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Unformatted text preview: 53.5º to represent
closing of valve.
4. Divide the angular displacement of the cam during opening and closing of the valve (i.e.
angle AOG and GOM) into same number of equal even parts as in displacement diagram.
5. Join the points 1, 2, 3, etc. with the centre O and produce the lines beyond prime circle as
shown in Fig. 32.33.
6. Set off points 1B, 2C, 3D, etc. equal to the displacements from displacement diagram.
7. Join the points A, B, C, ...L, M, A. The curve drawn through these points is known as pitch curve.
8. From the points A, B, C, ...K, L, draw circles of radius equal to the radius of the roller. Internal Combustion Engine Parts n 1211 Fig. 32.33 9. Join the bottoms of the circle with a smooth curve as shown in Fig. 32.33. The is the required
profile of cam. XER CISES
1. A four stroke internal combustion engine has the following specifications:
Brake power = 7.5 kW; Speed = 1000 r.p.m.; Indicated mean effective pressure = 0.35 N/mm2;Maximum
gas pressure = 3.5 N/mm2; Mechanical efficiency = 80 %.
Determine: 1. The dimesions of the cylinder, if the length of stroke is 1.4 times the bore of the cylinder; 2. Wall thickness of the cylinder, if the hoop stress is 35 MPa; 3. Thickness of the cylinder head
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- Spring '11