ISO 4182:1999
(Main)Motor vehicles — Measurement of variations in dipped-beam headlamp angle as a function of load
Motor vehicles — Measurement of variations in dipped-beam headlamp angle as a function of load
Automobiles — Mesurage des variations d'inclinaison du faisceau de croisement en fonction de la charge
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 4182
Third edition
1999-12-15
Motor vehicles — Measurement of
variations in dipped-beam headlamp angle
as a function of load
Automobiles — Mesurage des variations d'inclinaison du faisceau de
croisement en fonction de la charge
A
Reference number
ISO 4182:1999(E)
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ISO 4182:1999(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.
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.
International Standard ISO 4182, was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee
SC 8, Lighting and signalling.
This third edition cancels and replaces the second edition (ISO 4182:1986), which has been technically revised.
Annexes A to C form an integral part of this International Standard.
© ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
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Internet iso@iso.ch
Printed in Switzerland
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INTERNATIONAL STANDARD ISO ISO 4182:1999(E)
Motor vehicles — Measurement of variations in dipped-beam
headlamp angle as a function of load
1 Scope
This International Standard specifies a method for measuring variations in the dipped-beam inclination of motor
vehicle headlamps, in relation to the initial inclination, caused by changes in vehicle attitude due to loading. This
measurement method may be used particularly during vehicle type approval tests.
Loading conditions of vehicles are specified in annex A. They are to be used except when legal regulations require
different loading conditions.
Annex B establishes a classification of headlamps, and gives examples of measurement methods applicable
according to the classification. Annex C gives a photometric method of determining the position of a point of the
conventional cut-off, which is complementary to one of the measurement method examples in annex B.
This International Standard is applicable to motor vehicles as defined in ISO 3833.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 303:1986, Road vehicles — Installation of lighting and light signalling devices for motor vehicles and their
trailers.
ISO 612:1978, Road vehicles — Dimensions of motor vehicles and towed vehicles — Terms and definitions.
ISO 3833:1977, Road vehicles — Types — Terms and definitions.
ISO 7227:1987, Road vehicles — Lighting and light signalling devices — Vocabulary.
EEC Directive 76/756, Installation of lighting and light signalling devices on motor vehicles and trailers.
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 612 and the following definitions apply.
3.1 Classification
3.1.1 vehicle, category M: Motor vehicle intended for transporting people.
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ISO 4182:1999(E)
3.1.2 vehicle, category M : Motor vehicle, category M (3.1.1), containing not more than eight seats, in addition
1
to the driver's seat.
3.1.3 vehicle, category M : Motor vehicle, category M (3.1.1), containing more than eight seats, in addition to
2
the driver's seat, and having a maximum permissible mass not exceeding 5 t.
3.1.4 vehicle, category M : Motor vehicle, category M (3.1.1), containing more than eight seats, in addition to
3
the driver's seat, and having a maximum permissible mass exceeding 5 t.
3.1.5 vehicle, category N: Motor vehicle intended for transporting goods.
3.2 Initial inclination
3.2.1 stated initial inclination: Value of the dipped-beam initial inclination specified by the motor vehicle
manufacturer, which serves as a reference value for the calculation of permissible variations.
3.2.2 measured initial inclination: Mean value of dipped-beam inclination or vehicle inclination measured with
one person in the driver's seat for the category of vehicle under test, which serves as a reference value for the
assessment of variations in beam inclination as the load varies.
3.3 Reference centre
Intersection of the reference axis with the light-emitting surface. [ISO 7227:1987, 3.41]
4 Type of vehicle
For the purposes of this International Standard, vehicles shall be considered to be of the same type if they do not
differ in such essential respects as:
— wheel-base (wheel space) (as defined in ISO 612);
— location of headlamps on the motor vehicle;
— headlamp class (see annex B);
— characteristics of the suspension system;
— axle loads stated by the manufacturer;
— means used to correct dipped-beam angle according to load.
5 Dipped-beam inclination
The dipped-beam inclination is defined as follows:
— either as the angle, expressed in milliradians, between the direction of the beam towards a characteristic point
on the horizontal part of the cut-off in the luminous distribution of the headlamp and the horizontal plane; or
— by the tangent of that angle, expressed in percentage inclination, since the angles are small (for these small
angles, 1 % is equal to 10 mrad).
If the inclination is expressed in percentage inclination, it can be calculated by means of the following formula:
()-hh
12
·100
L
where
h is the height above the ground, in millimetres, of a characteristic point in the luminous spread of the headlamp,
1
measured on a vertical screen perpendicular to the vehicle longitudinal median plane, placed at a horizontal
distance L;
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ISO 4182:1999(E)
h is the height above the ground, in millimetres, of the centre of reference (which is taken to be the nominal origin
2
of the characteristic point chosen in h );
1
L is the distance, in millimetres, from the screen to the centre of reference.
Negative values denote downward inclination (see figure 1).
Positive values denote upward inclination.
NOTES
1 This drawing represents a category M vehicle, but the principle shown applies equally to vehicles of other categories.
1
2 Where the vehicle does not incorporate a headlamp levelling system, the variation in dipped-beam inclination is identical
with the variation in the inclination of the vehicle itself.
Figure 1 — Dipped-beam downward inclination of a category M vehicle
1
6 Measurement conditions
6.1 If a visual inspection of the dipped-beam pattern on the screen or a photometric method is used,
measurements shall be carried out in a dark environment (for example, a dark room) of sufficient area to allow the
vehicle and the screen to be placed as shown in figure 1. Headlamp centres of reference shall be at a distance from
the screen of at least 10 m.
6.2 The ground on which measurements are made shall be as flat and horizontal as possible, so that the
reproducibility of measurements of dipped-beam inclination can be assured with an accuracy of ± 0,5 mrad
(± 0,05 % inclination).
6.3 If a screen is used, its marking, position and orientation in relation to the ground and to the median longitudinal
plane of the vehicle, shall be such that the reproducibility of the measurement of the dipped-beam inclination can be
assured with an accuracy of ± 0,5 mrad (± 0,05 % inclination).
6.4 During measurements, the ambient temperature shall be between 10 °C and 30 °C.
7 Vehicle preparation
7.1 Measurements shall be carried out on a vehicle which has travelled a distance of between 1 000 km and
10 000 km, preferably 5 000 km.
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ISO 4182:1999(E)
7.2 Tyres shall be inflated to the full-load pressure specified by the vehicle manufacturer. The vehicle shall be fully
replenished (fuel, water, oil) and equipped with all the accessories and tools specified by the manufacturer.
NOTE — Full fuel replenishment means that the fuel tank is filled to not less than 90 % of its capacity.
7.3 The vehicle shall have the parking brake released and the gearbox in neutral.
7.4 The vehicle shall be conditioned for at least 8 h at the temperature specified in 6.4.
7.5 If a photometric or visual method is used, headlamps with a well-defined dipped-beam cut-off should preferably
be installed on the vehicle under test in order to facilitate the measurements. Other means are allowed to obtain a
more precise reading (for example, removal of the headlamp lens).
8 Test procedure
8.1 General
The variations in either dipped-beam or vehicle inclination, depending on the method chosen, shall be measured
separately for each side of the vehicle. The results obtained from both left and right headlamps under all the load
conditions specified in annex A, shall be within the limits set out in 8.5. The load shall be applied gradually without
subjecting the vehicle to excessive shocks.
8.2 Determination of the measured initial inclination
8.2.1 The vehicle shall be prepared as specified in clause 7 and laden as specified in annex A (first loading
condition of the respective vehicle category).
Before each measurement, the vehicle shall be rocked as specified in 8.4 below. Measurements shall be made
three times.
8.2.2 If none of the three measured results differs by more than 2 mrad (0,2 % inclination) from the arithmetic
mean of the results, that mean shall constitute the final result.
8.2.3 If any measurement differs from the arithmetic mean of the results by more than 2 mrad (0,2 % inclination), a
further series of 10 measurements shall be made, the arithmetic mean of which shall constitute the final result.
8.3 Measurement methods
Any method may be used to measure variations of inclination provided that the readings are accurate to within
± 0,2 mrad (± 0,02 % inclination).
8.4 Treatment of vehicle in each loading condition
8.4.1 Activation of vehicle suspension
The vehicle suspension and any other part likely to affect dipped-beam inclination shall be activated according to
the methods described in 8.4.2 to 8.4.4.
However, the test laboratories and manufacturers may jointly propose other methods (either experimental or based
upon calculations), especially when the test poses particular problems, provided such calculations are clearly valid.
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8.4.2 M category vehicles with conventional suspension
1
With the vehicle standing on the measuring site and, if necessary, with the wheels resting on floating platforms
(which shall be used if their absence would lead to restriction of the suspension movement likely to affect the results
of measurements), rock the vehicle continuously for at least three complete cycles; for each cycle, first the rear and
then the front end of the vehicle is pushed down.
The rocking sequence shall end with the completion of a cycle. Before making the measurements, the vehicle shall
be allowed to come to rest spontaneously. Instead of using floating platforms, the same effect can be achieved by
moving the vehicle backwards and forwards for at least a complete wheel revolution.
8.4.3 M , M and N category vehicles with conventional suspension
2 3
8.4.3.1 If the treatment method for category M vehicles described in 8.4.2 is not possible, the method described in
1
8.4.3.2 or 8.4.3.3 may be used.
8.4.3.2 With the vehicle standing on the measuring site and the wheels on the ground, rock the vehicle by
temporarily varying the load.
8.4.3.3 With the vehicle standing on the measuring site and the wheels on the ground, activate the vehicle
suspension and all other parts which may affect the dipped-beam inclination by using a vibration rig. This can be a
vibrating platform on which the wheels rest.
8.4.4 Vehicles with non-conventional suspension
For vehicles with non-conventional suspension,
...
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