BRITISH STANDARD AUTOMOBILE SERIES BS AU 193a 1990 (Superseding BS AU 193 1983) Specification for Replacement motor cycle and moped exhaust systems BS AU 193a 1990 This British Standard, having been p[.]
BRITISH STANDARD AUTOMOBILE SERIES BS AU 193a: 1990 (Superseding BS AU 193:1 983) Specification for Replacement motor cycle and moped exhaust systems BS AU 193a:1990 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Automobile Standards Policy Committee (AUE/- ) to Technical Committee AUE/9, upon which the following bodies were represented: Automobile Association Consumer Policy Committee of BSI Department of Trade and Industry (Consumer Safety Unit, C A Division) Department of Transport Garage Equipment Association Institute of Trading Standards Administration Motor Agents Association Ltd Motor Cycle Industry’s Association of Great Britain Ltd Royal Automobile Club Society of Motor Manufacturers and Traders Ltd This British Standard, having been prepared under the direction of the Automobile Standards Policy Committee was published under the authority of the Board of BSI and comes into effect on 29 June 990 © BSI 09- 999 First published September 983 Second edition June 990 The following BSI references relate to the work on this standard: Committee reference AUE/9 Draft for comment 89/76935 DC ISBN 0580 18492 Amendments issued since publication Amd No Date of issue Comments BS AU 193a:1990 Contents Page Committees responsible Inside front cover Foreword ii Scope Definitions General Fibrous material Permissible noise level Marking and packaging Appendix A Tests for durability of fibrous material Appendix B Conditioning of exhaust systems containing fibrous material Appendix C Methods of measuring noise levels Figure — Test apparatus for conditioning by pulsation Figure — Arrangement of test for measuring motor cycle noise (vehicle in motion) Table — Maximum noise level for motor cycles or mopeds of type A Table — Maximum noise level for motor cycles or mopeds of type B Table — Maximum noise level for motor cycles or mopeds of type C Table — Distances to be completed during conditioning Table — Number of test bench cycles to be completed by each class of motor cycle or moped Table — One test bench cycle Publications referred to © BSI 09- 999 Inside back cover i BS AU 93 a: 990 Foreword This British Standard has been prepared under the direction of the Automobile Standards Policy Committee with the assistance of the Department of Transport It supersedes BS AU 93: 983, which is withdrawn This revision reflects the Department of Transport’s adoption of the directive 78/1 01 5/EEC, amended by the directives 87/56/EEC and 89/235/EEC, on noise limits and replacement silencers This British Standard differs from the previous edition in that the following items have been included: a) definitions of motor cycle of type C (see 2.3) and moped of type C (see b) maximum noise levels for type C machines (see 6) ; ); c) a method to condition exhaust systems by pulsation (see B ) 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 omp liance with a British S tand ard d oes no t of itself confe r immunity from legal ob ligatio ns S ummary of p age s This document comprises a front cover, an inside front cover, pages i and ii, pages to 8, 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 ii © BSI 09- 999 BS AU 93 a: 990 S cop e This British Standard specifies requirements for the silencing properties of replacement exhaust systems or parts thereof for installation on motor cycles and mopeds It describes methods for measuring the noise emitted by motor cycles and mopeds fitted with these systems and specifies requirements for the durability of fibrous noise absorbing materials 2.6 mo p e d o f typ e C a two- wheeled or three- wheeled vehicle first used on or after April 991 that has a maximum design speed not exceeding 50 km/h, a kerb- side mass not exceeding 250 kg and, if propelled by an internal combustion engine, an engine capacity not exceeding 50 cm where these are used to meet the noise limits It also 2.7 includes requirements for marking these exhaust exhaust syste m systems and their packaging and for the supply of a complete set of components through which the installation literature exhaust gases escape from the engine unit, NOTE The titles of the publications referred to in this standard are listed on the inside back cover D e finitions including those that are necessary to limit the noise caused by the escape of these gases 2.8 fib ro us materials For the purposes of this British Standard the following definitions apply 2.1 mo tor cycle of typ e A a mechanically propelled vehicle, not being an invalid carriage, with less than four wheels and an unladen mass that does not exceed 400 kg, first used between April 970 and 31 March 983 2.2 motor cycle of typ e B a two- wheeled vehicle, with or without sidecar, fitted with an engine intended for use on the road and having a maximum design speed of more than 50 km/h, first used between April 983 and 31 March 991 2.3 motor cycle of typ e C a two- wheeled vehicle, with or without sidecar, fitted with an engine intended for use on the road and having a maximum design speed of more than 50 km/h, first used on or after April 991 materials of a fibrous nature that are placed within the exhaust system to limit the noise caused by the escape of the exhaust gases 2.9 maximum rate d p ow e r sp e e d S) ( the engine speed at which the motor cycle or moped develops maximum power General Exhaust systems shall be tamper- resistant so far as may be compatible with clearly defined maintenance and installation requirements Fib rous mate rial 4.1 Fibrous material shall not be used in the manufacture of exhaust systems unless it is asbestos- free and complies with 4.2 or 4.3 In addition, means shall be provided to keep the fibrous material in place 4.2 The exhaust gases shall not be directed through the fibrous material The fibrous material shall 2.4 have a durability commensurate with the exhaust mop e d o f typ e A system and shall comply with Appendix A a two- wheeled or three- wheeled vehicle first used between April 970 and 31 March 983 that has a maximum design speed not exceeding 50 km/h, a kerb- side mass not exceeding 250 kg and, if propelled by an internal combustion engine, an engine capacity not exceeding 50 cm 2.5 mop ed of typ e B a two- wheeled or three- wheeled vehicle first used 4.3 Exhaust systems containing fibrous absorbent material shall be prepared for testing in accordance with Appendix B, or by removing the fibrous material from the exhaust system Pe rmissib le noise leve l 5.1 The maximum noise level for motor cycles or mopeds of type A, when tested in accordance with C.4.2.2 , shall be as given in Table between April 983 and 31 March 991 that has a maximum design speed not exceeding 50 km/h, a kerb- side mass not exceeding 250 kg and, if propelled by an internal combustion engine, an engine capacity not exceeding 50 cm © BSI 09- 999 BS AU 93 a: 990 Tab le — Maximum no ise leve l for mo tor Marking and p ackaging cycles o r mop e ds o f typ e A E ngine cap acity cm Maximu m no ise Mopeds 77 Motor cycles not exceeding 50 77 le ve l information in a position such that it is readily dB(A) visible when fitted to the motor cycle or moped: a) the number and date of this British Standard and an indication of which of the three tests in Appendix C was used, Motor cycles greater than 50 but not more than 25 82 Motor cycles greater than 25 86 5.2 Each silencer of an exhaust system shall be clearly and indelibly marked with the following i e BS AU 93a: 990 1) /T1 , /T2 or /T3; b) the registered name or trade mark of the exhaust system manufacturer The maximum noise level for motor cycles or The manufacturer’s part number shall also be mopeds of type B, when tested in accordance clearly and indelibly marked on each component of with the exhaust system (excluding fixings) C.4.2.3, shall be as given in Table Tab le — Maximum no ise leve l for mo tor E ngine cap acity Maximu m no ise cm Mopeds a) the number and date of this British Standard and an indication of which of the three tests in Appendix C was used, i e BS AU 93a: 990 78 /T1 , /T2 or /T3; of the exhaust system manufacturer or, in the 80 case of imported goods, those of the UK supplier; c) a list of the specific motor cycle or moped 83 models for which the system is suitable Motor cycles greater than 350 but not more than 500 85 Motor cycles greater than 500 86 5.3 1) b) the registered name or trade mark and address Motor cycles greater than 25 but not more than 350 indelibly marked with the following information: dB(A) Motor cycles greater than 80 but not more than 25 The exhaust system shall be supplied with le ve l 73 Motor cycles not exceeding 80 packaging, or labelling, which shall be clearly and cycle s o r mop e ds o f typ e B In addition, the manufacturer of the exhaust system shall supply instructions that detail the correct method of attachment to the motor cycle or moped, The maximum noise level for motor cycles or instructions for maintenance of the exhaust system mopeds of type C, when tested in accordance and a list of component parts with the with corresponding part numbers (excluding fixings) C.4.2.4, shall be as given in Table Tab le — Maximum no ise leve l for mo tor cycle s o r mop e ds o f typ e C E ngine cap acity Maximu m no ise le ve l cm dB(A) Mopeds 73 Motor cycles not exceeding 80 77 Motor cycles greater than 80 but not more than 75 79 Motor cycles greater than 75 82 1) Marking BS AU 93a: 990 on or in relation to a product represents a manufacturer’s declaration of conformity, i e a claim by or on behalf of the manufacturer that the product meets the requirements of the standard The accuracy of the claim is therefore solely the responsibility of the person making the claim Such a declaration is not to be confused with third party certification of conformity, which may also be desirable © BSI 09- 999 BS AU 93 a: 990 Ap p e ndix A Te sts for durab ility of fib rous material The material shall withstand a temperature of 650 ± °C for h in a muffle furnace without reduction of average fibre length, diameter of fibre or bulk density After heating at 650 ± °C for h in a muffle furnace, at least 98 % of the material shall be retained in a sieve of nominal aperture size 250 4m (60 mesh) complying with BS 410 when tested in accordance with BS 1796 The loss in mass of material shall not exceed 10.5 % after soaking for 24 h at 90 ± °C in synthetic exhaust condensate of the following composition: hydrobromic acid c (HBr) = mol/L 10 mL 10 mL sulphuric acid c (H2SO 4) = mol/L distilled water to make up to 000 mL A A A NOTE The material should be washed in distilled water and dried for h at 105 °C before weighing Ap p e ndix B C onditioning of e xhaust systems containing fib rous mate rial B Ge ne ral Before testing in accordance with Appendix C, exhaust systems containing fibrous material shall either be conditioned in accordance with , or or the fibrous material shall be removed B B B B B C onditioning b y p ulsatio n The exhaust system shall be fitted to the motor cycle or to the engine In the former case, the motor cycle shall be mounted on a roller dynamometer In the latter case, the engine shall be mounted on a test bench The test apparatus shall be fitted at the outlet of the exhaust system B NOTE A typical test apparatus is shown in Figure but other apparatus that provides equivalent results may be used The test equipment shall be adjusted so that the flow of exhaust gases is alternately interrupted and restored 500 times by a rapid-action valve The valve shall open when the exhaust gas back-pressure, measured at least 100 mm downstream of the2) intake flange, reaches a value of between 0.35 bar and 0.40 bar If such a figure is unattainable because of the engine characteristics, the valve shall then open when the gas back-pressure reaches a level equivalent to 90 % of the maximum that can be measured before the engine stops It shall close when this pressure does not differ by more than 10 % from its stabilized value with the valve open The time-delay switch shall be set for the duration of the exhaust gases calculated on the basis of the requirements in Engine speed shall be 75 % of the maximum rated power speed (S) The power indicated by the dynamometer shall be 50 % of the full-throttle power measured at 75 % of S Any drainage holes shall be closed off during the test The entire test shall be completed within 48 h If necessary, a cooling period shall be allowed after each hour B B B B B C o ntinuous road o p e ration The minimum distances to be completed by mopeds and motor cycles during conditioning shall be as given in Table Town driving shall account for 50 ± 10 % of the operation and long-distance runs shall account for the remainder B NOTE Continuous road operation may be replaced by a corresponding track programme Tab le — D istance s to b e comp le te d during co nditioning E ngine cap acity D istance cm3 km Mopeds 000 Motor cycles not exceeding 80 000 Motor cycles greater than 80 000 but not more than 175 000 Motor cycles greater than 175 Town driving and long distance runs shall be alternated on at least six occasions B The complete test programme shall include a minimum of 10 breaks, each of at least h, in order to reproduce the effects of cooling and any condensation B B B B B C o nd itioning o n a test b ench The exhaust system shall be fitted to an engine representative of the type fitted in the motor cycle or moped for which the system is designed, coupled to a dynamometer Conditioning shall consist of the specified number of test bench cycles for the class of motor cycle or moped for which the exhaust system is intended The number of cycles for each class of vehicle shall be as given in Table B B 2) bar = 100 kN/m = 100 KPa © BSI 09-1999 BS AU 93 a: 990 Tab le — Numb er of test b e nch cycles to b e comp lete d b y each class of mo tor cycle o r E ngine cap acity Nu mb e r o f cycle s Mopeds Motor cycles not exceeding 80 Motor cycles greater than 80 but not more than 175 12 Motor cycles greater than 175 Each test bench cycle shall be followed by a break of at least h in order to reproduce the effects of cooling and any condensation Each test bench cycle shall consist of six phases The engine conditions for, and the duration of, each phase shall be as given in Table B Tab le — O ne te st b ench cycle Phase C o nd itio ns Minimu m d u ratio n o f p hase E ngine s E ngine s no t ab o ve ab o ve cm a b c d e f idling speed 25 % load at 75 % of S 50 % load at 75 % of S 100 % load at 75 % of S 50 % load at 100 % of S 25 % load at 100 % of S Total 40 40 30 12 22 2.5 h cm 50 50 10 12 22 2.5 h NOTE During conditioning, at the request of the manufacturer, the engine and silencer may be cooled in order that the temperature recorded, at a point no more than 100 mm from the exhaust port outlet, when the motor cycle or moped is running at 110 km/h or 75 % of S in top gear, whichever is the lesser, is not exceeded The engine and/or motor cycle or moped speed and load are determined to within ± % Ap p e ndix C Me thods of me asuring noise le ve ls C Pre p aration of motor cycle or mop e d for test Where an exhaust system is intended for use on several variants of a motor cycle or moped based on the same engine type and capacity but with differing power outputs, a worst case vehicle shall be selected C.1 mop ed cm NOTE Where a motor cycle is fitted with a sidecar, this should where possible, be removed for the purpose of the test NOTE The worst case vehicle is generally taken as the variant with the highest engine power for that model, but other factors that could affect the overall noise level, such as overall gearing and intake systems, should be taken into account in the selection C Te st site The test site shall consist of a central acceleration area surrounded by a substantially flat area The acceleration area shall be flat and its surface shall be such that rolling noise is consistently low The test site shall be such that hemispherical divergence exists to within ± dB(A) between a sound source at the centre of the test area and microphone, i.e the sound radiation is within ± dB(A) of the theoretical value for a point source on a plane reflecting surface C.2.1 NOTE This condition is satisfied if there are no large objects that reflect sound, such as fences, rocks, bridges or buildings, within 50 m of the centre of the test area The surface of the site shall be made of hard material, such as concrete or asphalt, within a minimum radius of 10 m around the centre of the test site and shall be free of powdery snow, tall grass, loose soil and cinders The microphone shall not be obstructed in any way that could affect the sound field, and no person shall stand between the microphone and the sound source The observer carrying out the measurements shall so position himself as not to affect the readings of the measuring instrument Measurements shall not be taken in unfavourable meterological conditions nor in gusting winds For measurements, the A-weighted sound level (see BS 5969) of sound sources other than those of the motor cycle or moped to be tested or of wind effects shall be at least 10 dB(A) below the sound level produced by the vehicle C.2.2 C.2.3 NOTE A suitable windscreen may be fitted to the microphone The motor cycle or moped shall comply with provided account is taken of its effect on the sensitivity and the manufacturer’s specification for the model for directionalthatcharacteristic of the microphone which the exhaust system is intended with the exception of any alterations necessary to Precision sound level meter, complying at least accommodate the item(s) under test with the for type of BS 5969, or If the motor cycle or moped is fitted with fans complyingrequirements with the specification of the meter for the with an automatic actuating mechanism, this original motor cycle’s approval procedure system shall not be interfered with For vehicles having more than one driven wheel, only the drive for normal road operation shall be used C.1 C Ap p aratus C.3.1 C.1 © BSI 09-1999 BS AU 93 a: 990 C Proced ure C.4.1 Method of measurement Before any measurements are made, bring the motor cycle or moped engine to the normal operating temperature Carry out acoustic measurements using the fast response time and the A-weighting curve At the beginning and end of each series of measurements, calibrate the sound level meter in accordance with the manufacturer’s instructions using a suitable sound source, e.g a pistonphone Using the precision sound level meter ( ), measure the maximum sound level in A-weighted decibels [dB(A)] as the motor cycle or moped is driven between lines AA and BB (see Figure 2) Ignore any peak value that is obviously out of character with the general sound level shown on the instrument Locate the microphone on reference line PP, 7.5 ± 0.2 m from reference line CC (see Figure 2) of the track and 1.2 ± 0.1 m above the ground Ensure that the axis of maximum sensitivity is horizontal and perpendicular to the path of the vehicle (line CC) Ensure that the test motor cycle or moped approaches line AA at an initial steady speed as described in When the front end of the vehicle reaches line AA, open the throttle as quickly as possible to the fully open position Maintain this position until the rear end of the vehicle reaches line BB Return the throttle as quickly as possible to the idle position C.3.1 C.4.2 C.4.2 Approach condition C.4.2.1 C 4.2.3.1 C.4.2.3.1 C.4.2.4.1 C.4.2.4.1 C.4.2.4.1 © BSI 09-1999 Ensure that the motor cycle or moped approaches line AA at a steady speed that is the lowest of the following: a) a speed corresponding to 75 % of the maximum rated power speed (S); b) a speed corresponding to 75 % of the engine speed permitted by the governor; c) a road speed of 50 km/h Determine the engine and/or motor cycle or moped speed to within ± % If the motor cycle or moped is fitted with a non-automatic gearbox with no more than four speeds, use second gear If it is fitted with a non-automatic gearbox with more than four speeds, use third gear Do not engage auxiliary step-up gears (“overdrive”) If the vehicle is fitted with an auxiliary reduction gearbox, use the latter with a gear ratio that allows the highest vehicle speed If the motor cycle or moped is fitted with an automatic gearbox with a selector having alternative forward drive positions, test in the position that results in the highest sound level on the vehicle between lines AA and BB Exclude the selector position that is used only for engine braking or for parking or similar slow manoeuvres of the motor cycle or moped If the transmission is provided with full manual override, carry out an additional test in accordance with If the motor cycle or moped is fitted with a manually operated auxiliary reduction gearbox, use this in the ratio allowing the highest vehicle speed C.4.2.2.1 C.4.2.2.2 C.4.2.2.3 C.4.2.2.2 General In the case of an exhaust system designed for use on a motor cycle or moped of type A, ensure that the test machine approaches line AA in accordance with , or , as requested by the exhaust system manufacturer In the case of an exhaust system designed for use on a motor cycle or moped of type B, ensure that the test machine approaches line AA in accordance with or In the case of an exhaust system designed for use on a motor cycle or moped of type C, ensure that the test machine approaches line AA in accordance with For all measurements, drive the motor cycle or moped in a straight line over the acceleration section in such a way that the longitudinal median plane of the machine is as close as possible to line CC Measure systems with adjustable elements that could affect their efficiency in the conditions of maximum noise level C 4.2.2.1 Test 1: measurement of the permissible noise level from a motor cycle or moped of type A C.4.2.2 C Test 2: measurement of the permissible noise level from a motor cycle or moped of type B NOTE At the request of the exhaust system manufacturer this method may be used for motor cycles or mopeds first used prior to April 1983 Ensure that the motor cycle or moped approaches line AA at a steady speed that is one of the following: a) less than 50 km/h, the speed of rotation of the engine being equal to 75 % of S; b) 50 km/h, the speed of rotation of the engine being between 50 % and 75 % of S; c) more than 50 km/h, the speed of rotation of the engine being equal to 50 % of S Determine the engine and/or motor cycle or moped speed to within ± % C.4.2.3.1 BS AU 93 a: 990 If the motor cycle or moped is fitted with a non-automatic gearbox with not more than four ratios, engage second gear If the motor cycle or moped is fitted with a non-automatic gearbox with more than four ratios: a) engage the third gear for vehicles with a cubic capacity of not more than 350 cm3 b) engage the second gear for vehicles with a cubic capacity of more than 350 cm3 If the motor cycle or moped is fitted with an automatic gearbox with a selector, ensure that the selector is in the position immediately below the position corresponding to the maximum speed of the vehicle C.4.2.3.2 Test 3: measurement of the permissible noise level from a motor cycle or moped of type C C.4.2.4 NOTE At the request of the exhaust system manufacturer this method may be used for motor cycles or mopeds first used prior to April 1991 Ensure that the motor cycle or moped approaches line AA at a steady speed that is one of the following: a) for machines fitted with a non-automatic gearbox, the lowest of: 1) 50 km/h; 2) an engine speed corresponding to 75 % of S; b) for machines fitted with an automatic gearbox without manual override, whichever produces the highest sound level: 1) 50 km/h; 2) 40 km/h; 3) 30 km/h; 4) 75 % of its maximum road speed if this value is lower; c) for machines fitted with an automatic gearbox with a manual override: 1) less than 50 km/h, the speed of rotation of the engine being equal to 75 % of S; or 2) 50 km/h, the speed of rotation of the engine being less than 75 % of S; if a change-down to first gear occurs, approach at a speed of up to 60 km/h sufficient to avoid such a change-down Determine the engine and/or motorcycle or moped speed to within ± % If the motor cycle or moped is fitted with a non-automatic gearbox with not more than four ratios, engage second gear If the motor cycle or moped is fitted with a non-automatic gearbox with more than four ratios: a) for vehicles with a cubic capacity of not more than 175 cm3, engage third gear; C.4.2.4.1 C.4.2.4.2 b) for vehicles with a cubic capacity of more than 175 cm3, engage second gear and then repeat the test engaging third gear If, during any test conducted in second gear, the engine speed is more than 110 % of S as the machine approaches line BB, the test is to be conducted in third gear If the motor cycle or moped is fitted with an automatic gearbox with manual override, ensure that the selector is in the highest position consistent with the avoidance of an automatic change-down (kick-down) C Recording o f results For a motor cycle or moped tested in accordance with , measurements shall be made on at least three runs in each direction The readings on a given side of the vehicle shall be within dB(A) If the range of readings on any one side exceeds dB(A), the whole test shall be repeated The arithmetic mean of each set of three readings on either side of the motor cycle or moped shall be calculated The highest average, to the nearest decibel shall be taken to be the sound level of the vehicle For a motor cycle or moped tested in accordance with at least two measurements shall be taken either side of the vehicle Readings shall be rounded to the nearest decibel Only measurements having variations in two consecutive tests on the same side of the machine of less than or equal to dB(A) shall be valid To take into account inaccuracies in the measurements, the results of each measurement shall be arrived at by deducting dB(A) from the meter reading The highest of the four results recorded shall be taken to be the sound level of the vehicle For a motor cycle or moped tested in accordance with at least two measurements shall be taken either side of the vehicle If the provisions of b) apply, each measurement shall be taken to be the mean of two consecutive readings taken with the second gear and then the third gear engaged Readings shall be rounded to the nearest decibel Only measurements having variations in two consecutive tests on the same side of the machine of less than or equal to dB(A) shall be valid To take into account inaccuracies in the measurements, the results of each measurement shall be arrived at by deducting dB(A) from the meter reading The highest of the four results recorded shall be taken to be the sound level of the vehicle C.5.1 C.4.2.2 C.5.2 C.4.2.3 C.5.3 C.4.2.4 C 4.2.4.2 © BSI 09-1999 BS AU 193a:1990 Figure — Test apparatus for conditioning by pulsation © BSI 09- 999 BS AU 93a:1 990 Figure — Arrangement of test for measuring motor cycle noise level (vehicle in motion) © BSI 09- 999 BS AU 193a:1990 Publications referred to BS 41 , Sp ecification for test siev es BS 96, Method of test siev ing BS 69 , Sp ecificatio n for so und lev el m etres © BS I 9- 99 BS AU 193a: 1990 BSI — British Standards Institution BS I is the indep endent national b ody res p ons ib le for p rep aring Britis h S tandards It p res ents the UK view on s tandards in E urop e and at the international level I t is incorp orated b y Royal C harter Revisions Britis h S tandards are up dated b y amendment or revis ion Us ers of Britis h S tandards should make s ure 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