Environmental Engineering Reference
In-Depth Information
(a) Find the average initial acceleration applied to the CIDI crankshaft,
given the engine speed waveform below for which
w
eng
(
t
¼
201 ms)
¼
24.74
rad/s and delay of 45 ms.
Engine crank speed
24.80
20.00
15.00
WM_...
10.00
5.00
1.98
n
0
250.00 m
500.00 m
750.00 m
1.00
1.25
1.50
1.75
2.00
79.3 rad/s
2
(b) Given that the starter motor produces a peak torque of 21.2 Nm at
t
A5:
(a)
<
a
>¼
¼
201 ms, using the average starter motor torque compute the engine rotating
inertia,
J
eng
.
Hint:
Given the engine friction is effectively 480 Nm and using the initial average
acceleration from (a), solve the following:
m
eng
¼
g
r
m
str
¼
J
eng
a þ
m
fric
J
eng
¼
1.967 kg m
2
/rad
Q6:
A feature of organic electrolyte ultra-capacitors that is beginning to be
exploited is to apply the Nernst equation of the cell electrochemical potential
to define its maximum operating potential in cold conditions. The following
figure shows that by exploiting this phenomena it is possible to store up to
60% more energy at
30
C, thereby further enhancing the benefit of ultra-
capacitor cold starting aide for engines:
RT
nF
ln
fg¼
E
0
2
:
303
RT
nF
E
cell
¼
E
0
Log
ð
Q
Þ
where
R
¼
8.3145 J/K-mol;
F
¼
96,485 C/mol;
n
¼
1 electron exchange and
Q
is the electrolyte concentration, which in this example does not change
much.
