Diesel Engine Power Plant Prepared By Nimesh Gajjar

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 q Introduction: v Diesel power plants produce power in the range of 2 to 50 MW. v They are used as standby sets for continuity of supply such as hospitals, telephone exchanges, radio stations, cinema theatres and industries. v They are suitable for mobile power generation and widely used in railways and ships. v 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

Fundamental of Diesel Engine Four Stroke Cycle • Intake / Suction Compression Power / Expansion Exhaust

Four stroke cycle theory Intake stroke Piston moving down Intake valve open Exhaust valve closed

Four stroke cycle theory Compression stroke Piston moving up Intake valve closed Exhaust valve closed

Four stroke cycle theory Power stroke Piston moving down Intake valve closed Exhaust valve closed

Four stroke cycle theory Exhaust stroke Piston moving up Intake valve closed Exhaust 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.

Diesel Animation UsefulDieselcycle 4 s. swf

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 Usefultwo-stroke. swf

Difference between 2 S and 4 S Engine

Advantages & Disadvantages to a 4 -Stroke Cycle Engine Disadvantages: Advantages: 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 • • • u u u Heavy Limited slope operation More moving parts

Advantages & Disadvantages to a 2 -Stroke Cycle Engine Advantages: u u Lighter Can be operated in all positions Less moving parts Higher horse power per cc displacement Disadvantages: • Low torque output • Erratic running Characteristic • Noisy • Higher emissions output • Gas/Oil mixing

2 Stoke Engines part names Cylinder Combustion Exhaust port chamber Still uses a flywheel (not shown) Crankcase Piston Connecting Intake port Rod Transfer port Reed valve Crankshaft

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. UsefulMAN Diesel Powerplant Medium. flv

Engine Related Terms • • TDC (top dead center) BDC (bottom dead center) Stroke Bore Revolution Compression Ratio Displacement Cycle UsefulDiesel engine. mp 4

Diesel Engine UsefulDiesel Engine Working. mp 4

Exhaust system of DPP

Fuel Injection System 1. The common rail system; Types of Fuel Injection 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…

UsefulCommon rail diesel. mp 4 UsefulCaterpillar Common Rail - You. Tube. flv UsefulDiesel Common Rail Injection Facts 1. mp 4

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. Usefuldiesel fuel inector - how it works. mp 4

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. UsefulDiesel fuel injection system - You. Tube. 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 System Following 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 case there 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 it may 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 are exposed to air directly.

Liquid Cooling System

Liquid cooling System cont…. Natural Circulation UsefulAir cooled and Water Cooled Engine. png

Liquid cooling System cont…. Forced Circulation UsefulCooling system. mp 4

Liquid cooling System cont….

Liquid Cooling System

Lubrication System Need for Lubrication In 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 lubricated The following are some engine parts that require adequate lubrication. 1. Crank shaft 2. Crank pin 3. Big and small end of the connecting rode 4. Piston pin 5. Internal surfaces of cylinder walls 6. Piston rings 7. Valve mechanisms 8. Cam shaft etc. Usefulengine cooling and lubricating. mp 4

Ref: http: //www. marinediesels. in fo/2_stroke_engine_parts/cr osshead. htm Piston rings Piston skirt Platform separating cylinder from crank case Piston rod Stuffing box Crosshead, crosshead bearing (reciprocating) Oil pumped at a certain pressure Connecting rod Crank pin, bottom end bearing (rotatory motion) Web Journal, journal bearing (rotatory motion)

Lubrication system • • TG- Temperature gauge PG- Pressure gauge PG TG ENGINE Shaft Bearings PG Cooler TG PG Storage tank Pump UsefulCar engine lubrication system. mp 4 Filter

Lubrication System cont…. Lubrication Systems The 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. UsefulSplash Lubrication. mp 4

Splash type lubrication Cylinder liner Piston rings Oil is picked up by the webs while rotating, and splashed onto the piston and liner Gudgeon pin Crank pin, bottom end bearing (rotatory motion) Connecting rod Journal, journal bearing (rotatory motion) Web extension Oil Web UsefulCrankshaft oil lubrication simulation. mp 4

Pressure feed lubrication system UsefulPressure Lubricated Air Compressor Pump. mp 4 UsefulPressure_System. flv. mp 4 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.

Splash and Pressure feed Lubrication system Cylinder walls are lubricated by splashing oil thrown off from the connecting-rod bearings 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.

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 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. Useful16 -Dry Sump Oil Tank. swf. mp 4

Staring System 1) Auxiliary Engine starting system 2) Electric Motor Starting System 3) Compressed Air Starting System