2. (Pts 30) A six cylinder, four stroke, spark ignition engine operating on the ideal Otto...
A single-cylinder four-stroke-cycle spark-ignition engine has a BSFC of 0.4 kg/kW-hr and a volumetric efficiency of 78% at a speed of 45 rps. The bore is 6 cm and the stroke is 8.5 cm. What is the fuel flow rate, fuel-air ratio, and brake torque if the brake power output is 6 kW with ambient conditions of 100 kPa and 22 C?
. A 4 stroke 4 cylinder spark ignition engine runs on a stoichiometric mixture of ethanol and air at wide open throttle. The 1 liter engine has a compression ratio of 9:1 and operates at 5000 rpm. The intake manifold conditions are standard pressure and temperature, no residual gas in engine combustion chamber. Using k-1.35 for all calculations the a. Calculate the indicated work done by the engine, in joules per cycle b. Calculate the indicated thermal efficiency c. Calculate...
Discuss the various processes of an actual four strokes spark ignition engine. What are the assumptions under which ideal Otto cycle can be utilized for the spark ignition engine?
2 Thermodynamics Equations (Cycles) • Solve the following problems from the textbook (Thermodynamics: An Engineering Approach, by Yunus A. Cengel and Michael A. Boles, 8th Edition, SI Version, 2015): Gas Power Cycles: Obtain problem statements from the textbook Air-Standard Cycles (Otto Cycles) Problems No.: 9-32 An ideal Otto cyele has a compression ratio of 8. At the beginning of the compression process, air at 95 kPa and 27°C, and 750 kJ/kg of heat is transferred to air during the constant-...
4. A4.6 L spark ignition engine operates on the ideal Otto cycle with a compression ratio of 10. At the beginning of the compression process the air is at 107 kPa and 21 C. The maximum cycle temperature is 1116°C. Accounting for variable specific heats, determine: (a) the heat addition per cycle in kJ. Ans: 3.368 kJ (b) the net work per cycle in kJ. Ans: 1.907 kJ (c) the mean effective pressure in kPa. Ans: 460.6 kPa (d) the...
A four-cylinder engine with 9.5-cm bore and an 8.75-cm stroke has 10% clearance. The engine rotates at 5500 rpm. The conditions at the beginning of compression are 27°C and 98 kPa. The maximum cycle temperature is 2900°K. The engine may be assumed to operate on an air-standard Otto cycle. Draw the P-V and T-S diagram of the cycle and determine: a) Pressure and Temperature at the end of the expansion process, b) Cycle work, kJ c) Mean Effective Pressure, kPa...
Consider a cold air standard Otto cycle for a 4-stroke engine with four cylinders. The compression ratio is 9. At the beginning of the compression the air in each cylinder is at 95 kPa, 5 C and occupies a volume of 555 cm^3. During the heat addition process the pressure triples. Determine the efficiency of the cycle and the net power output (per kg of air). If the engine is running at 2800 RPM determine the power output in horsepower....
A 4-stroke 3 litre V6 spark ignition petrol engine has a maximum power output of 100kW at 5500rev/min, and a maximum torque of 236Nm at 3000rev/min. The minimum sfc is 0.090 kg/MJ at 3000 rpm, and the air flow rate is 0.068m²/s. The compression ratio is 8.9:1 and the mechanical efficiency is 90%. The engine was tested under ambient conditions of 20°C and 1 bar. Take the calorific value of fuel to be 44MJ/kg. (a) Determine the power output at...
Problem 6. Compute the brake mean effective pressure of a four-cylinder, two-stroke engine, 100 mm bore 125 mm stroke when it develops a torque of 490 Nm. Problem = 7. Find the brake thermal efficiency of an engine which consumes 7 kg of fuel in 20 minutes and develops a brake power of 65kW. The fuel has heating value of 42000 kJ/kg. Problem # 8. Find the mean piston speed of a diesel engine running at 1500 rpm. The engine...
Α 4-stroke spark-ignition engine has a compression ratio of 10 and operates on the ideal constant volume cycle with intake pressure of 50 kPa (throttled) and intake temperature of 300 K. The exhaust pressure is 100 kPa. The heat input from combustion is 2500 kJ/kg and γ = 1.3 for the working fluid. a. Draw the p-V diagram of the full cycle and indicate all the processes. b. Calculate the residual gas fraction and the temperature decrease during the exhaust...