SPARK PLUG

A spark plug is a electronic device which is used to initiate the spark on the air+fuel mixture.The spark initiated by the spark plug is used to initiate the combustion so that the piston moves up and down,causing a reciprocating movement.In case of diesel engines spark plugs are not present as they work on compression ignition.Spark plug is an essential device in case of petrol engines.

FIG 1.0 SPARK PLUG

ESSENTIALS OF ENGINES

An engine has the following parts, which is to assembled with many other secondary components  to make a complete engine.The essential parts of an engine are:-

                                 *Engine cylinder

                                 *Piston

                                 *Piston rod

                                 *Connecting rods

                                 *Crank case

                                 *Crank shaft

                                 *Sump

                                 *Inlet and exhaust valves

                                 *Spark plug

                                 *Cam shaft

                                 *Fly wheel

 These are the essential parts present in an engine.

TYPES OF FUELS

 The fuel is the essential requirement of an engine to produce combustion.Many engines use different types of fuels,but the commonly used fuels in IC engines are petrol and diesel,rarely auto gases and CNG are used as fuel types.The fuel is ignited to produce combustion, and.at the time of combustion the compression ratio must be high to get maximum efficiency.The fuel inlet is controlled by the inlet valve and the exhaust is controlled by the outlet valve.Both the valves are controlled by timing section.
                       Engines which use petrol as a fuel has less maintenance while diesel has a greater maintenance. Petrol has less maintenance comparing with diesel.
                       Another type is the CNG and AUTO GAS fuels.Auto gases have higher efficiency than petrol and diesel engines in mileage,but there is a minimum factor of safety as the gases may leak due to some malfunctions.Also the engines don't go up to their expected speed when auto gas is used as a fuel.
                        All the fuel types have different types of ignition for combustion. Like wise the petrol engines have spark ignition and diesel engines have compression ignition.Both compression ignition and spark ignition play a important role in IGNITION SYSTEMS OF AUTOMOBILES(IC ENGINES) .  

 

CLASSIFICATION OF ENGINES

Mechanical engines are basically classified in to two types:
                                        *INTERNAL COMBUSTION ENGINES (IC)
                                         *EXTERNAL COMBUSTION ENGINES

In internal combustion engines the combustion of fuels takes place inside the engine cylinder and where as in external combustion engines the combustion of fuel take place outside the engine with the help of a grate or something.Basically coal is used as a fuel in external combustion engines.For eg.early 1940's trains used EC engines for which coal is used as a fuel.

                                         FIG 1.0      EXTERNAL COMBUSTION ENGINE

                                            FIG 2.0       INTERNAL COMBUSTION ENGINE

BASICS OF ENGINES

At the very first moment we should know what is an engine?
                                     we might have read different reviews about engines in various forms but an engine is a complicated mechanical device  which converts the thermal energy generated by the combustion of fuel in to mechanical energy.The mechanical output from the engine can be converted to other energies by suitable instruments and accessories.This is the basic simple explanation or definition for an engine.
                         say for example the output mechanical power from an engine is used to drive generators to produce electricity.

                       

FIG 1.0    2-STROKE ENGINE