BRITISH STANDARD AUTOMOBILE SERIES BS AU 217 1a 1987 Incorporating Amendment No 1 Maximum road speed limiters for motor vehicles — Part 1 Specification for installed requirements UDC 629 11 585 7 BS A[.]
BRITISH STANDARD AUTOMOBILE SERIES BS AU 21 7-1 a:1 987 Incorp orating Am endm ent No Maximum road speed limiters for motor vehicles — Part : Specification for installed requirements UD C 62 1 - 585 BS AU 21 7-1 a:1 987 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Automobile Standards Committee (AUE/- ) to Technical Committee AUE/1 3, upon which the following bodies were represented: British Railways Board Department of Transport (Highways) Freight Transport Association Institute of Road Transport Engineers (Incorporated) London Regional Transport Ministry of Defence National Bus Company Road Haulage Association Ltd Society of Motor Manufacturers and Traders Limited This British Standard, having been prepared under the direction of the Automobile Standards Committee, was published under the authority of the Board of BSI and comes into effect on Amendments issued since publication 29 May 987 © BSI 02- 2000 The following BSI references relate to the work on this standard: Committee reference AUE/1 Draft for comment 86/751 32 DC ISBN 80 91 Amd No Date of issue Comments 5969 June 988 Indicated by a sideline in the margin BS AU 21 7-1 a:1 987 Contents Page Committees responsib le Foreword Inside front cover ii Section General Scope D efinitions Section Performance Speed control on level ground Speed control on descending gradients Failure modes C hecking and calibration Section Installation General Tamper- proofing Power supply 10 Marking Appendix A Test conditions and procedure for demonstrating compliance with speed control requirements Figure — Allowed tolerances of limiter response characteristic Pub lication referred to © BSI 02 - 000 Inside back cover i BS AU 21 7-1 a:1 987 Foreword This Part of BS AU 21 has been prepared under the direction of the Automobile Standards Committee at the request of the Department of Transport Part of BS AU 21 1) deals with requirements relating to the performance of components of speed limiter devices A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application C ompliance with a British Standard does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages to 4, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover 1) ii In preparation © BSI 02- 2000 BS AU 21 7-1 a:1 987 Section General 2.8 kerbside mass Scope This Part of BS AU 21 specifies requirements for the performance and installation of devices designed to limit the maximum road speed of motor vehicles by control of engine power NOTE Unless otherwise referred to in clause , the device is referred to hereafter as the limiter NOTE Permitted tolerances of the system may allow the vehicle to exceed the set speed Definitions For the purposes of this Part of BS AU 21 the following definitions apply 2.1 sensed speed the speed of a motor vehicle as indicated by, or measured from, the speed sensing device used as part of the vehicle’s road speed limiter 2.2 set speed the intended mean vehicle speed when operating in a stabilized condition in accordance with 3.3 It is the mass of a vehicle when it carries: a) no person; and b) a full supply of fuel in its tank, an adequate supply of other liquids incidental to its propulsion and no load other than the loose tools and equipment with which it is normally equipped Section Performance Speed control on level ground 3.1 General When tested in accordance with the procedure given in Appendix A, the requirements given in 3.2 and 3.3 shall be met for each of the test runs Speed shall be sensed to an accuracy of within ± mile/h (± km/h) of actual vehicle speed within the range V to V max 3.2 Transient response (see Figure ) After the set speed is first achieved: a) sensed speed shall not exceed the set speed by more than mile/h (4 km/h); marked on the vehicle and used for calibration b) the rate of change of sensed speed shall not purposes exceed m/s ; and 2.3 c) the stabilized speed conditions specified in 3.3 V the minimum speed declared by the limiter supplier shall be attained within s of first reaching the set speed at which the limiter may be set and meet the 3.3 Stabilized speed (see Figure ) requirements of this standard When stable speed control has been achieved: V a) sensed speed shall not differ from the set speed the maximum speed declared by the limiter supplier b) sensed speed shall not vary by more at which the limiter may be set and meet the than mile/h (3 km/h); and 2.4 max by more than mile/h (3 km/h) ; requirements of this standard c) the rate of change of sensed speed shall not 2.5 exceed m/s limiter supplier in the case of maximum road speed limiters fitted in the course of construction of the vehicle, the vehicle Speed control on descending gradients constructor In all other cases, the limiter When the vehicle, running at its set speed and with manufacturer or his agent the driver’s accelerator at its position of maximum 2.6 limiter calibrator the person responsible for carrying out the final check of the installation and the calibration procedures (see clause ) 2.7 engine the source (or sources) of the vehicle’s motive power travel, is subj ect to an accelerating force due to a down gradient, the limiter shall control speed by restricting the engine power to the limiter’s minimum engine power control setting NOTE The limiter may allow normal accelerator control for the purposes of gear changing Failure modes No malfunction of the limiter shall result in an increase in engine power above that demanded by the position of the driver’s accelerator © BSI 02- 2000 BS AU 21 7-1 a:1 987 Checking and calibration Power supply The limiter supplier shall provide documentation All components necessary for the full function of the describ ing checking and calibration procedures It limiter shall b e energized whenever the vehicle is shall b e possible to check the set speed whilst the being driven vehicle is stationary Marking Section Installation The vehicle shall b e marked with the following a) The name or trade mark of the limiter General calib rator The limiter shall be suitable for installation in the vehicle and shall be installed in accordance with the limiter supplier’s technical instructions b ) The numb er and date of this British Standard, i e BS AU 7- a: 987 c) The set speed, expressed in mile/h, at which the Tamper-proofing The limiter and its connections necessary for its vehicle is calibrated NO TE Set speed may additionally be shown in km/h operation, except those essential for the running of the vehicle, shall b e capab le of b eing protected from any unauthorized adj ustments or the interruption of its energy supply by the attachment of sealing devices and/or the need to use special tools Figure — Allowed tolerances of limiter response characteristic © BSI 02 - 000 BS AU 21 7-1 a:1 987 Appendix A Test conditions and procedure for demonstrating compliance with speed control requirements NOTE Where the limiter is designed for fitting to a range of vehicles, it is recommended that the tests are performed on a “worst case” vehicle, so that the need for additional testing is minimized Examples of worst case situations are as follows a) Maximum engine power to mass ratio of the tested vehicle at Vmax + 10 % b) Lowest overall gearing which allows the set speed to be attained, i.e minimum vehicle speed to engine speed in top gear ratio c) Where the limiter actuator is a separate component in the engine power control, the minimum travel of the actuator between maximum and minimum engine power control positions A.1 Ambient weather conditions Mean wind speed shall be less than m/s with gusts not exceeding 10 m/s The test surface shall be free from standing water, snow or ice A.2 Vehicle condition The vehicle shall be at its kerbside mass, plus the mass of the driver and any observer and test equipment The tyres shall be nominally new, i.e negligible wear, and inflated to the pressure recommended by the vehicle manufacturer for operation at the vehicle’s maximum gross weight The power train components shall be within their normal operating temperature ranges © BSI 02-2000 A.3 Surface condition The test surface shall be suitable to enable stabilized speed to be maintained, and shall be free from uneven patches Gradients shall not exceed % and shall not vary by more than %, excluding camber effects A.4 Instrumentation During the test, the instantaneous actual vehicle speed and sensed speed shall be continuously recorded NOTE It is recommended that the accuracy of recorded measured speeds should be ± 0.2 % against a time base accurate to within 0.3 % NOTE To obtain an accurate measure of vehicle speed, a number of steady speed runs in the range Vmin to Vmax may be needed (using the limiter to provide these steady speeds if convenient) The runs should be performed over a known distance and the time taken to cover this distance recorded From the data collected calculations can then be made of the ratios between recorded speeds and derived speeds, their mean and standard deviations A.5 Procedure Drive the vehicle at a speed equal to 90 % of the set speed, and demand full engine power by moving the accelerator to its position of maximum travel as rapidly as possible Maintain the accelerator at its position of maximum travel for not less than 30 s Conduct the test three times in each gear, which allows the set speed to be reached blank BS AU 21 7-1 a:1 987 Publication referred to BS AU 7, Maxim um ro ad sp eed lim iters fo r m otor vehicles BS AU 7- , 2) Sp ecification fo r p erform ance of com p o nents Referred to in the foreword only © BSI 02 - 000 2) 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