33 Four stroke Petrol engine (spark ignition) Skip to main content

SPARK PLUG WORKING AND TYPES

Post a Comment

Four stroke Petrol engine (spark ignition)

Introduction: The modern petrol engines operate on Otto cycle this cycle was introduced by German scientist Otto in 1876.


Although it was described by french scientist Beande Roches in 1862.


 Mainly Four strokes in the Petrol engines.


1. Suction stroke.


2. Compression stroke.


3. Power (working, expansion) stroke


4. Exhaust stroke.


     Suction stroke : 


   During this stroke the the piston moves downword by the crankshaft which is revolved by the momentum of the flywheel & the power generated by the electric motor the inlet valve remains open & exhaust valve is closed during stroke.


The downword movement of the piston sucks the air- fuel mixture in the cylinder from the carburettor through the open inlet valve. And the petrol mixed with air, this stroke complete here now the process move the next stroke.


     Compression stroke :


    During the compression stroke the piston moves upward direction and compressing the charge, the heat produced by the compression makes more homogeneous mixture of air and fuel inside the cylinder. The heat makes the petrol easier to burn while the compression forces it's closer to combination with the air 


The mixture in under compression is ignited by the spark produced by a spark plug & combustion is about half- completed when the piston is at TDC.


Both value remains closed during this stroke


TDC ; Top dead centre 


BDC ; Bottom dead centre.


    Power stroke :


In this stroke the expansion of the gasesdue to the heat of combustion exerts a pressure on the cylinder & piston. Under this impulse the moves downword direction thus doing useful work.


Both the valves remain closed during this stroke.


    Exhaust stroke : 


During this stroke the inlet valve is closed and exhaust valve open. The maximum part of the burnt gases escapes because of their own expansion. The piston moves upward and pushes the remaining gases out of the open exhaust valve.


Only a small amount of exhaust gases remains in the clearance space which will dilute the fresh incoming charge. 


In this type of engine, four stroke of the piston are required to complete the cycle and four stroke make two revolution of the crankshaft .The operation are repeated over & over again in running the engine. Each revolution of the crankshaft has one power stroke.





Comments

Post a Comment

Please do not enter any spam link in the comment box

Popular posts from this blog

VALUE TIMING DIAGRAM OF A FOUR STROKE, OTTO CYCLE ENGINE

  VALUE 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 stroke and the exhaust valve opens during the exhaust stroke. The exact moment at which each of the valves opens and closes with reference to the position of the piston and crank can be show 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 close during power and compression stroke. The exhaust valve opens exactly at the beginning of exhaust stroke and closes at the end of the stroke. The theoretical valve timing diagram for a four stroke Otto cycle engine in shown in diagram. The opening and closing valves with reference to the position of piston and crank shaft during the four strokes are described as follow. 1.  ...
Post a Comment
Read more

Information of Cylinder block

  Cylinder block . Cylinder block, cylinder head and crankcase these three parts from the foundation and main stationary body of the automobile engines. They serve as support enclosure for moving parts. In modern engines the cylinder block and crankcase from a single casting which gives a rigid structure. The cylinder block may also have a separate crankcase for the crankshaft which is mainly confined to large engines, marine and stationary engines. A separate aluminium crankcase would result in saving the weight as well as enable cheaper and quicker replacement.  1. The cylinder in which the piston slide up and down 2. The ports or opening for the valves 3. The passages for the flow of cooling water The cylinder block is usually made from grey cast iron , and sometimes, with addition of nickel and chromium. Some blocks are cast from aluminium, in which cast iron or steel sleeves are used. For most engines cast iron has been found to be a satisfactory cylinder wall materia...
Post a Comment
Read more

FOUR STROKE, DIESEL CYCLE, COMPRESSION IGNITION ENGINE

          FOUR STROKE, DIESEL CYCLE, COMPRESSION IGNITION ENGINE The engine of heavy motor vehicle ( like truck, buses) stationary power plant big industrial units and ships mostly operate on diesel cycle or constant pressure cycle. It was introduced by Dr Rudolph Diesel in 1897. Diesel cycle differs from Otto cycle in one respect. The heat is added at constant pressure instead of at constant volume. Thus, it comprises two adiabatic process, one constant pressure heat addition process and one constant volume heat rejection process. Diesel cycle engines mostly use heavy oils. Diesel oil is the most common. Diesel cycle engine only air is compressed in the cylinder to a high pressure, the temperature of nice compressed air Sufficiently high to ignite fuel. Diesel is injected in the cylinder at the end of compression stroke which itself ignitor new to high temperature of the compressed air. There is no spark plug in diesel engine. In a four stroke diesel cycle, co...
Post a Comment
Read more