WLTP ROAD LOAD FAMILY CONCEPT

BMW, 21.03.2014

PROPOSAL ON A FAMILY DEFINITION FOR ROAD LOAD DETERMINATION

WLTP-06-11-rev1e

• In the current GTR two coast downs are necessary for one CO2-family.

• Coast down testing is very time consuming and inflexible (weather, track capacity, …)

• Many parameters that must be equal within one CO2-family (for good reasons) have no other effect on the road load except for their effect on weight and aerodynamics which is accounted for in the interpolation.

• Example: The engine is decoupled during coast down, therefore neither the engine type nor the engine temperature is relevant for road load determination.

• A definition of a road load family, that is bigger than the CO2-family, is possible.

• A road load family avoids unnecessary workload without losing accuracy.

• Such a family has synergistic effects e.g. a family for the alternative warm-up procedure or for a validation/calibration of a wind tunnel could also be this road load family.

If the concept of developing a road load family is agreed, the details should be worked out in a small subgroup.

Page 2

WLTP ROAD LOAD FAMILYSTATUS AND INTRODUCTION

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf

• The engine has no influence on road load, as it is decoupled, apart from:

• Weight, aerodynamic (and rolling resistance) influences. They are covered by the calculation of the individual road load coefficients!

Page 3

WLTP ROAD LOAD FAMILYCLARIFICATION OF ROAD LOAD INFLUENCES

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf

not relevantfor road

load

influences on road load

assessed by

masscombined approach

rolling resistancecombined approach

aerodynamicscombined approach

drivetrain type (2WD/4WD)

tbd inroad load family

drivetrain lossestbd inroad load family

gearbox type (MT, AT, …)

tbdroad load family

• 3.2.3.2.2.4. Calculation of road load for individual vehicles in the CO2 vehicle family

• 3.2.3.2.2.5. Calculation of cycle energy per phase

• 3.2.3.2.2.6. Calculation of the CO2 value for an individual vehicle by the CO2 interpolation method

Page 4

WLTP ROAD LOAD FAMILYCALCULATION OF ROAD LOAD INFLUENCES, ANNEX 7

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf

Formulas forroad load family

Formulas forboth families

Formulas forCO2-family

Proposal:1. Use CO2-family as a starting point.2. Exclude parts, which are decoupled in neutral.3. Increase transmission ratio tolerance, as its

influence on road load is almost negligible.4. Additionally define maximum range for weight,

rolling resistance and aerodynamics.

This would result in the following situation:• Diesel and gasoline (and different power of them)

can be in the same road load family.• 2WD/4WD and MT/AT would be in different road

load families.• Road load influence (e.g. mass-difference of

engines) to be included.

Next steps, if concept is agreed:• Work out exact figures.• Carry out at least one validation measurement.• Remark: Until now no expert discussion has taken

place.

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WLTP ROAD LOAD FAMILYPROPOSAL FOR ROAD LOAD FAMILY

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf

This discussion will take place within the following group:

Contact Persons:

Rob Cuelenaere (TNO), Christoph Lueginger (BMW)

Experts:

Markus Bergmann (Audi), Norbert Ligterink (TNO), Toshihisa Yamaguchi (Japan), Annette Feucht (Audi), Björn Ramacher (VW), Nakhawa (India), Iddo Riemersma (T&E), Bill Coleman (VW), Caro Hosier (Ford), Laura Bigi (PSA), Bob Latu (Renault), Bertrand Mercier (PSA)

Time frame:?

4. RLD – Family 5 series AT Gasoline / Diesel

2. RLD – Family 3 series AT Gasoline / Diesel

1. RLD – Family 3 series MT Gasoline / Diesel

WLTP – FAMILY DEFINITIONSEXAMPLE WITH LIMITED PARAMETERS

Page 6

3. RLD – Family 5 series MT Gasoline / Diesel

1. ATCT Family,Diesel MT / AT

2. ATCT Family,Gasoline MT / AT

2. ATCT Family,Gasoline MT / AT

CA Family 3 series

MT Gasoline

CA Family 3 series

MT Diesel

CA Family 3 series

AT Diesel

CA Family 5 series

MT Gasoline

CA Family 5 series

MT Diesel

CA Family 5 series

ATDiesel

CA Family 5 series

AT Gasoline

CA Family 3 series

AT Gasoline

RLD: Road Load DeterminationATCT: Ambient Temperature Correction TestCA: Combined Approach

Backup

Page 7

WLTP ROAD LOAD FAMILYBACKUP

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf

5.6. CO2 vehicle family

5.6.1. Unless vehicles are identical with respect to the following vehicle/powertrain/transmission characteristics, they shall not be considered to be part of the same CO2 vehicle family:

(a) Type of internal combustion engine: fuel type, combustion type, engine displacement, full-load characteristics, engine technology, and charging system shall be identical, but also other engine subsystems or characteristics that have a non-negligible influence on CO2 under WLTP conditions;

(b) Operation strategy of all CO2-influencing components within the powertrain;

(c) Transmission type (e.g. manual, automatic, CVT);

(d) n/v ratios (engine rotational speed divided by vehicle speed). This requirement shall be considered fulfilled if, for all transmission ratios concerned, the difference with respect to the transmission ratios of the most commonly installed transmission type is within 8 per cent;

(e) Number of powered axles;

(f) [RESERVED: family criteria for EVs].Page 8

WLTP ROAD LOAD FAMILYCO2-FAMILY DEFINITION

WLTP Road Load Family Concept, BMW, 10.03.2014

from WLTP-DTP-LabProcICE-172 - Comparison RLD flatbelt_VW.pdf