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 theref
2、rom, 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 2011 SAE International All rights reserved. No part of this pub
3、lication 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: +1 724-776-4970
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2684_201111SURFACEVEHICLERECOMMENDEDPRACTICEJ2684 NOV2011 Issued 2011-11FMVSS 105 I
5、nertia Brake Dynamometer Test Procedure for vehicles above 4 540 kg GVWR RATIONALEVehicle and braking systems development is fast-paced, and involves a global supplier base. This Recommended Practice provides an inertia-dynamometer test procedure that is repeatable and cost-effective. It evaluates t
6、he performance of the brake corner and its components (including friction material) by following the test procedure and sequence as indicated in the Federal Motor Vehicle Safety Standard (FMVSS) 105. Data from this Recommended Practice may be combined with other brake system and vehicle characterist
7、ics to predict vehicle performance. Since the first release of the FMVSS 105, there have been numerous inertia-dynamometer test protocols developed and used by the industry with different approaches and levels of detail. The SAE Truck and Bus Hydraulic Brake Committee considers laboratory test proce
8、dures useful in supporting harmonization to improve the overall performance and safety of motor vehicle braking systems.TABLE OF CONTENTS 1. SCOPE 22. REFERENCES 23. DEFINITIONS . 34. TEST CYCLES 75. TEST EQUIPMENT . 86. TEST CONDITIONS . 97. TEST PARTS PREPARATION AND TEST SETUP . 128. TEST PROCEDU
9、RES 129. TEST REPORT . 1710. NOTES 18APPENDIX A EXPLANATORY NOTES 19FIGURE 1 TYPICAL BRAKE APPLICATION TIME STAMPS . 7FIGURE 2 COOLING AIR FLOW DIRECTION RELATIVE TO CALIPER POSITION . 9FIGURE 3 PLUG-TYPE THERMOCOUPLE 9FIGURE 4 BRAKE PAD THERMOCOUPLE INSTALLATION . 10FIGURE 5 BRAKE SHOE THERMOCOUPLE
10、 INSTALLATION 10FIGURE 6 BRAKE SHOE AND BRAKE DRUM THERMOCOUPLE AXIAL LOCATION 10FIGURE 7 BRAKE DISC THERMOCOUPLE INSTALLATION 11TABLE 1 DEVELOPMENT TEST SEQUENCE . 14TABLE 2 FMVSS TEST SEQUENCE 16SAE J2684 Issued NOV2011 Page 2 of 19 1. SCOPE This Recommended Practice is derived from the FMVSS 105
11、vehicle test and applies to two-axle multipurpose passenger vehicles, trucks and buses with a GVWR above 4 540 kg (10 000 lbs) equipped with hydraulic service brakes. There are two main test sequences: Development Test Sequence for generic test conditions when not all information is available or whe
12、n an assessment of brake output at different inputs are required, and FMVSS Test Sequence when vehicle parameters for brake pressure as a function of brake pedal input force and vehicle-specific loading and brake distribution are available. The test sequences are derived from the Federal Motor Vehic
13、le Safety Standard 105 (and 121 for optional sections) as single-ended inertia-dynamometer test procedures when using the appropriate brake hardware and test parameters. This recommended practice provides Original Equipment Manufacturers (OEMs), brake and component manufacturers, as well as aftermar
14、ket suppliers, results related to brake output, friction material effectiveness, and corner performance in a laboratory-controlled test environment.The test sequences include different dynamic conditions (braking speeds, temperature, and braking history as outlined in the FMVSS 105); inertia loads e
15、quivalent to the vehicles LLVW and GVWR; fully operational, partial failure, and failed system conditions. All applicable sections of the FMVSS 105 are included. Optional sections include: parking brake output, water recovery, TP-121D dynamometer retardation, and 32 km/h (20 mph) stops to simulate F
16、ederal Motor Carrier Safety (FMCS) requirements. This Recommended Practice does not evaluate or quantify other brake system characteristics such as wear, noise, judder, ABS performance, or braking under extreme temperatures or speeds. Minimum performance requirements are not part of this recommended
17、 practice. Consistency and margin of pass/fail of the minimum requirements related to stopping distance or equivalent deceleration levels of the FMVSS 105 vehicle test can be assessed as part of the project in coordination with the test requestor when using the appropriate vehicle information and ve
18、hicle dynamics modeling. Nevertheless, this procedure and its results do not replace the vehicle-level test to demonstrate compliance to FMVSS (105 for hydraulic brake systems or 121 for air-over-hydraulic brake systems), or other mandatory regulations (like ECE R13 or equivalents). 1.1 Purpose The
19、purpose of this procedure is to assess the performance of a brake corner assembly during conditions that correspond to the FMVSS 105 vehicle test procedure for applications above 4 540 kg (10 000 lbs) of GVWR. 2. REFERENCES 2.1 Related Publications The following publications are provided for informa
20、tion purposes only and are not a required part of this SAE Technical Report.2.1.1 Government Publications Available from the National Highway Safety Administration (NHTSA) Headquarters, 1200 New Jersey Avenue, SE, West Building, Washington, DC 20590, Tel: 202-366-4000 or TTY: 1-800-424-9153, www.nht
21、sa.dot.gov.571.105 Standard No. 105 - Hydraulic and Electric Brake Systems TP-121D-01 May 9, 1990 NHTSA - Office of Vehicle Safety Compliance (OVSC) Laboratory Test Procedure for FMVSS 121D Air Brake Systems Dynamometer. http:/www.nhtsa.gov/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20F
22、iles/TP-121-d01.pdfTP-105-03 July 1, 2005 NHTSA - OVSC Laboratory Test Procedure for FMVSS 105 Hydraulic and Electric Brake Systems. http:/www.nhtsa.gov/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20Files/TP-105-03.pdfSAE J2684 Issued NOV2011 Page 3 of 19 2.1.2 Other publications Availab
23、le from the Government Printing Office - Federal Motor Carrier Safety Regulations, 732 North Capitol Street, NW, Washington, DC 20401-0001, Tel: 202.512.1800, http:/www.gpo.gov/fdsys/browse/collectionCfr.action?collectionCode=CFR .393.52 Federal Motor Carrier Safety Regulations Handbook (FMCSR) - Br
24、ake Performance. Code of Federal Regulations Title 49 Subchapter B Part 393 Subpart C 2.1.3 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J2115 Air Brake P
25、erformance and Wear Test Code Commercial Vehicle Inertia Dynamometer SAE J2784 FMVSS Inertia Dynamometer Test Procedure for Vehicles Below 4540 kg GVWR 2.1.4 ISO Publications Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.an
26、si.org.ISO611:2003 Road vehicles - Braking of automotive vehicles and their trailers - Vocabulary 3. DEFINITIONS 3.1 AIR-OVER-HYDRAULIC BRAKES Brake system that supplies air to a air-hydraulic intensifier to supply pressurized brake fluid to the foundation brake. This system is more common on front
27、disc brakes. The basic system uses an air actuator that applies load onto a hydraulic master cylinder.3.2 AIR-OVER-HYDRAULIC INTENSIFIER RATIO On an air-over-hydraulic brake system, the ratio is the actuator area on the air supply side to the master cylinder area on the hydraulic output side. The ai
28、r-over-hydraulic intensifier ratio varies from 13.5:1 to 23.5:1. 3.3 APPARENT FRICTION FOR DISC BRAKES Per Equation 1: (Eq. 1) where: = apparent friction for disc brakes. unitless SAE J2684 Issued NOV2011 Page 4 of 19 3.4 DRUM BRAKE EFFECTIVENESS (C*) Per Equation 2: %LGs 6:L F LPDNAODKH; #L 4ABB (E
29、q. 2) where:*C= effectiveness for drum brakes. unitless T = output torque. Nm, lbft p = brake pressure. kPa, psi Thresholdp= minimum pressure required to start developing braking torque. kPa, psi PA = total piston area acting on one side of the caliper for disc brakes; total wheel cylinder area for
30、drum brakes mm2, in effR = radial distance from centerline of the piston to the axis of rotation for disc brakes; internal drum diameter divided by 2 for drum brakes, unless other dimensions are provided by the requestor. mm, in = Brake efficiency100 unitless = Unit conversion factor; = 1x106for SI
31、units; and = 12 for English units 3.5 BRAKE CORNER Assembly of the foundation brake including friction material, brake assembly with mounting hardware, brake rotor or drum, and wheel hub assembly excluding wheel and tire. 3.6 BRAKE POWER ASSIST UNIT A device installed in a hydraulic brake system to
32、reduce the driver effort required to actuate the system, and that if inoperative does not prevent the driver from braking the vehicle by a continued application of pedal force on the service brake control. 3.7 BRAKE POWER UNIT A device installed in a brake system that provides the energy required to
33、 actuate the brakes, either directly or indirectly through an auxiliary device, with the driver action consisting only of modulating the energy application level. 3.8 BREAKAWAY TORQUE Torque required to initiate disc (or drum) rotation after input force (or pressure) is applied to the parking brake.
34、 Nm, lbfftSAE J2684 Issued NOV2011 Page 5 of 19 3.9 BRAKING FORCE DISTRIBUTION Ratio between the braking force of each axle and the total braking force for the vehicle, expressed as a percentage for each axle (e.g., 50% front, 50% rear). The braking force distribution between front and rear axles, i
35、s a function of brake input force and tire-to-road adhesion utilization3.10 BRAKE RETARDATION FORCE Force at the contact surface between the wheel and the ground, produced by the effect of the braking system, which opposes the speed or the tendency to movement of the vehicle3.11 DECELERATION-CONTROL
36、LED BRAKE APPLICATION Inertia-dynamometer control algorithm that adjusts the real time brake pressure to maintain a constant torque output calculated from the instantaneous deceleration specified in the test procedure.3.12 INITIAL BRAKE TEMPERATURE IBT Temperature of the most heavily loaded pad (or
37、shoe) at 0.32 km (0.2 mi) before the start of the service brake application. C, F 3.13 PRESSURE-CONTROLLED BRAKE APPLICATION Inertia-dynamometer control algorithm that maintains a constant input pressure to the brake irrespective of the torque output.3.14 GROSS VEHICLE WEIGHT RATING GVWR Maximum veh
38、icle weight declared by the manufacturer. kgf, lbf 3.15 GROSS AXLE WEIGHT RATING GAWR Maximum axle sprung weight declared by the manufacturer. When multiple axle component ratings are available instead of a unique value for the axle, use the lowest rating declared. kgf, lbf 3.16 LIGHTLY LOADED VEHIC
39、LE WEIGHT LLVW Unloaded vehicle weight plus 227 kg (500 lbf) (including driver and test instrumentation). kgf, lbf 3.17 PRESSURE LEVEL AT 667 N (150 LBF); FULLY OPERATIONAL P667N OPERATIONALBrake system pressure at the front or rear corner with 667 N (150 lbf) of pedal force applied with the brake s
40、ystem and power assist unit (including rear brake proportioning) fully operational. kPa, lbf 3.18 PRESSURE LEVEL AT 560 N (125 LBF); FULLY OPERATIONAL P560N OPERATIONALFor hand-operated parking brake systems, brake system pressure at the front or rear corner with 560 N (125 lbf) of input force appli
41、ed with the brake system and power assist unit (including rear brake proportioning) fully operational. kPa, lbf 3.19 PRESSURE LEVEL AT 667 N (150 LBF); FULLY DEPLETED P667N DEPLETEDBrake system pressure at the front or rear corner with 667 N (150 lbf) of pedal force applied and the power assist unit
42、 (including rear brake proportioning) fully depleted. kPa, psi SAE J2684 Issued NOV2011 Page 6 of 19 3.20 STATIC LOADED RADIUS SLR Effective radius of the tire when loaded to weight born by tire with axle loaded to the GAWR with the vehicle stationary. The SLR is available from the tire manufacturer
43、 specification, and is used to calculate the equivalent braking force at the tire-to-road interface for parking brake hill-holding ability. m, in 3.21 TIRE DYNAMIC ROLLING RADIUS Equivalent tire radius that will generate the Revolutions Per Mile (RPM) published by the tire manufacturer for the speci
44、fic tire size per Eq.3 for SI units and Eq.4 for English units. Use the tire dynamic rolling radius to calculate the dynamometer rotational speed for a given linear vehicle speed. mm RPMdynR=23446091(Eq. 3) RPMdynR=236063(Eq. 4) where:dynR = tire dynamic rolling radius. mm using Eq. 3; in using Eq.
45、4 RPM = tire manufacturer specification for revolutions per mile. Typically shown for the tire size on the manufacturers website3.22 WHEEL LOAD Portion of the total vehicle weight braked by the tested corner. Wheel load is a function of the vehicle load condition (LLVW or GVWR), brake system conditi
46、on (fully-operational, partial failure, or failed system), brake output, and tire-to-road adhesion limit. For braking forces exceeding the tire-to-road adhesion limit, wheel load is a function of the vehicle dynamic weight transfer instead of the brake force exerted by the brake corner. Unless other
47、wise specified, use: 3.22.1 25% of the vehicle test weight (GVWR or LLVW) for fully operational conditions. kg, lb 3.22.2 50% the vehicle test weight (GVWR or LLVW) for partial hydraulic system failure for front-rear split systems. kg, lb3.23 TEST INERTIA Mechanical or simuated (electrical) inertia
48、to replicate the rotational energy input as a function of the reflected wheel loadbraked by the corner and the tire dynamic rolling radius using Eq 5 kgm, lbfft (Eq. 5) SAE J2684 Issued NOV2011 Page 7 of 19 where:3.24 SNUB Braking deceleration of a vehicle from a higher reference speed to a lower reference speed that is greater than zero. 4. TEST CYCLES 4.1 Dynamic Brake Application Figure 1 illustrates the main time-stamps used to characterize the brake application. FIGURE 1 - TYPICAL BRAKE APPLICATION TIME STAMPS 4.1.1 Time t0Brake application initiation. At this time, the pressu
