BMW, EG-63, 19.04.2013 C. Lueginger WLTP ANNEX 4, ROAD LOAD CALCULATION VALIDATION DATA FOR ROAD LOAD CALCULATION AND ROAD LOAD FAMILIES
FAQ, PAGE 1 Q: What can be done, if the powertrain behaves non-linear? A: The CO 2 -range is limited (current proposal 20-30 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 10.15 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
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 120 115 110 105 individual vehicle 100 optional equipment / road load 95 0% 20% 40% 60% 80% 100% Page 3
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 61.5 0.00278 150 kg delta-co2, based on calculation method, example 9.9 3.3 3.8 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
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
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" F0 193.8 132.3 159 175.9 143.6 F1 0.292 0.293 0.293 0.293 0.293 F2 0.03015 0.02736 0.0282 0.02921 0.02778 test mass 1703 1553 1618 1578 1673 CO2 by simulation CO2 by interpolation "4-phases"-approach CO2 by interpolation "WLTC"-approach 134.6 119.1 125.3 128.2 123.8 125.4 128.1 124.0 125.4 128.1 124.0 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
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 (+ 0.070 m² c d *A and + 100 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