Leds and Power Consumption of Exterior Automotive Lighting: Implications for Gasoline and Electric Vehicles
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UMTRI-2008-48 OCTOBER 2008 LEDS AND POWER CONSUMPTION OF EXTERIOR AUTOMOTIVE LIGHTING: IMPLICATIONS FOR GASOLINE AND ELECTRIC VEHICLES BRANDON SCHOETTLE MICHAEL SIVAK YOSHIHIRO FUJIYAMA LEDS AND POWER CONSUMPTION OF EXTERIOR AUTOMOTIVE LIGHTING: IMPLICATIONS FOR GASOLINE AND ELECTRIC VEHICLES Brandon Schoettle Michael Sivak Yoshihiro Fujiyama The University of Michigan Transportation Research Institute Ann Arbor, Michigan 48109-2150 U.S.A. Report No. UMTRI-2008-48 October 2008 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipients Catalog No. UMTRI-2008-48 4. Title and Subtitle 5. Report Date LEDs and Power Consumption of Exterior Automotive October 2008 Lighting: Implications for Gasoline and Electric Vehicles 6. Performing Organization Code 302753 7. Author(s) 8. Performing Organization Report No. Schoettle, B., Sivak, M., and Fujiyama, Y. UMTRI-2008-48 9. Performing Organization Name and Address 10. Work Unit no. (TRAIS) The University of Michigan Transportation Research Institute 11. Contract or Grant No. 2901 Baxter Road Ann Arbor, Michigan 48109-2150 U.S.A. 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered The University of Michigan Industry Affiliation Program for 14. Sponsoring Agency Code Human Factors in Transportation Safety 15. Supplementary Notes The Affiliation Program currently includes Alps Automotive/Alpine Electronics, Autoliv, BMW, Chrysler, Com-Corp Industries, Continental Automotive Systems, Denso, Federal- Mogul, Ford, GE, General Motors, Gentex, Grote Industries, Hella, Hitachi America, Honda, Ichikoh Industries, Koito Manufacturing, Lang-Mekra North America, Magna Donnelly, Mitsubishi Motors, Muth, Nissan, North American Lighting, OSRAM Sylvania, Philips Lighting, Renault, SABIC Innovative Plastics, Sisecam, SL Corporation, Stanley Electric, Toyota Technical Center USA, Truck-Lite, Valeo, Visteon, and 3M Visibility and Insulation Systems. Information about the Affiliation Program is available at: http://www.umich.edu/~industry/ 16. Abstract This study evaluated the power consumption of traditional and LED-based exterior lighting systems on passenger vehicles, examining nominal consumption as well as realistic consumption based on real-world usage patterns of various lighting equipment. The results indicate that an all-LED system employing the current generation of LEDs would result in general power savings of about 50% (nighttime) to about 75% (daytime) over a traditional system. The effect on long-term savings for the LED system depends upon the type of vehicle in use (gasoline-powered vs. electric). While the long-term fuel- cost savings (dollars) were higher for the gasoline-powered vehicle, long-term distance savings (range) favored the electric vehicle. Also presented are calculations of potential savings for two different scenarios of future improvements in LED power consumption. 17. Key Words 18. Distribution Statement LED, exterior lighting, electric vehicle, power consumption Unlimited 19. Security Classification (of this report) 20. Security Classification (of this page) 21. No. of Pages 22. Price None None 21 i ACKNOWLEDGMENTS Appreciation is extended to the members of the University of Michigan Industry Affiliation Program for Human Factors in Transportation Safety for support of this research. The current members of the Program are: Alps Automotive/Alpine Electronics Lang-Mekra North America Autoliv Magna Donnelly BMW Mitsubishi Motors Chrysler Muth Com-Corp Industries Nissan Continental Automotive Systems North American Lighting Denso OSRAM Sylvania Federal-Mogul Philips Lighting Ford Renault GE SABIC Innovative Plastics General Motors Sisecam Gentex SL Corporation Grote Industries Stanley Electric Hella Toyota Technical Center, USA Hitachi America Truck-Lite Honda Valeo Ichikoh Industries Visteon Koito Manufacturing 3M Visibility and Insulation Systems The authors thank Michael Larsen of GM and Jeff Erion for assistance with this research. However, the authors are solely responsible for the content of this report. ii CONTENTS ACKNOWLEDGMENTS ............................................................................................. ii INTRODUCTION......................................................................................................... 1 APPROACH ................................................................................................................. 2 Lamp usage data...................................................................................................... 2 Lighting systems examined...................................................................................... 3 Baseline power ........................................................................................................ 3 Traditional system ............................................................................................. 3 LED system........................................................................................................ 3 Values used in the power consumption and savings calculations.............................. 4 Vehicle efficiency (kWh/km).............................................................................. 4 Fuel costs ($/kWh) ............................................................................................ 5 RESULTS..................................................................................................................... 6 General power requirements .................................................................................... 6 Daytime functions.............................................................................................. 6 Nighttime functions............................................................................................ 7 Long-term power consumption................................................................................ 7 Potential long-term power savings........................................................................... 9 Daytime savings per 100 km: No DRLs.............................................................. 9 Daytime savings per 100 km: Dedicated DRLs................................................... 9 Nighttime savings per 100 km ............................................................................10 Total annual savings..........................................................................................12 Potential savings with future reductions in LED power consumption .................13 DISCUSSION...............................................................................................................15 REFERENCES..............................................................................................................17 iii INTRODUCTION In a recent study, we documented the increasing use of light-emitting diode (LED) light sources for various external lighting functions on light vehicles sold in the U.S. (Schoettle, Sivak, and Takenobu, 2008). In that study, we surveyed 97% of all currently sold light-vehicle models, and provided sales-weighted information about the frequencies of LEDs. Although the results showed that overall penetration of LEDs for most external functions is still low, advances in technology have recently enabled vehicle manufacturers to offer completely LED-based exterior lighting systems for the first time. One of several advantages that LED lighting offers over traditional lighting systems is the reduction in power required to perform the same functions. Recent studies (DOE, 2003; Erion, 2006) have examined the power savings in automotive applications using LEDs. The critical factor in such calculations is the frequency of use of various functions. Previous work has relied on either estimates (DOE, 2003) or frequency of use by employees of a vehicle manufacturer (Erion, 2006). There are two main contributions of the present study. First, we used recent data on the usage of different lighting functions that were obtained in a naturalistic study employing a large, random sample of drivers. Second, we extended the focus of implications beyond gasoline-powered passenger vehicles to electric vehicles as well. Consequently, savings with LED lighting were expressed not only in terms of power and cost reductions, but also in terms of increases in range on an individual charge for current electric vehicles. 1 APPROACH Lamp usage data The usage data for various lamps and lighting functions on U.S. passenger vehicles came from Buonarosa, Sayer, and Flannagan (2008). In turn, those data were obtained in a field operational test at UMTRI of crash-warning systems, with 87 drivers using 11 instrumented vehicles. Each driver used one instrumented vehicle as a personal vehicle for between 13 and 27 days, with data collection occurring each time the vehicle was driven. Table 1 shows the summary data that were used in the present study. Table 1 Average usage rates for each function. Average usage rate Function Minutes per 100 km Hours per year DRL 116.5† 382.0 Low beam 97.6* 97.3 High beam 9.8* 9.8 Parking/position 107.4* 107.1 Turn signal, left 5.8 24.9 Turn signal, right 4.6 19.5 Side markers 107.4* 107.1 Stop 18.9 80.7 Tail 107.4* 107.1 CHMSL 18.9 80.7 Backup/reverse 0.9 3.8 License plate 107.4* 107.1 † Daytime driving only. * Nighttime driving only. 2 Lighting systems examined Two lighting systems were considered in this study: a traditional system using 100% incandescent and halogen light sources, and a 100% LED system. To simplify the comparisons, it was