Engines START Four stroke petrol Two stroke petrol Diesel Click an engine to select

Download Engines START Four stroke petrol Two stroke petrol Diesel Click an engine to select

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<ul><li><p>EnginesSTART</p></li><li><p>Four stroke petrolTwo stroke petrolDieselClick an engine to select</p></li><li><p>Four Stroke Petrol EngineFind out about the partsWatch an animation How it worksGalleryBackDifferent engine arrangements</p></li><li><p>Four stroke petrolExhaust ValveSpark PlugOil sumpPistonCylinderCrankInlet ValveConnecting RodBack</p></li><li><p>The Inlet ValveThe inlet valve is pushed down on its spring to open up a way for the petrol vapour and air mixture to go into the cylinderBack</p></li><li><p>CylinderThe cylinder is where the fuel is burned.The total volume of the cylinders is known as the engine capacityBack</p></li><li><p>Connecting RodThe connecting rod connects the piston which is moving up and down in a straight line to the crank which is rotatingBack</p></li><li><p>Exhaust ValveThe exhaust valve is pushed down on its spring to open up a way for the burnt fumes to leave the cylinderBack</p></li><li><p>Spark PlugThe spark plug creates a spark at just the right time to ignite the petrol vapour and air mixture Back</p></li><li><p>PistonThe piston moves up and down inside the cylinder.When the fuel explodes the piston is pushed downBack</p></li><li><p>CrankThe crank is the first part of the engine to move with rotating motionBack</p></li><li><p>Oil sumpThe oil used to reduce friction and keep the engine running smoothly collects in the sump at the bottom of the engineBack</p></li><li><p>Fuel InjectorIn a diesel engine the fuel is injected through these deveices at just the right momentBack</p></li><li><p>How it worksThere are four stages to the cycle.Click on each engine to find out about each stageBackINDUCTIONCOMPRESSIONCOMBUSTIONEXHAUST</p></li><li><p>BackInductionThe inlet valve opens</p><p>The piston is moving down</p><p>A mixture of petrol vapour and air is sucked into the cylinder</p><p>The inlet valve closes</p></li><li><p>BackCompressionBoth valves are now closed</p><p>The piston is moving up</p><p>A mixture of petrol vapour and air is being compressed (squashed)</p></li><li><p>BackCombustionBoth valves are now closed</p><p>The spark plug makes a spark which explodes the fuel</p><p>The piston and connecting rod are now pushed down, turning the crank shaft</p></li><li><p>BackExhaustThe exhaust valve opens</p><p>The piston is moving up</p><p>A waste fumes are pushed out of the cylinder</p><p>The exhaust valve closes</p></li><li><p>Different Engine ArrangementsIN-LINEMost engines have four cylinders arranged vertically in a straight line V6Some more powerful engine have 6 or eight cylinders arranged in a V shape FLAT4Some engines have 4 cylinders arranged in a flat horizontal way. Click each engine to see animations Back</p></li><li><p>GalleryFour stroke petrol engines are usually used in cars, small propelor planes, and larger pleasure boats Back</p></li><li><p>Four Stroke Diesel EngineFind out about the partsWatch an animation How it worksGalleryBack</p></li><li><p>Fuel InjectorCylinderConnecting RodFour stroke dieselAir Inlet Valve Oil sumpCrankPistonExhaust ValveBack</p></li><li><p>How it worksThere are four stages to the cycle.Click on each engine to find out about each stageBackINDUCTIONCOMPRESSIONCOMBUSTIONEXHAUST</p></li><li><p>The inlet valve opens</p><p>The piston is moving down</p><p>Air is sucked into the cylinder</p><p>The inlet valve closesBackInduction</p></li><li><p>BackCompressionBoth valves are now closed</p><p>The piston is moving up</p><p>Diesel fuel is injected into the cylinder just before the piston reaches the top.</p></li><li><p>BackCombustionBoth valves are now closedThere is no spark plug. Instead the air has been squashed so much that it is hot enough to ignite the fuel straight awayVIEW VIDEO CLIPThe piston and connecting rod are now pushed down, turning the crank shaft</p></li><li><p>These are video clips which show a piston being pushed very rapidly down a glass tube.The squashed air heats up so quickly that a small piece of tissue paper at the bottom of the tube bursts into flames.This is how a diesel engine ignites the fuel.BackClick the pictures to play</p></li><li><p>BackExhaustThe exhaust valve opens</p><p>The piston is moving up</p><p>A waste fumes are pushed out of the cylinder</p><p>The exhaust valve closes</p></li><li><p>GalleryUntil recently diesel engines were only used on big vehicles, nowadays they are quite common in small cars. Back</p></li><li><p>Two Stroke Petrol EngineFind out about the partsWatch an animation How it worksGalleryBackIs two stroke better than four ?</p></li><li><p>CylinderConnecting RodTwo stroke petrolCrankPistonBackSpark Plug</p></li><li><p>How it worksDown Stroke CombustionUp Stroke CompressionThe two stroke engine fires once every revolution whereas the four stroke only fires once every other revolution. There are just two parts to the cycle, the down stroke and the up stroke</p><p>Click on the pictures above to find out about each strokeBack</p></li><li><p>The down stroke CombustionThis starts when the spark ignites the fuel pushing the piston down.</p><p>Soon after starting to move down the exhaust port is uncovered and the exhaust gasses rush out</p><p>In a two stroke engine the fuel,air,and oil mixture surrounds the crank.</p><p>So as the piston moves down it squashes the fuel mixture. Continue</p></li><li><p>The down stroke continuedAs the piston moves down, the inlet port is uncovered and the squashed fuel mixture rushes into the cylinder.</p><p>Notice that at this point both the exhaust and inlet port are both uncovered. It is possible for some fresh fuel to pass straight out of the exhaust port.Back</p></li><li><p>The up strokeCompressionAs the piston moves up it begins to squash or compress the fuel mixture above it. </p></li><li><p>The up strokeCompressionOnce the inlet port has been covered the rising piston will cause a partial vacuum in the crank case below it. </p><p>The drop in pressure in the crank case causes the reed valve on the inlet to be sucked open.</p><p>A fresh fuel / air / oil mixture can now enter the crank case. Back</p></li><li><p>Is two stroke better than four ?Click on an expert to find out moreBack</p></li><li><p>Is two stroke better than four ?A two stroke engine fires once every revolution, whereas a four stroke engine only fires once every other revolution. This means it has a lot more power </p><p>If you need a light weight engine with a lot of power, then two stroke is much better.</p><p>This is important if the engine is on something that you have to lift, like a petrol hedge trimmer or chain saw.Back</p></li><li><p>Is two stroke better than four ?A two stroke engine doesnt have any valves and all the parts needed to drive the valves.</p><p>With fewer moving parts the engine can be lighter, and will be more reliable.This is important in small portable engines, and makes two stroke engines ideal for scooters and small motor bikes</p><p>Back</p></li><li><p>Is two stroke better than four ?In a two stroke engine the fuel / air mixture has to surround the crank. This means there is no pool of oil in the sump to lubricate the moving parts.</p><p>To overcome this special oil has to mixed with the fuel.</p><p>This means that the engine will work equally well at all angles, even upside down. Important for small hand held machines like chain saws.Back</p></li><li><p>Is two stroke better than four ?In a two stroke engine the fuel / air mixture has to surround the crank. This means there is no pool of oil in the sump to lubricate the moving parts.</p><p>To overcome this special oil has to mixed with the fuel.</p><p>This means that the engine will burn quite a lot of oil. Two stroke engines are often quite smoky. This doesnt go down to well when we are trying avoid pollution.Back</p></li><li><p>Is two stroke better than four ?Remember that there is one part of the cycle when both inlet and exhaust port are both open.New, un-burnt fuel can go straight out of the exhaust.This means that two stroke engines waste a lot of fuel. If you had a two stroke engine in your car you wouldnt get very many miles to each litre of petrol.Petrol which has leaked out of two stoke boat engines is often seen floating on the water. All of this makes two stroke engines very environmentally unfriendly Back</p></li><li><p>GalleryTwo stroke engines are ideal for small machinery which may have to operate at different angles and where it is important to keep the weight down.Back</p></li></ul>

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