Question

Absolute temperature and absolute pressure must be used in polytropic equations?   True or False

During a polytropic compression process, the exhaust valve is open. True or False

In a gasoline engine, if the temperature of the air/fuel mixture gets higher than the auto-ignition temperature of the fuel before the spark ignites, the fuel-air mixture explodes and causes engine damage   True or False

Answer 1

Problem-1:

Absolute temperature and absolute pressure must be used in the polytropic process- TRUE.

Problem-2:

During a polytropic compression process, the exhaust valve is open- TRUE.

• During the compression stroke, as air pressure reached a value, which is slightly more than the pressure of the compressed air acting outside the delivery value, the delivery (exhaust) value opens and the compressed air is then discharged from the cylinder.

Problem-3:

In a gasoline engine, if the temperature of the air/fuel mixture gets higher than the auto-ignition temperature of the fuel before the spark ignites, the fuel-air mixture explodes and causes engine damage- TRUE.

• If the temperature of air-fuel mixture gets higher than the auto-ignition temperature of the fuel before the spark ignites, then the air-fuel mixture explodes and causes engine damage which is called as knocking or detonation.
• This produces shock waves which causes engine damage.