1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58with ABS Open-loop test methodICS 43.040.40Passenger cars Stopping distance at straight-line brakin
2、g BRITISH STANDARDBS ISO 21994:2007BS ISO 21994:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007ISBN 978 0 580 55324 0Amendments issued since publicationAmd. No. Date CommentsCompliance with a British Standard cannot
3、confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of ISO 21994:2007. The UK participation in its preparation was entrusted to Technical Committee AUE/15, Safety related to vehicles.A list of organizations represented on this committee can be obtai
4、ned on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Reference numberISO 21994:2007(E)INTERNATIONAL STANDARD ISO21994First edition2007-06-15Passenger cars Stopping distance at straig
5、ht-line braking with ABS Open-loop test method Voitures particulires Distance darrt de freinage en ligne droite avec ABS Mthode dessai en boucle ouverte BS ISO 21994:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 1 5
6、Variables 2 5.1 Reference system . 2 5.2 Variables to be measured 2 6 Measuring equipment. 2 6.1 Description 2 6.2 Transducer installation 3 6.3 Calibration . 3 6.4 Data processing 3 7 Test conditions . 3 7.1 General test conditions 3 7.2 General data 4 7.3 Test track . 4 7.4 Environmental condition
7、s 4 7.5 Test vehicle . 4 8 Test procedure 5 8.1 Test preparation 5 8.2 Measurements. 6 9 Data evaluation and presentation of results 7 9.1 General. 7 9.2 Nomenclature of distances and decelerations 8 9.3 Determination of normalized stopping distance sA100,norm. 8 9.4 Determining of ABS-braking dista
8、nce sL90,norm(100) (optional) . 10 9.5 Determination of normalised build-up distance sF10,norm(optional) 10 Annex A (informative) Test report General data. 11 Annex B (informative) Test report Test conditions and results 12 Annex C (informative) Test sequence, specific terms and background informati
9、on 14 Annex D (normative) Method for determination of F_ABS 18 Annex E (normative) Requirements for measurements and measuring equipment. 22 Annex F (normative) Structure of the stopping distance calculation. 24 Bibliography . 25 BS ISO 21994:2007iv Foreword ISO (the International Organization for S
10、tandardization) is a worldwide 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 ri
11、ght 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 the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Internationa
12、l 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 International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as
13、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 be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO
14、 21994 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 9, Vehicle dynamics and road-holding ability. BS ISO 21994:2007vIntroduction The stopping distance of a road vehicle is an important part of vehicle performance and active vehicle safety. Any given vehicle, together
15、 with its driver and the prevailing environment, constitutes a unique closed-loop system. The task of determining the stopping distance is therefore very difficult, since there is a significant interaction between these driver-vehicle-environment elements, each of which is complex in itself. Test co
16、nditions and tyres have a strong influence on test results. Therefore, only vehicle stopping distances obtained under comparable test and tyre conditions are comparable to one another. BS ISO 21994:2007blank1Passenger cars Stopping distance at straight-line braking with ABS Open-loop test method 1 S
17、cope This International Standard specifies an open-loop test method to determine the stopping distance of a vehicle during a straight-line braking manoeuvre, with the Anti-lock Braking System (ABS) fully engaged. This International Standard applies to passenger cars as defined in ISO 3833 and light
18、trucks. This International Standard specifies a reference method and is especially designed to ensure high repeatability. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undate
19、d references, the latest edition of the referenced document (including any amendments) applies. ISO 3833, Road vehicles Types Terms and definitions ISO/TR 8349, Road vehicles Measurement of road surface friction ISO 8855, Road vehicles Vehicle dynamics and road-holding ability Vocabulary ISO 15037-1
20、:2006, Road vehicles Vehicle dynamics test methods Part 1: General conditions for passenger cars 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 8855 and the general conditions given in ISO 15037-1 shall apply. For specific terms see Annex C. 4 Princ
21、iple This International Standard specifies a method to determine the braking distances characterizing the deceleration build-up phase at the beginning of a braking manoeuvre and at full braking until the vehicle comes to a standstill. The driving situation represents an emergency or panic braking ph
22、ase (pushing the brake pedal with a very high activation speed) during straight-ahead driving on an even and dry road surface with a high coefficient of friction. BS ISO 21994:20072 Using this International Standard, three results become available: stopping distance from initial brake pedal contact
23、until vehicle comes to a standstill (sA100); ABS-braking distance describing the distance travelled under full ABS-controlled braking from 90 km/h until vehicle comes to a standstill (sL90); and estimation of the build-up distance from initial brake pedal contact until a velocity reduction of 10 km/
24、h is achieved (sF10). Apart from the technical equipment and especially the braking characteristics of the vehicle, the distance travelled after the first pedal contact very strongly depends on the individual pedal actuation of the driver. To minimize this influence, this International Standard spec
25、ifies rules for brake pedal actuation. To achieve reproducible, reliable and comparable measurement results, a multitude of further test conditions shall be observed. Measurement results can only be compared if measurements took place under identical conditions. In particular, this means: same track
26、 (see also Annex C); and very similar weather and ambient conditions (wind, temperature, etc.). 5 Variables 5.1 Reference system The reference system specified in ISO 15037-1 shall apply. 5.2 Variables to be measured The following variables shall be measured: longitudinal velocity: (vX); time of bra
27、ke pedal actuation: (t0); longitudinal distance: (s); brake pedal actuation force: (FP). The variable longitudinal velocity is defined in ISO 8855. 6 Measuring equipment 6.1 Description All variables shall be measured by means of appropriate transducers, and their time histories shall be recorded by
28、 a multi-channel recording system. Alternatively, data measured may be recorded and processed directly in a calculation unit of the measuring system without the possibility to access time histories. Typical operating ranges, and recommended maximum errors of the transducer and recording system, are
29、given in Table 1. If initial longitudinal velocities different from 100 km/h are chosen, the following operating ranges shall be changed accordingly, but maximum errors shall be unchanged. BS ISO 21994:20073Table 1 Variables, their typical operating ranges and recommended maximum errors Additions an
30、d exceptions to ISO 15037-1 Variable Typical operating range Recommended maximum error of the combined transducer and recorder system Initial longitudinal velocitya102 km/h 98 km/h 0,5 km/h Longitudinal velocityb93 km/h 5 km/h 0,5 km/h Longitudinal distance 100 m 1 % (u 50 m) 0,50 m ( 50 m) Brake fo
31、rce trigger u 10 N (triggering point) 5 N Brake pedal actuation forcec0 N 1 000 N (max. 1 500 N) 2 % aDetermined in averaging interval 0,2 s-0 s before brake pedal contact. bDeviations of the measured velocity are normally found in the transition area from steady state driving to full braking. cIt i
32、s recommended to use a lateral force compensated brake force transducer. The trigger signal for brake pedal contact shall be activated at a pedal force of 10 N or less. The time delay of the trigger signal shall be 5 ms or less. If the pedal force transducer does not fulfil this specification, it is
33、 recommended to use a contact switch on the brake pedals step pad. To monitor test preparation (run-in) and test conditions, the following measuring devices are required: brake (disc/drum or pad/lining) temperature sensor; and device for measuring and displaying vehicle deceleration (run-in). 6.2 Tr
34、ansducer installation The requirements of 4.2 of ISO 15037-1:2006 shall apply. In addition, it shall be ensured that transient vehicle pitch angle changes during braking do not affect the measurement of the velocity and distance variables for the chosen transducer system. 6.3 Calibration All transdu
35、cers shall be calibrated according to the manufacturers instructions. The transducer manufacturers recommended application software and firmware version shall be used. If parts of the measuring system used can be adjusted, such calibration shall be performed immediately before the beginning of the t
36、ests. For a detailed procedure of calibration, see Annex E. 6.4 Data processing The recording system and data processing requirements contained in 4.3 of ISO 15037-1:2006 shall apply. 7 Test conditions 7.1 General test conditions The test conditions shall be in accordance with Clause 5 of ISO 15037-
37、1:2006, unless otherwise specified in this International Standard. BS ISO 21994:20074 7.2 General data General data on the test vehicle and test conditions shall be recorded as specified in ISO 15037-1:2006, 5.4.1 and Annexes A and B, with the additions of the braking system and tyre data as listed
38、in Annex A of this International Standard. 7.3 Test track All tests shall be carried out on a smooth, clean, dry and uniform paved road surface. The gradient of the test surface to be used shall not exceed 1 % longitudinal inclination and 2 % transversal inclination when measured over any distance i
39、nterval between that corresponding to the vehicle track and 25 m. It is recommended to use a lane width of 3,5 m or more. The friction coefficient of the test surface shall be a minimum of 0,9, and its variation shall not exceed 5 % over the length of the test surface. These requirements are general
40、ly fulfilled on concrete and rough asphalt surfaces. (See also C.2.2 and C.2.3.) 7.4 Environmental conditions The weather conditions shall remain unchanged during a sequence of measurements. The ambient wind velocity (regardless of the wind direction) shall either not exceed 3 m/s or, if the wind ve
41、locity ranges between 3 m/s and 5 m/s maximum, an equal number of measurements specified shall be carried out in both driving directions. The total number of measurements shall remain the same (see 8.2.5). The ambient temperature shall be between + 5 C and + 35 C and its variation during a sequence
42、of measurements shall not exceed 10 C. The surface temperature of the test track shall be between + 10 C and + 40 C and its variation during a sequence of measurements shall not exceed 10 C. Additionally, the variation in surface temperature along the length of the test track (e.g. due to changes fr
43、om sunlit to shaded areas) shall not exceed 10 C. Measurements performed within acceptable temperature ranges as specified above can only be compared if, additionally, the temperature difference between one another is below 10 C. Special tests with specific structural components such as tyres may re
44、quire much smaller tolerance ranges in order to become comparable. 7.5 Test vehicle 7.5.1 General vehicle condition The condition of the test vehicle shall be in accordance with the vehicle manufacturers specifications, particularly with respect to the complete brake system, the suspension geometrie
45、s, power train (e.g. differentials and locks) configuration and tyres used. 7.5.2 Tyres Generally, all measurements shall be conducted with summer tyres. For a general tyre condition, new tyres shall be fitted on the test vehicle according to the manufacturers specifications. If not specified otherw
46、ise by the tyre manufacturer, they shall be run in on the test vehicle for at least 150 km on a road surface with high friction or on an equivalent vehicle without excessively harsh use, for example braking, acceleration, cornering, hitting the kerb, etc. Therefore, longitudinal and lateral accelera
47、tions shall not exceed 3 m/s2during run-in. After run-in the tyres shall be used at the same vehicle locations for the tests. BS ISO 21994:20075The existing tread depth and the type of wear have an impact on the length of the braking distance (see C.2.5). Therefore, when comparing vehicles or tyres,
48、 new tyres shall be used for the measurements as a general rule. If no new tyres are used, the tyre parameters and tread widths should show a steady wear condition with a tread depth of at least 90 % of the original value across the whole breadth of the tread and around the whole circumference of th
49、at of the new tyre. Tyres shall be manufactured not more than one year before the test. The date of manufacturing (DOT-stamp) shall be noted in the presentation of test conditions (see Annex A). Tyres shall be inflated to the pressure as specified by the vehicle manufacturer for the test vehicle configuration. The tolerance for setting the cold inflation pressure is 5 kPa for pressures up to 250 kPa and 2 % for pressure above 250 kPa. Tyre data, the infl
