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.…
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 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 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,…
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…
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…
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 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.
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:
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…
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 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…
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…
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…
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…
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