1、BRITISH STANDARD BSISO 8893:1997 Forestry machinery Portable brush cutters and grass trimmers Engine performance and fuel consumption ICS65.060.70; 65.060.80BSISO8893:1997 This British Standard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority
2、of the Standards Board and comes intoeffect on 15 March 1998 BSI 04-1999 ISBN 0 580 29658 X National foreword This British Standard reproduces verbatim ISO 8893:1997 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee AGE/29, Fo
3、restry machinery, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developmen
4、ts and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue
5、under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correc
6、t application. Compliance 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, theISO title page, page ii, pages 1 to 3 and a back cover. This standard has been updated (see c
7、opyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSISO8893:1997 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword ii Introduction 1 1 Sco
8、pe 1 2 Normative reference 1 3 Apparatus 1 4 Test conditions 1 5 Conditions of measurement 2 6 Operating method 2 7 Test report 2 Figure 1 Examples of characteristic curves 3ii blankBSISO8893:1997 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) is a worldwide federat
9、ion 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 that committe
10、e. 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. Draft International Standards adopted by the techn
11、ical 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. International Standard ISO 8893 was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture and f
12、orestry, Subcommittee SC17, Manually portable forest machinery. This second edition cancels and replaces the firt edition (ISO 8893:1989), of which it constitutes a technical revision (see Introduction). Descriptors: Agricultural machinery, coating processes, portable equipment, mechanically-operate
13、d devices, saws, brush cutters, grass-trimmers, propulsion engines, internal combustion engines, tests, performance tests, determination, fuel consumption.BSISO8893:1997 BSI 04-1999 1 Introduction The first edition of ISO 8893 was elaborated based on ISO 7293:1983. Extensive measurement experiences
14、not only at manufacturers but also at test stations revealed that the test procedure given in ISO 8893:1989 is no longer necessary due to advanced developments. The test procedure given in ISO 8893:1989 required an intermittent test run repeated over a specified range of rotational frequency. Within
15、 this range, one data print had to be recorded at every 10 s 1increment. The necessary reading had to be recorded within 50 s to 60 s after the application of full load. This sequence was then followed by 1 min of running with idling. According to gathered experiences, this intermittent procedure ha
16、s several disadvantages: the repeatability is poor due to the unstable test conditions: the temperature, and therefore the performance, is not steady within the defined time frame in which the test data have to be recorded; some machines have problems during idling due to the coupled masses of the d
17、ynamometer; the measuring time is lengthened due to the additional idling modes. In the steady-state procedure given in this International Standard, the power curve is measured over the same range of rotational frequency. After the torque and temperature have stabilized, all necessary data for the p
18、erformance and the fuel consumption measurement have to be taken. After recording the data, the next point on the power curve has to be measured without returning to idling. Due to the close temperature correlation from the previous point to the subsequent point, the stabilized conditions are reache
19、d in a much shorter time than in the previous procedure. 1 Scope This International Standard specifies a method for testing the performance and fuel consumption of internal combustion engines used to power portable brush cutters and grass trimmers. 2 Normative reference The following standard contai
20、ns provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate
21、the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 5164:1990, Motor fuels Determination of knock characteristics Research method. 3 Apparatus 3.1 Brake power test bench with a
22、torque accuracy of2 % of the measured value. 3.2 Tachometer with an accuracy of0,5 % of the measured value. 3.3 Fuel consumption measuring device with an accuracy of3 % of the measured value. 3.4 Thermometer with an accuracy of1 K. 3.5 Barometer with an accuracy of 0,5 % of the measured value. 3.6 H
23、umidity test device with an accuracy of2%. 4 Test conditions 4.1 Ambient temperature, measured at a distance of15 cm from the air intake: 15C to 27C. 4.2 Atmospheric pressure: 97,5 kPa to 105 kPa. 4.3 Correction to reference atmospheric conditions shall be made according to the following formulas: w
24、here r is the index for the standard reference conditions; x is the index for the actual measured conditions; C is the fuel consumption, in kilograms per hour; P is the brake power, in kilowatts; M is the torque, in newton metres;BSISO8893:1997 2 BSI 04-1999 4.4 The standard reference conditions sha
25、ll be the following: T r= 298 K (dry bulb); P r= 99 kPa (based on a total barometric pressure of 100 kPa and a water vapour pressure of 1 kPa). 4.5 The values T xand P xshall be calculated as theaverage of the values resulting from the tests in6.2.3 and 6.2.6. 4.6 The variation of T xduring the meas
26、urements shall not exceed 3 K. 4.7 Power-consuming auxiliaries (for example, electrical handle heating) shall be turned off. 4.8 The exhaust outlet shall operate against a pressure equal to that at the air intake. 4.9 No extra cooling or air supply is allowed. 4.10 The engine shall be coupled to the
27、 brake power test bench in such a manner that the engine crankshaft is aligned with the brake shaft and connected to it with a flexible coupling. The use of the engine clutch is optional. 4.11 The governor of the rotational frequency can sometimes be influlenced by the brake power test bench. Theref
28、ore the maximum free rotational frequency of the complete machine in hand-held operation shall be checked first. If this frequency cannot be reached in the bench, the governor of the rotational frequency shall be disengaged. 4.12 The fuel shall consist of petrol with a minimum octane number (RON) of
29、 90, measured according to ISO 5164, and, if it is a two stroke engine, mixed with two stroke oil according to the manufacturers recommendation. The density of the fuel shall be725 kg/m 3to 755 kg/m 3at 15C. If the fuel does not comply with these specifications, full details shall be given in the te
30、st report. 5 Conditions of measurement 5.1 Measurements shall be carried out on a machine with its standard equipment. 5.2 The engine shall be complete (except shaft tube, power transmission shaft and engine transmission) with all standard production auxiliaries for its operation (filter, silencer,
31、cooling system, etc). 5.3 The engine shall be run in accordance with the manufacturers instructions. 6 Operating method 6.1 General With the throttle in the fully open position, record the brake power, torque and fuel consumption as a function of the rotational frequency in steps of10s 1(r/s), start
32、ing from the lowest rotational frequency. No adjustments on the machine are allowed during the test. Take the readings during the 10 s interval after the temperature has stabilized. Take the readings at least over a rotational frequency range limited by the rotational frequency for maximum torque mi
33、nus 15 s 1 , and the rotational frequency for maximum power plus 15 s 1 . 6.2 Procedure Carry out the measurement according to the procedure given in 6.2.1 to 6.2.6. 6.2.1 Prior to mounting the engine on the power test bench, warm up the engine and set the idle speed adjuster and low speed mixture a
34、djuster for best idling at the rotational frequency recommended by the manufacturer. 6.2.2 Run the engine at fully open throttle on the power test bench at the maximum power rotational frequency specified by the manufacturer. Set the high speed mixture adjuster for maximum power. 6.2.3 Record the am
35、bient air temperature and pressure. 6.2.4 Run the engine with fully open throttle at the rotational frequency of maximum torque minus 15S 1 ; wait for temperature stabilization and take the readings in accordance with 6.1. 6.2.5 Repeat 6.2.4 by increasing the test rotational frequency by maximum 10
36、s 1over the rotational frequency as stated in 6.1. 6.2.6 Record the ambient air temperature and pressure. 7 Test report The test report shall include the following information: a) basic information specifying: 1) reference to this International Standard; 2) date and place of measurement; 3) names of
37、 the petitioner and the issuer of the report; K r is the reference adjustment factor; P r is the reference dry atmospheric pressure, in kilopascals; P x is the measured dry atmospheric pressure (i.e. total pressure minus the water vapour pressure), in kilopascals; T is the ambient temperature, in ke
38、lvins.BSISO8893:1997 BSI 04-1999 3 b) description of the machine including: 1) manufacturers name or make or brand name; 2) model (type); 3) serial number; 4) working cycle (for example two stroke); 5) bore, stroke and swept volume of the engine; 6) fuel density; 7) oil mixture ratio; 8) petrol octa
39、ne number (RON); 9) measuring equipment; 10) ambient air temperatures; 11) ambient air pressures; c) the following parameters, given as a function of the engine rotational frequency (see examples given in Figure 1): 1) power, in kilowatts; 2) torque, in newton meters; 3) fuel consumption, in kilogra
40、ms per hour; 4) specific fuel consumption, in grams per kilowatt hour. Figure 1 Examples of characteristic curvesBSISO 8893:1997 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK
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