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…
The first law of thermodynamics, also called by extension, the law of conservation of energy, is a fundamental assumption of the theory of thermodynamics.
The first law of thermodynamics is a formulation of the principle of conservation of energy and states that:
"The internal energy of an isolated thermodynamic system is constant."
A thermodynamic universe, which consists of the system and its environment, is an isolated system. Energy is not created or destroyed, but is transformed from one form to another: energy can be transferred through the exchange of heat (heat…
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…
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
The second law of thermodynamics is a principle of classical thermodynamics that establishes the irreversibility of many thermodynamic events, such as the passage of heat from a hot body to a cold one. Unlike other laws of physics such as the law of universal gravitation or Maxwell's equations, the second principle is fundamentally linked to the arrow of time.
The second principle of thermodynamics has several equivalent formulations, one of which is based on the introduction of a state function, entropy: in this case the second principle states that the 'entropy of a system isolated…
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…
Second law of thermodynamics
No real or ideal engine can turn all the heat introduced into mechanical work.
Therefore, only a fraction of the heat supplied by the combustion will be converted into work; This fraction represents the thermal performance of the engine. Then we define,
Ideal thermal performance
Relation between the amount of heat transformed into useful work and the amount of heat supplied to the fluid.
As useful work equals the difference between the supplied…
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…
Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the limits of the laws of thermodynamics. Chemical thermodynamics involves not only laboratory measurements of various thermodynamic properties, but also the application of mathematical methods to the study of chemical issues and the spontaneity of processes.
The structure of chemical thermodynamics is based on the first two laws of thermodynamics. From the first and second laws of thermodynamics, four equations called "fundamental Gibbs equations"…
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 universal motor is a type of electric motor that can operate both with direct current and with single-phase alternating current.
Its constitution is similar to that of a direct current series motor, although with some modifications:
The polar nuclei, and the entire magnetic circuit, are built with silicon iron plates isolated and stacked to reduce energy losses by parasitic currents. These currents occur because of magnetic flux variations when connected to an alternating current network.
It has a lower number of turns in the inductor to not magnetically saturate…
The pascal (symbol: Pa) is a unit derived from the International System used to measure internal pressure, mechanical stress, Young's modulus and tensile strength. It is defined as one newton per square meter. It is called in honor of the French mathematician Blaise Pascal.
Some common multiples of the pascal are the hectopascal (1 hPa = 100 Pa), which is equivalent to one millibar, the quilopascal (1 kPa = 1000 Pa), the megapascal (1 MPa = 1,000,000 Pa) and the gigapascal (1 GPa = 1,000,000,000 Pa).
The unit of measure called standard atmosphere (atm) is defined as 101,325 Pa…
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
Synchronous motors are a type of electric AC motor. Its speed of rotation is constant and depends on the frequency of the voltage of the electrical network to which it is connected and the number of pairs of poles of the motor, the speed is known as "synchronous speed".
The mathematical expression that relates the speed of the machine with the mentioned parameters is:
The electric motor is an electrotechnical machine that converts electrical energy into mechanical energy. That is, when the electric motor is connected to the proper power source, it begins to rotate, which also begins to rotate the machine or the machine associated with it. That is, it works inversely to the electric generator, which produces electrical energy with mechanical energy.
The electric motor was made possible thanks to the discoveries of Franz Ernst Neumann and James Clerk Maxwell. His discoveries were published in the years 1841 and 1873.
The electric motors can be…
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.…
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,…
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 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…
In classical thermodynamics, the first field in which entropy was introduced, S is a state function of a system in thermodynamic equilibrium, which, by quantifying the lack of availability of a system to produce work, is introduced together with the second principle of thermodynamics. On the basis of this definition, we can say, in an explanatory but not strict way, that when a system moves from a state of equilibrium it ordered a disordered one to increase its entropy; this fact provides indications about the direction in which a system evolves spontaneously. Entropy and disorder…
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…
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…
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:
Altern current motors are electric motors that are powered by alternating current. Electric motors convert electrical energy into mechanical rotation energy through the mutual action of magnetic fields.
There is a wide variety of altern current motors, among which the following basic types stand out:
- The universal motor that can also be direct current.
- The synchronous motor. In this type of electric motor the speed of rotation is constant and depends on the frequency.
- The asynchronous motor. It is a three-phase motor.
In some cases, such as…
The first figure shows a diagram of a typical indicated 2-stroke engine. We need not make a detailed description thereof will suffice to clarify some obscure points, examination of the corresponding path diagram as a function of angular displacement of the crank. This diagram illustrates the second figure.
Nor is there, in this case, correspondence between "time" and "race", for convenience of exposition we have matched the start of the two-stroke points that correspond, respectively, at the beginning of phase COMBUSTION , n at the start of the scanning phase.
A) First Half. Point…
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,…
The electric motors can be distinguished between them according to the type of power supply:
- Electric motors of direct current. The DC electric motor can be, in turn, a permanent induction motor or a continuous induction motor. In addition to these more general classifications there are also other more modern types of engines such as stepper motors and linear motors.
- Electric motors of alternating current. The AC motor can be classified as universal motor, synchronous motor or asynchronous motor.
The classic division is between direct current (DC) and alternating…
The conversion of electrical energy into mechanical energy by means of electro-magnetism was first demonstrated by the British scientist Michael Faraday in 1821. In his pilot he made the end of a free-hanging contact conductor with a pool of mercury in the that a permanent magnet was placed. At the moment when a current flows through the conductor, the driver performs a rotary movement around the magnet. In this way we obtain kinetic energy.
This electric motor is the simplest version of a homopolar motor. An improved form of this is the Barlow wheel. Due to their primitive construction,…
Thermodynamic transformation is a process by which a thermodynamic system passes from a state of thermodynamic equilibrium to another.
A thermodynamic system is in principle in a state of thermodynamic equilibrium when the main variables of the system (ie pressure, volume and temperature) do not experience any additional variation over time.
In the event that two or all of the above variables change (the variation of only one of them is impossible because they are all interconnected by an inverse or direct proportion ratio) we are in the presence of a thermodynamic transformation,…
James Watt (Greenock, January 19, 1736 - Handsworth, August 25, 1819) was a Scottish mathematician, engineer, and inventor. Watt's inventions were of great importance for the development of the thermal engine and the steam engine.
Watt invented a control valve (which is still known as regulator "Watt", the centrifugal regulator) to keep constant the speed of the steam engine, he found a way to transform the reciprocating reciprocating movement of the plunger into a movement of continuous rotation of a flywheel. It introduced the "double effect", that is, the steam input alternately at…
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…
The first reference of the steam engine is found in the Hellenistic period. Then we talk about experiments to take advantage of the expansion of the compounds due to the change of the liquid phase to the gas (vapor) phase: in particular, the Aeolus cell of the heron. It is a hollow metal sphere filled with water, with the arms tangential to the outlet hole: when water is heated, it vaporizes and the water vapor that comes out of the holes, by rotating the ball itself.
You should also remember the attempts to use Leonardo da Vinci's steam with his car called the Architano. In 1606 the…
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…