an element, the spark plug, which is capable of causing a spark when it receives electric energy. In this way, the spark plug is capable of transforming the electrical energy coming from the battery into a spark.
Around the spark causing the spark plug creates the so-called initial ignition source. In the initial ignition focus fuel combustion is spread forming a flame front.
As the flame…
An electric generator is a machine that transforms rotational mechanical energy into electrical energy. In this sense, it works in the opposite sense of how an electric motor works.
An electric generator is any device capable of maintaining an electrical potential difference (voltage) between two points, called poles or terminals. Electric generators are electrical machines designed to transform mechanical energy into electrical. This transformation is achieved by the action of a magnetic field on the electric conductors arranged in coils on a sheet metal frame. If a relative movement…
In some applications, doubts arise as to whether it is better to use an electric motor or to use a thermal motor. One of the important elements in making this decision will be to know the differences in energy efficiency.
Main problems of thermal motors:
- Rising prices of fossil fuels combustibe (oil, coal, etc.)
- Scarce projections of evolution in an immediate future.
- Emission of greenhouse gases.
- Not reversible, when braking, can not generate power.
Main advantages of electric motors:
- You are a clean alternative if we…
The actual operating conditions of diesel engines differ markedly from those that are represented in the ideal Otto and Diesel cycles. For diesel engines, the combustion process transformational approaches a constant pressure only in case of unusually large motors and slow.
The actual plot shows that, under normal conditions, the combustion takes place, in Diesel engines, according to a process that approximates a transformational combustion and a constant volume at pressures n…