200 likes | 448 Views
Learn about Tyre Rolling Resistance (RR) and how it influences CO2 emissions, EU regulations, and WLTP tyre selection. Discover the significance of RR values in reducing environmental impact and complying with labelling standards.
E N D
Content RR explanation and influence RR EU regulation and labelling bandwidth Present discussion for WLTP
RR explanation and influence. From SAE 2008-01-0154, the reduction by 1 kg/t of tyre RR reduces the CO2 emissions of 2.2 to 3 g.CO2/km (midsize EU PC) to 4 g.CO2/km (average SUV). See below presentation on rolling resistance
Thresholds / max values for Rolling Resistance REG-661/2009 * For snow tyres, the limits shall be increased by 1 N/kN.
Enforcement calendar. C1 : Passenger Car tyres–C2 : Light truck–C3 : Truck and Bus * Tyres that were manufactured prior to this date and which therefore do not comply with the requirements, may be sold for a period not exceeding 30 months from this day. ** C1 tyres only for the moment
Limit values for EU labelling. C2 ≥ 1.40 [1.25, 1.39] [1.10, 1.24] Empty [0.95, 1.09] ≤ 0.94 C2 ≤ 5.5 [5.6, 6.7] [6.8, 8.0] Empty [8.1, 9.2] [9.3, 10.5] ≥10.6 C1 ≥ 1.55 [1.40, 1.54] [1.25, 1.39] Empty [1.10, 1.24] ≤ 1.09 C1 ≤ 6.5 [6.6, 7.7] [7.8, 9.0] Empty [9.1, 10.5] [10.6,12.0] ≥12.1 For PC tyres (C1) RR labelling bandwidth is 1.5 kg/t for E and F classes and 1.2 kg/t for B and C.
WLTP tyre selection. • Reference: ECE-TRANS-WP29-2014-027: • Definitions of Vehicles "H" and "L" §3.2.21 & 22 page 10. • Tyre selection: Annex 4 § 4.2.2 page 95. • Interpolation method for individual vehicles in the CO2 vehicle family: paragraph 1.2.3.1. of Annex 6 (page 169) and paragraph 3.2.3.2.2.2 of Annex 7 (page 198). • Impact: See following chart.
Tyre selection WLTP Interpolation Vehicle H Highest cycle energy demand including aero, options, mass, tyres … Vehicle L Lowest cycle energy demand including aero, options, mass, tyres … Vehicle Ind Individual commercial version CO2 B C E VH measured VInd VL measured + + + + RRL RRind 1 RRind 2 RRH RR R117-aligned Up to 0.6 kg/t difference leading to 1.2 – 2.4 g Middle of labelling class for RRind Impossibility to benefit from lower RR tyres less than 1 class within vehicle family Does not respect WLTP spirit to introduce real values, as for inertia
WLTP tyre selection Current discussion at EU level “For tyres fitted to the test vehicles (VH and VL) and to individual vehicles in the CO2 vehicle family, the CO2 interpolation method shall be based on the RRC class values as shown in Table A4/1.” Impact: See following charts
Tyre selection WLTP Vehicle H Highest cycle energy demand including aero, options, mass, tyres … Vehicle Ind Individual commercial version Vehicle L Lowest cycle energy demand including aero, options, mass, tyres … CO2 B C E VH measured VInd VL measured RR R117-aligned + + + RRL RRind 1 RRind 2 RRH Middle of labelling Class for RRL Artificially increases CO2 emission values Middle of labelling Class for RRind No remaining possibility to use real RR value Middle of labelling Class for RRH
Tyre selection WLTP Vehicle H Highest cycle energy demand including aero, options, mass, tyres … Vehicle Ind Individual commercial version Vehicle L Lowest cycle energy demand including aero, options, mass, tyres … CO2 B C E VH measured VInd VL measured + + + RR R117-aligned RRL RRind 1 RRind 2 RRH Middle of labelling Class for RRL Artificially decreases CO2 emission values Middle of labelling Class for RRind No remaining possibility to use real RR value Middle of labelling Class for RRH
Data availability (RR). The main question is to know whether vehicle manufacturers can have access to actual tyre RR values. Extract from EU regulation 458/2011 "concerning type-approval requirements for motor vehicles and their trailers with regard to the installation of their tyres and…" Annex 1 "Administrative provisions for the type-approval of vehicles with regard to the installation of their tyres":
Data availability (RR). OEMs and OE tyre manufacturers commercial relations are built on contracts which specify the technical requirements and information supply, including about tyre Rolling Resistance. See ETRMA response to DG CLIMA on "Tyre rolling resistance coefficient values in view of HDV-CO2 emissions' simulation and Certification"