the concept is also used in diesel compression ignition engines in large and weight insensitive applications, such as ships and locomotives.??? (wiki two stroke)
Crankcase :-It is a body of Engine.It contains most of moving parts of engine.Compression Rings :-First two are compression rings. They can move slightly up and down and expand slightly in and out.It act as a power seal ensuring that a maximum amount of the combustion pressure is used in forcing the piston down the cylinder.Flywheel :-The flywheel is mounted on the tapered end of crankshaft.It helps to smooth out the operation of engine.
Intake stroke: Air and vaporized fuel are drawn in.
Compression stroke: Fuel vapour and air are compressed and ignited.
Combustion stroke: Fuel combusts and piston is pushed downwards.
Exhaust stroke: Exhaust is driven out. Unlike 2 – stroke engine where oil is mixed with the fuel. In 4 – stroke engine, oil is put separately in the crank case. It gets splashed with the movement of crank and does lubrication
Please go to http://www.youtube.com/watch?v=uB2cmkWbCMI to watch the video of four stroke engine.
in diesel compression ignition engines in large and weight insensitive applications, such as ships and locomotives..
These tables were in the curriculum so have been included for completeness
Diesel EnginesEnergy & Environment
Uses of Diesel EnginesCars & Buses & Lorries Motor bikes MillsPump water from wells Agriculture equipment
Diesel Engines Heat Kinetic ChemicalThey are very useful in areas where electricity is notreliable.
Why is a Diesel Engine also known as Compression-Ignition Engine? Uses the heat of compressed air to ignite fuel which is injected into the combustion chamber. Compressed Air heats the air to 550 °C Examples ofcombustion under compression Compression-Ignition Engine does not require a spark plug like a petrol engine.
The Internal Combustion Engine(IC Engines) 1. Fuel and air is Burns its mixed in the combustion chamber fuel inside the engine 2. Mixture pressurizes 3. Mixture ignites and expands 4. Forces the piston down 5. Turns the crankshaft that through gears turns wheels
The External Combustion Engine(EC Engines) Fuel is burned in a boiler and then steam is carried out to the engine Steam used to force piston down Fuel is burnt outside the engine
Two types of Internal Combustion enginesTwo Stroke Engine Fuel is burnt inside the Four Stroke Engine engine
Four Stroke EngineMost commonly used for automotiveand industrial purposes The piston completes four separate strokes This makes two separate revolutions of the engines crankshaft ( rotating disk). This is connected to gears that often make wheels turn.The four-stroke cycle is more efficient, larger and quieter than the two-stroke cycle, but requires more moving parts and manufacturing expertise
Essential parts of 4 stroke diesel engine Cylinder is hollow &Combustion Chamber. StationaryWhere the aircombusts due to Piston slides up andincreased pressure down in cylinder Piston rings provide aCrankshaft turns the up tight seal between theand down motion into a piston and cylinderrotating motion wall. Reduce friction and control the lubrication.
Four Stroke Engine: Intake stroke 4. Air & Fuel enters in2. Inletvalve open 1. Piston at top 3. Piston moves down reducing pressure in cylinder
Four Stroke Engine: Compression Stroke1. Inlet Valve 3. Air-Fuel mixtureclosed gets compressed. Heats air to 550°C 2. Piston moves up
Four Stroke Engine: Power Stroke 1. Air-Fuel mixture2. The burning fuel puts gets so compressedpressure on piston, that it combustspushing it downwards
Exhaust Stroke . 1. Exhaust valve opens. Exhaust gas leaves cylinder 2. This releases the pressure so the piston goes up
Four Stroke Engine 1.Intake Stroke 2. Compression Stroke 3. Power Stroke 4. Exhaust Stroke 4 strokes means 2 revolutions of the crankshaft
Operation of a Four Stroke EngineStrokes Movement Intake Valve Exhaust Action in of Piston Valve combustion chamber/ CylinderIntake Stroke Open Closed Fuel & air enters chamberCompression Closed Closed Fuel & air isStroke compressedPower Stroke Closed Closed Compressed fuel and air ignitesExhaust Closed Open Piston pushesStroke exhausts out of cylinder
4 Stroke Diesel EngineThe four strokes complete the engine’s cycle. As soon as onecycle is complete, the other beginsThe pistons move due to momentumBut to get started, they need externalenergyAn electric motor or manual rotationof the crank is needed to start theengine 4 stroke engines have a dedicated lubrication system
Two Stroke EngineIn a two stroke engine, a cycle is completed in two strokesof a piston or one complete revolution (360º) of acrankshaft. Up Down This is achieved by exhausting and recharging the cylinder at the same time
Two Stroke Engine:Intake/Exhaust Stroke No valves for exhaust and air but holes on the side of the cylinder wall. The piston covers and uncovers these holes.Exhaust Intake hole is open and air and fuel comes in. This forces exhausts out
Two Stroke Engine: Compression Stroke Up Inlet port gets closed and Air-fuel mixture in thePiston moves chamber starts getting compressed.upwards
Two Stroke Engine: Power Stroke Fuel combusts Down The engine is lubricated using special oil mixed with the diesel.Piston getspushed downby hot gasesThis leads tothe intake andexhaust holesbeing open andso the engineexhausts &recharges
Two Stroke Engine Fuel combustsAir & Fuel in 2 strokes of Exhaust out piston 1 rotation of crank shaft
Two Stroke EngineAdvantages Simple Design Less weight Easier to manufacture High power to weight ratioDisadvantagesDo not consume fuel efficiently.Produce more pollution. 2-stroke engines should be used for light vehicles that are used for short periods of time
Advantages of Diesel Enginesagainst Petrol EnginesThey burn less fuel than a petrol engine performing thesame work More efficient than petrol enginesThey are more reliable as less electrical partsDiesel engines last about twice as long as petrolengines due to the increased strength of parts used
Noise & Air Pollution This can cause asthma, lung cancer, and early deathDiesel produces carbondioxide, soot & nitrogenoxides Diesel contains impurities that which makes acid rain Diesel Engines can be very noisy and can disturb people and animals.
Summary Questions1. Why is an IC engine different from an EC engine?2. What is different about petrol and diesel engines with the way they ignite fuel?3. Where would you expect to find a 4 stroke engine?4. What are some of the advantages of a 2 stroke engine and when should they be used?5. What type of pollution do we get from diesel engines?
Trouble Shooting of Diesel Engine.Cause / Fault Remedy To Remove it.No fuel in tank Fill tank with fresh fuel.Water in fuel Drain the tank. Clean carburetor and fuel lines. Fill tank with fresh and clean fuel.Carbon in Remove the cylinder.combustion Clean carbon from head and pistonchamberLoose flywheel Check fly key Tighten flywheelLoose Replace connecting rod.connecting Rod
Trouble Shooting of Diesel Engine. Engine Overheats Cause / Fault Remedy / To Remove it. 1 Engine improperly Time the Engine timed 2 Carburetor Adjust Carburetor improperly adjusted 3 Excessive load on Check operation of associated engine equipment Reduce excessive load. 4 Lack of Lubrication Full crankcase with proper oil.
Trouble Shooting of DieselEngineEngine Vibration (heavy) Cause / Fault Remedy / To Remove it.1 Engine not securely Tighten the loose mounting mounted bolts.2 Bent crankshaft Replace crankshaft3 Associated equipment out Check associated equipments of balance