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