1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/J2908_201709 SURFACE VEHICLE TECHNICAL INFORMATION REPORT J2908 SEP2017 Issued 2017-09 Vehicle
5、Power Test for Electrified Powertrains RATIONALE Power ratings provided for ICE vehicles are obtained from component-level tests of the engine power output (SAE J1349). However, electrified powertrains often consist of multiple power-producing components that may include an engine and one or more el
6、ectric motors. These components are coupled in a wide variety of configurations and can operate as a system to produce propulsion power in ways that are not predictable a priori. As a result, a new power test procedure is needed for all types of electrically propelled vehicles to measure and report
7、powertrain power as a full system. This powertrain-level testing approach addresses the challenge of providing fair and unbiased comparisons among all vehicle powertrain designs. FOREWORD This SAE Technical Information Report is intended as a guide toward achieving common methods and practices and i
8、s subject to change in order to keep pace with added experience and technical advances. TABLE OF CONTENTS 1. SCOPE 3 2. REFERENCES 3 2.1 Applicable Documents 3 2.2 SAE Publications . 3 2.3 Other Publications . 3 3. TERMS AND DEFINITIONS . 3 4. LABORATORY AND VEHICLE EQUIPMENT 5 4.1 Laboratory Condit
9、ions . 5 4.2 Vehicle Condition 5 4.3 Hub Dynamometer 5 4.4 Chassis Dynamometer 6 4.5 Axle/Wheel Torque Sensors . 6 4.6 Fuel . 6 4.7 Vehicle Network Diagnostic Scan Tool (for SOC %) 6 4.8 Exhaust Handling 6 4.9 Cooling Requirements. 6 5. MEASUREMENTS 6 5.1 Initial and Final Measurements . 6 5.2 Param
10、eters Logged at 10 Hz during Testing 7 5.3 Vehicle-Reported Parameters . 7 SAE INTERNATIONAL J2908 SEP2017 Page 2 of 18 6. VEHICLE WARMUP AND PRECONDITIONING PROCEDURES . 7 6.1 Preconditioning for HEVs and PHEVs in CS Mode 7 6.2 Preconditioning for PHEVs with Blended Charge-Depleting Mode 8 6.3 Prec
11、onditioning for BEVs and PHEVs with All-Electric Charge-Depleting Mode . 8 6.4 For Reference: Preconditioning for Conventional ICE Vehicle . 8 7. POWERTRAIN SYSTEM POWER TEST . 9 7.1 Power Sweep Test to Find VMP . 9 7.1.1 Power Sweep Test Procedure 9 7.1.2 Power Sweep Test Data Analysis . 9 7.2 Fixe
12、d Speed Power Tests . 9 7.2.1 Fixed Speed Power Test Procedures . 9 7.2.2 Repeatability and Retests . 10 7.3 Post Processing and Reporting “J2908 Vehicle Power” . 10 7.3.1 J2908 Vehicle Impulse Power (2 Second Maximum) . 10 7.3.2 J2908 Vehicle Sustained Power (2 second window from t = 8 to 10 second
13、s) 10 8. PHEV ELECTRIC-ONLY DRIVE POWER TEST (PHEV ONLY) . 10 8.1 Vehicle Warmup and SOC Preconditioning for PHEVs in Charge-Depleting mode . 11 8.2 PHEV Electric-Drive Power Test Procedure . 11 8.3 Post Processing and Reporting PHEV Electric-Drive Power 11 9. PEAK ELECTRIC ASSIST POWER TEST (xEVS O
14、NLY) 12 9.1 Data Source 12 9.1.1 Option 1: Data from Section 7.1 (Power Sweep Test to Find VMP) . 12 9.1.2 Option 2: Data from Section 7.2 (Fixed Speed Power Tests) . 12 9.1.3 Option 3: Dedicated Testing . 12 9.2 Post Processing and Reporting Peak Electric Assist Power Rating . 12 10. PEAK ELECTRIC
15、REGENERATIVE BRAKING POWER TEST (HEV, PHEV, AND BEV ONLY) . 12 10.1 Option 1: Speed Drive Cycles in Dynamometer Road Load Mode 12 10.2 Option 2: Fixed Speed Braking Testing 12 10.3 Post Processing and Reporting Peak Electric Regenerative Braking Power . 13 11. NOTES 13 11.1 Revision Indicator 13 App
16、endix A Guidance on SOC Conditioning 14 Appendix B Comparing J2908 Power to “Engine Power” (J1349 or UN R85) . 15 Appendix C Approaches for Powertrain System Power Test . 16 Appendix D Summary of DC Electrical Bus Measurement Points . 18 SAE INTERNATIONAL J2908 SEP2017 Page 3 of 18 1. SCOPE This doc
17、ument provides test methods for evaluating the maximum power of electrified vehicle powertrain systems by direct measurement at the drive wheel hubs or axles. Additional tests are included specifically for PHEVs to measure electric-only propulsion power and for HEVs to measure electric power assist
18、and regenerative braking. The testing requires either a chassis or hub dynamometer for all driven wheels. Results are processed to provide fair and consistent comparisons of power capabilities among different designs of electrified powertrains. Tests can also be performed on conventional vehicles if
19、 precise comparisons to electrified vehicles are desired. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.2 SAE Publications Available f
20、rom SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. SAE J1349 Engine Power Test Code - Spark Ignition and Compression Ignition - As Installed Net Power Rating SAE J1715 Hybrid Electric Vehi
21、cle (HEV) and Electric Vehicle (EV) Terminology SAE J1798 Recommended Practice for Performance Rating of Electric Vehicle Battery Modules SAE J2758 Determination of the Maximum Available Power from a Rechargeable Energy Storage System on a Hybrid Electric Vehicle 2.3 Other Publications Copies of the
22、se documents are available online at http:/webstore.ansi.org/ ISO 20762 Determination of power for propulsion of hybrid electric vehicle 3. TERMS AND DEFINITIONS For terms and definitions not listed below relating to electrified vehicles, refer to SAE J1715. 3.1 ALL-ELECTRIC CHARGE-DEPLETING (CD) MO
23、DE A particular type of PHEV Charge-Depleting Mode wherein all driving, up to and including full performance, is satisfied by electric-only propulsion. 3.2 BLENDED CHARGE-DEPLETING (CD) MODE A particular type of PHEV Charge-Depleting Mode wherein the engine is used occasionally to blend with the ele
24、ctric motor(s) to support vehicle propulsion power requests. 3.3 CHARGE-DEPLETING (CD) MODE A PHEV operating mode in which the state of charge (SOC) of the rechargeable energy storage system (RESS) may fluctuate but, on average, decreases while the vehicle is driven. 3.4 CHARGE-SUSTAINING (CS) MODE
25、An operating mode where the HEV runs by consuming the fuel energy while sustaining the electric energy level of the RESS. SAE INTERNATIONAL J2908 SEP2017 Page 4 of 18 3.5 DC BATTERY POWER The DC electric power flowing to or from the RESS terminals. This includes the power for propulsion, going to th
26、e DC/DC converter, and all other accessories powered on that DC bus. 3.6 DC/DC CONVERTER The power converter device typically found on an xEV that converts power from the traction RESS bus to the low-voltage (12 V nominal) bus. 3.7 DC PROPULSION POWER The DC electric power flowing to the propulsion
27、system. It does not include power flowing to the DC/DC converter or any other accessory on that DC bus. 3.8 ELECTRIC PROPULSION SYSTEM The motor or system of motors that provides propulsion power to the drive axles powered by the RESS. 3.9 FULL CHARGE For PHEVs and BEVs, the RESS state after the veh
28、icle has completed recharging according to the manufacturers recommended procedures. The recharging must be complete, as indicated by the vehicle recharging light changed to the “off” state or other dash display indicating “full.” If the vehicle has been at rest in a fully charged state for more tha
29、n 36 hours, it is recommended that the operator repeat the recharge cycle to re-establish full charge. 3.10 MOVING AVERAGE FILTER A moving mean or rolling mean calculation applied to the raw collected data. This filter calculation creates a series of averages based on the raw data. The peak value of
30、 the Moving Average Filter data represents a peak in the context of a specific duration. 3.11 RECHARGEABLE ENERGY STORAGE SYSTEM (RESS) A rechargeable storage system that provides electric energy for electrical propulsion. The RESS may include subsystem(s) together with the necessary ancillary syste
31、ms for physical support, thermal management, electronic control, and enclosures. Can also be referred to as simply “battery.” 3.12 REPORTED STATE OF CHARGE The RESS energy state as reported by the vehicles control computer(s), expressed in units of percentage. A high energy state corresponds to a hi
32、gh SOC value. Note: for the purposes of these procedures, 100% could mean usable energy, total energy, nominal energy, or any other logical choice made by the vehicle manufacturer. The reported value is useful in any case so long as the reported SOC level represents a consistent actual RESS SOC. 3.1
33、3 STATE OF CHARGE (SOC) Relative remaining capacity of the RESS, expressed as a percentage of the total capacity. It is not measured directly; changes in SOC are inferred by integrating the RESS current and tracking the remaining charge over time. 3.14 STATE-OF-CHARGE SET POINT The SOC level establi
34、shed at the conclusion of the appropriate preconditioning procedure detailed in Section 6. It can be tracked and returned to that level for testing by monitoring the vehicle-reported SOC % level or by measuring the RESS change in integrated A h. SAE INTERNATIONAL J2908 SEP2017 Page 5 of 18 3.15 STAT
35、E-OF-CHARGE (SOC) CONDITIONING Any series of steps taken with the test vehicle on the dynamometer that actively changes the SOC to a target SOC level by depleting the RESS or recharging the RESS using propulsion and/or regenerative braking functions. More details of SOC Conditioning can be found in
36、Appendix A. 3.16 VEHICLE SPEED AT MAXIMUM POWER (VMP) The specific vehicle speed where wheel power is measured to be at the maximum. The value of VMP is either provided to the tester by the manufacturer (or other third party) or determined using the procedures detailed in 7.1. 3.17 WHEEL ASSEMBLY A
37、pneumatic tire in combination with a wheel that can be mounted on a vehicle. 3.18 WHEEL HUB (OR HUB) A rotating member that provides for wheel mounting. 3.19 xEV A vehicle with an “electrified” powertrain system. This includes hybrid-electric, plug-in hybrid-electric, fuel cell hybrid-electric, and
38、battery electric vehicles. 4. LABORATORY AND VEHICLE EQUIPMENT 4.1 Laboratory Conditions Parameter Standard Condition Test Limits Atmospheric pressure 100 kPa 90-105 kPa Test area air temperature 25C 15-35 C Humidity (for powertrains with engines) 70% relative humidity 70% relative humidity NOTE: If
39、 humidity levels are above 70%, engine controls may suppress knock with changes in spark timing, and this suppression will affect engine power output when compared to standard conditions. 4.2 Vehicle Condition Before testing, a new vehicle shall have been properly broken in (mechanical run-in), acco
40、rding to the manufacturers recommendations and/or sound engineering practice, to avoid additional frictional losses resulting from fresh bearings and wear surfaces in the powertrain components. 4.3 Hub Dynamometer A hub dynamometer is suitable for all testing covered in this document. Because of low
41、 rotating inertia, special care needs to be taken to avoid oscillations, overshoots, or other transient problems that may interfere with measurement or could damage the test and measurement hardware or vehicle components. A hub dynamometer connects to the vehicles hub (usually with the brake assembl
42、y remaining intact). Absorption mode is required for all tests (Sections 7, 8, 9, and 10), and motoring capability is required for the Peak Electric Regenerative Braking Power Test (Section 10). Vehicles tested on a hub dynamometer shall be operated with the same vehicle control used in normal on-ro
43、ad driving. This may require speed synchronization of all axles and proper vehicle posture (among other vehicle testing properties). SAE INTERNATIONAL J2908 SEP2017 Page 6 of 18 4.4 Chassis Dynamometer A chassis dynamometer is suitable for all testing covered in this document, provided instrumentati
44、on is added to the vehicle that accurately measures all powertrain propulsion power (torque and speed) at either the axles or the wheels. Absorption mode is required for all tests (Section 7, 8, 9, and 10); motoring capability is required for only the Peak Electric Regenerative Braking Power Test (S
45、ection 10). 4.5 Axle/Wheel Torque Sensors When using a chassis dynamometer, total powertrain power (torque and speed) can be measured from axle torque sensors or torque sensor assemblies that measure torque between the wheel hub and the tire. Direct measurement of wheel (axle) speeds are necessary,
46、as chassis dynamometer speed will not be accurate because of tire slip. 4.6 Fuel Fuel energy content and specifications that affect engine power shall match what a customer would expect to use when following the manufacturers recommendations. For more detailed information on fuel, refer to the Refer
47、ence Gasoline and Fuel Specifications sections in SAE J1349. 4.7 Vehicle Network Diagnostic Scan Tool (for SOC %) The driver and/or operator must be able to read the vehicle RESS SOC. Typically, the diagnostic scan tool provides this information (among many other vehicle parameters). The resolution
48、of the reading should be at least 1% or better. Dashboard SOC readings are typically not reliable or precise enough for SOC conditioning. 4.8 Exhaust Handling Use common laboratory practice in routing exhaust out of the lab safely. Route exhaust using methods that avoid generating backpressure or su
49、ction from the lab exhaust system that would affect engine peak power. 4.9 Cooling Requirements Fans shall be used to cool the vehicle to maintain proper operating temperatures. However, excessive cooling is prohibited. The fan speed shall not generate air speeds higher than vehicle speeds encountered in the test. 5. MEASUREMENTS 5.1 Initial and Final Measurements The following shall be recorded at the beginning and end of the test ph
