ISO 6855-3:2012
(Main)Mopeds — Measurement method for gaseous exhaust emissions and fuel consumption — Part 3: Fuel consumption measurement at a constant speed
Mopeds — Measurement method for gaseous exhaust emissions and fuel consumption — Part 3: Fuel consumption measurement at a constant speed
ISO 6855-3 specifies the methods of measurement for fuel consumption at a constant speed on the road and on the chassis dynamometer. It is applicable to mopeds as defined in ISO 3833 equipped with a spark ignition engine (four-stroke engine, two-stroke engine or rotary piston engine).
Cyclomoteurs — Méthode de mesure des émissions de gaz polluants et de consommation de combustible — Partie 3: Mesure de consommation de combustible à vitesse constante
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INTERNATIONAL ISO
STANDARD 6855-3
First edition
2012-09-15
Mopeds — Measurement method for
gaseous exhaust emissions and fuel
consumption —
Part 3:
Fuel consumption measurement at a
constant speed
Cyclomoteurs — Méthode de mesure des émissions de gaz polluants et
de consommation de combustible —
Partie 3: Mesure de consommation de combustible à vitesse constante
Reference number
ISO 6855-3:2012(E)
©
ISO 2012
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ISO 6855-3:2012(E)
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© ISO 2012
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Published in Switzerland
ii © ISO 2012 – All rights reserved
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ISO 6855-3:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 General requirements . 2
6 Road measurement method . 3
6.1 Rider and riding position . 3
6.2 Test track . 3
6.3 Ambient conditions for the road test . 3
6.4 Measuring instruments on the test moped for the road test . 4
6.5 Test method . 4
7 Chassis dynamometer measurement method . 5
7.1 Test method . 5
8 Presentation of results . 6
Annex A (normative) Determination method of fuel consumption . 7
Annex B (normative) Presentation of results of fuel consumption . 9
Bibliography .15
© ISO 2012 – All rights reserved iii
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ISO 6855-3:2012(E)
Foreword
ISO (the International Organization for Standardization) 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 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.
International 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 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 6855-3 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 23, Mopeds.
ISO 6855-3 cancels and replaces ISO 6855:1983and ISO 7859:2000, which have been technically revised.
ISO 6855 consists of the following parts, under the general title Mopeds — Measurement method for
gaseous exhaust emissions and fuel consumption:
— Part 1: General test requirements
— Part 2: Test cycles and specific test conditions
— Part 3: Fuel consumption measurement at a constant speed
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ISO 6855-3:2012(E)
Introduction
This part of ISO 6855 defines specific requirements for measurement of fuel consumption at a constant
speed. The measurement can be carried out by referring to this part of ISO 6855 and ISO 6855-1.
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INTERNATIONAL STANDARD ISO 6855-3:2012(E)
Mopeds — Measurement method for gaseous exhaust
emissions and fuel consumption —
Part 3:
Fuel consumption measurement at a constant speed
1 Scope
This part of ISO 6855 specifies the methods of measurement for fuel consumption at a constant speed
on the road and on the chassis dynamometer. It is applicable to mopeds as defined in ISO 3833 equipped
with a spark ignition engine (four-stroke engine, two-stroke engine or rotary piston engine).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6855-1:2012, Measurement methods for gaseous exhaust emissions and fuel consumption — Part 1:
General test requirements
ISO 7116, Road vehicles — Measurement method for the maximum speed of mopeds
ISO 28981, Mopeds — Methods for setting the running resistance on a chassis dynamometer
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
target test speed
constant speed at which the moped is tested
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ISO 6855-3:2012(E)
4 Symbols
Table 1 — Symbols
Symbols Definition Unit
F specific fuel consumption of the first test km/L
c,ai
F specific fuel consumption of the second test km/L
c,bi
F average specific fuel consumption of first and second tests km/L
c,i
F mean value of average specific fuel consumptions km/L
c,j
L test section length to measure the fuel consumption km
road
p total barometric pressure during the test kPa
T
p total barometric pressure at the standard reference condition kPa
0
T air temperature during the test K
T
r relative air density during the test ─
T
r relative air density at the standard reference conditions ─
0
T air temperature at the standard reference conditions K
0
t time during the measurement of fuel consumption of the first test h
c,ai
t time during the measurement of fuel consumption of the second test h
c,bi
V measured volume of consumed fuel during the first test L
c,ai
V measured volume of consumed fuel during the second test L
c,bi
v moped speed during the first test km/h
c,ai
v moped speed during the second test km/h
c,bi
v average moped speed of first and second tests km/h
c,i
v mean value of average moped speeds km/h
c,j
v target test speed km/h
T
5 General requirements
5.1 Measurement of fuel consumption of a moped based on the constant speed method shall be
performed on a road or on a chassis dynamometer.
5.2 Fuel shall be supplied to the engine by a device capable of measuring the quantity of fuel supplied with
an accuracy of ± 2 %, and which does not interfere with the supply of fuel to the engine. Where the measuring
system is volumetric, the temperature of fuel in the device or in the outlet of the device shall be measured.
5.3 Switching from the normal supply system to the measuring supply system shall be effected by a
valve system and shall take no more than 0,2 s.
ISO 6855-1:2012, Annex A, gives the description and the methods of use of the appropriate devices. The carbon
balance method can also be applied for the measurement of fuel consumption on the chassis dynamometer.
5.5 Before the test, all parts of the moped shall be stabilized at the normal temperature for the moped in use.
5.6 The total test mass, including the masses of the rider and the instruments, shall be measured before
the beginning of the test.
5.7 The test shall be performed at a constant speed in the highest gear. A lower gear may be selected in
case the test moped cannot be run stably; the gear used shall be reported in test results.
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ISO 6855-3:2012(E)
6 Road measurement method
6.1 Rider and riding position
6.1.1 The rider shall wear a close-fitting suit (one-piece) or similar clothing, a protective helmet, eye
protection, boots and gloves.
6.1.2 The rider in the conditions given in 6.1.1 shall have a mass of 75 kg ± 2 kg and be 1,75 m ± 0,02 m tall.
6.1.3 The rider shall be seated on the seat provided, with his/her feet on the footrests and his/her arms
normally extended. This position shall allow the rider at all times to have proper control of the moped
during the test.
The position of the rider should remain unchanged during the whole measurement; the description of
the position shall be indicated in the test report or shall be replaced by photograph(s).
6.2 Test track
6.2.1 The total length of test track shall be the sum of the following sections:
a) the acceleration section to reach at the stabilized target test speed;
b) the test section to measure the fuel consumption;
c) the deceleration section to stop the test moped safely.
6.2.2 The test section shall be either long enough to consume the fuel of at least 10 mL or be longer than
300 m. The length of the test section shall be measured within the tolerance of 0,1 %.
6.2.3 The test road shall be flat, level, straight and smoothly paved. The road surface shall be dry and
covered with asphalt, concrete or similar material, and free of obstacles or wind barriers that might impede
the measurement of the fuel consumption. The slope of the surface shall not exceed 0,5 % between any
two points at least 2 m apart.
6.3 Ambient conditions for the road test
During data collecting periods, the wind shall be steady. The wind speed and the direction of the wind
shall be measured continuously or with adequate frequency at a location where the wind force during
fuel consumption measurement is representative.
The ambient conditions shall be within the following limits:
a) maximum wind speed: 3 m/s;
b) maximum wind speed for gust: 5 m/s;
c) average wind speed, parallel: 3 m/s;
d) average wind speed, perpendicular: 2 m/s;
e) maximum relative humidity; 95 %;
f) air temperature: 278 K to 308 K.
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ISO 6855-3:2012(E)
The relative air density during the test, r , shall be calculated by Formula (1):
T
p T
T 0
r =×r × (1)
T 0
p T
0
...
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