Energy efficiency of the agricultural tractor The tests for the survey of the performance of tractors

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1 EIMA 2018 Energy efficiency of the agricultural tractor The tests for the survey of the performance of tractors Maurizio Cutini Consiglio per la ricerca in agricoltura e l analisi dell economia agraria CREA-IT November 8, 2018, Bologna, Italy 1

2 Introduction Optimizing tractor efficiency is an actual topic for industry and research in particular in terms of emissions and energetic points of view. It s very interesting the fast development in terms of transmission, tires and engine management. 2

In this frame, the OECD Tractor Codes could be considered a reference for many experimental procedures.

3 Tractor testing: technical standards Tractors testing has followed this technical development and a wide range of methodologies, both standard or following manufacturers internal protocols, have been developed. In this frame, the OECD Tractor Codes could be considered a reference for many experimental procedures. The adoption of OECD Code 2 standard for drawbar power and fuel consumption assessment allows obtaining comparable data. 3

4 The OECD Code 2 This standard code indicates how to measure the tractor s performance in terms of power and fuel consumption. The main assessments are the power take off (PTO) test and the drawbar power test. 4

In the last years, it s interesting the work developed from Gil Sierra et al.

5 Tractor efficiency: state of the art An explanation of the tractor s behavior during drawbar work in terms of power and fuel consumption is found in the works of Grisso et al. In the last years, it s interesting the work developed from Gil Sierra et al. that defined an efficiency index and a method for tractor classification according to the energy efficiency. In particular they found that fuel consumption could vary between different tractor s model of ±17%. 5

6 Engine performance The four main characteristics parameter are: Power (kw) Torque (Nm) Hourly fuel consumption (kg/h) Specific fuel consumption (g/kwh) These performance refer to engine rpm/min P F r 2 n 60 6

7 Power measurement? Dynamometer P F r 2 n 60 7

8 Fuel consumption measurement methods 1. Weight 2. Volumetric 3. Coriolis effect 8

9 Which power? 9

10 The different standard test conditions SAE J /25/EC ECE R 24 DIN OCSE Rilevamento potenza al volano al volano al volano al volano alla pdp Pressione atmosferica (bar) 0, ,99 1,027 0,996 Temperatura ambiente ( C) Temperatura combustibile ( C) 40± ,5 40 raccomandato dal costruttore Tipo di combustibile 40 CFR 86 CEC RF75 T 96 CEC RF03 A 84 raccomandato dal costruttore raccomandato dal costruttore Turbocompressore Intercooler Pompa alim. gasolio Pompa iniezione Pompa raffreddamento Pompa olio Radiatore olio Filtro aria Silenziatore Alternatore Radiatore motore Ventilatore max. slittamento min. slittamento Pompe azionate dal motore Pompe idrauliche Compressore aria condizionata Compressore imp. frenatura 10

Power (kw) Power and standard 120 100 80 60 40

105 105 100 ISO TR 14396 ECE- R120 97/68/EG

11 Power (kw) Power and standard Source: Landis, SAE J ISO TR ECE- R120 97/68/EG ECE-R24 EWG 80/1269 Standard 90 DIN OECD Code 2 11

12 Power (kw) Torque (Nm) Power and torque ,0 % C max Torque P max Power 33,3 % Engine balance Engine speed (rev/min) 12

13 Hourly consumption (kg/h) Specific consumption (g/kwh) Hourly and specific fuel consumption 30,0 28,0 26,0 Hourly consumption ,0 22,0 20,0 18,0 16,0 14,0 12, ,0 8,0 6,0 4,0 Specific consumption , Engine speed (rev/min) 13

14 Characteristic curves 14

15 Fuel consumption test: 5 extra points With the aim of focusing typical operation, five extra points are required: 1) Heavy drawbar work 2) Heavy power take-off at standard speed 3) Light power take-off or drawbar work 4) Heavy drawbar or power take off at at economy power speeds 5) Light drawbar or power take off work at reduced speed 15

16 Practical application (Source: DLG 6283F, 2015) 16

17 Drawbar power 17

18 735 N Drawbar test and data measurement P F v F = 75 kg v = 1 m/s 735 N x 1m/s = 735 W=0,735 kw * 1,36 = 1 CV 18

19 The test track 19

There is the need of a device generating the horizontal force at the drawbar of the tested tractor up to a maximum wheel slip of 15%

20 The dynamometric vehicles The drawbar test is carried out with the engine at full throttle and in different selected gears, or speeds if the tractor has continuously variable transmission. There is the need of a device generating the horizontal force at the drawbar of the tested tractor up to a maximum wheel slip of 15% or the maximum drawbar power, in each gear or speed. Max. drawbar power: 200 kw Max. pulling force: 120 kn Max. measuring speed: 50 km/h Transmission: 6WD Total weight: kg (6.800 kg front; kg rear) 20

21 Slippage S ( Nc Nv) 100 Nc Slip = f D, W, η Drawbar force Tractor weight Friction Asphalt or concret S<15% Soil S<35% Snow or ice S<5% 21

22 Drawbar power kw OECD drawbar performance Force dan With ballast Unballasted Speed km/h

23 Power efficiency index Example of tractor with nominal power at the flywheel: kw Declared power Power at the PTO Drawbar power Fuel consumption N. kw measured kw Index (%) measured kw Index (%) PTO test g/kwh Drawbar test g/kwh

Drawbar test, fuel consumption In order to provide information on operational efficiency at part loads, fuel consumption will be measured in two gears/speed settings typically used for fieldwork.

24 Drawbar test, fuel consumption In order to provide information on operational efficiency at part loads, fuel consumption will be measured in two gears/speed settings typically used for fieldwork. One of which shall have a nominal speed of 7.5 km/h and the other a speed between 7 and 10 km/h. These 10 additional points follow the principle to measure the differences in consumption of three different gear that have to develop a comparable work. The fuel consumption of the gear with a nominal speed of 7.5 km/h is compared with the gear up, and the gear with a nominal speed between 7 and 10 km/h with the subsequent. 24

25 Discussion The results show the possibility of evaluating the efficiency of tractors not only as specific fuel consumption at the power take off, that remain obviously one of the main indicator characterizing engine efficiency, but also as driveline contribution. Moreover OECD data allow classification of tractor as type, mass, capacity, power, geometry, etc. and the results could be extended to attempts of clustering that could allow to find the parameters that could contribute to improve the efficiency of tractor. The approach could be extended as methodology also to test on field. In this case ASAE presents interesting models that could provide useful indications for the development of model representing the studied relation when tractors are run on soil. 25

26 Thank you for your attention CREA-IT

NEBRASKA OECD TRACTOR TEST 1773 SUMMARY 308 JOHN DEERE 8210 DIESEL 16 SPEED

NEBRASKA OECD TRACTOR TEST 1773 SUMMARY 308 JOHN DEERE 8210 DIESEL 16 SPEED POWER TAKE-OFF PERFORMANCE Power Crank HP shaft (kw) speed Gal/hr lb/hp.hr Hp.hr/gal Mean Atmospheric rpm (l/h) (kg/kw.h) (kw.h/l)