This SAE Automotive Lighting Materials Recommended Practice incorporates several test methods in order to provide performance requirements facilitating a more accurate assessment of headlamp lens systems (lens substrate plus coating(s) if applicable) durability versus the established practice.
The 16 papers in this technical paper collection discuss automotive lighting and human factors in driving vision. Topics include: image processing methods; adaptation into automotive of the NASA developed CATS (Cognitive Avionic Tool Set); safety and performance benefits associated with the use of a spotter mirror; automotive legibility; 25W HID headlamp; automotive illumination design with LED modules; and more.
Exatec� PC glazing technology team, has developed advanced weathering and abrasion resistant coatings technology that can be applied to protect polycarbonate. It is of particular interest to quantify and understand the factors that determine the surface abrasion performance of coated PC in rear window and backlight applications that have a wiper system. In the present study we describe Exatec's lab scale wiper testing equipment and test protocols. We also describe adaptation of optical imaging system to measure contrast and nano-profiling using nano-indenter, as post wiper surface characterization methods. These methods are more sensitive to fine scratches on glazing surface than standard haze measurement and mechanical profilometry. Three coating systems were investigated; Siloxane wetcoat (A), Siloxane wetcoat (B), and Siloxane wetcoat (B) plus plasma coat (Exatec� E900 coating). The performance comparisons were made using all these surface characterization methods.
Noise inside the passenger cabin is made up of multiple sources. A significant reduction of the major sound sources such as the engine, wind and tire noise helped to improve the comfort for passengers. As a consequence, the HVAC sound (heating, ventilation and air-conditioning) is unmasked as a primary noise source inside the passenger cabin and has to be taken into consideration when designing passenger cabin sound. While HVAC sound is often evaluated at stop, the most common situation of its use is while driving. In case of fresh air as mode of operation, the HVAC system is coupled to the environment through the air intake. Any change in the boundary conditions due to on-road driving events and gusts of wind affects the flow field in the HVAC system and in turn influences HVAC noise. This study investigates the effect of mass flow and pressure fluctuations on the HVAC noise. In a first step, major influences on the HVAC system are identified in an on-road test.
Squeak and rattle noise in a vehicle's interior is perceived as an annoying sound by customers. Since persistent noise (e.g. engine, wind, or drive train noise) has been reduced continuously during the last decades, the elimination of sounds, which have their origin in the vehicle's interior components, is getting more important. Therefore, noise prediction based on simulation models is useful, since design changes can be realized at lower costs in early virtual development phases. For this task, linear simulation methods are state of the art for the identification of noise risk, but in general without knowing if a sound is audible or not. First approaches have been developed based on the Harmonic Balance Method to predict squeak noise and assess their audibility. This paper presents vibroacoustic measurements at a door trim panel for squeaking and non-squeaking configurations. Vibrations are excited harmonically by a force controlled low noise shaker.
CONSTRUCTIVE criticism of automobile bodies as now built is given herein, based on experience gained in driving five-passenger sedan cars of many makes a total distance of nearly 10,000,000 miles in one year in tests at the General Motors Proving Ground. The fault finding, although humorously exaggerated, will be valuable if taken seriously, as it gives to all body designers and builders the benefit of testing experience that few companies are in a position to gain at first hand. The author treats his subject from the viewpoint of the abstract customer; that is, the automobile-purchasing public as a whole and as represened by the imaginary average man, who is assumed to have average stature and body structure and to drive all the different makes of car. Thus he is assumed to change from one to another make frequently, instead of becoming used to only one or two cars.
CONVEYORS and handling systems often are planned and installed after a building is erected. The Pontiac plant, described in this paper, is an exception because it was designed without limitations as to space and for a definite production program. With the aid of photographs and floor plans on which the positions from which the photographs were taken are indicated, the complete production line of the plant is shown in detail. The order of assembly and the points at which various units are applied to the chassis are shown; also the locations of the storage spaces for many of the parts and the provisions for transporting them to the assembly line. Among the striking features of the chassis-assembly line is a hump, midway of the length of the building, which raises the chassis to the mezzanine level to allow passage underneath.
“IN making these comments,” Mr. Chase says, “I am well aware that engineers are rarely given an opportunity to design a car incorporating even a large proportion of the improvements they would like to see included. “Unless some more or less ‘ideal’ types of construction are visualized, however, there may be no well-considered objective.” Visualizing these “more or less ideal types of construction,” Mr. Chase, in the following paper, throws a blanket indictment at the car designers, says what he thinks about current automobiles in no uncertain terms, and states specifically what he thinks ought to be done about it. Bodies, frames, springs, headlights, seats, engines-no unit of the modern car escapes Mr. Chase's stimulating criticism.
PRIME consideration must be given to the garaging and servicing of fleets of vehicles, according to the author, because numerous corporations operating on a large scale have come into existence in the last several years. After mentioning the variations in dimensions of motorcoaches and motor-trucks, he discusses the multiple-story structure and specifies the requirements of design, afterward going into detail concerning the planning of a motorcoach garage, particularizing on numerous details that will tend toward ease of operation and economy in both housing and servicing the vehicles. Desirable structural materials are commented upon, such as truss spans, brick or concrete for walls, plastered wall for waiting rooms, office and staff rooms, and cement for floors. Numerous advantageous features are mentioned in connection with height of ceilings, roof design, and mechanical operators either hand or motor-driven for opening and closing the window sash.
Instead of representing light intensity by lines to indicate photometric values the author recommends an arrangement for denoting the intensity by varying degrees of tint on the surface of a chart that is supposed to represent the roadway. In the opening paragraph the thought is brought out that present-day automobile lighting-equipment is not designed in such a way as to make its performance a selling feature and the several reasons why the efficient distribution of light on the road has been overlooked are pointed out, emphasis being laid on the fact that the average car-designer is not an illuminating engineer, and that even if he did wish to use the best light available on the car he would have to make personal tests of the devices under all conditions of night driving before being in a position to recommend the most efficient head-lighting device.
General considerations that affect the attainment of adequate lighting are mentioned, it being stated that proper lighting of the interior of a motorbus is influenced by limitations peculiar to the service, such as vibration, scant headroom, a restricted energy supply and relatively large voltage-variations. Available types of bus-lighting equipment are analyzed as to their suitability, from six different standpoints that are stated. “Glare” is defined and means of obviating it are suggested, inclusive of a discussion of desirable types of finish for the interior with regard to reflecting surfaces. The severe vibration produced by many motorbuses demands head-lamps of more rugged construction than that used for the headlighting of private cars. Eight essentials for motorbus head-lamps are specified. A very large percentage of the glare and poor illumination of the motor vehicles on the roads results from improper adjustment or the lack of any means for adjustment of the head-lamps.
This subject is treated in a paper in two parts. Part I, by Alex Taub, deals with laboratory tests to prove by comparative data that the higher average operating-temperatures maintained in the engine by the constant-temperature, or evaporation, system of cooling have negligible detrimental effects. Part II, by L. P. Saunders, gives the results of road-tests of cars operated under the same conditions when fitted with a standard water-cooling radiator-core and with a constant-temperature cross-flow condenser-core. Although contamination of the crankcase oil by heavy ends of the fuel is not prevented by the higher temperature of constant-temperature operation, it is asserted that this higher temperature is effective in striking an acceptable balance in such contamination and results of the tests show that the cylinder-walls are maintained at temperatures sufficiently above the vaporization point of water to reduce the condensation of water vapor to the minimum.
LABORATORY and road tests of headlighting on dry and wet road-surfaces, with various types of head-lamp beam, are described and the effects obtained are shown pictorially and data are given statistically. The test equipment and the conditions of the tests are described. Strength of the beam was controlled and the photographs were made under standard conditions so that results would be comparable. Results obtained show that depressing the beam of a depressible-beam head-lamp when an asphalt or concrete road surface is wet greatly increases the apparent intensity of the beam above the road, evidently due to reflection from the road surface, and that this intensity extends far above the horizontal height of the head-lamp, thereby defeating the object of depressing the beam.
Although agreeing in general with the sentiments expressed by Mr. Crane and Mr. Hunt, exception is taken to the statement that the solution of the headlighting problem is to be found in diffused lighting, because it has not sufficient range, is too glaring and is too dangerous in a fog. The trouble is said to lie not in the specifications but in the devices that they are supposed to cover. Suggestions are offered regarding modifications that might advantageously be made in the present specifications, and a detailed summation is given of the requirements considered essential to a first-class headlight. The statement is added that a headlight embodying all the points enumerated, while at the same time using a 21-cp. bulb, has already been perfected.
After referring to the recommendations made to the National Conference on Street and Highway Safety by the Committee on Motor Vehicles and the Committee's further explanation of the recommendations, the author amplifies more fully the difficulties that have arisen in the operation of the system of headlight regulations sponsored by the Illuminating Engineering Society and this Society and suggests a line of fundamental research with a view to drafting more desirable regulations. Inasmuch as road conditions have changed greatly since the regulations at present in force were first proposed, he believes that a new study of the subject might result in marked improvement. Definite control of a concentrated headlight beam, deflected below a horizontal line, as originally proposed by the Society, failed to produce the desired result, and the next step was the formulation of the regulations listed in the S.A.E. HANDBOOK.
Two points are cited as illustrating the difficulty of enforcing the present regulations, namely, (a) the variation in the angle of the headlight beam caused by the compression of the springs when the loading of the car is changed from no load to full load and (b) the variation of the tilting of the beam caused by the pitching of the car on an ordinary road, the effect being similar to that produced by flashes of lightning in a pitch-dark night. Denial is made of the author's alleged advocacy of diffused lighting and comparison is made of the distribution-curves obtained with frosted bulbs and those obtained with fairly good lamps conforming to the Society's specifications.
The complementary-color headlighting system is based upon the use of differentiated light, that is, light having different wave-lengths. Each head-lamp is oval and contains two paraboloid reflectors, one emitting light through an orange glass filter, the other through one of blue glass. While driving at night, the driver looks through a viewing-filter of transparent glass of the same color as that of the headlight which is in use. The viewing-filters are arranged so that whenever one is used, the headlight of the same color is automatically turned on. When the headlights are not in use, the filters are held in the filter-box and are out of sight. It is the intention that cars traveling in a general direction, say north and east, shall use the blue light; that those traveling south and west shall use the orange light. Each viewing-filter is transparent to the light that is thrown on the road by the headlights of the same car but is opaque to the lights of approaching cars.
After pointing out the existing dearth of easily workable data and formulas covering automobile suspensions, the author mentions the elements that contribute to riding comfort. He then outlines what he considers a good suspension, tabulating the spring dimensions of five hypothetical cars, typical of those on the American market. Curves of spring deflection are included in the paper. Functions of rear springs, the damping effect essential in good suspensions, “thin leaf” springs and spring lubrication are next discussed. In conclusion the author covers means of improving a car's riding qualities and cites a very interesting test for determining spring performance by means of the impressions made on a photographic plate by light from electric lamps mounted on wheels and fenders of an automobile and on the passengers.