WLTP ANNEX 4, ROAD LOAD CALCULATION

Transcription

1 BMW, EG-63, C. Lueginger WLTP ANNEX 4, ROAD LOAD CALCULATION VALIDATION DATA FOR ROAD LOAD CALCULATION AND ROAD LOAD FAMILIES

2 FAQ, PAGE 1 Q: What can be done, if the powertrain behaves non-linear? A: The CO 2 -range is limited (current proposal g/km). It should be chosen in a way, that the error due to non-linear behavior is smaller than the measurement tolerance. But as big as possible, to avoid (expensive) measurements. For measurement tolerance not only CO 2 -measurement has to be considered, but also road load determination and chassis dyno setting. This can be a few grams of CO 2. Q: Systems like cylinder management could make e.g. aerodynamics more sensitive. A: If we focus on a NEDC or Mode with its constant-speed phases, there could be an effect. But a WLTC has a very homogeneous a-v distribution, so therefore the CO 2 -influence of a system like a cylinder-management will be nearly continuous. There is no kind of technology or type of drivetrain known, which is influenced especially by aerodynamics only it is the road load as a whole, which increases CO 2. Slide 2 and 3 show, that even with (plugin-)hybrid vehicles (where the ICE is starting and stopping) the calculation method works. Therefore systems like cylinder management will not make the calculation inaccurate. Q: What is the benefit for authorities? A: With this method, the individual road load of the vehicle is available. Therefore within e.g. a COP the individual CO 2 -value of the vehicle can be checked (and not only at TMH or TML). Page 2

3 FAQ, PAGE 2 Q: Why is the calculated road load and CO 2 derived from best case and not from worst-case? A: The result will be the same and it seems more logical to put in some optional equipment than subtracting options, which are not installed. See picture: CO2-emission individual vehicle 100 optional equipment / road load 95 0% 20% 40% 60% 80% 100% Page 3

4 VALIDATION BY SIMULATION vehicle description testtype [%] [g CO2 / km] < 2 g/km max. error max. error % F0 % F2 % inertia delta-road-load, example from Excel-calculation kg delta-co2, based on calculation method, example CO2-percentage of range, based on calculation method 58% 19% 22% compact, Otto, UM=1100kg 60% 19% 21% 2.4% 0.5 OK middle class, Otto, UM=1400kg 59% 19% 22% 1.3% 0.3 OK SUV, Otto, UM=2100kg 60% 19% 21% 1.7% 0.3 OK compact, Diesel, UM=1100kg 60% 19% 21% 2.0% 0.4 OK middle class, Diesel, UM=1400kg 59% 19% 22% 1.3% 0.3 OK SUV, Diesel, UM=2100kg 62% 19% 19% 4.2% 0.8 OK mild-hybrid, UM=1400kg. Simulation order: F0, F2, inertia 63% 21% 16% 5.8% 1.2 OK mild-hybrid, UM=1400kg. Simulation order: F0, inertia, F2 63% 21% 16% 5.9% 1.2 OK mild-hybrid, UM=1400kg. Simulation order: F2, inertia, F0 62% 19% 19% 3.9% 0.8 OK CD 63% 22% 15% 6.9% 1.4 OK plugin-hybrid, UM=2200kg CS 51% 21% 28% 6.6% 1.3 OK Label 58% 22% 20% 2.6% 0.5 OK CD 57% 25% 19% 5.7% 1.1 OK plugin-hybrid, UM=1900kg CS 64% 21% 16% 6.4% 1.3 OK Label 62% 22% 16% 6.4% 1.3 OK Based on simulation data, default simulation order: F0, F2, inertia. Weighing of charge depleting and sustaining for label with current NEDC formula. Max. error in g CO 2 / km is defined for a CO 2 -range of 20 g/km (currently proposed limit), 5 % error 1 g/km Page 4

5 VALIDATION BY SIMULATION 100% 90% 80% 70% 60% inertia typical F0 50% measurementtolerance: F2 40% 30% +/-2 g/km 20% 10% 0% Based on simulation data, default simulation order: F0, F2, inertia. Except mild-hybrid: Variation. Weighing of charge depleting and sustaining for label with current NEDC formula. Max. error in g CO 2 / km is defined for a CO 2 -range of 20 g/km (currently proposed limit), 5 % error 1 g/km Page 5

6 VALIDATION BY SIMULATION Parameter worst case best case 17 inch wheels with rim 2 and massage seat 18 inch wheels and glass roof 16 inch wheels and massage seat and "rest" F F F test mass CO2 by simulation CO2 by interpolation "4-phases"-approach CO2 by interpolation "WLTC"-approach Information: Based on simulation data. Middle class vehicle, 4cyl-diesel, manual transmission. Based on latest calculation version 8 with 4-phases approach and former version with calculation over whole WLTC. Road load is taken from Excel example. Interpolation with calculation method is very close to the simulation result! Page 6

7 FAMILY CONSIDERATION WITHIN ROAD LOAD CALCULATION Road load calculation should have limits: Minimum delta-co 2 : E.g. [5] g/km. Maximum delta-co 2 : E.g. [20-30] g/km. Extrapolation in both directions: E.g. [2] g/km. There is no minimum delta-weight needed, as long as the minimum delta-co 2 is fulfilled. For physical reasons there is no difference if only optional equipment is considered or body shapes as well - as long as they only influence weight and aerodynamics. E.g. BMW 5series 530d, automatic, 258 PS: Sedan: 139 g/km Touring: 145 g/km ( m² c d *A and kg) The Delta-CO2 is small enough to be able to consider Touring as an option. Hint: Values are from NEDC, CO2-Delta may be different in a WLTC. Page 7