Diesel Engine Power Plant Prepared By: Nimesh Gajjar

Plant Layout of DPP

Schematic Layout of a Diesel power plant 23 April 2017 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.

Engine Related Terms TDC (top dead center) BDC (bottom dead center) Stroke Bore Revolution Compression Ratio Displacement Cycle

Diesel Engine

Exhaust system of DPP

Types of Fuel Injection System 1. The common rail system; 2. The distributor-injection system; and 3. The pump and pressure operated nozzle systems. Types of Fuel Injection System

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…

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.

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.

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

Liquid cooling System cont…. Forced Circulation

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.

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

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.

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 Connecting rod Crank pin, bottom end bearing (rotatory motion) Journal, journal bearing (rotatory motion) Web extension Oil Web

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.

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 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.

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