221) The loud pulsating noise heard within the cylinder of an internal combustion engine is known as

222) The air-fuel ratio of the petrol engine is controlled by

223) If the compression ratio in I.C. engine increases, then its thermal efficiency will

224) The relative efficiency of an I.C. engine is the ratio of the indicated thermal efficiency to the air standard efficiency.

225) The volumetric efficiency ofa well designed engine may be