ENGINE OPERATION

Hello friend's, so in this post we will talk about engines.

1. INTRODUCTION

Internal combustion engines are those heat engines that burn their fuel inside the engine cylinder. On the other side, extermal combustion engines are those heat engines that burn their fuel outside the engine cylinder. These are steam engines. The energy developed during the combustion of fuel is transmitted to steam, which acts on the piston inside the cylinder. In internal combustion engines, the chemical energy stored in the fuel is converted into heat energy by combustion. The heat energy is converted into mechanical energy by the expansion of gases against the piston attached to crankshaft that can rotate. The engines that burn petrol are known as petrol engines. Other types of internal combustion engines burn heavier oils, of these types the diesel engine has come into the widest use.

2. I.C. ENGINE AND STEAM ENGINE

Both I.C. engines and steam engines are basically heat engines and convert heat energy into mechanical energy. But I.C. engines are now widely used for this purpose due to some reasons. The class of service is the main factor in many cases. One of the outstanding uses is in the field of transportation. In many industries, farms, simplicity and low cost of operation are the determining factors in the adoption of I.C. engines. The main differences between the I.C. engine and steam engine are as follows :

1. In I.C. engines, the combustion of fuel takes place inside the engine cylinder, while in steam engines, the combustion of fuel takes place outside the cylinder.

2. The working temperatures and pressures in I.C. engines are much higher than those in steam engines.

3. Due to high temperatures and pressures, materials having better resistance are required for I.C. engines.

4. I.C. engines are single acting. Piston is directly connected to connecting rod. There is no piston rod and hence no stuffing box.

5. I.C. engines have high efficiency as compared to that of steam engines.

6. Steam engine requires a big boiler to store water for converting it into steam and a condenser to condense exhaust steam into water. But I.C. engines require only a small tank to store fuel ; and there is no steam condenser in it.

7. I.C. engines are easy and quick to start and stop. Steam engines take time in lighting the fire and generating the steam.

8. I.C. engines are lighter and cheaper as compared to steam engines.

Comments

VALVE TIMING DIAGRAM OF A FOUR-STROKE, OTTO CYCLE ENGINE

Hello friend's in this post we will talk about valve timing diagram of a four stroke, otto cycle engine It has already been explained in the operation of four stroke, Otto cycle engine that the inlet valve opens during the suction stroke and the exhaust valve opens during the exhaust stroke. The exact moment at winch each of the valves opens and closes with reference to the position of piston and crank can be shown graphically in a diagram. This diagram is known as valve timing diagram. Theoretically, the inlet valve opens exactly at the beginning of suction stroke and closes at the end of the stroke. Both the valves remain closed during compression and power strokes. The exhaust valve opens exactly at the beginning of exhaust stroke and closes at the end of stroke. The theoretical valve timing diagram for a four-stroke Otto cycle engine is shown in Fig. 3.3. The opening and closing of valves with reference to the position of piston and crank shaft during the four strok

FOUR - STROKE , OTTO CYCLE , SPARK IGNITION ENGINE

Hello friend's so in this post we will talk about four strock engines. The modern petrol ( gasoline ) engines operate on Otto ( constant volume ) cycle . This cycle was introduced in practical form by a German scientist Otto in 1876 , although it was described by a French scientist Beande Roches in 1862. In a four - stroke Otto cycle , spark ignition engine , the four strokes are as follows : 1. Suction stroke During suction stroke , the piston is moved downward by the crankshaft , which is revolved either by the momentum of the flywheel or by the power generated by the electric starting motor . The inlet valve remains open and the exhaust valve is closed during this stroke . The downward movement of the piston sucks air - fuel mixture in the cylinder from the carburettor through the open inlet valve . Here the fuel is petrol mixed with air , broken up into a mist and partially vaporized in the carburettor . 2. Compression stroke During compression stroke , the p

PRESSURE-VOLUME DIAGRAM OF FOUR-STROKE, OTTO CYCLE ENGINE

Hello friend's in this post we will talk about pressure - volume diagram of four - stroke, otto cycle engine Fig. 3.8 shows theoretical p-v diagram of a four-stroke Otto cycle engine. During the suction stroke, the charge is admitted in the cylinder increasing the volume from 1 to 2, at the atmospheric pressure. Cylinder volume is the sum of clearance volume and stroke volume. During the compression stroke, the charge is compressed from 2 to 3. Volume decreases to clearance volume and pressure rises. The compressed charge is ignited at constant volume, which increases the pressure as represented by 3- 4 line. During the working stroke the volume increases and pressure decreases as represented by 4-5line. At 5, the exhaust valve opens and exhaust takes place at constant decreases the pressure suddenly as represented by 5-2 line. Finally the piston moves onward rushing out the exhaust gases at atmospheric pressure as represented by 2-1 line. The volume again decreases to clearance vo

AUTOMOBILE ENGINEERING

Search This Blog