Types of Gasoline Engines

Types of Gasoline EnginesABSTRACTApetrol locomotive (a.k.a. throttle engine inNorth America) is aninternal combustion enginewithspark-ignition, designed to exceed on petrol and similar volatile give the sacks.It was invented in 1876 in Germany by German inventorNicolaus August Otto.Till date more than or less vehicles run on petrol much more than any other fuel i.e. the consumption of petrol is highest among the fuels.We know that the fossil fuels be getting strange and with the increasing rates of the fuel, there atomic number 18 high concerns regarding the efficiency of the engines that we use.The Obama administ ration has required automakers to nearly double the average fuel parsimoniousness of new automobiles and light up trucks to 54.5 miles per gallon by 2025 under rules that took power in 2012. The attention to fuel efficiency, Obama said, has resulted in lower costs, improved carry quality and created jobs in the auto industry.(sourceThe Guardian)The subject deals with getting a brief idea of the types of gasoline engines (namely 2 cerebrovascular accident and 4 shot), their transporting and most importantly forget include a nurture of the factors that affect the fuel efficiency.INTRODUCTIONA petrol engine (a.k.a. gasoline engine inNorth America) is aninternal combustion enginewithspark-ignition, designed to run on petrol and similar volatile fuels.Internal combustion engine The combustion of fuel takes place inside the engine speculator chamber and inflame is generated inwardly the cylinder. This heat is added to the melodic line inside the cylinder and thus the pressure of the air is increased trem land upously which moves the plumbers helper , rotates the crank shaft and thus mechanical work is d aceSpark ignition engine a classification of air and fuel is drawn into the engine cylinder. The spark plug produces a spark and ignites the air- fuel miscellany. Such combustion is called constant volume combustion(C.V.C.).Bas ed on its working cycle, it throne be divided into -1. Four cam jibe cycle engine When the cycle is completed in two revolutions of the crankshaft, its called four stroke cycle engine.2. Two stroke cycle engine. When the cycle is completed in one revolution of crankshaft, its called two stroke cycle engine.WORKING PRINCIPLE OF I.C. ENGINE/ FOUR STROKE rack ENGINE / TWO STROKE CYCLE ENGINEA mixture of fuel with correct amount of air is exploded in an engine cylinderwhich is shut at one end. As a result of this explosion, heat is released which causes the pressure of the burning gases to increaseThis pressure forces a tightfitted piston to move down the cylinder which in turn rotates the crankshaft . violence is utilized from the rotating crank shaft to do mechanical work. To obtaincontinuous rotation of the crankshaft ,the use gases are expelled from the cylinder, before the next ignition takes place .Fresh charge of fuel and air are admitted in to the cylinder and the piston m oved back to its starting position. The ranks of until nowts taking place in an engine constitute theworking cycle of an engine. The sequence of events taking place inside the engine are as follows-1. Admission of air or air-fuel mixture inside the engine cylinder ( suction )2. crush of the air or air fuel mixture inside the engine ( abridgment)3. Injection of fuel in compressed air for ignition of the fuel or ignition of air- fuel mixture by an electric spark using a spark plug to produce thermal plyinside the cylinder (power )4. Removal of all the burnt gases from the cylinder to receive fresh charge ( outfox)Note Charge means admitting fresh air in to the cylinder or admitting a mixture of air and fuel in to the cylinder in the case of spark ignition engines.FOUR STROKE CYCLE ENGINEIn four stroke cycle engines the four events suction, compression, powerand wipe out take place inside the engine cylinder. They are completed in fourstrokes of the piston ( i.e 2 revolutions of t he crank shaft). The engine has separate valves for controlling the inlet of charge and outlet of exhaust gases. The opening and closing of the valve is controlled by cams, fitted on camshaft. The camshaft is set by crankshaft with help of suitable gears or chains. The camshaft runs at half the speed of the crankshaft. The events that take place are1. Suction stroke 2. Compression stroke3. Power stroke 4. Exhaust strokeSuction strokeIn suction stroke ,the inlet valves open and the piston moves downwards. The exaust valve remains closed and air or mixture of air and fuel is sucked in.Compression strokeIn this stroke, both the valves are closed and the piston moves upwards. The charge taken inis compressed by the upward stroke.The mixture is ignited by a spark plug.Power strokeAfter ignition of fuel, high amount of heat is produced which pushes the piston down. The downwardmovement of the piston at this point is called power stroke. The connecting rod or pin transmits the power from the piston to the crank shaft and the crank shaft rotates. Both valves remain closed during the power stroke.Exhaust strokeIn this stroke the exhaust valve opens and the piston moves upwards, expelling the burnt gases out. The inlet valve remains closed.remains closed .Thus it is open up that out of four strokes, there is only one power stroke and three idle strokes in four stroke cycle engine. The power stroke supplies necessary momentum for useful work.TWO STROKE CYCLE ENGINE (PETROL ENGINE)In two stroke cycle engines, all the events i.e., suction,compression, power and exhaust are completed in two strokes of the piston (i.e., one revolution of the crankshaft).There is no valve in this type of engine.The gas movement takes place by means of holes called ports in the cylinder. The crankcase of the engine is air tight in which the crankshaft rotates.Two stroke cycleUpward stroke of the piston (Suction Compression)When the piston moves upward it covers two of the ports which are t he exhaust port and the transfer port, which are normally almost opposite to each other. As a result it traps the charge of air- fuel mixture drawn already into the cylinder. The further upward movement of the piston compresses the charge and uncovers the intake port. Following it fresh mixture is drawn through this port into the crankcase. Just before the end of this stroke, the mixture in the cylinder is ignited by a spark plug and thus, during this stroke both suction and compression events are completed.Downward stroke (Power + Exhaust)The burning of gases increases the pressure and forces down the piston. When the piston moves down, it closes the suctionport, which traps the fresh charge drawn into the crankcase during the previous upward stroke. The further downward movement of the piston uncovers the exhaust port first and then the transfer port. Now fresh charge in the crankcase moves into the cylinder through the transfer port. The burnt out gases are driven out through the exhaust port. Specialshaped piston crown deflect the incoming mixture up around the cylinder so that it offer help in driving out the exhaust gases . During the downward stroke of the piston, power and exhaust events are completed.THE COMPARISION (2 STROKE VS 4 STROKE)The 2-stroke engine fires once all revolution, giving it twice the power of a four stroke, which only fires once every other revolution. The 2 stroke has a higher(prenominal) weight to power ratio because it is much lighter than the 4 stroke. It is less expensive because of its simpler design.These qualities make two stroke engines very everyday for a variety of uses from dirt bikes, small fry skis, mopeds and small outboard motors, to lawn and garden equipment such as mowers, leaf blowers,edgers, hedge trimmers and chain saws.Many 2 strokes are simple engines and lack valves. Thus the quantify of the intake and exhaust cannot be made optimal on 2 strokes. While on the other hand ,the timing of intake and exhaust can be controlled using timing gear in 4-stroke engines. As a result they burn less cleaner than the 4 stroke.The 2-stroke engines turn over faster cod and shorter engine life than a four stroke due to the lack of a dedicated lubricating system .Another thing to consider is that 2 stroke engines have lubricating oil mixed with the fuel because of which it leads to incomplete combustion of the fuel. Which in turn also affect the efficiency and often cause more pollution.The 2 stroke engines also produce higher decibels of noise. Hence it is banned in some places.Thus in a sense 4 stroke engines are more fuel efficient than 2 stroke engines.FACTORS AFFECTING EFFICIENCYOf the total heat energy released by thegasoline acquired, about 70-75% is rejected as heat without being turned into useful work ie to the crankshaft.Approx half of this rejected heat is carried a focus by the exhaust gases, and half passes through the cylinder walls or cylinder head into the engine cooling system, a nd is passed to the atmosphere via the cooling system radiator. Some of the work generated is also lost as friction, noise, air turbulence, and work employ to turn engine equipment and appliances such aswater and oil pumpsand the electricalgenerator, leaving only about 25-30% of the energy released by the fuel consumed available to move the vehicle.Thus the available energy desires to be used effectively in order to gain the most out of it.WeightOne of the best ship canal to increase the fuel efficiency of the vehicles is to reduce down the weight. Which means replacing the heavier separate with the lighter ones .This needs to be done without compromising with the safety,performance and consumer preference of the vehicle.The lightest strong for the car bodies is deoxycytidine monophosphate fiber.though it comes with a hefty price. It is currently reserved for the very expensive cars and the high end sports car industry.Ten years ago, carbon fibre cost $150 for a pound.Now it co sts around $10 a pound. On the other hand steel costs less than a dollar. renew the steel components with carbon fibre ones can reduce the car weight by approx 60 percent. This 60 percent reduce in weight would decrese the cars fuel consumption by 30 percent and would cut the emissions of greenhouse gases by 10-20 percent.DisplacementDisplacementis the volume of air the engine can consume in a single revolution. It is generally denoted in litres.The more air the engine can move in, the more fuel it can burn.Thus a small compact bike engine will be more efficient than a trucks engine.Compression ratioMost gasoline (petrol) engines have the compression ratio calculated purely from the geometry of the mechanical parts(geometriccompression ratio). 101 (premium fuel) or 91 (regular fuel), with some engines reaching a ratio of 121 or more. The greater the compression ratio the more efficient is the engine, in principle . Higher compression-ratio conventional engines in principle need gaso line with higheroctanevalue .High octane value gives the fuel the tendency to burn nearly instantaneously (known asdetonation or knock) at high compression conditions.Fuel intakeThe carburetor system is adapted for the fuel intake.The carburetor contains jets that push the gas into the combustion chambers. The amount of fuel that can flow through these jets depends completely on the amount of air that can be pulled into the carburetor .The main issue with obtaining the best performance using a carburetor is that it bevel square monitor the air to fuel ratio for each individual cylinder.Fuel injection systems on the other hand are becoming more popular for best performance from the engines.The main benefits to using direct injection is that the amount of fuel and air can be perfectly released and then injected into the cylinder match to the engine load conditions. The electronics used in the system will calculate this information and constantly adjust. This type of controlled fuel injection results in a higher power output, greater fuel efficiency and much lower emissions. The main issues is that these systems are sophisticated and will cost much more than a carburetor.In the past years direct injection systems haveincreased the efficiency of the engines equipped with this fueling system up to 35%OxygenIf there is not enough group Ofor proper combustion, the fuel will not burn completely and will produce less energy. Relatively, an excessively rich air fuel ratio will increase pollutants from the engine.The fuel burns in three stages. Firstly, the hydrogen burns to form water vapour. Second, carbon burns to carbon monoxide and finally, the carbon monoxide burns to carbon dioxide. This last stage produces most of the power of the engine.If all of theoxygenis consumed before this stage, engines power is reduced.To increase the amount of oxygen, we need to increase the air intake.One way is through forced induced intake. A compressor can be added to force a larg er charge .This can be done by mechanically driven supercharging or exhaust driven turbo charging.Mechanical ResistanceType of resistance car manufacturers are concerned with, called mechanical resistance, which has more to do with a vehicles mechanical components other than the tires. Mechanical resistance is described as the amount of effort it takes to move each individual piece of the vehicles drivetrain.The automatic transmissions generate more resistance than their manual counterparts.Mechanical resistance usually accounts for about a 15 percent drop in power from what the engine produces to what actually makes it to the pavement. Which means if an engine produces 100 horsepower, then only about 85 of those horses make it to the ground.An engine has many moving parts that producefriction. Some of these friction forces remain constant while some of these friction losses increase as engine speed increases, such as piston side forces and connecting bearing forcesSynthetic lubrica nts, light weight materials and tighter manufacturing tolerances can all contribute to less mechanical resistance in a vehicle.aerodynamicsAt high speeds, and on exceptionally windy days,air resistance(the forces acted upon a moving object by the air also defined asdrag) has a tremendous effect on the way a car accelerates, handles and achieves fuel mileage.Engineers have developed several ways ofreducing it. For instance, more rounded designs and shapes on the exterior of the vehicle are crafted to channel air in a way so that it flows around the car with the least resistance possible. Some high-performance cars even have parts that move air smoothly across the underside of the car. Many also include aspoileralso known as arear wing to keep the air from lifting the cars wheels and making it unstable at high speeds.CONCLUSIONEven after years of its discovery in the 19th century, gasoline (petrol) engines account for the most used engines currently ,much ahead of its diesel counterpa rt which is evident enough to denote our dependency on petrol. However petrol as we know is a express resource. the rate at which it replenishes is way much lower than the rate at which we are consuming it .Moreover burning of the fuel causes pollution.Keeping that in mind and pursuit the context of my study, I feel it is a great move by president Obama to order the vehicle industry to double the gross fuel economy of their vehicles by the year 2025