SORT Double Deck GAS A d d e n d u m UITP PROJECT SORT SORT calculation for gas vehicles @Iveco Bus
Foreword For more than ten years, SORT has demonstrated that fruitful work is possible between manufacturers and operators. This publication is widely recognised as the public transport sector s premier reference for energy consumption testing and for comparable energy consumption data. The most recent and entirely revised 2014 edition provides an additional protocol, called SORT-HY, for hybrid vehicles that cannot be externally re-charged (charge sustaining HEV ). This edition complements both the 2004 edition (12-metre single-chassis, single-deck buses mounted with diesel engines) and the 2009 edition (providing SORT formula for different single-deck bus sizes). This edition features a new formula for gas vehicles, which will be of particular interest to UITP members who operate and thus are involved in the process of tendering for gas vehicles. The issue of SORT testing on gas vehicles was raised in the SORT working group, who set about amending the original SORT method, which was originally designed for diesel buses. UITP has now revised the method to adjust the factors for gas vehicles. Suppliers can now be asked to provide SORT data for the gas vehicles they propose to supply. Our sincere thanks to all those who have taken part in this working group. We hope these efforts will contribute to quality improvements within our business and in the service of our members and the public. Please contact UITP if you require any further information or clarification. Regards Christophe Martin, SORT Working Group leader Mike Weston Chairman UITP Bus Committee Addendum UITP 2016 International Association of Public Transport, 2016 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means without the written permission of the International Association of Public Transport. Legal Deposit: D/2016/0105/4 This publication completes the previous edition SORT 2015 (UITP D/2015/0105/4) 1 SORT stands for Standardized On-Road Test Cycles and it refers to a standardized fuel measurement referential for use at tender stage to compare different bus products on their fuel consumption. The programme exists already for more than 10 years. 2 Charge sustaining HEV as defined in SAE J2711. 2
SORT GAS SORT energy consumption for gaseous fuels The way of calculating weight, number of seats and other bus setup conditions are the same as for diesel buses. Only the way to measure the consumption should be adapted. To allow comparison between different energy sources (diesel, gas, electricity ), a general recommendation would be that all consumptions should be expressed in terms of energy by distance (kw.h/km), instead of liter or kilograms/km. Consumption of gaseous fuels must always be expressed in kwh/km. Regarding the energy consumption of gaseous fuels, any mass method can be used, as long as it achieves a measurement uncertainty of less than 2 %. The gas consumption (in kg), must then be converted into energy content, using the Lower Heating Value (LHV) of the test gas. Two cases can appear: - In case of using a reference gas: use the composition according to Directive 582/2011 EU; - In case of use of a gas from the grid: proceed to a sample analysis, to measure the real LHV (Lower Heating Value) of the test gas, according to recommended standards: - for analysis of natural gas: ISO 6874-4 - for the calculation of calorific/heating values, density, relative density and Wobbe index from composition: ISO-6976 - Methane number calculation: AVL or MWM method (MWM will be published in EN16726.) Energy content of motor fuels ( Annexe Directive 2009/33/EC 1 ) To allow comparison between different energy sources (diesel, gas, electricity ), UITP s recommendation is that all fuel consumptions shall be expressed in terms of energy by distance: kw.h/km (instead of liter or kilograms/km). Note: For gaseous fuels, the real value of the gas used for the test has to be used. Fuel Diesel Energy content 36 MJ/litre Hydrogen 11MJ/Nm 3 Table 1: Energy content of motor fuels 2. Conversion in kwh can be easy obtained as it is a practical energy measurement unit that is equal to 3,6 megajoules. 1 kwh = 3,6 MJ Example for a SORT diesel with a consumption of 40 L/100 km => 4 kwh / km Note: Natural Gas, is the expression used regardless if the origin is fossil or biological. DVGW G 260 (A)x The final consumption can then be calculated by the formula: ( ) C(kg).LHV MJ kg C(kW.h/km)= (3,6.d(km) 1 Directive 2009/33/EC also called the GPP for Green Public Procurement. Source:http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX- :32009L0033&from=EN 2 Source: from the ANNEX Data for the calculation of operational lifetime costs of road transport vehicles, Table 1.? 3
Vehicle set-up : Load We take as a starting point a 12 m bus with the following characteristics: - length: 12 m. - width: 2.55 m. - lump load: 3.2 ton (half-load). - number of seats: 30. - content of the gas tank: 800 L. - nominal pressure: 200 bar. - gas: Gr according to Directive 582/2011 EU, ISO 6976 & ISO 12213. Gas weight in this vehicle is 162kg considering following assumptions - Gr composition : 87% CH4 + 13% C2H6 - Compressibility z (15 C & 200 bar) : 0.73488 - Mass density (15 C & 200 bar) : 202.955 kg/m3 The above-mentioned values must be adapted to the real characteristics of the measured vehicles. The ratios can be calculated in to the following way: Surface: (12.00-1.20) x 2.55 = 27.54 m². Load versus the surface: 3,200 / 27.54 = 116.19 kg/m². The driver cabin and the forefront of the vehicle are not accessible to passengers and as a consequence cannot be taken into account for the calculation of the lump load. This fact is compensated, by way of convention, by diminishing the effective vehicle length by 1.20 m. So we find by calculation a mean lump load-ratio of 116.19 kg/m2. The same way of reasoning can be applied to fix the number of seats and the conventional quantity of fuel: Ratio seats/surface: 30 / 27.54 = 1.09 seat/m². Ratio gas weight/surface: 162 / 27.54 = 5.90 kg/m². Application: The above-mentioned formulas allow one to fix the parameters for lump load, seats and gas weight, respectively CL, CS et CG, for vehicles of length L and width W: Bus type CL = 116.19 x (L - 1.20) x W CS = the integer of {1.09 x (L - 1.20) x W} CG = 5.90 x (L - 1.20) x W In which CL is the foreseen set lump load, CS the number of seats, CG quantity of gas. Dimensions [m] Load [kg] Seats Gas [kg] Standard 12 X 2,55 3,200 30 162 Midibus 8 X 2,35 1,857 17 94 Articulated 18 X 2,55 4,978 47 253 For test purposes, the vehicle will be loaded + driver. Thus the weight of the driver should not be deducted from the load. On the contrary, the weight of people present in the vehicle and equipment will be deducted from this lump load. The weight of optional non-movable equipment is deducted as well. 4
UITP Publication: UITP Project SORT The only highly efficient tool for measuring fuel consumption of buses Brochure in English + CD-Rom containing the English, French, German, Spanish and Italian versions Price UITP members: 90 Price non members: 180 5
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