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…
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 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…
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 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 carburetor is the device that makes the air-fuel mixture in gasoline engines. To get the engine to run more economically and get the most power output, it is important that gasoline is in the best condition. To achieve an optimum air-fuel mixture, the carburetor will use various techniques.
The carburetor basically operates with the same principle of an airbrush. When the air is blown, crossing the axis of the spray pipe, the internal pressure of this pipe falls. The liquid inside the sprayer is consequently pushed into the pipeline and atomized thanks to the friction with the air.…
The cylinder of an engine is the enclosure by which a piston moves. The cylinder name comes from its practically cylindrical form.
The materials used to make the cylinders are specific to each type of engine. The way of building and the chosen materials of the cylinder makes vary the performance of the engine. A cylinder made of a gray cast matrix with laminar graphite provides good sliding properties. A motor cylinder made of high quality alloys such as molybdenum, chromium, nickel and manganese, improves hardness and resistance to wear and corrosion.
Engine cylinders are characterized…
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 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 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 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 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 Joule effect, also called Joule's law, is the thermal manifestation of electrical resistance. If electricity circulates in an electric conductor, a part of the kinetic energy of the electrons is transformed into heat due to the shock that the electrons experience with the molecules of the conductor through which they circulate, which increases the temperature of the conductor. It is named in honor of the English physicist James Prescott Joule.
Definition of the Joule effect:
The amount of heat energy produced by an electric current is directly proportional to the square of…
Alternative engines can be classified in many different ways. The main forms of classification are the following:
Classification according to the arrangement of the cylinders
- According to the arrangement of the cylinders in the engine
- According to the displacement
- According to the compression ratio
- According to the diameter and stroke ratio
- According to the number of movements of each cycle
A typical way of classifying the reciprocating engine is to use the number and arrangement of the cylinders. In this way we have:
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,…