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Diesel Engine Power Plant
Prepared By: Nimesh Gajjar
Definition
A generating station in which diesel engine is used as the prime mover for the generation of electrical energy is known as diesel power station.
Diesel power plant
Introduction:
Diesel power plants produce power in the range of 2 to 50 MW.
They are used as standby sets for continuity of supply such as hospitals, telephone exchanges, radio stations, cinema theatres and industries.
They are suitable for mobile power generation and widely used in railways and ships.
Generally 2 stroke diesel engine used for power generation.
USES OF DIESEL ENGINES
TODAY, DIESEL ENGINES ARE USED TO PROVIDE POWER IN A VARIETY OF APPLICATIONS IN MANY INDUSTRIES
THERE ARE SIX MAJOR USES OF DIESEL ENGINES
AGRICULTURE/FARM
TRANSPORTATION
CONSTRUCTION
FORESTRY
MARINE
ELECTRICAL GENERATION PLANTS
Advantages and Disadvantages of DPP Advantages
(a) The design and layout of the plant are quite simple.
(b) It occupies less space as the number and size of the auxiliaries is small.
(c) can be located at any place.
(d) It can be started quickly and it can pickup load in a short time.
(e) There are no standby losses.
(f) It requires less quantity of water for cooling.
(g) The overall cost is much less than that of steam power station of same
capacity.
(h) The thermal efficiency of the plant is higher than that of a steam power station.
(i) It requires less operating staff. Disadvantages
(a) The plant has high running charges as the fuel (diesel) used is costly.
(b) The plant doesn’t work satisfactorily under overload conditions for a longer period.
(c) The plant can only generate small power.
(d) The cost of lubrication is generally high.
(e) The maintenances charges are generally high
Four Stroke Cycle
• Intake / Suction Compression Power / Expansion Exhaust
Fundamental of Diesel Engine
Four stroke cycle theory
Intake strokePiston moving downIntake valve openExhaust valve closed
Four stroke cycle theory
Compression strokePiston moving upIntake valve closedExhaust valve closed
Four stroke cycle theory
Power strokePiston moving downIntake valve closedExhaust valve closed
Four stroke cycle theory
Exhaust strokePiston moving upIntake valve closedExhaust valve open
Four Stroke Cycle Animation
Four-Stroke Cycle Diesel Engine
• The piston travels from one end of the cylinder to the other four times during
each cycle.
• The fuel is ignited at the beginning of the third stroke of each cycle.
• Intake air flows into each cylinder through intake valves in the cylinder head.
• Exhaust gases leave through exhaust valves.
• On the intake stroke, atmospheric pressure pushes air into the cylinder through
the intake valve.
• The exhaust stroke forces burned gases out through the exhaust valve.
• During the compression and power strokes, both valves are closed.
Two-Stroke Cycle Diesel Engine
• They have only two strokes per cycle.
• The fuel is ignited on every other stroke of the piston.
• In the two-stroke diesel engine, air is forced in and exhaust
gases are forced out on a single stroke.
• Usually a blower forces air into the cylinder through intake
ports.
• The incoming air pushes remaining exhaust gases out of the
cylinder through an exhaust valve.
Two Stroke Animation
Useful\two-stroke.swf
Difference between 2S and 4S Engine
Advantages & Disadvantagesto a 4-Stroke Cycle Engine
• High torque output• Smooth running• Quieter operation• Lower emissions output• More forgiving to poor
operational practices• Higher horse power
availability• Heavier construction• No Gas/Oil mixing
Advantages: Disadvantages:
Heavy Limited slope operation More moving parts
Advantages & Disadvantagesto a 2-Stroke Cycle Engine
• Low torque output• Erratic running
Characteristic• Noisy• Higher emissions output• Gas/Oil mixing
Advantages: Disadvantages:
Lighter Can be operated in all positions Less moving parts Higher horse power per cc
displacement
2 Stoke Engines part names
Piston
Cylinder
CrankshaftConnectingRod
Still uses a flywheel(not shown)Combustion
chamber
Intake port
Exhaust port
Reed valve
Transfer port
Crankcase
Diesel
Plant Layout of DPP
Schematic Layout of a Diesel power plant
The essential components of a Diesel Electric Plant are: (1) Engine (2) Engine air intake system (3) Engine fuel system (4) Engine exhausts system (5) Engine cooling system (6) Engine lubrication system (7) Engine starting system.
Useful\MAN Diesel Powerplant Medium.flv.flv
Engine Related Terms
• TDC (top dead center)• BDC (bottom dead center)• Stroke• Bore• Revolution• Compression Ratio• Displacement • Cycle
Useful\Diesel engine.mp4
Diesel Engine
Useful\Diesel Engine Working.mp4
Exhaust system of DPP
Fuel Injection System
Types of Fuel Injection System
1. The common rail system;
2. The distributor-injection system; and
3. The pump and pressure operated nozzle systems.
Common Rail Fuel Injection System
A high pressure header or 'common rail' is supplied by a single pump with built in pressure regulation which adjusts pumping rate to maintain the desired injection pressure.
Common Rail Fuel Injection System cont…
Common Rail Fuel Injection System cont…
Useful\Caterpillar Common Rail - YouTube.flv
Useful\Common rail diesel.mp4
Useful\Diesel Common Rail Injection Facts 1.mp4
Distributor-injection system
In this system, a single injection pump supplies fuel to a distributor. The distributor directs fuel to the injectors in the right firing order. The metering of fuel is done at the pump.
Useful\diesel fuel inector - how it works.mp4
Individual Pump Injection system
In this system, the injection pump and injector are combined into one unit and are driven by the overhead camshaft. The plunger is a part of the injector. Pressurization, timing, and metering of the fuel all take place in the unit injector. An engine with this system has one unit injector for each cylinder.
Useful\Diesel fuel injection system - YouTube.flv
Air Cooling System
In this system fins or extended surfaces are provided on the cylinder walls, cylinder head, etc. Heat generated due to combustion in the engine cylinder will be conducted to the fins and when the air flows over the fins, heat will be dissipated to air.
Air Cooling System cont…
Advantages of Air Cooled SystemFollowing are the advantages of air cooled system :(a) Radiator/pump is absent hence the system is light.(b) In case of water cooling system there are leakages, but in this casethere are no leakages.(c) Coolant and antifreeze solutions are not required.(d) This system can be used in cold climates, where if water is used itmay freeze.
Disadvantages of Air Cooled System(a) Comparatively it is less efficient.(b) It is used in aero planes and motorcycle engines where the engines areexposed to air directly.
Liquid Cooling System
Liquid cooling System cont….
Natural Circulation
Useful\Air cooled and Water Cooled Engine.png
Liquid cooling System cont….
Forced Circulation
Useful\Cooling system.mp4
Liquid cooling System cont….
Liquid Cooling System
Lubrication SystemNeed for LubricationIn an I.C. engine, moving parts rub against each other causing frictional force. Due to the frictional force, heat is generated and the engine parts wear easily. Power is also lost due to friction, since more power is required to drive an engine having more friction between rubbing surfaces.
To reduce the power lost and also wear and tear of the moving part substance called lubricant is introduced between, the rubbing surfaces.
Function of Lubrication(a) Lubricant reduces friction between moving part(b) It reduces wear and tear of the moving parts.(c) It minimizes power loss due to friction.(d) It provides cooling effect. While lubricating it also carries some heat from the moving parts and delivers it to the surroundings through the bottom of the engine (crank case).(e) It helps reduce noise created by the moving parts.
Engine parts which are lubricatedThe following are some engine parts that require adequate lubrication.1. Crank shaft 2. Crank pin 3. Big and small end of the connecting rode4. Piston pin 5. Internal surfaces of cylinder walls6. Piston rings 7. Valve mechanisms 8. Cam shaft etc.
Useful\engine cooling and lubricating.mp4
Piston
Piston rod
Crank pin, bottom end bearing (rotatory motion) Journal, journal bearing
(rotatory motion)
Crosshead, crosshead bearing (reciprocating)
Connecting rod
Piston rings
Oil pumped at a certain pressure
Ref: http://www.marinediesels.info/2_stroke_engine_parts/crosshead.htm
Web
Piston skirt
Stuffing box
Platform separating cylinder from crank case
Lubrication system• TG- Temperature gauge• PG- Pressure gauge
ENGINE Shaft
Cooler
Storage tank PumpFilter
Bearings
PG
PG
TG PG
TG
Useful\Car engine lubrication system.mp4
Lubrication System cont….
Lubrication SystemsThe main lubrication systems are:1. Mist lubrication system.2. Wet sump lubrication system.
(a) Splash lubrication system(b) Pressure / Forced Feed Lubrication system(c) Splash and Pressure feed lubrication system
3. Dry sump lubrication system.
1. Mist Lubrication System.This system of lubrication is used in scooters and motor cycles. About 3% to 6% of lubricating oil is added with petrol in the petrol tank. The petrol evaporates when the engine is working. The lubricating oil is left behind in the form of mist. The parts of the engine such as piston cylinder walls, connecting rod are lubricated by being wetted with the oil mist
Disadvantage(i) If the added oil is less, there will not be sufficient lubrication and even result in seizure of the engine, (ii) If the added oil is more, it will lead to excess exhaust smoke and carbon deposits in the cylinder, exhaust parts and spark plugs.
Splash Lubrication system
As the engine is operating, dippers on the ends of the connecting rods enter the oil supply, pick up sufficient oil to lubricate the connecting-rod bearing, and splash oil to the upper parts of the engine. The oil is thrown up as droplets, or fine spray, which lubricates the cylinder walls, piston pins and valve mechanism.
Useful\Splash Lubrication.mp4
Splash type lubrication
Piston rings
Web
Crank pin, bottom end bearing (rotatory motion)
Connecting rod
Gudgeon pin
Cylinder liner
Journal, journal bearing (rotatory motion)
Web extension
Oil
Oil is picked up by the webs while rotating, and splashed onto the piston and liner
Useful\Crankshaft oil lubrication simulation.mp4
Pressure feed lubrication system
In the pressure-feed system, oil is forced by the oil pump through oil lines and drilled passageways. The oil, passing through the drilled passageways under pressure, supplies the necessary lubrication for the crankshaft main bearings, the connecting-rod bearings piston-pin bushings, camshaft bearings, valve lifters, valve push rods, and rocker studs.
Useful\Pressure Lubricated Air Compressor Pump.mp4
Useful\Pressure_System.flv.mp4
Splash and Pressure feed Lubrication system
In a combination splash and force feed, oil is delivered to some parts by means of splashing and other parts through oil passages under pressure from the oil pump.The oil from the pump flows to the main bearings and camshaft bearings. The main bearings have oil-feed holes or grooves that feed oil into drilled passages in the crankshaft. The oil flows through these passages to the connecting rod bearings. From there, on some engines, it flows through holes drilled in the connecting rods to the piston-pin bearings.
Cylinder walls are lubricated by splashing oil thrown off from the connecting-rod bearings
Dry sump lubrication system
Dry Sump engines carry their oil in an oil tank that is separate from the engine. This can be an actual tank or inside of the tubes of the frame. This engine lubrication type uses two oil pumps. One to pump oil to the engine, where it lubes everything and then drops to the bottom of the engine. From there, the second or scavenge pump pumps the oil back to the oil tank. Sometimes the scavenge pump also pumps oil to the transmission, valves and other places in the engine. The scavenge pump is twice as big as the main oil pump. Useful\16-Dry Sump Oil Tank.swf.mp4
Staring System
1) Auxiliary Engine starting system
2) Electric Motor Starting System
3) Compressed Air Starting System
