STATISTICAL TESTING PROCEDURE TO VERIFY THE FUEL CONSUMPTION AND DISTANCE DETERMINED BY THE OBFCM DEVICE
ANNEX IISupplementary provisions
ANNEX II STATISTICAL TESTING PROCEDURE TO VERIFY THE FUEL CONSUMPTION AND DISTANCE DETERMINED BY THE OBFCM DEVICE 1. INTRODUCTION 1.1. This Annex sets out the statistical testing procedure to verify the accuracy of the total fuel consumption and total distance as determined by the OBFCM device. 2. STATISTICAL VERIFICATION TESTING PROCEDURE FOR FUEL CONSUMPTION AND DISTANCE 2.1. Vehicle selection The vehicle shall be selected from the OBFCM family which exceeded the accuracy requirements in any of the monitoring tests set out in point 4.2. of Annex I, or from the OBFCM family that was selected by the granting approval authority based on a suspicion of non-compliance. A minimum of 3 and maximum of 8 vehicles shall be selected from this family for testing. 2.2. Vehicle conditions Vehicle conditions are described in point 4 of Annex Xa to Regulation (EU) 2017/2400. For the fuel consumption measurement as described in point 6.1.5.5 of Annex Xa to Regulation (EU) 2017/2400, the fuel used shall be the one set out in point 2.3 of this Annex. 2.3. Test fuel The test procedure shall be performed with a reference fuel specified in Annex IX to Regulation (EU) No 582/2011 on which the parent engine has been type-approved under that Regulation. 2.4. Measurement equipment specifications The actual fuel mass consumed shall be measured on-board with a measurement device as set out in point 5.7 of Annex Xa to Regulation (EU) 2017/2400. If a run-in phase took place in accordance with point 6.1.2 of that Annex Xa, the vehicle shall be equipped with the fuel consumption measurement system after the run-in phase. 2.5. Vehicle preparation The vehicle preparation is described in points 6.1.2, 6.1.3, and 6.1.4 of Annex Xa to Regulation (EU) 2017/2400. The vehicle shall be equipped with the fuel measurement system as specified in point 5.7 of that Annex. The vehicle tested shall be equipped with the on-board fuel consumption device as type-approved for that vehicle family. 2.5.1. Vehicle warm-up Before start of statistical verification test sequence the vehicle may be driven for warm up in accordance with Table 3 of Annex Xa to Regulation (EU) 2017/2400. The warm up phase shall not be considered in the evaluation of the verification test. 2.5.2. Measurement signals The fuel measurement signals to be measured are described in point 5.9 in Annex Xa to Regulation (EU) 2017/2400. Those include the ‘fuel mass flow for liquid fuels’, ‘fuel mass flow for gaseous fuels’. The engine fuel rate signals as determined by the OBFCM device shall also be recorded. 2.5.2.1. Vehicle speed The recorded vehicle speed shall be the CAN signal for vehicle speed in the unit km/h as provided by a digital tachograph complying with Regulation (EU) No 165/2014 of the European Parliament and of the Council ( 1 ) . 2.5.2.2. Global positioning system The longitudinal and latitudinal position shall be provided via a global positioning system. Required accuracy: Position: < 3 m 95 % Circular Error Probable Update rate: ≥ 4 Hz 2.5.2.3. Ambient temperature Required accuracy: ± 1 °C Update rate: ≥ 1 Hz 2.5.3. Fuel consumption measurement The fuel consumption measurement shall start at vehicle stand still directly before the measuring run. The vehicle shall be driven during the measurement in a driving style avoiding unnecessary braking of the vehicle, gas pedal pumping and aggressive cornering. The setting for the advanced driver assistance systems which is activated automatically at key-on shall be used, and gear shifts shall be performed by the automated system (in the case of AMT or APT transmissions) and the cruise control shall be used (if applicable). The duration of the fuel consumption measurement shall be within the tolerances set out in Table 3 of Annex Xa to Regulation (EU) 2017/2400. The fuel consumption measurement shall end at vehicle stand still directly after the measuring run. 2.5.4. OBFCM data read-out during the measuring run The recording of the total distance travelled (lifetime), total fuel consumed (lifetime) (kilograms), vehicle fuel rate, engine fuel rate, as determined by the OBFCM device, shall start no later than when the fuel consumption measurement has started and end together with the fuel consumption measurement. The odometer reading shall be taken at vehicle stand still directly before the measuring run and shall be taken at vehicle stand still directly after the end of the fuel consumption measurement. 2.5.5. Measuring run The route selected shall fulfil the requirements described in point 6.1.5.1 of Annex Xa to Regulation (EU) 2017/2400. 2.5.6. Boundary conditions for the verification test The boundary conditions to be met for a valid verification test are set out in point 6.1.5.7 of Annex Xa to Regulation (EU) 2017/2400. 2.6. Data evaluation The recorded data shall be synchronised and aligned to 1 Hz temporal resolution, either by arithmetical average, nearest neighbour or linear interpolation. 2.6.1. Evaluation of the accuracy of the fuel consumption determined by the OBFCM device The fuel consumption from the OBFCM device shall be compared with the fuel consumption measured on-board with a measurement device reporting the total amount of fuel consumed in grams. The accuracy ratio C OBFCM,FUEL shall be calculated as follows: where: Fuel_Consumed TEST is the fuel consumption measured during the statistical test procedure, in accordance with point 2.5.3. Fuel_Consumed OBFCM is the fuel consumption measured by the OBFCM device during the statistical test, as specified in point 2.5.4, and calculated by taking the difference between the total fuel consumed (lifetime) reading from the OBFCM device at the end of the test and the total fuel consumed (lifetime) reading from the OBFCM device at the start. This ratio shall be calculated for each of the statistical tests and shall be used to perform the statistical evaluation as set out in point 3. 2.6.2. Evaluation of the accuracy of the distance determined by the OBFCM device The accuracy ratio C OBFCM,DISTANCE shall be calculated as follows: where: D ODOMETER is the difference between the odometer reading at the end of the test and the odometer reading at the start of the test referred to in point 2.5.4. D OBFCM is the difference between the lifetime distance reading from the OBFCM device at the end of the test and the lifetime distance reading from the OBFCM device at the start of the test as recorded in point 2.5.4. That ratio shall be calculated for each of the statistical tests, and shall be used to perform the statistical evaluation as set out in point 3. The lifetime distance of the OBFCM device shall be compared with the distance read from the odometer, and in the case of a discrepancy over ± 5 %, the manufacturer shall provide an explanation of that discrepancy to the approval authority, which shall notify the Commission of the discrepancy and the explanation thereto. 3. EVALUATION OF THE STATISTICAL TESTING PROCEDURE FOR FUEL CONSUMPTION AND DISTANCE 3.1. Starting point The starting point for the statistical evaluation are the values for C OBFCM calculated for 3 individual test vehicles ( N = 3 ) in accordance with point 2.6.1 for fuel consumption and in accordance with point 2.6.2 for the total distance. The criteria set out under point 3.3(3) determine if additional vehicles need to be tested, which shall be verified separately for fuel consumption and total distance. 3.2. Statistical parameters For the total number of vehicles tested ( N ), the average ( X tests ) and the standard deviation ( s ) of the test results shall be determined: and where: x i is the value C OBFCM calculated for the individual test vehicle i according to point 2.6.1 of this Annex for fuel consumption, and according to point 2.6.2 of this Annex for the total distance. 3.3. Evaluation For the 3 vehicles initially tested and after each additional vehicle tested, the value X tests shall be assessed as set out below in order to reach one of the following conclusions for the in-service verification family or road load family concerned: (1) Pass the family if: (2) Fail the family if: (3) Test an additional vehicle if: where: t P and t F are as set out in the table below. s is the standard deviation determined in accordance with point 3.2. A is 1,03. Table 1 Values for the pass/fail decision t-parameters for the fuel consumption and distance verification Number of vehicles tested t P t F 3 1,5889 Highest value of 1,1060 and (0,02/s) ( 2 ) 4 0,9279 0,5068 5 0,6117 0,2836 6 0,3758 0,1528 7 0,1734 0,0646 8 0,0000 0,0000 3.4. Calculation of the size of the deviation For the calculation of the size of the deviation, the average ( C OBFCM ) is defined as X tests for the total number of vehicles tested, after the family has failed according to point 3: average (C OBFCM ) = X tests ( 1 ) Regulation (EU) No 165/2014 of the European Parliament and of the Council of 4 February 2014 on tachographs in road transport, repealing Council Regulation (EEC) No 3821/85 on recording equipment in road transport and amending Regulation (EC) No 561/2006 of the European Parliament and of the Council on the harmonisation of certain social legislation relating to road transport ( OJ L 60, 28.2.2014, p. 1 , ELI: http://data.europa.eu/eli/reg/2014/165/oj ). ( 2 ) Where s is the standard deviation determined in accordance with point 3.2. In the case where the standard deviation s is equal to zero, then the value used for t F will be 1,1060.