MAHA LPS 3000 User Manual

34 BA052301-en
2.9 Calculation Basis
2.9.1 Road Load
Equation
m a
v
3,6 P
v
v 3,6 P
v
v 3,6 P
F
ref
Roll
2
ref
Flex
3
ref
2
Air
x
+

+

+

=
with
• v
ref
Reference speed for resistance performance values - normally 90
km/h.
• v Driving speed
• P
air
Air resistance performance [kW]
• P
flex
Flex performance [kW]
• P
Roll
Roll resistance performance [kW]
• a.m Vehicle mass
Air resistance power P-Air [kW]
The air resistance power is proportional to the surface
of the vehicle front and air resistance coefficient c
w
.
v ) v (v A c 0,5 P
2
0FrontWAir
+= 
with e.g.
• Air density
 (rho)
=
1.1 kg/m
3
• air resistance coefficient
c
W
=
0.38
• Front surface (VEH-width x Height)
A
Front
=
1.7 m · 1.47m
=
2.5 m
2
• Driving speed
v
=
90 km/h
=
25 m/s
• Head wind speed
v
0
=
0 m/s
results:
• P
air
= 0,5 · 1,1 · 0,38 · 2,5 · 25
2
· 25
=
8.164 kW at 90 km/h
Flex power P-Flex [kW]
Flex power or resistance is defined as the power loss
which occurs due to the flexing of the tire on the road
surface and/or roller.
v g m P
wFlex
= 
Generally speaking the flex power does not have a relevant influence on the test results due to
the minimal flex resistance coefficient.

MAHA LPS 3000 Specifications

General

Brand	MAHA
Model	LPS 3000
Category	Measuring Instruments
Language	English