26-09-2013, 04:54 PM
A PROJECT REPORT ON Diesel Engine Power Plant
Diesel Engine.docx (Size: 915.77 KB / Downloads: 111)
ABSTRACT
This project explains about the power plant concept which is use the diesel engine as the prime mover. This power plant need to output electric energy
Generally it is used for heavy duty vehicles. It can also be used for power generation, pumping of water etc.
Maintenance of engine is an essential part which may be done in different engine maintenance shops. Our engine condition indicated that the engine was out of order, i.e. the engine was not in running condition. The main causes were fracturing piston pin and straight thread for the load balance.
We replaced those components for which the engine was failed to run. We manufactured the piston pin i.e. gudgeon pin and the straight thread for the engine and also cleaned piston, piston rings, cylinder block and other components. All the parts were cleaned properly and reassembled in proper position. Then the engine was performed for running and also for performance test. The maximum efficiency was found 32.52 % and the calculated maximum rated power was 2.89 kW at 920 rpm.
Introduction
Diesel engine power plant is suitable for small and medium outputs. It is used as central power station for smaller power supplies and as a standby plant to hydro-electric power plants and steam power plants.
The diesel power plants are commonly used where fuel prices or reliability of supply favors oil over coal, where water supply is limited, where loads are relatively small, and where electric line service is unavailable or is available at too high rates. Diesel power plants in common use have capacities up to about 5 MW.
Fig. 4.1 (a) shows various parts of an I.C. engine. The cylinder is the main body of the engine where in direct combustion of fuel takes place. The cylinder is stationary and the piston reciprocates inside it. The connecting rod transmits the force given by the piston to the crank, causing it to turn and thus convert the reciprocating motion of the piston into rotary motion of the crankshaft.
Method of Ignition.
According to method of ignition: I.C. engines are of two types
(а) Spark ignition engines
(б) Compression ignition engines.
In spark ignition engines such as in petrol engines the air fuel mixture is compressed and ignited at the end of compression stroke by an electric spark. The compression ratio in such varies between 5to8. In compression ignition engines or diesel they are often called air admitted into the cylinder is compressed. The compression ratio being nearly 12 to 20. The temperature of air becomes very high due to compression. At or near to the end of Compression stroke fuel is injected through an injection nozzle into l lie hot air in the engine cylinder. Due to high temperature of air the fuel oil burns. The burning gases expand do work on the piston and hence on the load coupled to the engine. The gases are then exhausted from the cylinder and this cycle is repeated. In I.C. engine the charge of fuel and air in correct proportions should be supplied and combustion products should be exhausted from the cylinder when air expansion is complete in order that fresh charge may enter the cylinder.
Usually well designed compression ignition engines shows greater efficiency than spark ignition engines because of their higher compression ratios. Part load efficiency of compression ignition engine is higher.
Two-stroke Diesel Engine
The various operations of a two-stroke diesel engine are shown I in Fig. 4.5. During the downward movement of piston (down stroke) The exhaust port is uncovered and the removal of burnt gases takes I place Fig. 4.5 (a). Further movement of the piston uncovers tin* transfer port Fig. 4.5 (6). At this stage the crank case and cylinder space are in direct communication. The slightly compressed air in the crank case is transferred to the cylinder (at a pressure of about)0.05 kg/cm2 gauge) through the transfer port. While the transfer of change from the crank case to the cylinder is taking place the removal of products of combustion is also taking place simultaneously example the incoming charge in helping in the rejection of burnt gases, this is known as scavenging. As the piston moves upward (up stroke) the compression of air starts, Fig. 4.5 ©. Near the end of comparison stroke [Fig. 4.5 (d)] the fuel is injected and ignition of fuel is injected place due to heat of compressed air. Then due to expansion of products of combustion the piston moves downward. As inlet port is uncovered a fresh change of air gets entered in crank case.
Heat Balance Sheet
Heat balance sheet is a useful method to watch the performance of the plant. Of all the heat supplied to an engine only part of it is converted into useful work, the remaining goes as waste. The distribution of the heat imparted to an engine is called as its heat balance. The heat balance of an engine depends on a number of factors among which load is primary importance. The heat balance of an internal combustion engine shows that the cooling water and exhaust gases carry away about 60-70% of heat produced during combustion of fuel. In order to draw the heat balance sheet of internal combustion engine, the engine is run at constant load and constant speed and the indicator diagram is drawn with the help of indicator.
Supercharging
The I.H.P. produced by an I.C. engine is almost directly proportional to the air consumed by the engine. Increasing the air consumption on permits the greater quantities of fuel to be added and result in greater power produced by the engine. It is, therefore, desirable that the engine should take in the greatest possible mass of air. The supply of air is pumped into the cylinder at a pressure fail Hum the atmospheric pressure and is called supercharging. When greater quantity of air is supplied to an internal combustion engine it would be able to develop more power for the same size and conversely a small size engine fed with extra air would produce the same us a larger engine supplied with its normal air feed is used to increase rated power output capacity of a to make the rating equal at high altitudes corresponding the un supercharged sea level rating.
Supercharging is done by installing a super charger between engine and air inlet through air cleaner super charger is merely a compressor which provides a denser charge to the engine thereby enabling the consumption of a greater mass of charge with the same total piston displacement. Power required to drive the super charger is taken from the engine and thereby removes from over all engine output some of the gain in power obtained through supercharging.
There are two types of compressors that may be used as super chargers.
CONCLUSION
The engine is now in running condition though some little defects are available. It was tried our best to improve the engine condition hence highest possible maintenance performed using lowest cost and number of parts changes were reduced. The rate of fuel consumption would be reduced if the piston and piston rings were changed because there have some erosion occurred in the top of the piston head. It would also increases the efficiency of the engine. The engine may be used in required purposes as it is ok.