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1、BRITISH STANDARD BS ISO 23671:2006 Passenger car tyres Method for measuring relative wet grip performance Loaded new tyres ICS 83.160.10 ? Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 23671:2006 This British Standard was published
2、under the authority of the Standards Policy and Strategy Committee on 31 March 2006 BSI ISBN 0 580 47989 7 National foreword This British Standard reproduces verbatim ISO 23671:2006 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Comm
3、ittee AUE/4, Tyres and wheels for motor vehicles, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be
4、found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are r
5、esponsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and ke
6、ep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 16, an inside back cover and a back cover. The BSI copyright
7、notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 23671:2006(E) INTERNATIONAL STANDAR
8、D ISO 23671 First edition 2006-02-15 Passenger car tyres Method for measuring relative wet grip performance Loaded new tyres Pneumatiques pour voitures particulires Mthode de mesure de ladhrence relative sur revtement mouill Pneumatiques neufs en charge BS ISO 23671:2006 Licensed Copy: sheffieldun s
9、heffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 1 4 Methods for me
10、asuring wet grip . 2 5 General test conditions 2 6 Measurement of tyre wet grip on a standard vehicle 4 7 Test method using a trailer or a tyre test vehicle 9 Annex A (informative) Example test report of wet grip index 14 Bibliography. 16 BS ISO 23671:2006 Licensed Copy: sheffieldun sheffieldun, na,
11、 Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical
12、 committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with
13、 the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Intern
14、ational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires 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
15、be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 23671 was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves, Subcommittee SC 3, Passenger car tyres and rims. BS ISO 23671:2006 Licensed Copy: sheffieldun sheffieldun
16、, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 Passenger car tyres Method for measuring relative wet grip performance Loaded new tyres 1 Scope This International Standard specifies the method for measuring relative wet grip braking performance index to a reference under loade
17、d conditions for new tyres for use on passenger cars on a wet-paved surface. The methods developed are meant to reduce variability. The use of a reference tyre is necessary to limit the variability of the testing procedures. This International Standard applies to all passenger car tyres. 2 Normative
18、 references The following referenced documents are indispensable for the application 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 4000-1, Passenger car tyres and r
19、ims Part 1: Tyres (metric series) ASTM E 303:1993 (re-approved in 1998), Standard Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester ASTM E 501, Standard Specification for Standard Rib Tire for Pavement Skid-Resistance Tests ASTM E 965, Standard Test Method for
20、 Measuring Pavement Macrotexture Depth Using a Volumetric Technique ASTM E 1136, Standard Specification for a Radial Standard Reference Test Tire NF P 98-216-2:1994, Test relating to pavements. Measurement of the macrotexture Part 2: Method for measuring, without contact 3 Terms and definitions For
21、the purposes of this document, the following terms and definitions apply. 3.1 test run single pass of a loaded tyre over a given test surface 3.2 candidate tyre (set) test tyre (set) that is part of an evaluation programme BS ISO 23671:2006 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:1
22、9:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 3.3 reference tyre (set) special test tyre (set) that is used as a benchmark in an evaluation programme NOTE These tyres usually have carefully controlled design features to minimize variation. 3.4 control tyre (set) tyre (set) that is part of an eva
23、luation programme; it is an intermediate tyre (set) which is used when the candidate tyre and the reference tyre cannot be directly compared on the same vehicle 3.5 braking force of a tyre longitudinal force, expressed in newtons, resulting from braking torque application 3.6 braking force coefficie
24、nt of a tyre ratio of braking force to vertical load 3.7 peak braking force coefficient of a tyre maximum value of tyre braking force coefficient that occurs prior to wheel lockup as the braking torque is progressively increased 3.8 lockup of a wheel condition of a wheel in which its rotational velo
25、city about the wheel spin axis is zero and it is prevented from rotating in the presence of applied wheel torque 3.9 vertical load normal reaction of the tyre on the road 3.10 tyre test vehicle dedicated vehicle which has instruments to measure the vertical and the longitudinal forces on one tyre du
26、ring braking 4 Methods for measuring wet grip Relative wet grip braking performance for loaded passenger car new tyres travelling straight ahead on a wet, paved surface can be measured by one of the following methods: vehicle method consisting of testing a set of tyres mounted on a standard vehicle;
27、 test method using a trailer or a tyre test vehicle equipped with the test tyres. 5 General test conditions 5.1 Track characteristics The surface shall have a uniform grade of not more than 2 % and shall not deviate more than 6 mm when tested with a 3 m straight edge. The test surface shall have a p
28、avement of uniform age, composition, and wear. The test surface shall be free of loose material and foreign deposits. BS ISO 23671:2006 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 It shall be a dense asphalt surface. The maximum chippi
29、ng size shall be from 8 mm to 13 mm. The sand depth measured as specified in NF P 98-216-2 and ASTM E 965 shall be (0,7 0,3) mm. In order to verify the frictional properties of the surface, a) or b) shall be used. a) British Pendulum Number (BPN) method The averaged British Pendulum Number (BPN) (Br
30、itish Pendulum Tester method as specified in ASTM E 303 using the pad as specified in ASTM E 501) shall be (50 10) BPN after temperature correction. Pad rubber component formulation and physical properties are to be requested. BPN shall be corrected by the wetted road surface temperature. Unless tem
31、perature correction recommendations are indicated by the British pendulum manufacturer, the following formula can be used: 2 temperature correction0,001 8 0,34 6,1tt= + where t is the wetted road surface temperature in degrees Celsius. Effects of slider pad wear: The pad shall be removed for maximum
32、 wear when the wear on the striking edge of the slider reaches 3,2 mm in the plane of the slider or 1,6 mm vertical to it in accordance with ASTM E 303:1993, 5.2.2 and Figure 3. Checking track surface BPN constancy for the measurement of wet grip on a standard vehicle: To decrease the dispersion of
33、test results, the BPN values of the track should not vary over the entire stopping distance. The operation shall be repeated five times at each point of the BPN measurement. So the BPN shall be measured every 10 m on the braking lane and the coefficient of variation of the BPN averages shall not exc
34、eed 10 %. b) Standard Reference Test Tyre (SRTT) method The average peak braking coefficient (peak,ave) of the ASTM E 1136 SRTT1) (see Clause 7) shall be 0,7 0,1 at 65 km/h. For the trailer method, testing is run in such a way that braking occurs within 2 m of where the surface was examined. The ave
35、rage peak braking coefficient (peak,ave) of the ASTM E 1136 SRTT shall be corrected by the wetted road surface temperature: ()temperature correction0,003 520t= where t is the wetted road surface temperature in degrees Celsius. 5.2 Wetting conditions The surface may be wetted from the track-side or b
36、y a wetting system incorporated in the test vehicle or the trailer. If “external watering” is used, water the test surface at least half an hour prior to testing in order to equalize the surface temperature and water temperature. External watering should be supplied continuously throughout testing.
37、1) The size of the ASTM E 1136 SRTT is P195/75R14. BS ISO 23671:2006 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 For the whole testing area, the water depth shall be between 0,5 mm and 1,5 mm. 5.3 Atmospheric conditions The wind condit
38、ions shall not interfere with wetting of the surface (wind-shields are allowed). The wetted surface temperature shall be between 5 C and 35 C and shall not vary during the test by more than 10 C. 5.4 Reference tyre The specifications of the SRTT are defined in ASTM E 1136. 6 Measurement of tyre wet
39、grip on a standard vehicle 6.1 Principle The test method covers a procedure for measuring the deceleration performance of passenger car tyres during braking, using an instrumented passenger car having an Antilock Braking System (ABS). Starting with a defined initial speed, the brakes are applied har
40、d enough on four wheels at the same time to activate the ABS. The average deceleration is calculated between two defined speeds, with an initial speed of 80 km/h and a final speed of 20 km/h. When the braking system is not operating automatically, a minimum of 600 N pedal effort is required. 6.2 Equ
41、ipment 6.2.1 Vehicle Permitted modifications using a standard-model passenger car equipped with an ABS are as follows: those allowing the number of tyre sizes that can be mounted on the vehicle to be increased; those permitting automatic activation of the braking device to be installed. Any other mo
42、dification of the braking system is prohibited. 6.2.2 Measuring equipment The exposed portions of the system shall tolerate 100 % relative humidity (rain or spray) and all other conditions, such as dust, shock and vibrations, which may be encountered in regular operation. The vehicle shall be fitted
43、 with a sensor suitable for measuring speed on a wet surface and distance covered between two speeds. To measure vehicle speed, a fifth wheel or non-contact speed-measuring system should be used. The following tolerances shall be respected: for speed measurement: 1 % or 0,5 km/h, whichever is greate
44、r; for distance: 1 101 m. The measured speed or the difference between the measured speed and the reference speed for the test should be displayed inside the vehicle, so that the driver can adjust the speed of the vehicle. A data acquisition system can be used for storing the measurements. BS ISO 23
45、671:2006 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 14:19:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 5 6.3 Conditioning of the test track Condition the pavement by conducting at least ten test runs with tyres not involved in the test programme at 90 km/h (which is higher than the init
46、ial test speed to guarantee that a sufficient length of track is conditioned). 6.4 Test speed measurement requirements The speed at the start of braking shall be (85 2) km/h. The average deceleration shall be calculated between 80 km/h and 20 km/h. 6.5 Tyres and rims 6.5.1 Tyre preparation and break
47、-in Trim the test tyres to remove all protuberances on the tread surface caused by mould air vents or flashes at mould junctions. Fit the test tyres on rims in accordance with ISO 4000-1 using conventional mounting methods. Ensure proper bead seating by the use of a suitable lubricant. Excessive use
48、 of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. Place the fitted test tyres in a location such that they all have the same ambient temperature prior to testing, and shield them from the sun to avoid excessive heating by solar radiation. For tyre break-in, perform tw
49、o braking runs. 6.5.2 Tyre load The static load on each front axle tyre shall lie between 60 % and 90 % of the tested tyre load capacity. Tyre loads on the same axle should not differ by more than 10 %. 6.5.3 Tyre inflation pressure On the front and rear axles, the inflation pressures shall be 220 kPa (for standard- and extra-load versions). Check the tyre pressure just prior to testing at ambient temperature. 6.6 Procedure First, mount the set of re