MAHA LPS 3000, Руководство по эксплуатации, Страница: 40 / 115

40
BA052301-en
2.9.7 Extrapolation of Drag Power by 2nd Coast Down Trial
A traction is loaded with the second coast down trial so that there is a shorter coast down time.
An inference about the vehicle mass can be made from the various decelerations and the exact
drag power determined.
The traction loaded for the coast down trial 2 is calculated from the following equation:
F =
) (
m ax _
m ax _
wheel
wheel
withP v
P
Factor
The factor normally has a value of 650.
The following regularities apply:
1.) m =
1
1
a
F F
Rot
+
2.) m =
2
2
a
F F
Rot
+
F
1
: Traction F
x
with coast down trial 1 by residual magnetization
F
2
: Traction F
x
with coast down trial 2
a
1
: Acceleration with coast down trial 1
a
2
: Acceleration with coast down trial 2
F
Rot
: Force of the rotating mass
F
rot
=
1 2
2 1 1 2
. .
a a
a F a F
−
−
m
Rot
=
1
1
a
F F
Rot
+
With the continuous power measurement, an additional error is made during high acceleration if
the set mass deviates from the actual mass. The measurement power is projected from the
determined mass. The result is now the same as if the trial had been driven with this mass.
If an amount for the engine (which was not considered at coast down) is added to the mass
determined with the help of the coast down trial 2, then the true wheel power can be projected.
Assuming the proper setting, the wheel power agrees with the discrete measured power
assuming the proper setting.
P
wheel
(projected) = P
wheel
(measured) · a · v · (m
rot
+ m
engine
- m
default
)
a=
Nominal speed of the dyno
Ramp – climbing time 3.6
The share of the engine is entered in percentage of the rotating vehicle mass.