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…
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 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…
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
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 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 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…
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…
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…
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:
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…
Cylinder head, cylinder cap or engine block cover is the top of an internal combustion engine that allows the combustion chamber to close. It constitutes the upper closing of the motor block and in motors on it the valves are seated, having holes for this purpose. The cylinder head has a double wall to allow circulation of the coolant. If the internal combustion engine is ignited (Otto engine), it has threaded holes where the spark plugs are located. In case of being ignition by compression (Diesel engine) in its place it takes the holes for the injectors. The cylinder head is made of cast…
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.…
What is the indicated diagram?
The indicated diagram is the diagram that represents the real cycle of a heat engine (a diesel engine or an Otto engine).
The actual cycle of a thermal engine reflects the effective operating conditions. 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. Study of the indicated diagram
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…
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.
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 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…
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…
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…
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…
In the 2-stroke motors, the operating cycle is carried out in two races. The admission of the active fluid must be made during a fraction of the compression stroke, and the exhaust must be produced during a fraction of the working stroke.
For this to be verified, it is necessary that the active fluid be pre-compressed to be able to enter the cylinder and that the exhaust of the combustion gases be carried out by its own pressure.
The 2-cycle cycle was conceived to simplify the distribution system, eliminating and reducing the number of valves, and to obtain a greater power with…
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…
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…
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:…
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…
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,…
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.
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…
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 uses of the steam engine have been changing with the passage of time.
Initially, since the early eighteenth century, steam engines have been used to power a multitude of uses. At first, the steam engine was used as a piston pump. A piston pump is a hydraulic pump that generates movement in it by the movement of a piston.
Subsequently, from the years 1780 began to appear alternative engines. With the alternative motors a new use of the steam engine appears: to give power to the factories and to the industrial one. At the beginning of the 19th century, steam…
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 used to power a wide variety of self-transport applications. These are a few examples:
- Marine applications, naval transport: steamships, steam boats, steam yachts.
- Applications of the steam engine in the field of rail transport: Steam locomotive.
- Agricultural applications: used as traction motor for agricultural machinery. The first tractors in the sector were steam tractors.
- Road transport: Steam vans, steam buses, steam tricycles, steam car.
- Applications in construction machinery: Steam steamroller, steam excavator…