|Engine parts - Problems, Numericals & mini projects on Machine Design|
|By Prof S S Chauhan, IEC College of Engineering & Technology, Greater Noida|
|Unit-5 Engine parts
Objective: It gives the basic knowledge about the design of different engine parts like connecting rod crank shaft, Piston etc
1. What are the main function of the piston of an internal combustion engine.
2. Why the rings provided in the piston .What are the various type of liners ?
3. What are the various type of crankshafts.
4. Why the area of inlet valve port is made larger than the area of the exhaust port?
5. A horizontal four stroke diesel engine has the following specifications
Brake power = 5KW
Speed = 1200RPM
I.M.E.P. = 0.35N/mm2
Mechanical efficiency = 80% Calculate the dimension of the cylinder and the cylinder head.
6. Design the piston. Piston rings and gudgeon pin for single acting four stroke engine for the following given data.
Cylinder bore = 100mm
Stroke = 125mm
Maximum gas pressure = 5MPa
B.M.E.P. = 0.6MPa
Fuel consumption = 0.15kg/BrakekW/h
Speed = 2000RPM
7. Design and draw a piston for a single acting four stroke engines from following data using design data book.
Cylinder bore : 75 mm
Stroke: 125mm speed : 2000RPM
Maximum gas pressure : 5N/mm2
Indicated mean effective pressure: 0.75N/mm2
Mechanical efficiency : 80%
Fuel consumption : 0.15 kg per brake power
Higher calorific value of fuel : 42 *103 KJ/ Kg
Any other data required for the design may be assumed.
8. Design and draw a connecting rod of a petrol engine from following data using design data book. Also generate the program in c language.
Dia of Piston : 110 mm
Mass of reciprocating parts : 2 Kg
Length of connecting rod : 325 mm
Stroke : 150mm
Speed : 1500RPM
Maximum explosion pressure : 2.5 Mpa.
Any other data required for design may be assumed.
9. A connecting rod is to be designed for a four stroke petrol engine having the following specifications:
Piston diameter = 150mm
Stroke length = 150mm
Length of connecting rod = 320mm
Mass of reciprocating parts = 2 Kg
Speed = 1500RPM
Compression ratio = 4:1
10. Design a center crank shaft for a single acting four stroke single cylinder engine for the following data: Piston diameter = 400mm
Stroke = 600mm
Speed = 200RPM
I.M.E.P. = 0.5MPa
Maximum combustion pressure = 2.5MPa
Gas pressure at maximum torque = 1MPa at 35 degree crank angle
Ratio of length of CR to Crank radius = 5
Total belt pull = 6.5KN
Assume any other missing data
11. Design a crankshaft for a 400mm* 600mm single acting four stroke single acting four stroke single cylinder engine to operate at 200RPM. The mean effective pressure is 0.5 MPa and the maximum combustion pressure is 2.75MPa. The maximum torque is at 35degree of crank angle when gas pressure is 1MPa. The ratio of length of connecting rod to the radius of crank is 4.8. The flywheel is used as a pulley whose weight is 55KN. The total belt pull is 6750N.
12. Design and draw the exhaust valve gear for a horizontal diesel engine for following Data using Design Data book.
Brake power : 8 Kw
Bore : 140 mm
Stroke : 270mm
Speed : 475 RPM
Maximum gas pressure : 3.5 Mpa
Back pressure : 0.4 Mpa
Suction pressure : 0.025 Mpa
Mean velocity of gas through the port : 2100 RPM
The valves open 33 degree before outer dead center and closer 1 degree after inner dead center. It opens and closes with constant acceleration and deceleration for each half of the lift. The length of the rocker arm on either side of the fulcrum is 150mm and the included angle is 60 degree the weight of the valve is 3N..
13. Design the various components of a valve gear mechanism for a horizontal diesel engine having the following specifications:
Brake power = 10KW
Bore = 140mm
Stroke = 270mm
Speed = 500RPM
Maximum gas pressure = 3.5Mpa
The valves open 33 degree before top dead center and closer 20 degree after bottom dead center. It opens and closes with constant acceleration and deceleration for each half of the lift. The length of the rocker arm on either side of the fulcrum is 150mm and the included angle is 135 degree . The mass of the valve is 300g.
14. Design a plain carbon steel centre crankshaft for a single acting four stroke single cylinder engine for the following data:
Ore = 400 mm; Stroke = 600 mm; Engine speed = 200rpm; Mean effective pressure = 0.5 N/mm2; Maximum combustion pressure = 2.5 N/ mm2; Weight of flywheel used ad a pulley = 50 kN; Total belt pull = 6.5 kN. When the crank has turned through 35 degree from the top dead centre, the pressure on the piston is 1N/mm2 and the torque on the crank is maximum. The ratio of the connecting rod length to the crank radius is 5. Assume any other data required for the design.
15. The conical valve of an I.C. engine is 60mm in diameter and is subjected to a maximum gas pressure of 4N/mm2. The safe stress in bending for the valve material is 46Mpa. The valve is made of steel for which k= 0.42. The angle at which the valve disc seat is tapered is 30 degree
16. Design a rocker arm, and its bearings, tappet, roller and valve spring for the exhaust valve of a four stroke I.C. engine from the following data:
Diameter of the valve head = 80mm; Lift of the valve =25 mm; Mass of associated parts with the exhaust valve opens is 0.4 N/mm2 and the greatest suction pressure is 0.02 N/mm2 below atmosphere.
The rocker arm is to be I-section and the effective length of each arm may be taken as 180mm; the angle between the two arms being 135 degree. The motion of the valve may be assumed S.H.M., without dwell in fully opened position. Choose your own materials and suitable values for the stresses. Draw fully dimensioned sketches of the valve gear.