Machine Parts

Crankcase Ventilation: PCV means positive crankcase ventilation. Air from carburator air is drawn through the crankcase. This air carries pollution from oil to the intake manifold and burned in the cylinder with fuel.                 Engine Cooling System: The cooling system is used to keep the engine in the most efficient condition. About 30 to 35 %   of heat produced during combustion is removed by cooling system. Temperature during combustion rises to about 3300 o C in the cylinder. Types of Engine Cooling System: There are two types of   Engine Cooling System- 1.       Air cooled 2.       Liquid cooled. Main Components of Engine Cooling System:  Radiator,  pump fan,  cooling lines,     water jacket,  thermostat.

Functions of Engine Lubrication System: 1.       Lubricate Engine parts to minimize wear. 2.       Lubricate Engine parts to minimize power loss due to friction. 3.       Act as a seal between piston and cylinder wall. 4.       Absorbs shock between bearings and other engine parts. Thus extending engine life reducing noise and breakage of engine parts. 5.       Act as a cooling agent. 6.       Also act as a cleaning agent. Properties of oil: a.       Viscosity. b.       Power point. c.        Resistance to carbon formation. d.       Oil oxidization   resistance. e.       Compression and rust protection. f.         Foaming resistance. g.       Extreme pressure resistance.

Scavenging Systems: There are three types of scavenging systems a.       Uniflow scavenging. b.       Cross scavenging. c.        Loop scavenging.   Scavenging Pumps: There are four types of scavenging pumps 1.       Crank case. 2.       Pistions. 3.       Roots. 4.       Centrifugal blows. Types of Supercharger: o. Centrifugal compressor. o . Reciprocating compressor. o . Root blowers compressor. Turbo Charger : When the supercharger is driven by exhaust gases from the engine is called turbo Charger. What is Super-Charging? It is defined as supply of compressed air during suction.  Objectives of Super charging: a.       To increase the output for a given bilb and weight of the engine. b.       To compensate for power loss when the engine is operating at high altitude.

Delivery Ratio:   Ratio of volume of air delivered by scavenging to displacement volume. It is denoted by L. It can be mathematically expressed as- L = V del/ V displacement Sacvenging Efficiency: Measure of the success is during the cycle of residual gases from the procedding cycle. It is denoted by n s and mathematically expressed as a n s= V rea / V ch     = V rea / ( V rea+ V rea) Trapping Efficiency: n s= V rea / V du Relative cylinder Charge: Ratio of (air retained +residual gas) to displacement volume. It is mathematically expressed as   a C rcl = ( V ret+ V res) / V displacement          = V charge /V displacement Excess air factor:  Excess air factro=( C rcl   - 1 ) Charging efficiency: n cr= V rct / V displacement