133) Number of working strokes per min. for a four stroke cycle engine are __________ the speed of the engine in r.p.m.

134) The air standard efficiency of an I.C. engine depends on

135) The mean effective pressure of a diesel engine having fixed compression ratio will __________ if cut off ratio decreases.

136) The knocking tendency in spark ignition engines may be decreased by

137) In a two stroke engine, the working cycle is completed in two revolutions of the crankshaft.