Otto cycle
L
t
=Q -
Q
o
Otto cycle
L
t
=Q -
Q
o
Diesel cycle
L
t
=Q -
Q
o
Sabathe cycle
p
v
o
t
q
q
q
1
- theoretical efficiency
2
3
3
4
1
5
2
3
3
4
1
5
1
1
T
T
T
T
k
T
T
T
T
c
T
T
c
T
T
c
v
p
v
t
factors definition
2
3
p
p
3
4
v
v
2
1
v
v
2
3
3
4
1
5
2
3
3
4
1
5
1
1
T
T
T
T
k
T
T
T
T
c
T
T
c
T
T
c
v
p
v
t
1
1
1
1
1
1
1
1
3
4
2
3
2
3
1
5
2
1
2
3
2
3
4
3
1
5
1
T
T
T
T
k
T
T
T
T
T
T
T
T
T
T
T
T
k
T
T
T
t
t
1
1
1
1
3
4
2
3
2
3
1
5
2
1
T
T
T
T
k
T
T
T
T
T
T
t
2
3
p
p
3
4
v
v
2
1
v
v
1
4
5
1
2
1
2
3
3
4
4
5
1
2
2
3
3
4
4
5
1
5
k
k
T
T
v
v
p
p
v
v
T
T
T
T
T
T
T
T
T
T
T
T
1
1
1
1
2
3
4
1
5
3
3
4
1
5
4
4
5
k
k
k
k
k
v
v
v
v
v
v
v
v
v
v
T
T
k
k
k
k
T
T
1
1
1
1
5
1
1
1
1
3
4
2
3
2
3
1
5
2
1
T
T
T
T
k
T
T
T
T
T
T
t
2
3
p
p
3
4
v
v
2
1
v
v
k
k
k
k
T
T
1
1
1
1
5
1
1
2
1
1
2
k
k
v
v
T
T
2
3
2
3
p
p
T
T
3
4
3
4
T
T
1
1
1
1
1
1
k
k
k
t
1
1
1
1
1
1
k
k
k
t
Sabathe cycle theoretical efficiency
for Otto cycle: =1
1
1
1
k
t
1
1
1
1
1
1
k
k
t
k
for Diesel cycle: =1
isothermal cooling with
temperature T
0
- cooling agent (?)
isobaric cooling with a
pressure p
0
- cylinder use (?)
isochoric cooling
c
o
b
o
a
o
T
T
T
_
_
_
c
t
b
t
a
t
_
_
_
ambient
temperature
T
o
a
z
n
S
D
p
P
i
i
4
2
p
i
– indicated pressure, S – piston jump, n – rotation frequency, z – cylinder number
D – cylinder diameter, a – for two-stroke engine: 1, a – for four stroke engine: 2
indicated power – inner power
4-stroke
engine
2-stroke
engine
delivered heat
useful energy
outlet losses
cooling losses
friction losses
theoretical and real cycles – a comparision
reversible processes
irreversible processes
an agent – an ideal gas
real gas
closed system
breathing system
an agent – fixed chemical
composition
an agent – variable
chemical composition
heat exchange through a
cylinder wall
conversion of chemical
energy to internal one
(combustion)
no leakages
leakages
mechanical friction losses
fuel parameters
• octane number –
a measure of
ability to no-tap combustion. Isooctane has
a octane number equal to 100, and heptane
has 0. a value of octane number for a fuel is
a percent of octane in a mixture of octane
and heptane of the same features as the
fuel combustion ability
.
• cetin number –
ability to ignition without a
delay. Cetin has a cetin number equal to 100, and
metylonaftalen has 0.