Design and Simulation of Two Stroke Engines

Design and Simulation of Two-Stroke Engines
10%Cthr3000rpm
DR=0.274
10 12 14 16 18
AIR-FUEL RATIO
r 0.42
-0.40
Fig. 7.6 Air-fuel ratio effect on bmep and bsfc at 10% throttle.
CL
Q
S
ppm
z
o
SSI ^
LLI
O
X
1800
1700
1600
1500
1400
1300
1200
_
.
~
1( ) 12
/
bsHC
1 i
QUB 400 ENGINE
10%Cthr3000 rpm
DR=0.274
14
HC
AIR-FUEL RATIO
i
16
^
M 3
-28
-26
-24
-22
-20
- 18
1fi
CC
Q
2^
sz
1&>
z"
o
ISS
^
LU
sHC
Fig. 7.7 Air-fuel ratio effect on HC emissions at 10% throttle.
bsfc is very low at 0.40 kg/kWh at 6.2 bar bmep and 0.30 kg/kWh at 2.65 bar bmep. The
carbon monoxide level is also low at 0.2% by volume at full throttle and 0.1% at one-tenth
throttle; while low CO values are to be expected close to the stoichiometric air-to-fuel ratio,
these values are sufficiently low as to indicate very good combustion, and would be remarkably
low for any four-stroke cycle engine. The oxygen emission is 7.5% at full throttle and
3% at one-tenth throttle; remember that the majority of the oxygen emission derives from the
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-Q