Equations used Otto Cycle Equations 14 R = 287 Ideal gas (KK) Specific gas constant for air, Ꭲ, =rY-1 P2 T =rY-1 ―= T₁ P1 T3 7-11 Y-1 gamma (y) = 1.4 Specific heat ratio for air Assume complete combustion for simplicity (Stoichiometric Reaction with ❤=1) p1 = 1x105 Pa Inlet air pressure (Pa) T1 = 300K Inlet air temperature (K) R Cv = = 0.718 V-1 kJ kg. K P3 × T₂ T3 = P2 Qin m Cv (T3T₂ ) Qout mCv (T4 T₁ ) 1 ŋ = 1 - ry-1

(8) An SI, six-liter, V8 race car engine operates at WOT (wide open throttle) on a four- stroke cycle at 6000 r.p.m. using stoichiometric nitromethane. fuel enters the engine at a rate of 0.198 kg and combustion efficiency is 99%. calculate: (a) Volumetric efficiency of engine. (%) sec (b) flow rate of air into engine. (ke sec (c) Heat added per cycle per cylinder. (kj) ANS: (a) 95, (b) 0.337, (c)5.35

INTERNAL COMBUSTION.

2. A Spark-Ignition Engine has 4 cylinders in-line, a compression ratio of 8.7 and a displacement of 2.6Liters and with S = 1.05B. Fuel used is C 8 H 18 with an equivalence ratio of 1.05 with combustionefficiency of 100%. The heating value of the fuel is 44,300 kJ/kg. While operating at 3200 rpm,mechanical efficiency is 86 % and indicated engine efficiency is 96%. Conditions at the start ofcompression stroke are 100 kPaa and 60 o C. It can be assumed that there is a 3 % exhaust residual leftfrom the previous cycle.Determine: a) P and T at cycle state points, b) mass of air per cylinder, c) mass of fuel per cylinder, d)brake thermal efficiency, e) torque produced, f) fmep, g) isfc, h) volumetric efficiency, i) Specific Power

Q6. Answer following questions by True or False 1. Injector that sprays into the intake system operate at the same pressure of the carburetor. 2. Swirl in the cylinder enhances the mixing of air and fuel to give a homogeneous mixture in the very short time. 3. Flame development region is consumed 80% of the air-fuel mixture. 4. Maximum temperature and pressure of flame propagation occurs somewhere between 20" and 30° aTDC for a four-stroke cycle. 5. Knock caused by self-ignition could occur in S1 engines as well as in CI engines. 6. Detonation is the minimum combustion time possible without actually having an instantaneous constant-volume reaction. 7. Combustion in a CI engine is a flame front moving through a homogeneous mixture. 8. Fuel injection time in CI engine is usually starting at about 15° bTDC and ending about 5° aTDC. 9. Exhaust blowdown occurs when the exhaust valve starts to open somewhere around 60° to 40° bTDC. 10. The average temperature in the exhaust system of a…

ler eniine of a light truck owned by a utility company has been converted to run on . A dry analysis of the engine exhaust gives the following volumetric percentages : CO,(4.90%) , COO.79%) , 05(2.45%) Calculate the equivalence ratio at which the engine is operating .

intake valve intake compression JO BI Tuel injector the temperature of the gas; power exnaust vaive 0010 exhaust The diagrams show the cylinder of a petrol engine in 4 stages. Petrol vapour and air are drawn into the cylinder, The mixture is then squeezed together, and then exploded by a spark. The explosion pushes down the piston. The exhaust gases are then expelled from the cylinder. Use the first law of thermodynamics to analyse the energy changes during the process. At each stage explain what happens to i) the pressure of the gas; ii)

2 A six-cylinder, four-stroke, direct-injection oil engine is to deliver 120 kW at 1600 rpm. The fuel to be used has a calorific value of 43 MJ/kg and its percentage composition by mass is carbon 86.0%, hydrogen 13.0%, non combustibles 1.0%. The absolute volumetric efficiency is assumed to 80%, the indicated thermal efficiency 40% and the mechan- ical efficiency 80%. The air consumption to be 110% in excess of that required for theoretically correct combustion. (i) Estimate the volumetric composition of dry exhaust gas (ii) Determine the bore and stroke of the engine, taking a stroke to bore ratio as 1.5. Assume the volume of 1 kg of air at the given conditions as 0.77 m³. Oxygen in air is 23% by mass and 21% by volume.

127#5 state for a dual combustion engine is 01=1atm and T1=60.3degree C; rK=18; at the end constant volume combustion process the pressure is 7695kPa,rC=1.5. based on 1kgm/cycle of a hot-air standard with k=1.31, determine (a) the percentage clearnace, (b) p,V and T at each corner point on the cycle, (c) Wnet, (d) e and (e) Pm.

Sketch and explain a PV Diagram and a Temperature Entropy Diagram for a 4 stroke diesel engine   please, please explain into detail the difference bewteen the two and referance the a diagram. Please include a sketch or an image of each diagram