Total Engine Friction

·         The difference between I.P. and B.P. is known as total engine friction loss.

Answer: True

·         In four stroke cycle engines, an ample amount of ____________ is used during intake and exhaust processes.

Answer: power

·         The pumping loss is negligible in two-stroke cycle engines.

Answer: The pumping loss is negligible in two-stroke cycle engines since the incoming fresh mixture is used for scavenging the exhaust gases and charging the cylinder.

·         The standard practice for sizing the exhaust valve is to make them a certain percentage ____________ than the inlet valves.

Answer: smaller

·         If due attention is not given to the valve size, valve timing and valve flow coefficients there may be a substantial loss with the increase in engine speed.

Answer: True

·         The exhaust throttling loss occurs due to the restrictions imposed by air cleaner, carburetor venturi, throttle valve, intake manifold and intake valve.

Answer: The inlet throttling loss occurs due to the restrictions imposed by air cleaner, carburetor venturi, throttle valve, intake manifold and intake valve.

·         Combustion chamber pump loss is caused due to the pumping work required to pump gases into and out of the pre-combustion chamber.

Answer: True

·         ____________ losses are caused due to the leakage of combustion products past the piston from the cylinder into the crankcase.

Answer: Blowby

·         Blowby losses ____________ directly with compression ratio.

Answer: decreases

·         When a smaller number of large cylinders are used, the friction and economy improve.

Answer: True

·         The frictional mean effective pressure ____________ as the compression ratio is increased.

Answer: increases