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
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4、 Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SURFACE VEHICLE RECOMMENDED PRACTICE J2784 SEP2009 Issued 2007-12 Revised 2009-09 Superseding J2784 DEC2007 FMVSS Inertia Dynamometer Test Procedure for Vehicles Below 4540 kg GVWR RATIONALE This Recommended Practice
5、 is the result of an industry effort to develop inertia-dynamometer test procedures based upon the FMVSS 105 and 135 vehicle tests. Results from these tests provide a laboratory assessment of the brake corner performance. Data from this document may be combined with other brake system and vehicle ch
6、aracteristics to predict vehicle performance. The conditions defined in this document are drawn from FMVSS 105 or 135 vehicle test experience. The deceleration levels are not necessarily based on those needed to meet the requirements of the FMVSS. These procedures are intended to properly represent
7、the lining conditioning which occurs during an FMVSS vehicle test. This revised document includes test procedures for vehicles below 4540 kg of Gross Vehicle Weight Rating. FMVSS 135 test procedure is covered by Section 8.1 and Table 2. FMVSS 105 test procedure is covered by Section 8.2 and Table 3.
8、 The different items, definitions, and sections indicate clearly whenever it applies only to the FMVSS 105 or the FMVSS 135 test procedure. TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 2. REFERENCES 3 2.1 Applicable Publications . 3 2.1.1 ISO Publications 3 2.2 Related Publications . 3 2.2.1 Governm
9、ent Publications 3 3. DEFINITIONS . 4 3.1 Apparent Friction for Disc Brakes . 4 3.2 Drum Brake Effectiveness (C*) . 4 3.3 (FMVSS 105) Brake Power Assist Unit 4 3.4 (FMVSS 105) Brake Power Unit . 4 3.5 Breakaway Torque 4 3.6 Deceleration-Controlled Brake Application . 5 3.7 Initial Brake Temperature
10、IBT 5 3.8 Pressure-Controlled Brake Application . 5 3.9 Gross Vehicle Weight GVWR 5 3.10 Lightly Loaded Vehicle Weight LLVW 5 3.11 Maximum Vehicle Speed Vmax. 5 SAE J2784 Revised SEP2009 Page 2 of 26 3.12 (FMVSS 135) Pressure Level at 500 N Pedal Force with Brake Power Assist System Operational p500
11、N operational5 3.13 (FMVSS 135) Pressure Level at 500 N Pedal Force with Brake Power Assist System Fully Depleted p500N depleted5 3.14 (FMVSS 105) Pressure Level at 667 N Pedal Force with Brake Power Assist or Brake Power Unit System Operational p667N operational5 3.15 (FMVSS 105) Pressure Level at
12、667 N Pedal Force with Brake Power Assist System Fully Depleted p667N depleted5 3.16 (FMVSS 105) Pressure Level at 890 N Pedal Force with Brake Power Assist or Brake Power Unit System Operational p890N operational5 3.17 (FMVSS 135) Pressure Level During Best Cold Effectiveness Stop p best cold effec
13、t. 6 3.18 (FMVSS 105) Spike Stop 6 3.19 Tire Dynamic Rolling Radius . 6 4. TEST CYCLES 6 4.1 Dynamic Brake Application . 6 4.1.1 Time t0. 7 4.1.2 Time t1. 7 4.1.3 Time t2. 7 4.1.4 Time t3. 7 4.1.5 Time t4. 7 4.2 Parking Brake Application . 7 5. TEST EQUIPMENT . 7 6. TEST CONDITIONS AND SAMPLE PREPAR
14、ATION 8 7. DYNAMOMETER TEST INERTIA 9 8. TEST PROCEDURES 10 9. TEST REPORT . 14 9.1 Graphs 14 9.2 Tabular Data . 14 9.3 Cooling Air Temperature and Humidity for Each Section of the Test . 15 9.4 Wear Measurements and Final Integrity Inspection . 15 9.5 Test Conditions . 15 9.6 Cooling Air Conditions
15、 15 10. NOTES 15 10.1 Marginal Indicia . 15 APPENDIX A PARKING BRAKE TEST SEQUENCE . 16 APPENDIX B EXPLANATORY NOTES 20 APPENDIX C SAMPLE IN-STOP PLOTS AND SUMMARY TABLE - EXAMPLE FOR FMVSS 135 . 24 APPENDIX D VEHICLE AND TEST PARAMETERS 26 FIGURE 1 TYPICAL BRAKE APPLICATION TIME STAMPS . 6 FIGURE 2
16、 WATER SPRAY SETUP FOR DISC BRAKES . 8 FIGURE A1 TYPICAL STATIC PARKING BRAKE APPLICATION SEQUENCE 16 FIGURE A2 HILL-HOLD ACTING FORCES AND TORQUES . 17 FIGURE C1 IN-STOP PLOT FOR ADHESION UTILIZATION RAMPS . 24 FIGURE C2 IN-STOP PLOT FOR COLD AND HIGH SPEED EFFECTIVENESS . 24 FIGURE C3 SAMPLE SECTI
17、ONS OF TABULAR REPORT 24 FIGURE C4 SAMPLE GRAPH FOR PARKING BRAKE TEST OUTPUT 25 SAE J2784 Revised SEP2009 Page 3 of 26 TABLE 1 EQUATIONS TO CALCULATE CORNER TEST INERTIA PER SECTION AND AXLE 9 TABLE 2 SERVICE BRAKES TEST PROCEDURE - FMVSS 135 11 TABLE 3 SERVICE BRAKES TEST PROCEDURE - FMVSS 105 (EX
18、CEPT SCHOOL BUSES) 13 TABLE A1 EXAMPLE CALCULATIONS FOR HILL-HOLD TORQUE VALUES 17 1. SCOPE This document is derived from the Federal Motor Vehicle Safety Standards 105 and 135 vehicle test protocols as single-ended inertia-dynamometer test procedures. It measures brake output, friction material eff
19、ectiveness, and corner performance in a controlled and repeatable environment. The test procedures also include optional sections for parking brake output performance for rear brakes. It is applicable to brake corners from vehicles covered by the FMVSS 105 and 135 when using the appropriate brake ha
20、rdware and test parameters. The FMVSS 135 is applicable to all passenger cars and light trucks up to 3500 kg of GVWR. The FMVSS 105 is applicable to all passenger cars, multi-purpose vehicles, buses, and trucks above 3500 kg of GVWR. This document does not include testing for school bus applications
21、 or vehicles equipped with hydraulic brakes with a GVWR above 4540 kg. 1.1 Purpose The purpose of this procedure is to assess the performance of a brake corner assembly during conditions that correspond to the FMVSS 105 and 135 vehicle test procedures. 2. REFERENCES 2.1 Applicable Publications The f
22、ollowing publications form a part of this specification to the extent specified herein. Unless otherwise specified, the latest issue shall apply. 2.1.1 ISO Publications Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ISO/PAS 12158:2002 Road vehicle
23、Braking systemsTemperature measuring methods 2.2 Related Publications The following publications are provided for information purposes only and are not a required part of this document. 2.2.1 Government Publications Available from NHTSA Headquarters, 400 Seventh Street, SW, Washington, DC 20590, Tel
24、: 888-327-4236 or TTY: 1-800-424-9153, www.nhtsa.dot.gov. 571.105 Standard No. 105Hydraulic and Electric Brake Systems 571.135 Standard No. 135Light Vehicle Brake Systems TP-105-03 July 1, 2003 NHTSAOVSC Laboratory Test Procedure for FMVSS 105 Hydraulic and Electric Brake Systems TP-135-01 Dec 5, 20
25、05 NHTSAOVSC Laboratory Test Procedure for FMVSS 135 Light Vehicle Brake Systems SAE J2784 Revised SEP2009 Page 4 of 26 3. DEFINITIONS 3.1 Apparent Friction for Disc Brakes Per Equation 1: ()effPThresholdrAppT=2105(Eq. 1) where: g541 = apparent friction for disc brakes. unitless 3.2 Drum Brake Effec
26、tiveness (C*) Per Equation 2: ()effPThresholdrAppTC=510*(Eq. 2) where: *C = effectiveness for drum brakes. unitless T = output torque. Nm p = brake pressure. kPa Thresholdp = minimum pressure required to start developing braking torque. Unless otherwise directed, use threshold pressure derived from
27、Table 2 Section 20 or Table 3 Section 30. kPa PA = total piston area acting on one side of the caliper for disc brakes; total wheel cylinder area for drum brakes mm2 effr = radial distance from centerline of the piston to the axis of rotation for disc brakes; internal drum diameter divided by 2 for
28、drum brakes, unless other dimensions are provided by the requestor. mm 3.3 (FMVSS 105) Brake Power Assist Unit A device installed in a hydraulic brake system to reduce the driver effort required to actuate the system, and that if inoperative does not prevent the driver from braking the vehicle by a
29、continued application of pedal force on the service brake control. 3.4 (FMVSS 105) Brake Power Unit A device installed in a brake system that provides the energy required to actuate the brakes, either directly or indirectly through an auxiliary device, with the driver action consisting only of modul
30、ating the energy application level. 3.5 Breakaway Torque Torque required to initiate brake rotation after cable tension is applied to the parking brake. Nm SAE J2784 Revised SEP2009 Page 5 of 26 3.6 Deceleration-Controlled Brake Application Inertia-dynamometer control algorithm that adjusts the real
31、 time brake pressure to maintain a constant torque output calculated from the instantaneous deceleration specified in the test procedure. 3.7 Initial Brake Temperature IBT Rotor or drum temperature at the start of the brake application. C 3.8 Pressure-Controlled Brake Application Inertia-dynamometer
32、 control algorithm that maintains a constant input pressure to the brake irrespective of the torque output. 3.9 Gross Vehicle Weight GVWR Maximum vehicle weight indicated by the manufacturer. kgf 3.10 Lightly Loaded Vehicle Weight LLVW Unloaded vehicle weight plus 180 kg for driver and test instrume
33、ntation. kgf 3.11 Maximum Vehicle Speed VmaxHighest speed attainable by accelerating at a maximum rate from a standstill to a distance of 3.2 km on a level surface, with the vehicle at LLVW for vehicles per FMVSS 135 or at GVWR for vehicles per FMVSS 105. For electric vehicles, the speed attainable
34、is determined with the propulsion batteries at a state of charge of not less than 95% at the beginning of the run. See sections 50 and 70 on Table 2 and sections 70 and 250 on Table 3. km/h 3.12 (FMVSS 135) Pressure Level at 500 N Pedal Force with Brake Power Assist System Operational p500N operatio
35、nalBrake system pressure at the front or rear corner with 500 N of pedal force applied and the brake system and power assist unit fully operational including rear brake proportioning. kPa 3.13 (FMVSS 135) Pressure Level at 500 N Pedal Force with Brake Power Assist System Fully Depleted p500N deplete
36、dBrake system pressure at the front or rear corner with 500 N of pedal force applied and the power assist unit fully depleted, including rear brake proportioning. kPa 3.14 (FMVSS 105) Pressure Level at 667 N Pedal Force with Brake Power Assist or Brake Power Unit System Operational p667N operational
37、Brake system pressure at the front or rear corner with 667 N of pedal force applied and the brake system and power assist unit fully operational including rear brake proportioning. kPa 3.15 (FMVSS 105) Pressure Level at 667 N Pedal Force with Brake Power Assist System Fully Depleted p667N depletedBr
38、ake system pressure at the front or rear corner with 667 N of pedal force applied and the power assist unit fully depleted, including rear brake proportioning. kPa 3.16 (FMVSS 105) Pressure Level at 890 N Pedal Force with Brake Power Assist or Brake Power Unit System Operational p890N operationalBra
39、ke system pressure at the front or rear corner with 890 N of pedal force applied and the brake system and power assist unit fully operational including rear brake proportioning. This load level is required for the Spike Stops Section. kPa SAE J2784 Revised SEP2009 Page 6 of 26 3.17 (FMVSS 135) Press
40、ure Level During Best Cold Effectiveness Stop p best cold effectLowest distance-weighted average brake pressure from all the brake applications on Section 40, Table 2, Cold Effectiveness. kPa 3.18 (FMVSS 105) Spike Stop A stop resulting from the application of a service brake pressure of p890N opera
41、tionalin 0.08 seconds. 3.19 Tire Dynamic Rolling Radius Equivalent tire radius that will generate the Revolutions Per Mile (RPM) published by the tire manufacturer for the specific tire size per Equation 3. Use the tire dynamic rolling radius to calculate the dynamometer rotational speed for a given
42、 linear vehicle speed. mm RPMg652RR=23446091(Eq. 3) where: RR = tire dynamic rolling radius mm RPM = tire manufacturer specification for revolutions per mile. Typically shown for the tire size on the manufacturers website 4. TEST CYCLES 4.1 Dynamic Brake Application Figure 1 illustrates the main tim
43、e-stamps used to characterize the brake application. FIGURE 1 - TYPICAL BRAKE APPLICATION TIME STAMPS SAE J2784 Revised SEP2009 Page 7 of 26 4.1.1 Time t0Brake application initiation. At this time, the pressure starts to rise. 4.1.2 Time t1Time at level reached. At this time, the brake reaches its t
44、arget level for torque or pressure control. At time t1, the calculation of average by time and the average by distance begins. 4.1.3 Time t2Time at the end of averages. At time t2the inertia-dynamometer data acquisition system terminates the calculation of average by time and average by distance. Ti
45、me t2is the end of the stable portion of the brake application. t2is defined as the time at which speed is 0.5 km/h above the release speed (t3). 4.1.4 Time t3Time at release speed. At time t3, the inertia-dynamometer servo controller releases the brake (specified in 8.1.3). 4.1.5 Time t4Time at bra
46、ke pressure and torque lost. At time t4, pressure and torque are below the minimum thresholds. The inertia-dynamometer considers the braking event complete. 4.2 Parking Brake Application See Appendix A. 5. TEST EQUIPMENT 5.1 Single-ended brake inertia-dynamometer capable of performing deceleration a
47、nd pressure controlled brake applications. 5.2 Automatic data collection system capable of recording digitally the following channels at 50 Hz minimum: 5.2.1 Brake equivalent linear speed. km/h 5.2.2 Brake input pressure. kPa 5.2.3 Brake output torque. Nm 5.2.4 Brake fluid displacement. mm3 5.2.5 Pa
48、rking brake cable tension (rear brakes testing only). N 5.2.6 Parking brake cable travel (rear brakes testing only). mm 5.3 Automatic data collection system capable of recording digitally the following channels at 10 Hz minimum: 5.3.1 Brake rotor or drum temperature. C 5.3.2 Brake pad or brake shoe
49、temperature. C 5.3.3 Cooling air temperature, relative humidity, and speed. SAE J2784 Revised SEP2009 Page 8 of 26 5.4 Control brake cooling air temperature 25 5 C, and humidity to 9.92 g/kg (11.57 g/m3) at sea level. Use a psychrometric chart to find acceptable air temperature and relative humidity conditions to meet absol
