Question

What is the range of angles made between common face and seat angle of valve?

(a) 50°-60°

(b) 30°-45°

(c) 70°-85°

(d) 10°-20°

I have been asked this question in a national level competition.

Enquiry is from I.C Engine in portion Internal Combustion Engine of Farm Machinery

Answer 1

Right option is (b) 30°-45°

To explain I would say: Each valve (inlet and exhaust) is opened or closed once during each cycle. A strong spring with the help of retainer and a key holds the valve tightly against the seat and thus prevents leakage on the compression and power stroke. The common face and seat angle of valve is 45° but 30° angle is also used for intake valves.