1、BRITISH STANDARD BS6916-7: 1998 ISO 7293:1997 Chainsaws Part 7: Method of evaluating engine performance including fuel consumption ICS 65.060.80BS6916-7:1998 This British Standard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standar
2、ds Board and comes intoeffect on 15 March1998 BSI 04-1999 ISBN 0 580 29657 1 National foreword This British Standard reproduces verbatim ISO7293:1997 and implements it as the UK national standard. It supersedes BS6916-7:1988 which is withdrawn. The UK participation in its preparation was entrusted t
3、o Technical CommitteeAGE/29, Forestry 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 intern
4、ational and European developments 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
5、in the BSI Standards Catalogue 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 a
6、re responsible for their correct 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, pages1 to3 and a back cover. This sta
7、ndard 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. Amendments issued since publication Amd. No. Date CommentsBS6916-7:1998 BSI 04-1999 i Contents Page National foreword Inside front cover Fore
8、word ii Introduction 1 1 Scope 1 2 Normative references 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 characteristics curves 3ii blankBS6916-7:1998 ii BSI04-1999 Foreword ISO (the International Organization for Standardiza
9、tion) 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 right to be
10、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. Draft International St
11、andards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO7293 was prepared by Technical Committee ISO/TC23, Tractors and machine
12、ry for agriculture and forestry, Subcommittee SC17, Manually portable forest machinery. This second edition cancels and replaces the first edition (ISO7293:1983), of which it constitutes a technical revision (see Introduction). Descriptors: Agricultural machinery, forest equipment, portable equipmen
13、t, mechanically-operated devices, saws, chain saws, propulsion engines, internal combustion engines, tests, performance tests, determination, fuel consumption.BS6916-7:1998 BSI 04-1999 1 Introduction The first edition of ISO7293 was elaborated from1979 to1980 according to the special conditions of c
14、hain-saws at that time. Extensive measurement experiences not only at manufacturers but also at test stations revealed that the test procedure given in ISO7293:1983 is no longer appropriate due to advanced developments. The test procedure given in ISO7293:1983 required an intermittent test run repea
15、ted over a specified range of rotational frequency. Within this range, one data print had to be recorded at every10s 1increment. The necessary reading had to be recorded within50s to60s after the application of full load. This sequence was then followed by1min of running with idling. According to ga
16、thered experiences, this intermittent procedure has 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 problem
17、s during idling due to the coupled masses of the dynamometer; 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 tempera
18、ture have stabilized, all necessary data for the performance 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 subs
19、equent point, the stabilized conditions are reached 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 chain-saws. 2 Normative reference T
20、he following standard contains 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 ar
21、e encouraged to investigate 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. ISO5164:1990, Motor fuels Determination of knock characteristics Research method. 3 Apparatus 3.1 Bra
22、ke power test bench with a torque accuracy of 2% of the measured value. 3.2 Tachometer with an accuracy of 0,5% of the measured value. 3.3 Fuel consumption measuring device with an accuracy of 3% of the measured value. 3.4 Thermometer with an accuracy of 1K. 3.5 Barometer with an accuracy of 0,5% of
23、 the measured value. 3.6 Humidity test device with an accuracy of 2%. 4 Test conditions 4.1 Ambient temperature, measured at a distance of15cm from the air intake:15 C to27 C. 4.2 Atmospheric pressure: 97,5 kPa to105 kPa. 4.3 Correction to reference atmospheric conditions shall be made according to
24、the following formulas: P r= K r P x M r= K r M x C r= K r C x where 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; K r i
25、s the reference adjustment factor; p r is the reference dry atmospheric pressure, in kilopascals; K r p r p x - T x T r - 0,5 =BS6916-7:1998 2 BSI 04-1999 4.4 The standard reference conditions shall be the following: T r= 298 K (dry bulb); p r= 99 kPa (based on a total barometric pressure of100 kPa
26、and a water vapour pressure of1 kPa). 4.5 The values T xand p xshall be calculated as the average of the values resulting from the tests in6.2.3 and6.2.6. 4.6 The variation of T xduring the measurements shall not exceed 3 K. 4.7 Power-consuming auxiliaries (for example, electrical handle heating) sh
27、all 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 brake power test bench in such a manner that the engine crankshaft is aligned with the brake shaft and co
28、nnected 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 influenced by the brake power test bench. Therefore the maximum free rotational frequency of the complete saw in hand-held operation shall be checked first
29、. 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) of90, measured according to ISO5164, and, if it is a two stroke engine, mixed with two stroke oil according to th
30、e manufacturers recommendation. The density of the fuel shall be725kg/m 3to755kg/m 3at15 C. If the fuel does not comply with these specifications, full details shall be given in the test report. 5 Conditions of measurement 5.1 Measurements shall be carried out on a saw with its standard equipment. 5
31、.2 The engine shall be complete (except chain and guide bar) with all standard production auxiliaries for its operation (filter, silencer, 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 full
32、y open position, record the brake power, torque and fuel consumption as a function of the rotational frequency in steps of10s 1(r/s), starting from the lowest rotational frequency. No adjustments on the saw are allowed during the test. Take the readings during the10s interval after the temperature h
33、as stabilized. Take the readings at least over a rotational frequency range limited by the rotational frequency for maximum torque minus15s 1 , and the rotational frequency for maximum power plus15s 1 . 6.2 Procedure Carry out the measurement according to the procedure given in6.2.1 to6.2.6. 6.2.1 P
34、rior to mounting the engine on the power test bench, warm up the engine and set the idle speed adjuster and low speed mixture adjuster 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
35、 rotational frequency specified by the manufacturer. Set the high speed mixture adjuster for maximum power. 6.2.3 Record the ambient air temperature and pressure. 6.2.4 Run the engine with fully open throttle at the rotational frequency of maximum torque minus15S 1 ; wait for temperature stabilizati
36、on and take the readings in accordance with6.1. 6.2.5 Repeat6.2.4 by increasing the test rotational frequency by maximum10S 1over the rotational frequency as stated in6.1. 6.2.6 Record the ambient air temperature and pressure. 7 Test report The test report shall include the following information: a)
37、 basic information specifying: 1) reference to this International Standard; 2) date and place of measurement; 3) names of the petitioner and the issuer of the report; b) description of the saw including: 1) manufacturers name or make or brand name; 2) model (type); p x is the measured dry atmospheri
38、c pressure (i.e.total pressure minus the water vapour pressure), in kilopascals; T is the ambient temperature, in kelvins.BS6916-7:1998 BSI 04-1999 3 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)
39、 petrol octane number (RON); 9) measuring equipment; 10) ambient air temperatures; 11) ambient air pressures; c) the following parameters, given as a function ofthe engine rotational frequency (see examples given in Figure 1): 1) power, in kilowatts; 2) torque, in newton meters; 3) fuel consumption,
40、 in kilograms per hour; 4) specific fuel consumption, in grams per kilowatt hour. Figure 1 Examples of characteristic curvesBS6916-7: 1998 ISO 7293:1997 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStand
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