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Universidad de San Carlos de Guatemala Faculty of Engineering Intensive Technical English 2 Teacher Soraya Martinez Project Internal combustion engines Name: ID: Eswin Juan Pablo Aparicio Pérez 2012-22682 Kevin Ottoniel Rodríguez Cahueque 2012-12494 Alejandro Cortez De Leon 2012-22602 Guatemalan June 13, 2015

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  • Universidad de San Carlos de Guatemala

    Faculty of Engineering

    Intensive Technical English 2

    Teacher Soraya Martinez

    Project Internal combustion engines

    Name: ID: Eswin Juan Pablo Aparicio Prez 2012-22682 Kevin Ottoniel Rodrguez Cahueque 2012-12494 Alejandro Cortez De Leon 2012-22602

    Guatemalan June 13, 2015

  • Introduction

    An internal combustion engine operation is based, as its name implies, in the burning of a mixture

    of compressed air and fuel in a closed chamber or cylinder, in order to increase the pressure and

    generate enough power reciprocating linear motion piston.

    In this type of engine it is necessary to prepare the mixture of air and fuel appropriately dosed,

    which was conducted before the carburetor and today with the injectors with electronic control

    systems. After introducing the mixture into the cylinder, it is necessary to cause combustion

    chamber of the cylinder through a high voltage spark that provides the ignition system.

    This paper presents the manner in which these products, major types, operating principles and

    cycles of operation that they possess work.

  • Objectives

    General project.

    Through the technical analysis of the different topics of technical English 2, spoke of an

    internal combustion engine as a subject of research, in which is related, pollution,

    thermodynamics and electricity, themes seen throughout the course.

    General theme.

    Get a complete and detailed description of the main operation of an internal combustion

    engine, taking into account electrical and thermal aspects that occur within it, for its proper

    functioning, whereas the contribution of pollution that provide the ground due to the type

    of fuel used to operate.

    Specific

    1. Analyze the thermal cycles operating in an internal combustion engine, so that the

    operation in him was be the best.

    2. Analysis referred to an internal combustion engine ignition system.

    3. Obtain the types of cooling system that occur in an internal combustion engine, due to

    the high temperatures that are handled.

    4. Obtain more knowledge concerning the amount and types of pollution that can produce

    an internal combustion engine.

    5. Learn about the type of power generation that can occur due to an internal combustion

    engine.

  • Internal combustion engines

    The indispensable to put into action different machines mechanical energy can be obtained using

    thermal, hydro, solar and wind energy. The most widely used is thermal energy from fuels organic

    nature. Energy teams that have been accepted are internal combustion engines (MCI) to them to

    more than 80% of all energy produced in the world.

    Main types

    Alternative.

    The combustion engine Otto cycle, named after the German coach who developed it,

    Nikolaus August Otto, is the conventional gasoline engine, but it is also known as engine

    Beau cycle Rochas because the French inventor who patented it in 1862.

    The diesel engine, named after the German engineer Rudolf Diesel was born in France,

    works on a different principle and usually consumes diesel.

    The gas turbine.

    The rotary engine.

    Atkinson Cycle.

    Operating Principles

    An internal combustion engine operation is based, as its name implies, in the burning of a mixture

    of compressed air and fuel in a closed chamber or cylinder, in order to increase the pressure and

    generate enough power reciprocating linear motion piston.

    This movement is transmitted through the rod to the main motor shaft or crankshaft, where it is

    converted into rotary motion, which is transmitted to mechanisms power transmission (gearbox,

    shafts, differential, etc.) and finally the wheels, with the necessary to move the vehicle to the

    desired speed and the power needed to transport cargo.

    By the combustion process developed in the cylinder, the chemical energy contained in fuel is

    converted first into heat energy, part of which is converted into kinetic energy (motion), which in

    turn is converted into useful work applicable to the drive wheels; the other part is dissipated in the

    cooling system and the exhaust system, the accessory drive and friction losses.

    In this type of engine it is necessary to prepare the mixture of air and fuel appropriately dosed,

    which was conducted before the carburetor and today with the injectors with electronic control

    systems. After introducing the mixture into the cylinder, it is necessary to cause combustion

    chamber of the cylinder through a high voltage spark that provides the ignition system.

  • The thermodynamic cycle

    Most internal combustion engines work based on a four stroke cycle, whose principle is the

    thermodynamic Otto cycle (fuel gas or petrol) and diesel thermodynamic cycle (diesel fuel).

    Therefore, its efficiency is based on the temperature variation in both isotropic compression

    process, and the heating volume (Otto) or constant pressure (Diesel).

    The cycle consists of two rising runs and two downward strokes of the piston. Each race coincides

    with a phase of the cycle, and called the action taken at the time as well:

    1. Admission

    2. Compression

    3. Engine - Expansion

    4. Exhaust

  • Description of cycle

    An ideal Otto cycle is a theoretical approach to the behavior of an internal combustion engine. The

    phases of operation of this engine are:

    Admission (1)

    Lowers the piston valve open admission, increasing the amount of mixture (air + fuel) on the

    camera. This is modeled as a constant pressure expansion (since being open valve pressure is equal

    to the outside). In the PV diagram it appears as a straight line E A.

    Compression (2)

    The piston rises compressing the mixture. Given the speed of the process it assumes that the

    mixture has no possibility to exchange heat with the atmosphere, so that the process is adiabatic. It

    is modeled as a reversible adiabatic curve A B, although in reality it is not for the presence of

    irreversible factors such as friction.

    Combustion

    With the piston at its highest point, the spark of the spark plug. The heat generated in the

    combustion abruptly heated air, which increases its temperature almost constant volume (since the

    piston has not had time to lose). This is represented by an isometric B C. This step is clearly

    irreversible, but for the case of an isometric process gas in an ideal balance is the same as one

    reversible.

    Expansion (3)

    The high temperature of the gas pushes the piston down, performing work on it. Again, being a

    very fast process it is approximated by a reversible adiabatic curve C D.

    Exhaust (4)

    The exhaust valve opens and the gas comes out, pushed by the piston greater than the initial

    temperature, being replaced by the same amount of cold mixture in the following intake. The

    system is really open, because mass exchanges with the outside. However, since the amount of air

    leaving and entering is the same can, for the energy balance, assuming that is the same air that has

    cooled. This cooling occurs in two phases. When the piston is at its lowest point, the volume

    remains approximately constant and we isocora D A. When the piston pushes air outward, with

    the valve open, we use the isobaric A E, closing the cycle.

    In total, the series consists of two ascents and two descents of the piston, which is why it is called

    four-stroke engine.

    In a real multi-cylinder internal combustion engine act simultaneously so that the expansion of one

    of them performs the compression work of others.

  • Ignition of internal combustion engine

    Engines need a way to initiate combustion of the fuel within the cylinder. In gasoline engines, the

    ignition system is a component called ignition coil, a high voltage auto-transformer which is

    connected to a switch which interrupts the primary current to an electric high-voltage pulse is

    induced in Right.

    Said pulse is synchronized with the compression stroke of each cylinder; the impulse is carried to

    the corresponding cylinder (who is in compression at the time) using a rotary distributor and wires

    that carry high voltage discharge to the spark plug. The device produces the ignition of the fuel / air

    mixture is a spark plug, which, installed in each cylinder, has a few tenths of a millimeter apart

    electrodes, the electrical pulse produces a spark in the gap between an electrode and another that

    inflames fuel; there is spark plugs with several electrodes, spark plugs using the process of 'surface

    discharge' to produce the spark, and 'glow plugs' (Glow-plug).

    If the coil is messed it overheats; that result in energy losses, reduced spark plugs and cause failures

    in the ignition system of the car. Systems of electricity generation in motors, magnets give a low

    voltage at low rpm, increasing the spark voltage to increase rpm, while battery systems give a good

    spark at low rpm, but the intensity of the low spark to increase rpm.

  • Cooling of a combustion engine

    The cooling internal combustion engines is required to reduce the heat generated by burning the

    fuel (greater than 2000 C) and not transformed into mechanical energy during operation thereof.

    The main function of cooling all components is maintained within the temperature range of engine

    design preventing deformation and destruction by seizing.

    Because combustion produces heat, all engines must have some type of cooling system. Some

    stationary engines of cars and planes and outboard engines are air-cooled. The cylinder engines

    using this system have on the outside with a set of metal sheets that emit the heat produced inside

    the cylinder. In other engine cooling water is used, which means that the cylinders are within a

    housing filled with water which in automobiles is circulated by a pump. The water is cooled by

    passing through the blades of a radiator. It is important that the liquid used for cooling the engine is

    not ordinary water because combustion engines working regularly higher than the boiling point of

    water temperatures. This causes high pressure in the cooling system resulting in faulty gaskets and

    seals water and the radiator; a refrigerant is used, it does not boil at the same temperature as the

    water, but at higher temperature, nor is frozen at very low temperatures.

    Reasons for cooling the engine

    During combustion, part of the energy generated is not converted into mechanical energy is

    dissipated as heat. Depending on the design of the engine for about 33% of potential fuel energy is

    transformed into mechanical work, and the rest is converted into heat that must be dissipated to

    avoid compromising the mechanical integrity of the engine. The system must not only limit the

    maximum temperature of the motor to prevent damage thereto, but also maintaining optimum

    operating temperature which, depending on the engine design, is in the range of 80 to 100 C. Its

    smooth operation depends largely on the thermal efficiency of the engine.

    If the motor operates above its optimal temperature, you run the risk of lowering oil viscosity and

    increase engine wear, overheating of parts and increased friction between these occurs. Explosions

    can also occur when the fuel mixture ignited prematurely.

    If the engine operates below its optimum temperature, oil consumption and the wear of parts is

    increased, since they are designed to expand by heat to a certain size, the power is reduced due to

    lack of temperature for a efficient combustion, carbon deposits on valves, spark plugs and pistons

    are produced.

  • Cooling systems

    Water

    Actually what we call water cooling systems are using a different liquid oil as a primary coolant.

    Most commonly, a mixture of ethylene glycol and water in different proportions depending on

    ambient temperature.

    Thermosyphon circulation

    Its operation is based on the density difference between the hot refrigerant in the block and head,

    and the cold water is in the radiator. For this low resistance it is required coolant circulation. The

    upper reservoir should be of great ability to keep the liquid level in case of evaporation does not fall

    below the level of port of arrival to the radiator. This system is no longer used due to restrictions of

    thermal capacity, position and volume.

    Forced circulation

    It is the most used. Coolant flow is driven through a centrifugal pump, it passes through the

    cylinders of the engine block, then the cylinder head, and finally through the radiator, where the

    cooling occurs. By circulating the coolant through the radiator panel, exchanges heat with the air of

    the march, or forced by a fan. The cooled liquid returns to the engine where the cycle begins again.

    The pump is usually driven by belts and pulleys, which, in some cases, they also turn the fan. In

    most modern systems, the fan is driven by an electric motor controlled by a thermo contact, and

    comes into operation only when the liquid temperature required. The system consists of a tank for

    storing a refrigerant and as an eventual expansion vessel. It is also common to find a parallel circuit

    used for heating the vehicle.

  • Contamination of a combustion engine The environmental impact of the internal combustion engine is closely related to social problems

    arising from the growing use of the same: reducing emission levels of toxic substances and so-called

    "greenhouse gases", and reduced levels noise.

    International discussions about the causes and implications for humanity in the so-called

    "greenhouse effect" caused by rising emissions of gases such as CO2, methane, nitrous oxide and

    chloro-flurocarbonatos reflect the need for an approach comprehensive in addressing

    environmental and development problems, and the need for concerted action by the international

    community to mitigate the effects of global warming.

    The most important forms of motor action on the environment are:

    Depletion of non-renewable raw materials consumed during operation of the MCI.

    Oxygen consumption containing atmospheric air.

    Emission and air pollution with toxic gases that harm the man, flora and fauna.

    Emission of substances that cause the so-called greenhouse effect contributing to raising

    the temperature of our planet.

    Water consumption.

    Issuance of high noise levels in the atmosphere decreases the performance of workers and

    causes discomfort in general.

    Types of gases produced in combustion and their consequences The gases emitted by an internal combustion engine fuel are mainly of two types: inoffensive and

    contaminants. The former consist mainly of nitrogen, oxygen, carbon dioxide, water vapor and

    hydrogen. The second or contaminants are formed mainly by the carbon monoxide, hydrocarbons,

    nitrogen oxides and lead.

    Harmless

    Nitrogen is an inert gas that is present in the air we breathe in a concentration of 79%. Due to the

    high temperatures existing in the engine,

    Nitrogen is oxidized to form small amounts of nitrogen oxides, albeit an inert gas at room

    temperature.

  • Oxygen is one of the indispensable elements for combustion and is present in the air at a

    concentration of 21%. If the mixture is too rich or too lean, the oxygen cannot oxidize all links

    Hydrocarbons and ejected with the other exhaust gases.

    Water vapor occurs as a result of combustion, by oxidation of hydrogen, and is released with the

    exhaust gases.

    Carbon dioxide produced by the complete combustion of the carbon is not harmful to living things

    and is a source of food for green plants, through photosynthesis. It occurs as a natural consequence

    of the combustion, that is to say, the higher the concentration, the better the combustion.

    However, a disproportionate increase in the concentration of carbon dioxide in the atmosphere can

    produce large-scale climatic variations (the greenhouse effect).

    Pollutants

    Carbon monoxide in high concentrations and long exposure can cause blood irreversible

    transformation of hemoglobin, the molecule responsible for transporting oxygen from the lungs to

    the body's cells in carboxyhemoglobin, unable to fulfill that role. Therefore, higher concentrations

    of CO 0.3% volume are fatal.

    The lack of oxygen in the combustion causes it to not fully occur and to form carbon monoxide

    rather than carbon dioxide. In a vehicle, the appearance of higher concentrations of CO in the

    exhaust indicates the existence of a rich starting mixture or lack of oxygen.

    Hydrocarbons, depending on their molecular structure, have different effects. Benzene, for

    example, is poisonous in itself, and exposure to this gas causes irritation of eyes, skin and

    respiratory passages; if the level is too high, it will cause depression, dizziness, headaches and

    nausea. Benzene is one of multiple cancer-causing. Its presence is due to incombustible

    components of the mixture or the intermediate reactions of the combustion process, which are also

    responsible for the production of aldehydes and phenols. The simultaneous presence of

    hydrocarbons, nitrogen oxides, ultraviolet rays and atmospheric stratification leads to the

    formation of photochemical smog, very serious health consequences of living beings.

    Nitrogen oxides not only irritate the mucosa but in combination with the hydrocarbons contained

    in the smog and humidity produced Nitrous Acid, which then fall on the earth as acid rain and

    pollute large areas, sometimes located at hundreds of kilometers from the source of pollution.

  • Lead is the most dangerous metal content in fuel additives. Inhaled can cause formation of blood

    clots in the blood, very serious pathological consequences. It is present in gasoline as Tetra-ethyl

    lead and is used in production to raise its octane and also in older engines as a lubricant for the

    valve seats. In Unleaded gasoline it has replaced the metal with less polluting components also

    provide a high octane.

    Power generation internal combustion engines

    A generator is a machine that moves a generator of electricity through an internal combustion

    engine. It is commonly used when there is a deficit in generating energy from somewhere, or when

    cutting off power and is necessary to maintain the activity. One of its more common utilities is in

    those places where there is no supply through the grid, are generally agricultural areas with little

    infrastructure or isolated dwellings. Another case in public places, hospitals, factories, etc., which,

    in the absence of electricity network, need another alternative energy source for emergency

    supplies. A generator consists of the following parts:

    Internal combustion engine. The motor driving the generator is usually designed specifically

    to run this task. Its power depends on the characteristics of the generator. They can be

    gasoline or diesel.

    Cooling system. The engine cooling system is problematic, because it is a rotating motor,

    and can be cooled by water, oil or air.

    Alternator. The output power is produced by an alternator shielded, splash-proof, self-

    excited, self-regulating brushless motor coupled accurately. The size of the alternator and its

    performance is highly variable depending on the amount of energy that must be generated.

    Fuel tank and bench. The engine and generator are coupled and mounted on a steel frame.

    The bench includes a fuel tank with a capacity of full load operation according to technical

    specifications that has the group in its autonomy.

    Control system. You can install one of the different types of panels and control systems that

    exist to control the operation, exit the group and protection against possible malfunctions.

    Output circuit breaker. To protect the alternator, take installed an automatic switch

    suitable for the model output and output rate generator. There are other devices that help

    control and maintain, automatically, the correct functioning.

    Engine control. The motor controller is a mechanical device designed to maintain a constant

    engine speed relative to the load requirements. The motor speed is directly related to the

    output frequency of the alternator, so that any variation in engine speed will affect the

  • frequency of the output power.

    500 kVA generator installed at a resort in Egypt.

  • Conclusions

    The thermal cycles operating within an internal combustion engine can be Otto cycle or diesel cycle, elementary difference in each of these cycles is based on, the type of fuel used and the efficiency with which produce power, since an Otto cycle based its efficiency in the variation of temperature at constant volume and constant pressure for the diesel both cycles depend on key States which are, intake, compression, explosion and exhaust.

    The ignition system is one of the most complex engine systems, since you need to all the elements that in the interact are in total sync, since when the piston is located in the State of compression, it mixture of air and fuel, initiate a reaction which created a small controlled explosion, to generate a couple using a spark plug the spark plug is activated through the application of a coil which, in turn, is activated when closes the circuit by a switch which sends the necessary voltage to make active the coil to the spark plug.

    Cooling on a motor is of sum importance because the lack of it would lead to the fusion of the internals of the engine, due to the combustion produced between the fuel and air in a compressed State, since in the combustion chamber temperatures arrive to reach up to 2000 orC, in the heat, temperatures to make an engine work with optimum performance are between 80-100 orc , working below this range, the engine would consume more oil and the serious mayor, beyond this range wear parts the internal elements due to their heat tolerance they merge, the cooling types are, by water, by Thermo siphon circulation and forced circulation.

    The pollution produced by an internal combustion engine, can be auditory, that is which arises due to excessive noise that can result when a motor to start or be on, but the greatest contribution of pollution greenhouse it is performed by the gas produced during the State of escape, the gases produced in combustion can be of two types : harmless and contaminants, the harmless are formed primarily by nitrogen, oxygen, carbon dioxide, water vapor and hydrogen, and pollutants, carbon monoxide, hydrocarbons, nitrogen oxides and lead.

    The generation of energy from alternative sources such as an engine, are indispensable in areas where a drop in electric power network would involve aid losses both monetary and material, we can say that a generator is a machine that moves a generator of electric power, through an internal combustion engine, the generator is located at the exit of the engine to capture energy from the rotation , and provide it to the alternator, which is responsible for transmitting energy from the point of supply to computers that use it, the motor starter circuit is powered by a switch which is commissioned to protect the operator from possible electrostatic discharges which occur, commonly internal combustion engine generator found in buildings.

  • Recommendations

    To avoid the noise excision produced by engines, it is advisable to buy a whole new system

    of exhaust gases.

    Otto engines are more efficient than the diesel, diesels are designed to withstand large

    loads.

    It is advisable to check the fuel air mixture to get oxygen in the right proportions avoiding

    rich mixtures.

    Service to the coils and the engine ignition system is important because as we all know the

    coils are responsible for feeding to the spark plugs.

    For the generation of electric power by means of an internal combustion engine, it is

    important to take into account the risks that are due to the concentration of different types

    of loads that may be fatal.

    The observation on the cooling system is critical, since system allows an engine its correct

    performance without a possibility of malformations due to excessive heat.

  • Glossary

    Combustion: Chemical reaction that occurs between oxygen and an oxidizable material which is

    accompanied by release of energy and usually manifests filament or flame.

    Mechanical Energy: The sum of the potential energy (energy stored in a system), kinetic (energy

    that arises in the same movement) and the elastic of a body in motion.

    Carburetor: A device that is responsible for preparing the air-fuel mixture in gasoline engines.

    Injector: Element component fuel injection system whose function is to introduce a certain amount

    of fuel in the combustion chamber as a spray, distributing as evenly as possible within the air

    contained in the chamber.

    Piston: Core element of the internal combustion engine.

    Biela: Mechanical element that subjected to tensile or compression, articulating transmits to other

    parts of the machine movement. In an internal combustion engine piston connected to the

    crankshaft.

    Crankshaft: Cranked shaft, with elbows and balances present in certain machines, applying the

    principle of crank mechanism - crank, transforms the reciprocating rectilinear uniform circular

    motion and vice versa.

    Heat Energy: Demonstration of energy as heat.

    Thermodynamic cycle: thermodynamic process such that, over all, the system returns to its initial

    state; the variation of thermodynamic quantities own system is zero.

    Valve: mechanism that regulates the flow of communication between two parts of a machine or

    system.

    Adiabatic Process: One in which the thermodynamic system (usually a fluid performs work) does

    not exchange heat with its surroundings.

    Spark: element that produces the ignition of the fuel-air mixture in the cylinder by a spark in an

    internal combustion engine spark ignition (MEP), both Otto cycle as alternative Wankel.

    Isochoric process: Called isometric or is a volumetric process is a thermodynamic process in which

    the volume remains constant.

    Isobar: Isogram pressure, is a curve of equal or constant pressure on a chart, or map layout view

    used to accurately weather maps.

    Electrode: Electrical conductor used to make contact with a metal part of a circuit, for example a

    semiconductor, an electrolyte, a vacuum (in a thermionic valve), a gas (in a neon lamp), etc.