Choose the best compression ratio for an Otto cycle reciprocating engine: a. 5 b. 10 c. 15 d. 20

b) 10

Explanation:

We know that in Otto cycle there are four process. In first process mass of air fuel mixture enters in the cylinder. In second process that intake mass is compresses up to a specified limit. In general compression ratio in Otto cycle is about 9 or 10. In third process burning of fuel takes place where certain amount of work is obtained. Last process is exhaust process in which burning gas escape out from the cylinder.

Best compression ratio in Otto cycle is about 10. Beyond this value of compression ratio the cycle will not proved best work out put. So our option b is right.