Week 3.1 Flashcards
What is the compression ratio of the engine?
r = V1/Vc, where V1 is the maximum volume and Vc is the minimum cylinder volume
What is the displaced volume?
This is the difference in volumes between the maximum and minimum = V1-Vc= pib^2s, where s is the stroke and b is the bore.
What is the equation for mean piston speed?
Up = 2*N(engine speed rpm) *s (stroke)/60.
what is the equation for brake power?What is brake power?
Wb = Tw(angular velocity), or 2pi N/60.Brake power is the rate at which work is done.
What is the indicated power?
Wi = integral (pdV). It is the power transferred from the gas to the piston in a cycle
What is the equation for indicated power in a four-stroke engine and a two-stroke engine?
Wi = nc (no of cylinders) * Wi * N/2 (four stoke)
Wi = nc *Wi *N (two stroke)
What is the brake mean effective pressure?
This is the external unit shaft work per unit volume of the engine. It is directly related to the brake power.
What is the brake mean effective pressure?
This is the external unit shaft work per unit volume of the engine. It is directly related to the brake power.
What is the BMEP equation?
BMEP= Wb/ Vd N/2= 4pi T(torque)/Vd
What is friction mean effective pressure?What is the friction mean effective pressure equation?
This is the pressure due to losses, this is equal to the indicated mean effective pressure- the brake mean effective pressure.
What is volumetric efficiency?
It is the mass of fuel and air inducted into the cylinder divided by the mass of fuel and air in the inlet.
What is the volumetric efficiency equation?
nv = mi/ pi Vd N/2
What is the inducted mass equal to ?
mi = ma (mass of air) +mf (mass of fuel)
What is the brake specific fuel consumption?
It is the fuel rate/ brake power = mf/Wb
What is the brake thermal efficiency?
Brake power/ mass fuel flow rate *qo
