Problem 2.2 A four-cylinder, four stroke petrol engine is to develop 40 kW at 40 rev/s, when it is designed for a volumetric compression ratio of 10.0 to 1. The ambient air conditions are 1 bar and 18°C, and the calorific value of the fuel is 44 MJ/kg. If the indicated overall efficiency is 50% of the corresponding air-standard Otto cycle, and the mechanical efficiency is 90%, then the specific fuel consumption. g/MJ of brake work. The specific heat capacity ratio for air is 1.4. (Correct upto one decimal place).

Problem 2.2 A four-cylinder, four stroke petrol engine is to develop 40 kW at 40 rev/s, when it is designed for a volumetric compression ratio of 10.0 to 1. The ambient air conditions are 1 bar and 18°C, and the calorific value of the fuel is 44 MJ/kg. If the indicated overall efficiency is 50% of the corresponding air-standard Otto cycle, and the mechanical efficiency is 90%, then the specific fuel consumption. g/MJ of brake work. The specific heat capacity ratio for air is 1.4. (Correct upto one decimal place).

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Cylinder conditions at the start of compression in a spark ignition engine operating atwide open throttle on an air-standard Otto cycle are 60oC and 98kPa.The engine has a compression ratio of 9.5:1 and uses petroleum with an air-fuel ratio(AF) of 15.5.Combustion efficiency is 96%, and it can be assumed that there is no exhaust residual.If the petroleum has a heating value (QHV) of 43kJ/kg,Calculate the following: 1) Temperature in oC and Pressure in kPa at all states in the cycle 2) Specific work done during the power stroke in kJ/kg 3) Heat added during combustion in kJ/kg 4) Net specific work done in kJ/kg5) Indicated thermal efficiency
Q2: An engine with a compression ratio of 13:1 draws in air at a temperature of 20 °C and pressure of 1 bar and operates with air-fuel ratio of 20:1. (a) Select the suitable ideal air cycle to represent operation of this engine and draw its p-V and T-s diagrams. Note: You have to justify your selection. (b)Estimate the temperature and pressure at the end of the compression stroke. (c) If the calorific value of the fuel is 44 MJ/kg, estimate the temperature and pressure immediately after combustion. (d)Determine the work done per cycle; mean effective pressure and thermal efficiency of the engine based on the air-standard analysis of the selected cycle. Assume: Cp =1.005 kJ/kg.K and C, = 0.717 kJ/kg.K.
Q2: An engine with a compression ratio of 13:1 draws in air at a temperature of 20 °C and pressure of 1 bar and operates with air-fuel ratio of 20:1. (a) Select the suitable ideal air cycle to represent operation of this engine and draw its p-V and T-s diagrams. Note: You have to justify your selection. (b)Estimate the temperature and pressure at the end of the compression stroke. (c) If the calorific value of the fuel is 44 MJ/kg, estimate the temperature and pressure immediately after combustion. (d)Determine the work done per cycle; mean effective pressure and thermal efficiency of the engine based on the air-standard analysis of the selected cycle. Assume: Cp = 1.005 kJ/kg.K and Cy = 0.717 kJ/kg.K.
The displacement volume of an internal combustron engine is 5.6 liters. The processes within each cylinder of the engine are modeled as an air-standard Diesel cycle with a cutoff ratio ß of 2.4. The state of the air at the beginning of compression is fixed by P 95 kPa, T= liters. For air, take specific heat ratio y 1.4, and R 0.287 kJ kg.K. Determine the net work per cycle, in kl. //int find the temperatures at all states and apply Ocycle= Weycle) b. If the net work per cycle is equal to 4.78 kJ. determine the indicated mean effeetive pressure in kPa, Determine the thermal efficiency. d. Determine the power developed by the engine, in kW, if the cycle is executed 1500 times 27°C, and V = 6.0 a. C. per min
In an engine working on the Diesel eycle the ratios of the weights of air and fuel supplied is 50: 1. The temperature of air at the beginning of the compression is 60 °C and the compression ratio used is 14: 1. What is the ideal efficiency of the engine, Calorifie value of fuel used is 42000 k.J/kg. Assume C, - 1.004 kJ/kg K and C, = 0.717 kJ/kg K for air.
A 2-stroke engine that works based on the diesel cycle admits air conditioning 100kPa and 280K. The compression ratio is 20:1 and the fuel-air ratio is 7.5x10^-3 kg fuel/kg air. If the calorific value of the fuel is 42750 KJ/kg, the displacement volume is 0.8L (with a diameter equal to 1.1 the stroke of the piston) The engine is 6-cylinder and rotates at 3600 rpm, use air tables and tables of combustion products with 200% excess air to determine: a) The cycle in a pressure-volume diagram with its corresponding numbering. b) The maximum temperature of the cycle, in K c) The cutoff ratio d) The temperature of the combustion gases at the engine outlet, in K e) The cooling water mass flow, in kg/s f) The motor power, in kW g) The mean effective pressure, in kPa h) Thermal efficiency, in %
1. There are supplied 317 kJ/cycle to an ideal Diesel engine operating on 227-g air; P1 = 97.91kPa, T1 = 48.9˚C. At the end of the compression, P2 = 3930 kPa. Determine: Determine the compression ratio (rk). Determine the cut-off ratio (rc). Determine the work (W) done by the system in kJ. Determine the thermal efficiency (η) of the system.
An air-standard dual cycle has a compression ratio of 8.6 and displacement of V = 2.2 L. At the beginning of compression, p1 = 95 kPa, and T1 = 290 K. The heat addition is 4.25 kJ, with one quarter added at constant volume and the rest added at constant pressure. Determine: a) each of the unknown temperatures at the various states, in K. b) the net work of the cycle, in kJ. c) the power developed at 3000 cycles per minute, in kW. d) the thermal efficiency. e) the mean effective pressure, in kPa.
(a) Derive an expression for the air standard efficiency of a Brayton cycle in terms of pressure ratio. (b) An engine working on Diesel cycle has a compression ratio of 15 and fuel supply is cut off at 8% of stroke. If the engine has a relative efficiency of 50%, determine the fuel consumption per kW-hr. Assume the fuel has a calorific value of 42000 kJ/kg.
5. A 6-cylinder reciprocating engine operates on air-standard Diesel cycle, each cylinder having 115 mm bore and 125 mm stroke and a speed of 2000 rpm. The temperature and pressure at the beginning of compression stroke are 300 K and 100 kPa respectively and the maximum temperature permitted is 1650 K. The clearance volume is one-eighth of the stroke volume. Assume air as an ideal gas with Cp = 1.005 kJ/kg K and Cy = 0.718 kJ/kg K. Calculate: (a) The compression ratio (b) The temperature and pressure after compression
5. A 6-cylinder reciprocating engine operates on air-standard Diesel cycle, each cylinder having 115 mm bore and 125 mm stroke and a speed of 2000 rpm. The temperature and pressure at the beginning of compression stroke are 300 K and 100 kPa respectively and the maximum temperature permitted is 1650 K. The clearance volume is one-eighth of the stroke volume. Assume air as an ideal gas with Cp = 1.005 kJ/kg K and Cy = 0.718 kJ/kg K. Calculate: (a) The compression ratio (b) The temperature and pressure after compression (c) The thermal efficiency (d) The power output from the engine.
At the beginning of the compression process of an air-standard Diesel cycle operating with a compression ratio of 18, the temperature is 300 K and the pressure is 0.1 MPa. The cut-off ratio for the cycle is 2 and mass flow rate in the system is 1900 kg/hr.cp = 1.006 kJ/kg K cv = 0.717 kJ/kg K 1. calculate the thermal efficiency of the cycle in %?Answer to 1 decimal place. 2. calculate the work output of the engine in kW?Answer to 0 decimal place.