representative road load test procedure peter smeds – swedish transport administration iddo...
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Representative road load test procedure
Peter Smeds – Swedish Transport AdministrationIddo Riemersma – Transport & Environment
WLTP-DTP-LabProcICE-029,22-11-2010
Problem descriptionCustomer expectation:
Realistic fuel consumption figuresRequired:
Test procedure aiming at representative road load for production vehicles
Road load not tested on production vehicle, but on a pre-production vehicle
Many ‘flexibilities’ in current ISO 10521 road load test procedure
Manufacturers need a level playing field
Road load data
TŰV Nord showed reductions of CO2 emissions up to 10% on NEDC test cycle for reduced road load(-20% at 20 km/h, -10% at 40 – 120 km/h)
Source: presentation at Vienna meeting, document WLTP-DTP-LabProcICE-023
Flexibilities in current ISO 10521Vehicle preparation / adjustmentsWheel alignment
> fixed tolerance to avoid unrealistic range of settings
Brake pads> mandatory braking action before testing
Other adjustments or setting issues?
Flexibilities in current ISO 10521Test tracksClimatic conditions (tracks in hot climate
beneficial)> review and adjust correction formulas
Asphalt type> only allow commercially available asphalt on the track
Other track issues?
Flexibilities in current ISO 10521TyresWear
> representative alternative: 30 – 40% from new to bald
Pressure> require at least the same tyre pressure
Choice> require at least same dimensions and rolling resistance
Other tyre issues?
Flexibilities in current ISO 10521Vehicle characteristicsWeight
> require at least the same vehicle weightBody
> require at least the same aerodynamic characteristics
Other vehicle related issues?
Alternative approachFeed forward approach
Feed back approach
> Feed back loop via CoP and/or in-use compliance
Coast down test
vehicle
Production vehicle
Road load dataRequiremen
ts
Coast down test
vehicle
Production vehicle
Road load data
Requirements
Road load data
Requirements
RequirementsRequirements
Requirements
Conclusions &recommendationsIdentified flexibilities in ISO 10521 can be
solved to some extentSome gaps will stay and tolerances have to be
allowed Best guarantee for a representative road load a
feed back approach Existing legislation and targets for CO2 need
to be reviewed if RLD procedure is changed
Next stepsA document is being prepared with an
inventory of issues in ISO 10521 and options for solving them.
This will be input for further discussions within the ICE LabProcesses group, generating feedback
A proposal will be prepared for an improved RLD procedure in the draft GTR.
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