194Tomczuk Piotr-artykuł.pdf

Piotr Tomczuk

Faculty of Transport

Warsaw University of Technology

EXPLOITATION RESEARCH OF TRAM’S HEAD

LIGHTING

Abstract : The article presents the current state of tram’s front lighting. Qualitative analysis has

been conducted of presently used light beams of low beam lights with the use of image

analyzer of CCD camera for luminance measurement. A method of luminance measurement on

photometric screen has been described. Comparative results have been presented of luminance

measurement in measurement points and areas on the borderline of light and shade, and on the

glare line of a tram driver coming from the opposite direction.

Key words: tram’s head lighting, low beam lights, CCD camera, luminance.

1. INTRODUCTION

The factor influencing driving safety of a track vehicle is the quality and state of tram’s

head lighting. Proper distribution of a light beam within the area of a vehicle’s foreground

plays a decisive role in the perception of luminous sensations by the tram driver.

Appropriately shaped light beam conditions proper visibility from the tram driver’s seat

and facilitates correct assessment of traffic situations connected with the behaviour of other

road traffic participants.

Review of Polish and worldwide literature within the field of foreground lighting of

track vehicles indicates a scarce number of publications concerning systemic approach to

this issue. Poland lacks legislative solutions dedicated to this field. Current requirements

concerning technical parameters of lighting solutions used in tram vehicles are included in

the Directive of Minister of Infrastructure [1], [2].

Requirements included in the abovementioned directives contain only general

information, which can be used when drawing up a method of quality assessment of tram’s

lighting. What they are lacking in is detailed measurement guidelines taking into account

the specificity of tram’s foreground lighting in urban traffic conditions. Guidelines

included in the abovementioned directives stipulate only borderline values of luminous

flux density and ranges of particular light beams of a tram. There is a possibility of

defining more detailed requirements, for example, by defining a photometric measurement

screen for this group of vehicles. Therefore, it is justifiable to make an attempt at

application of modern photometric tools in order to optimise the quality of light beams

used in tram’s front lighting.

It should be mentioned that according to the knowledge of the author of the present

paper, there is no research being currently conducted on the head lighting of tram vehicles

either in Poland or in Europe.

Lamps exploited in tram vehicles in most cases are obsolete constructions [9].

Traditional paraboloidal reflectors are mainly used with classic (R2) (fig.3, fig.5 and fig.7)

or halogen (H4) (fig.9, fig.11 and fig.13) sources of light. In the latest constructions of

optical-luminous lamps, more modern solutions for creating luminous flux are used by

means of application of ellipsoidal reflectors (fig.1) with halogen H1 and H7 light bulbs.

The solutions for optical-luminous systems used in motor car vehicle technology are

most often directly implemented in tram vehicles. Frequently, they fail to fulfil

requirements [9] referring to light beam distribution and direction. Different observation

conditions from the tram driver’s cabin, the level of tram driver’s eyes, the level at which

tram’s head lighting is installed as well as track features diametrically differ from the

requirements for foreground observation in a motor vehicle.

ECE regulations and Polish Norms [5] stipulate lighting used in motor vehicles. In the

case of tram light equipment, no detailed photometric requirements exist. The lack of such

regulations clearly leads to negligence in head lighting exploitation. The most frequent

cases of negligence refer to the following: wrong direction of a light beam, application of a

light bulb with an underestimated light beam, usage of overexploited reflectors with partly

damaged reflecting elements or lamp bowls.

Measurements presented in the paper are an introduction to an analysis of the quality of

tram vehicle’s foreground with the use of mathematical tools. Researches are underway on

the possibility of application of uniform technical solution for tram vehicle’s foreground

lighting [7] and application of automatic light beam control system of a tram [8]. Detailed

requirements for particular light beams used in tram vehicles are currently being prepared.

In Poland, researches on the quality of light beams are conducted for the needs of motor

car vehicle lighting. Within the range of analysis of a light spot image of motor vehicle’s

head lights, a device was created at the Institute of Road Transport, which makes it

possible to assess the quality of a light spot of the optical-luminous solution applied [6].

The analyser of motor car vehicle lighting assesses light beam emitted in terms of

exploitation parameters. Borderline of light and shade and measurement points and areas

are being assessed among others in accordance with normative requirements for particular

kinds of light beams. The measurement is conducted by means of CCD converter, and the

values are presented in luminous intensity units. It should be mentioned that the

constructed analyser is a prototype dedicated to motor car lighting devices and as such

cannot be directly applied to the analysis of tram head lighting quality.

To date, due to normative requirements [5], assessment of light beam quality has been

conducted by means of direct measurement of luminous intensity on measurement screen

[4]. Such an analysis can only answer the question referring to the value of luminous

intensity in particular measurement points and areas. It does not, however, allow for

assessment of a full light beam distribution. The solution applied by the author of the

present paper consists in direct measurement of luminance on measurement screen,

obtained for a measured light beam. In such a way a full picture of luminance of

a measured light beam is obtained. This method, because of measuring equipment applied,

is unique in Poland.

2. LUMINANCE MEASUREMENT ON PHOTOMETRIC SCREEN

The first stage of work on the subject was conducting laboratory measurements of tram

reflectors and projectors. A series of measurements was conducted by means of classic

goniometric method [4]. The results of these measurements were verified on the basis of

luminance assessment method on photometric screen.

The advantage of luminance method is the possibility of assessment of light beam

distribution regularity on the analysed image of a light spot.

In the present publication, the author presents only the results of luminance

measurement of light spots of low beam lights exploited in tram vehicles.

The measurements of luminance were conducted by means of specialist portable camera

LMK MOBILE ADVANCED made by the company Techno Team Bildverarbeitung

GmbH [3]. The tool used allows taking a photo of a light spot image scaled in luminance

units [cd/m 2 ]. Additionally, it is equipped with specialist software LMK 2000 making it

possible to process and scale obtained luminance images for the purpose of assessment and

comparison of obtained results.

Reflectors and projectors with dedicated sources of light underwent research. It is worth

mentioning that real and not model sources of light were used. Such an approach made it

possible to assess the current state of light beams exploited in tram vehicles. The

researches were conducted with the use of the reflectors and projectors presented in

figures 1,3,5,7,9,11,13.

Luminance measurements were conducted for seven light beams of low beam lights on

measurement screen placed at a distance of 5m perpendicularly to the tested lighting

device. The measurements of the screen equal 3.6m within horizontal plane and 2m within

vertical plane. Measurement screen is produced from material characterized by Lambertian

reflectance.

Luminance measurement results obtained are presented in figures 2,4,6,8,10,12,14

where logarithmic scale was adopted (log 2 ) calibrated from 0 to 75 cd/m 2 .

Fig.1. Low beam light projector of 1BL-

008 type with H7 light bulb

Fig.2. The view of a light spot of low beam light projector 1BL-

008 (H7) together with indicated places of luminance

measurement

Fig.3. Main light and low beam light

reflector of 0-300-181-003 type with

BA20D light bulb

Fig.4. The view of a light spot of low beam light reflector 0 -

300-181-003 (BA20D) together with indicated places of

luminance measurement

Fig.5. Main light and low beam light

reflector of RE09237 type with R2 light

bulb

Fig.6. The view of a light spot of low beam light reflector

RE09237 (R2) together with indicated places of luminance

measurement

Fig.7.Main light and low beam light

reflector of RE03210 (019469) type with

R2 light bulb

Fig.8. The view of a light spot of low beam light reflector

RE03210 (R2) together with indicated places of luminance

measurement

Fig.9. Main light and low beam light

reflector of RE22879 type with H4

light bulb

Fig.10. The view of a light spot of low beam light reflector

RE22879 (H4) together with indicated places of luminance

measurement

Fig.11. Main light and low beam light

reflector of RE03411 (029804) type with

H4 light bulb

Fig.12. The view of a light spot of low beam light reflector

RE03411 (H4) together with indicated places of luminance

measurement

Fig.13. Main light and low beam light

reflector of RE03210 (029939) type with

H4 light bulb

Fig.14. The view of a light spot of main light reflector RE03210

(H4) together with indicated places of luminance measurement

Measurement points and zones were adopted in accordance with the guidelines

of ECE R 112 regulations [5]. The above figures present a network of measurement points

plotted on the image.

Normative guidelines stipulate luminous flux density values in particular

measurement points and zones. The article proposes assessment of reflectors on the

basis of luminance measurement making use of coordinates of measurement points and

areas.

3. LABORATORY RESEARCH RESULTS

For measurement points, straight lines and areas presented in Table 1, luminance

values for selected light beams of trams were registered. Table1 presents overall results

of luminance measurement of tested light beams of low beam lights.

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: