SAE J 1626-2-2017 Recommended Practice for Braking Stability and Control Performance Test Procedure for Air-Brake-Equipped Trucks and Buses.pdf

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4、24-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on thisTechnical Report, please visithttp:/standards.sae.org/J1626/2_201701SURFACE VEHICLERECOMMENDED PRACTICEJ1626-2 JAN2017Issued 2017-01Recommended Practice for Braking, Stability,

5、 and Control Performance Test Procedurefor Air-Brake-Equipped Trucks and BusesRATIONALEThis SAE Recommended Practice is intended as a guide toward industry practice and subject to change so as to keep pace with experience and technical advances. The usage of this recommend practice is limited to tru

6、cks and buses equipped with air brake systems with a GVWR greater than 10000 pound.This document has been modified from SAE J1626-1 truck tractor to incorporate air brake equipped trucks and buses test procedure. The following sections were modified; changed all truck tractor wording to trucks and b

7、uses throughout the document, 3.1 definitions add trucks and buses, 3.5 was removed based on combination weight not applicable, 3.7.1 was removed based on tractor trailer combination not applicable and modified for trucks and buses, 3.13 remove unbraked control trailer not applicable, 6.8 removed co

8、ntrol trailer reservoir not applicable, 6.13 and 8.2.2 removed the additional brake adjustment at the completion of the 500 snub burnish not applicable with trucks and buses, 7.0 test sequence was modified to follow FMVSS 121 truck and bus sequence, 8.1.3 truck and bus loading changes, 9.1.3, 10.1.2

9、 and 11.1.2 removed brake adjustments not applicable, 9.1.1 corrected 20 foot cone spacing, 9.2.1 changed 35 to 30 mph and changed 44 to 40 mph, 9.2.2 corrected reference 3.9 to 3.8, 11.2.1a removed the word only, Figure 5D removed LLVW, and corrected all header spacing between 2 digit section numbe

10、r and header. Figures (Data Sheets) removed trailer ballast C.G. height measurement, bobtail proportional and fifth wheel height not applicable.1. SCOPEThis Recommended Practice provides a road test procedure for trucks and buses, to evaluate their compliance with Federal Motor Vehicle Safety Standa

11、rd (FMVSS) 121; Air Brake Systems. Units of measure are English in lieu of metric to be consistent with FMVSS 121.2. REFERENCES2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE p

12、ublications shall apply.2.1.1 SAE PublicationsAvailable from 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 J293 Truck and Bus Grade Parking Performance RequirementsSAE J299 Stopping Di

13、stance Test ProcedureSAE J360 Truck and Bus Grade Parking Performance Test ProcedureSAE INTERNATIONAL J1626-2 JAN2017 Page 2 of 24SAE J693 Truck Overall Widths Across Dual TiresSAE J971 Brake Power Rating Test Code - Commercial Vehicle Inertia DynamometerSAE J1626 Braking, Stability, and Control Per

14、formance Test Procedures for Air and Hydraulic Brake Equipped Trucks, Truck Tractors and BusesSAE J1626-1 Recommended Practice for Braking, Stability, and Control Performance Test Procedurefor Air-Brake-Equipped Truck-Tractors SAE J1729 Parking Brake Drawbar Pull Test Procedure - Truck and BusSAE J2

15、503 Drawbar Pull Performance Criteria2.1.2 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM E1136 Specification for a Radial Standard Reference Test TireASTM E1337 Standard Test Method for

16、 Determining Longitudinal Peak Braking Coefficient of Paved Surfaces Using a Standard Reference Test Tire2.1.3 FMVSS PublicationAvailable from U.S. Government Printing Office, Superintendent of Documents, Mail Stop: SSOP, Washington, DC 20402-9328.FMVSS 121 Air Brake Systems3. DEFINITIONS3.1 TRUCKS

17、AND BUSES3.1.1 For the purpose of this standard, a truck is a motor vehicle designed to transport cargo. 3.1.2 For the purpose of this standard, a bus is a motor vehicle designed to transport people. 3.2 SNUBMeans the braking deceleration of a vehicle from a higher speed to a lower speed that is gre

18、ater than zero.3.3 STOPPING DISTANCEMeans the distance traveled by a vehicle from the point of application of force to the brake control to the point at which thevehicle reaches a complete stop (0 mph).3.4 UNLOADED VEHICLE WEIGHT (UVW)Is the weight of a motor vehicle with standard equipment, maximum

19、 capacity of engine fuel, oil, and coolant.3.5 GROSS AXLE WEIGHT RATING (GAWR)Is the maximum rated capacity of a single axle system (axle with tires, wheels, and suspension) as measured at the tire-road interface as stated on the vehicle certification label.SAE INTERNATIONAL J1626-2 JAN2017 Page 3 o

20、f 243.6 GROSS VEHICLE WEIGHT RATING (GVWR)3.6.1 Is the maximum rated capacity of a single vehicle as stated on the vehicle certification label. Liftable axles shall be down for GVWR tests. Unless otherwise specified, vehicles are loaded to GVWR. The ballast center of gravity height should be at the

21、vehicle manufacturers recommendations. Actual vehicle test weight is to be within +2/-0% of the specified weight. Axle weights are to be within 2% of their proportional share of the test weight.3.7 LIGHTLY LOADED VEHICLE WEIGHT (LLVW)3.7.1 Truck LLVW is the unloaded vehicle weight (UVW) plus up to 5

22、00 pound including driver, observer, and instrumentation. An additional 1000 pound can be allotted for vehicles that require a roll bar for testing purposes. Liftable axles shall be lifted for LLVW vehicle tests.3.7.2 Bus LLVW is the unloaded vehicle weight (UVW) plus up to 500 pound including drive

23、r, observer, and instrumentation. An additional 1000 pound can be allotted for vehicles that require a roll bar for testing purposes. Liftable axles shall be lifted for LLVW vehicle tests.3.8 FULL BRAKE APPLICATION3.8.1 Air Full Brake Application means an application of the brake control (treadle or

24、 brake pedal) in which pressure in any of the valves output circuits reaches 85 psi, or the brake control has reached maximum displacement, within 0.2 seconds after application is initiated.3.9 INITIAL BRAKE TEMPERATURE (IBT)Means the average temperature of the service brakes on the hottest axle of

25、the vehicle 0.2 mile before any brake application.3.10 MAXIMUM DRIVE - THROUGH SPEEDMeans the highest possible constant speed at which the vehicle can be driven through 200-foot arc of a PFC no greater than 0.5 in a 500-foot radius curve without leaving the 12-foot lane width.3.11 PEAK FRICTION COEF

26、FICIENT (PFC)Means the ratio of the maximum value of longitudinal force to the simultaneous vertical force occurring prior to wheel lockup,as the braking torque is progressively increased, as measured using the procedure in ASTM E1337.3.12 WHEEL LOCKUPMeans 100% wheel slip.3.13 ANTILOCK BRAKE SYSTEM

27、 (ABS)Means a portion of a service brake system that automatically controls the degree of rotational wheel slip during braking by: (a) sensing the rate of angular rotation of the wheels; (b) transmitting signals regarding the rate of wheel angular rotation to one or more controlling devices which in

28、terpret those signals and generate responsive controlling output signals; and (c) transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response to those signals.SAE INTERNATIONAL J1626-2 JAN2017 Page 4 of 244. INSTRUMENTATION AND EQUIPMENT4.1 Anemom

29、eter or equivalent device to measure wind velocity. Twenty-five (25) mph range with 1 mph accuracy at 15 mph, maximum non-linearity of 2 mph over the range and visual output resolution of 1 mph.4.2 Ambient temperature device to record ambient test temperatures, 32 to 100 F range with 0.5 F accuracy

30、at 70 F, maximum non-linearity 1.0 F over the range, and visual output resolution of 1 F. 4.3 Tire pressure gauge, 1.0% of indicated value.4.4 Brake lining thermocouples, 10.0 F at 300 F, maximum non-linearity of 20 F over the range and visual output resolution of 5 F, installed per SAE J971, and di

31、splay for brake lining temperature.4.5 Fifth wheel, optical or other equivalent device to measure and display (or record) vehicle speed, 0.5 mph, and stopping distance accuracy of 1% of indicated value, and visual output resolution of 0.1 feet.4.6 A device to indicate first brake control (treadle or

32、 brake pedal) movement, 1.0% of indicated value, and full brake control displacement, or brake control pressure, 1% of indicated value, versus time, capable of 0.1 secondresolution.4.7 Wheel lockup detector or equivalent measuring device providing an electrical indication of wheel rotation (or wheel

33、 lockup) to a continuous recorder or digital data recorder. The lockup detector or measuring system must provide an indication for wheels that lockup above 10 mph, +1 mph, -0 mph. Measure wheel velocity or identify wheel lockup of 1 second duration or more.4.8 Decelerometer or equivalent device to m

34、easure vehicle deceleration rate, 1G range with 0.5 ft/s2 (feet per second per second) accuracy at 32.2 ft/s2, maximum non-linearity of 0.5 ft/s2 over the range, and visual output resolution of 0.5 ft/s2.4.9 Solenoid valve(s) with a 0.5 (+0.1/-0.0) in diameter ports and/or with equivalent exhaust ca

35、pacity to deplete the reservoir with the air compressor charging at engine RPM to attain vehicle test speed.4.10 Pressure, 1.0% of the indicated value, for measuring brake control pressure and system pressure.4.11 Static Retardation Force (Drawbar Pull) Parking Brake TestRefer to SAE J1729 for requi

36、red instrumentation and equipment.4.12 Grade Holding Parking Brake TestRefer to SAE J360 for required instrumentation and equipment.4.13 Weighing scales, 1.0% of indicated weight.4.14 A continuous recorder, i.e., an oscillograph or computer utilizing a digital data acquisition system and/or equivale

37、nt system, to make a permanent, supplemental record of service brake pedal application, parking brake force, deceleration, individual wheel lockup, brake lining temperatures, distance and speed versus time, with the same accuracies as the above direct reading instrumentation or as otherwise indicate

38、d.SAE INTERNATIONAL J1626-2 JAN2017 Page 5 of 245. VEHICLE INFORMATIONThe vehicle information will be contained on Data Sheet 1.6. TEST CONDITIONS AND FACILITIES6.1 Ambient air temperature must be between 32 and 100 F.6.2 Wind velocity should not exceed 15 mph. Stops must not be performed with a tai

39、l wind component in excess of5 mph.6.3 Unless otherwise specified, the transmission shall be in the highest gear appropriate for a speed of 40 mph during burnish snubs and test stops conditioning.6.4 All vehicle openings (doors, windows, hood, etc.) must be closed except as required for instrumentat

40、ion purposes.6.5 Unless otherwise specified, the brake control can be applied and modulated at any desired rate.6.6 Service and emergency stopping distance tests are conducted on a straight 12-foot (+0/-2 inch) wide roadway with a PFC no greater than 0.9 (dry Portland cement concrete or equivalent s

41、urface). The vehicle shall be aligned with the center of the roadway at the beginning of each stop. The roadway shall be marked on both sides.6.7 Stability and control tests are performed on a 12-foot (+0/-2 inch) wide lane curved on a 500-foot radius (to lane centerline) on a surface with a PFC no

42、greater than 0.5. The arc length must be at least 300 foot. A 100-foot approach to the arc is recommended to properly align the vehicle to the lane. Lane boundaries are defined by 12 to 18-inch-high vertical markers (such as cones) on a 20-foot spacing with the inside edge of the markers placed on t

43、he 12-footwide lane boundaries.6.8 Roadway shall be flat with no more than a 1% grade in all directions, including crown.6.9 Tires must be inflated to the pressure specified by the vehicle manufacturer for the gross vehicle weight rating, measured cold (at the beginning of each test day).6.10 Initia

44、l Brake Temperature (IBT)Reference 3.9 for definition. The IBT must be between 150 and 200 F for each stability and control, service, emergency stops and parking brake tests. Warm brakes to the required temperature by making 40 to 20 mph snubs at 10 ft/s2.6.11 Automatic adjusters must remain activat

45、ed for the duration of the test.6.12 Unless otherwise specified, the brakes may be adjusted up to three times during the burnish procedure, at intervals specified by the vehicle manufacturer, in accordance with the vehicle manufacturers recommendation.6.13 Individual brake lining temperatures should

46、 be less than 200 F when being adjusted or checked.6.14 The air system reservoir pressure must be at compressor governor cut out pressure (+0/-10 psi) within 0.2 mile before the beginning of any stability and control and service or emergency brake stop or just prior to any parking brake test.6.15 Ve

47、hicles equipped with an interlocking axle system or front-wheel-drive system capable of being manually engaged by the driver shall be tested with the system disengaged.6.16 Any auxiliary braking device (driveline retarders) capable of being manually engaged by the driver shall be tested with the aux

48、iliary device(s) both engaged and disengaged for the stability and control, service and emergency tests.6.17 The driver may steer as necessary to stay within the lane.6.18 Vehicle speed shall be within +0, -2 mph and stopping distance corrected per SAE J299.SAE INTERNATIONAL J1626-2 JAN2017 Page 6 o

49、f 246.19 The static retardation (drawbar pull) tests shall be conducted per SAE J1729 and SAE J2503.6.20 The grade holding tests shall be conducted per SAE J360 and SAE J293.7. TEST SEQUENCE AIR BRAKE TRUCKS AND BUSES7.1 Burnish (Section 8 and Data Sheet 2).7.2 Stability and control test at GVWR (Section 9 and Data Sheet 3). This test is optional and not required.7.3 Service brake GVWR stopping distance t