48
BA053101-en
P
1
: Is converted to heat by the air cooled eddy current brake and normally emitted into the test room.
P
5
: This energy is suctioned out with the exhaust suction system and does not contribute to heat volume in the test room.
Generally speaking the engine power to be measured is known. If this is specified with 1, the
following factors are given:
P
1
Engine power
1
P
2
Heat flow surface engine block
0.8
P
3
Coolant heat flow
0.7
P
4
Heat flow vehicle exhaust system
0.5
The heat volume in test room is then: 1 + 0.8 + 0.7 + 0.5 = 3
This means that the energy quantity of the engine power multiplied by 3 is the volume of heat
energy in the test room.
Example 1
P
1
Engine power
= 100 kW
P
2
Heat flow surface engine block
0.8 x 100 = 80 kW
P
3
Coolant heat flow
0.7 x 100 = 70 kW
P
4
Heat flow vehicle exhaust system
0.5 x 100 = 50 kW
Heat burden on the room = 300 kW
Separate suction of the heat energy P
1
converted by the eddy current brake can considerably
lower the burden on the room.
The heat volume in the test room would then be: + 0.8 + 0.7 + 0.5 = 2
This means that the energy quantity of the engine power multiplied by 2 is the volume of heat
energy in the test room.
Example 2
P
2
Heat flow surface engnine block
0,8 x 100 = 80 kW
P
3
Coolant heat flow
0,7 x 100 = 70 kW
P
4
Heat flow vehicle exhaust system
0,5 x 100 = 50 kW
Heat burden on the room = 200 kW
•
Time period
An LPS 3000 performance test takes, on the average:
CAR
1.5 minutes
TRUCK
3 – 4 minutes
A short working break follows (vehicle change, set up work, etc.)
•
Ventilation concept criteria
The following points must be considered for the ventilation concept:
- Engine power
- Frequency of measurements
- Room temperature increase allowed by operator
- Room size
- Energy storage volume of the walls
MAHA Experiences
Cooling air is of special importance as modern engine management systems are equipped with
control systems which reduce the engine power when intake temperatures are too high. The full
engine power is however to be measured on the dyno.
Do not fall below the following values when testing vehicles under full load:
- Air power > 25 000m³/h
- Flow speed > 90 km/h
- Securing of under body flow (catalytic converter)
Pos: 171 /Technis che Dok umentation/ Leis tungsmesstechnik/POWE RDYNO/052301 LPS 3000 R100/BA/Inhalt: 0523 Wärmebilanz (Bild) @ 13\mod_ 1234271111837_ 0.d ocx @ 337725 @ @ 1
