INTERNAL COMBUSTION ENGINES LECTURER PROF.Dr. DEMIR BAYKA

INDUCTION PROCESS Indicated Thermal Efficiency also shows the fuel conversion efficiency

Fuel / Air Ratio INDUCTION PROCESS

PRIMARY GOAL OF INDUCTION INDUCTING MAXIMUM AMOUNT OF AIR RETAINING THE INDUCED AIR IN THE CYLINDER

CHARACTERISTIC PARAMETERS 4 STROKE CYCLE ENGINES VOLUMETRIC EFFICIENCY 2 STROKE CYCLE ENGINES SCAVENGING EFFICIENCY TRAPPING EFFICIENCY

1. INLET MANIFOLD 2. INLET PORTS 3. INLET VALVES 4. SUPERCHARGING IMPORTANT DESIGN FACTORS

IMPORTANT OPERATIONAL FACTORS 1. CHARGE HEATING 2. RESIDUAL GAS FRACTION 3. THROTLING IN SI ENGINES 4. ENGINE SPEED

SI ENGINE CI ENGINES DO NOT HAVE CARBURETORS AND HENCE NO THROTTLE VALVE ( WITH SOME EXCEPTIONS ) FUEL INJECTION SYSTEMS WILL ALSO HAVE A THROTTLE VALVE

PRIMARY GOAL INDUCE MAXIMUM AMOUNT OF AIR

OTHER GOALS 1. MIX AND EQUALLY DISTRIBUTE FUEL VAPOR INTO AIR

2. EQUALLY DISTRIBUTE MIXTURE STRENGTH AMONG CYLINDERS OTHER GOALS

3. INCREASE LEVEL OF TURBULENCE IN THE CYLINDERS OTHER GOALS

EXHAUST VALVE INLET VALVE BLOWDOWN VALVE OVERLAP

INERTIA SUPERCHARGING BLOWDOWN

VOLUMETRIC EFFICIENCY CALCULATION ACTUAL mass of induced air mass of air that can THEORETICALLY be induced

MASS OF AIR THAT CAN THEORETICALLY BE INDUCED IS CALCULATED FOR A STANDARD AIR DENSITY   single cyl. per cycle number of cyl. rate of induction

THE ACTUAL INDUCED AIR IS RELATED TO THE FUEL CONSUMPTION THRU THE AIR/FUEL RATIO

OPERATIONAL FACTORS 1. HYDRAULIC LOSSES 2. CHARGE HEATING 3. RESIDUAL GAS FRACTION

HYDRAULIC LOSSES ARE AFFECTED BY 1. ENGINE SPEED 2. GEOMETRY OF COMPONENTS

APPROXIMATE CALCULATION OF THE PRESSURE DROP DUE TO HYDRAULIC LOSSES CONTINUITY EQUATION is assumed to be constant

BERNOUILLI EQUATION ACROSS THE INDUCTION SYSTEM assume

slowfast CISI

where and

for a 45 degree angle