1、 Reference number ISO 16234:2006(E) ISO 2006INTERNATIONAL STANDARD ISO 16234 First edition 2006-12-01 Heavy commercial vehicles and buses Straight-ahead braking on surfaces with split coefficient of friction Open-loop test method Vhicules utilitaires lourds Freinage en ligne droite sur surfaces adhr
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6、ither ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reservedISO 16234:2006(E) IS
7、O 2006 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms, definitions and symbols 1 3.1 Terms and definitions. 1 3.2 Symbols . 1 4 Principle. 2 5 Measuring equipment. 2 6 Variables 2 7 Test conditions . 3 7.1 General. 3 7.2 Test track . 3
8、 7.3 Test vehicle . 4 8 Test method. 4 8.1 Condition and temperature of the brakes 4 8.2 Initial driving conditions 4 8.3 Performance of the braking procedure 4 8.4 Time references 5 9 Data evaluation . 6 9.1 General. 6 9.2 Validity criteria 7 9.3 Time history. 7 9.4 Characteristic values 7 9.5 Furt
9、her additional evaluation 8 Annex A (normative) Test report General data and test conditions 9 Annex B (normative) Test report Presentation of results . 10 Bibliography . 15 ISO 16234:2006(E) iv ISO 2006 All rights reservedForeword ISO (the International Organization for Standardization) is a worldw
10、ide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on th
11、at committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in
12、accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard r
13、equires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16234 was prepared by Tech
14、nical Committee ISO/TC 22, Road vehicles, Subcommittee SC 9, Vehicle dynamics and road-holding ability. ISO 16234:2006(E) ISO 2006 All rights reserved v Introduction The dynamic behaviour of a road vehicle is a most important aspect of active vehicle safety. Any given vehicle, together with its driv
15、er and the prevailing environment, constitutes a unique closed-loop system. The task of evaluating the dynamic behaviour is therefore very difficult, since significant interactions of these driver-vehicle-road elements are each complex in themselves. A description of the behaviour of the road vehicl
16、e must inevitably involve information obtained from a number of tests of different types. Since this test method quantifies only a small part of the complete handling characteristics, the results of this test can only be considered significant for a correspondingly small part of the overall dynamic
17、behaviour. Moreover, sufficient knowledge is not available to correlate overall vehicle dynamic properties with accident prevention. A large amount of work is necessary to acquire sufficient and reliable data on the correlation between accident prevention and vehicle dynamic properties in general, a
18、nd the results of this test in particular. Therefore, it is not possible to use this method and test results for regulation purposes. INTERNATIONAL STANDARD ISO 16234:2006(E) ISO 2006 All rights reserved 1 Heavy commercial vehicles and buses Straight-ahead braking on surfaces with split coefficient
19、of friction Open-loop test method 1 Scope This international Standard describes an open-loop test method for determining vehicle reactions during a straight-line braking manoeuvre on a surface having a split coefficient of friction. It applies to heavy vehicles, i.e. commercial vehicles, commercial
20、vehicle combinations, buses and articulated buses as defined in ISO 3833 (trucks and trailers with maximum weight above 3,5 tonnes and buses and articulated buses with maximum weight above 5 tonnes, according to ECE and EC vehicle classification, categories M3, N2, N3, O3 and O4). The method is limi
21、ted to vehicles in which at least the first unit is equipped with an anti-lock braking system. It is valid for braking with service-brake systems only or in combination with retarders and/or engine brakes. 2 Normative references The following referenced documents are indispensable for the applicatio
22、n of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 611, Road vehicles Braking of automotive vehicles and their trailers Vocabulary ISO 3833, Road vehicles Types Terms
23、and definitions ISO 8855, Road vehicles Vehicle dynamics and road-holding ability Vocabulary ISO 15037-2:2002, Road vehicles Vehicle dynamics test methods Part 2: General conditions for heavy vehicles and buses 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this Inter
24、national Standard, the terms and definitions in ISO 611, ISO 15037-2:2002 and ISO 8855 apply. 3.2 Symbols For the purposes of this International Standard, the symbols in ISO 15037-2:2002 and ISO 8855 apply. ISO 16234:2006(E) 2 ISO 2006 All rights reserved4 Principle The objective of this test method
25、 is to determine the effects on the yaw reaction and the longitudinal acceleration of a vehicle produced by a braking manoeuvre on a straight roadway having a low coefficient of friction on one side and a high coefficient of friction on the other side. Test results are strongly influenced by frictio
26、n coefficients as well as the difference in friction between the left and right side of the course. A large difference between the left- and right-side friction conditions is desirable. Surface properties other than friction coefficient (e.g. roughness, ice or synthetic materials, etc.) that are not
27、 quantified by the friction coefficient alone exert an important influence on the test results. For this reason, it is difficult to establish the surface conditions in a reproducible way. Therefore, comparison of results should only be made for tests done on a given track within a short time period.
28、 It may also be useful to include tests of a reference vehicle. The initial condition for the test is driving in a straight line at constant velocity. The steering wheel is held fixed after the braking manoeuvre is initiated. During the test, the operating functions and vehicle responses are measure
29、d and recorded. Characteristic values are determined from the measured signals. 5 Measuring equipment The measuring equipment, transducer installation and data processing shall be in accordance with ISO 15037-2:2002. 6 Variables The variables of motion used to describe the behaviour of the vehicle s
30、hall be related to the intermediate axis system (X, Y, Z) of the individual vehicle units (See ISO 8855 and ISO 15037-2:2002). The variables that shall be determined for compliance with this International Standard are: longitudinal velocity, x , v yaw velocity of each unit of the test vehicle, i,i 1
31、 , number of units , nn = brake pedal position (for vehicles with air brake systems), brake pedal force (for vehicles with hydraulic brake systems), steering-wheel angle, H , yaw articulation angles, , J i longitudinal acceleration, x , a initial brake temperatures, B,0 . T It is also recommended th
32、at the following variables be determined: supply pressure and brake pressures of interest, p B , rotational velocity of wheels, i, i 1,. n =or equivalent wheel speeds from electronic systems, sideslip angle of the first unit, , 1 lateral acceleration, . y a ISO 16234:2006(E) ISO 2006 All rights rese
33、rved 3 Typical operating ranges of the variables to be determined for this International Standard are shown in Table 1 and in ISO 15037-2:2002. Table 1 Variables, typical operating ranges and recommended maximum errors of variables not listed in ISO 15037-2:2002 Variable Typical operating range Reco
34、mmended maximum errors of the combined transducer and recorder system Brake pedal position 0 mm to 100 mm 1 % Brake pedal force 0 N to 1 000 N 2 % Brake pressure in air systems 0 kPa to 1 500 kPa 15 kPa Brake pressure in hydraulic systems 0 mPa to 30 MPa 0,3 MPa Rotational velocity of wheels 0 /s to
35、 6 000 /s 5 /s Yaw velocity 20 /s 0,2 /s Initial brake temperature 50 C to 200 C 10 C 7 Test conditions 7.1 General The test conditions described in ISO 15037-2:2002, along with the following additions and exceptions, shall apply to this International Standard. Any deviations shall be shown in the t
36、est report. NOTE Large yaw angles and/or large articulation angles may develop during the test. Loss of control is a realistic risk in these tests. For safety, sufficient open space should be provided adjacent to the test surface in case of loss of control. 7.2 Test track The test surface shall have
37、 a high coefficient of friction on one side and a low coefficient of friction on the other side. The difference between the coefficients of friction of the high-friction and low-friction surfaces shall be at least 0,4. This difference and the value of the low-friction coefficient shall be determined
38、 at least once before and once after the test and shall be recorded in the report. Either natural ice or an artificial surface may be used for the low-friction surface. If a lubricated, artificial surface is used, the lubricant shall be evenly distributed prior to each test run. The high-friction su
39、rface shall be as described in ISO 15037-2:2002 except that it may be wet. The following shall be taken into account: 1) that substitute materials may have slip characteristics which differ significantly from that of natural ice; and 2) that the friction of natural ice may change rapidly during a te
40、st series. The split-coefficient track shall be long enough to accommodate the entire period of observation (see 8.4). Both the low- and high-friction portions of the path should also be wide enough to allow testing to determine a reference coefficient of friction for the surface. NOTE There are two
41、 methods to determine friction coefficients: The first method is according to ISO 8349 1 . In the second method, a reference friction coefficient is determined from ABS-braking tests conducted with all wheels of the test vehicle on the surface being measured 2 . A reference coefficient of friction d
42、etermined in this manner only approximates the actual coefficient of friction and is dependent on the performance of the ABS. ISO 16234:2006(E) 4 ISO 2006 All rights reserved7.3 Test vehicle 7.3.1 Tyres The tyre conditions shall be in accordance with ISO 15037-2:2002. 7.3.2 Safety equipment An anti-
43、jack-knife device should be used when executing tests with heavy vehicle combinations. For vehicles with a risk of rollover, outriggers should be used and reported in Annex A. 7.3.3 Loading conditions Tests may be performed at the minimum, maximum or other loading conditions as specified in ISO 1503
44、7-2:2002. 7.3.4 Condition of the brakes Prior to testing, the brakes of the test vehicle shall be burnished. The method of burnishing the brakes shall be reported in Annex A. The brakes of the test vehicle shall not be contaminated with foreign material. NOTE If brake burnishing or testing are condu
45、cted on roads that have been treated with salt or other materials for melting ice, dust from the dried material may be present in the brakes and may change their friction properties. 8 Test method 8.1 Condition and temperature of the brakes The user shall identify an acceptable range for initial bra
46、ke temperature. Prior to each individual run, the brakes shall be warmed up or allowed to cool as required such that the initial brake temperatures are within this range. The initial temperature of the brakes shall be reported in the General Data (Annex A). NOTE Typical initial temperatures of disc
47、brakes are from 50 C to 200 C and for drum brakes from 50 C to 150 C. 8.2 Initial driving conditions The initial driving conditions for the test shall be driving straight ahead as specified in ISO 15037-2:2002 with the addition that the steering wheel be held fixed within 3 during the time interval
48、from t 1to t 2 . For safety reasons, the first test runs should be conducted with an initial longitudinal velocity of 30 km/h. The initial longitudinal velocity, v x0 , of subsequent tests should be increased in increments of 10 km/h up to the maximum velocity of interest. 8.3 Performance of the bra
49、king procedure The test track should be approached in such a way that the border between high- and low-friction surfaces is located in the X-Z plane of symmetry of the vehicle. After reaching the initial driving conditions, the steering wheel shall be held fixed by the test driver or by a mechanical device, and the accelerator pedal shall be released and the brakes applied as quickly as possible to 100 % of full braking and maintained during
