bore is 0.4meters.Calculate (i)Inertia force (ii) Force on piston (iii) Piston effort (iv) Thrust on the side of the cylinder walls (v) Thrust in the connecting rod (vi)Crank effort. (16) 7. A horizontal gas engine running at 210rpm has a bore of 220mm and a stroke of 440mm. The connecting rod is 924mm long the reciprocating parts weight 20kg.When the crank has turned through an angle of 30˚ from IDC, the gas pressure on the cover and the crank sides are 500KN/m2 and 60KN/m2 respectively. Diameter of the piston rod is 40mm.Determine, 1. Turning moment on the crank shaft 2.Thrust on bearing 3. Acceleration of the flywheel which has a mass of 8kg and radius of gyration of 600mm while the power of the engine is 22KW. (16)
8. A single cylinder vertical engine has a bore of 300mm and a stroke of 400mm.The connecting rod is 1000mm long. The mass of the reciprocating parts is 140kg.On the expansion stroke with the crank at 30˚from the top dead center, the gas pressure is 0.7MPa.If the runs at 250rpm, determine; 1. Net force acting on the piston 2.resultant load on the gudgeon pin 3. Thrust on cylinder walls 4. The speed above which other things remaining same, gudgeon pin loads would be reversed in direction. (16) 9. A vertical double acting steam engine has a cylinder 300mm diameter and 450mm stroke and runs at 200rpm.The reciprocating parts has a mass of 225kg and the piston rod is 50mm diameter. The connecting rod is 1.2m long. When the crank has turned 125˚ from IDC the steam pressure above the piston is 30KN/m2.calculate, (i)Crank-pin effort (ii)The effective turning moment on the crank shaft. (16) 10. The turning moment diagram for a petrol engine is drawn to a scale of 1mm to 6N-9-9m and the horizontal scale of 1mm to 1˚.The turning moment repeat itself after every half revolution of the engine. The area above and below the mean torque line are 305, 710, 50,350,980and 275mm2. The mass of rotating parts is 40kg at a radius of gyration of 140mm.Clculate the coefficient of fluctuation of speed if the mean speed is 1500rpm. (16) 11. The torque delivered by a two stroke engine is represented by T= (1000+300sin2θ-500cos2θ) N-m where θis the angle turned by the crank from the IDC. The engine speed is 250rpm.The mass of the flywheel is 400kg and radius of gyration 400mm. Determine , (i)the power developed (ii)the total percentage fluctuation of speed (iii)the angular acceleration of flywheel when the crank has rotated through an angle of 60˚ from the IDC. (iv) the maximum angular acceleration and retardation of the flywheel. (16) UNIT-II (BALANCING) PART-A (2 marks) 1. What is meant by balancing of rotating masses? 2. Why rotating masses are to be dynamically balanced? 3. Define static balancing. 4. Define dynamic balancing. 5. State the conditions for static and dynamic balancing. 6. State the conditions for complete balance of several masses revolving in different planes of a shaft. 7. Why complete balancing is not possible in reciprocating engine? 8. Can a single cylinder engine be fully balanced? Why? 9. Differentiate between the unbalanced force caused due to rotating and reciprocating masses. 10. Why are the cranks of a locomotive, with two cylinders, placed at 90˚ to each other? 11. List the effects of partial balancing of locomotives.