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

Ex-1 Asix cylinder, four-stroke petrol engine with abore of 125 mm and a stroke of 190 mm under test was supplied with petrol of composition C = 82% and H2 = 18% by mass. The dry exhaust composition by volume was CO₂ = 11.19%; 02 = 3.61% and N₂ = 85.2%. Determine The mass of air supplied per kg of petrol, ②The percentage excess air. عماد داود عبود 3 The volume of mixture per kg of petrol, at 17°C and 1 bar which were the condition for the mixture entering the cylinder during the test. The volumetric efficiency of the engine based on intake conditions when the mass of petrol used per hour was 31.3kg and the engine speed wass 1500 rev/min. The Petrol is completely evaporated before entering the cylinder and the effect of its volume on the volumetric efficiency should be included. Taut Tombed Take the density of petrol vapour as 3.35 times that of air at the same temperatu and pressure. 1kg of air at o°C and 1.013 bar occupies 0.773 m³. Air Contains 23 oxygen by mass. 0.101 FF.21

(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

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.

use perrys chem eng handbook note: this is solution thermodynamics

Identify the correct order of the cycles in the four-stroke engines analyzed in lab, with the first cycle beginning when the piston is at Top Dead Center and no air-fuel mixture is present in the combustion chamber. Combustion, Intake, Compression, Exhaust Intake, Compression, Combustion, Exhaust Intake, Combustion, Compression, Exhaust Intake, Combustion, Exhaust, Compression

During the compression stroke of a certain gasoline engine, the pressure increases from 1.00 atm to 19.0 atm. The process is adiabatic and the air-fuel mixture behaves as a diatomic ideal gas. (a) By what factor does the volume change? Vfinal = Vinitial (b) By what factor does the temperature change? Tinal = Tinitial Assume the compression starts with 0.016 mole of gas at 28.5°C. (c) Find the value of Q that characterizes the process. (d) Find the value of AEnt that characterizes the process. (e) Find the value of W that characterizes the process.