Disel Cycle

Question 1

What is the main difference between otto and diesel engine?

Answer 1

Otto uses a spark for ignition

Diesel uses compression

Question 2

Four stages of a diesel cycle.

Answer 2

1) Isentropic compression
2) Constant pressure heat addition
3) Isentropic expansion
4) Constant volume heat rejection

Question 3

Using the first law of thermodynamics, what is the change in work in process 1 to 2?

Answer 3

q12=0
u=-w12
w=(p2V2-p1V1)/(1-y)

Question 4

Using the first law of thermodynamics, what is the change in work in process 2 to 3?

Answer 4

u=q-w
q=c(T3-T2)
w=R(T3-T2)

Question 5

Using the first law of thermodynamics, what is the change in work in process 3 to 4?

Answer 5

u=q34-w34
q34=0
w34=(p4V4-p3V3)/(1-y)

Question 6

Using the first law of thermodynamics, what is the change in work in process 4 to 1?

Answer 6

u=q41-w41
w41=0
q41=c(T1-T4)

Question 7

What is the equation of efficiency for the diesel cycle?

Answer 7

nth=1-(1/r^(y-1)