Working paper No. WLTP-05-05
WLTP Phase 1B
Main Open Issues Road and Dyno Load
Presentation at WLTP IG Meeting Geneva 8.1.2014
Open Issues Road and Dyno Load- K. Kolesa
Open Issues Phase 1B for WLTP Road and Dyno Load
3.2.
wind tunnel criteria
4
4.1.
wind conditions
general review for on board anemometry
4
4.3.
coast down procedure
review of definitions and selection of
speed range, speed points, reference
speeds for RLD and dyno load setting
4
4.3.2.
on board anemometry based
review of the method (comments IR 85 coast down method e.g.
87, 92)
4.3.2.6.1.
4
4.4.
torque meter method
4.4.2.2. torque meter method
4
4.5.5.
road load curve correction
4
5.2.
default road load parameter
4
6.
4
7.3.4.
wind tunnel method for RLD
alternative warm up
procedure
4
8.2.3.2.
4,
App. 2.3.
1
2
general review required
4
chassis dyno load setting
with torque meter method
close link to #18
validation
measurements
required
to be discussed,
then modify if
necessary
to be developed
YES
NO
YES
NO
NO
to be reviewed,
then modify if
necessary
ascending ? or descending ?
to be decided
to be reviewed,
use always three coefficients, formulae to
then modify if
be developed (comments IR 101 - 103)
necessary
Industry objects to current parameters.
to be reviewed,
Based of future data the parameters can
then modify if
be reviewed and adapted
necessary
(LabProcICEdoc 269)
method to be developed
to be developed
YES
definition of family or procedure
NO
general review of torque meter method
(comment IR 95, IR 132)
to be developed
review and/or development of a method
with 3 coefficients,
to be reviewed,
10 N criteria to be checked/applied
then modify if
transfer of road to dyno load - clarification necessary
needed
The simulated road load
calculation for each reference postpone to phase-1b
speed v_j
Titel oder Name, Abteilung, Datum
Open Issues Road and Dyno Load- K. Kolesa
to be reviewed,
then modify if
necessary
NO
NO
NO
NO
NO
NO
On-Board Anemometry for RLD
WLTP Annex 4 § 4.1.1.1.2
►
Road load determination of vehicles on road has to consider actual wind
influence by measuring ambient wind speeds . For low wind speeds a stationary
anemometry is sufficient. Measuring under higher wind speed conditions is only
allowed using onboard wind speed measurement.
►
This anemometry method is of regional importance using test tracks with a
more open structure and higher wind speed conditions. Therefore this method
was introduced in WLTP.
►
The maximum permissible wind speed conditions were discussed at length in
Phase 1A and it was concluded to perform further investigations in accuracy of
correction functions to obtain a robust and equivalent anemometry method.
►
Contact persons. A. Rijnders (NL) and C. Hosier (OICA)
Initial proposal is expected in meeting # 8, final decision in meeting #8
3
Open Issues Road and Dyno Load- K. Kolesa
Windtunnel Criteria
WLTP Annex 4 § 3.2
►
Background: The combined approach is based on measurement data
for the vehicle with lowest and highest cycle energy demand. The
vehicles between these extremes can be measured or calculated with
data of mass, tire rolling resistance and aerodynamic resistance of
available options.
►
Aerodynamic data of available options can be measured on road with a
high uncertainty or better in a wind tunnel. Therefore basic criteria for
windtunnel characteristics were introduced in WLTP.
►
Discussions with CP revealed need for a further review of these criteria
as some windtunnel actually cannot fulfill the requirements. Especially
the requirement for moving ground belt and the air pressure coefficient
have to be discussed with CP’s.
►
Contact Person: BMW
Initial proposal expected at WLTP meeting #8, decision in meeting #12
4
Windtunnel / Chassis dyno as alternative RLD method
WLTP Annex 4 § 6
►
Current WLTP provides 4 methods for road load determination:
1. Coast down method
2. Torquemeter method
3. Use of windtunnel/Chassis Dyno
4. Calculation of road load based on vehicle parameters
►
Method (3) was reserved in gtr, but not developed yet.
►
Measurement principle: Driving resistance of vehicles on road is caused by aerodynamic
drags and resistance of tires and mechanical/electrical drags. Vehicle aerodynamic
resistance is measured in wind tunnel with specified characteristics, rolling resistance is
determined at chassis dynamometer equipment. The discrete evaluated forces can be
superposed to obtain the driving resistance.
►
Accuracy is expected to be far better than on road measurements due to lack of
influencing ambient factors, like wind, road, temperatures.
►
Critical is the definition of windtunnel and chassis dyno equipment. The equivalency to the
method 1 has to be shown by validation testing. Calibration for measurement equipment
is to be defined.
►
Contact Person is BMW, initial proposal is expected in WLTP meeting #6, decision in
meeting #12
5
Open Issues Road and Dyno Load- K. Kolesa
Torque meter method as alternative RLD method
WLTP Annex 4 § 4.4
►
Current WLTP provides 4 methods for road load determination:
1. Coast down method
2. Torquemeter method
3. Use of windtunnel/Chassis Dyno
4. Calculation of road load based on vehicle parameters
►
Method (2) was introduced as an alternative method to coasting down a vehicle
►
Measurement principle: Driving resistance of vehicles on road is caused by
aerodynamic drags and resistance of tires and mechanical/electrical drags. Vehicle
aerodynamic resistance is measured at constant speed points and the energy demand
for superseding the driving resistance is determined by special torquemeters between
driving axle and tire.
►
Advantage is measurement of driving resistance under positive torque. Parasitic drags
(e.g. electric braking or regeneration) during deceleration phase of vehicle can be
avoided.
►
Critical is the validation of equivalency to coast down method. Validation testing
required. Calibration of measurement equipment is to be validated.
►
Contact person are TNO and C. Hosier (OICA) , initial proposal is expected in WLTP
meeting #9, decision in meeting #9.
6
Alternative Warming Up Procedure on Dyno
WLTP Annex 4 § 7.3.4
►
Background: Road Load of vehicle has to be simulated on chassis dyno
to obtain similar conditions as in real life. For comparison of dyno load
with road load the vehicle has to be in comparable temperature
conditions
►
Current WLTP provides a prescription for warming up the vehicle
preceding dyno load determination
►
For alternative warming up procedures the equivalency criteria and the
applicable family definition have to be reviewed.
►
Contact Person: Yamaguchi, Japan
Initial Proposal expected at WLTP meeting #6, final decision in
meeting#7
7
Open Issues Road and Dyno Load- K. Kolesa
Calculation of default road load based on vehicle parameters
WLTP Annex 4, § 5
►
As an alternative for determining road load with the coast down or
torque meter method , a calculation method for default road load
parameters may be used.
►
Situation: Industry objects to current defined parameters. Based on
future data the parameters can be reviewed and adapted
►
Contact Person: A. Rijnders (NL)
Initial proposal expected in WLTP meeting #8, final decision in meeting
#9
8
Open Issues Road and Dyno Load- K. Kolesa