Cost-effective centrifuge coating method for silver nanowire-based transparent conducting electrode

Dual-separated cooling channel performance evaluation for high-power led Pcb in automotive headlight

While a vehicle is driving, the air filter is gradually being clogged. Thus, there is a condition for air mass delivered into the engine’s cylinders to be reduced. It can further degrade the vehicle’s ability to accelerate and, therefore, have an impact on road driving safety, or it can eventually make a vehicle performance worse or cause a change in the exhaust gas composition. The article pays attention to the impact of clogged air filter on selected vehicle characteristics including a vehicle’s dynamic features, fuel consumption and composition of the exhaust gases. The measurements have been performed under laboratory conditions. For higher result objectivity, the measurements have been done under some extreme conditions as well, with both the air filter fully clogged and forced air induction. The importance of the article lies in quantification of the impact of clogged air filter on selected vehicle features. The results from this article show a relatively low impact of air filter on the features studied. The biggest differences were measured under extreme conditions when the air filter had been almost fully clogged, or the air had been delivered into the engine under pressure.

https://www.mdpi.com/2071-1050/12/22/9326/pdf

Air Filter and Selected Vehicle Characteristics

Although visible light communication (VLC) systems provide high density links for use in Internet-of-Things (IoT) devices, the design of high rate VLC transmitters that maintain luminaire efficacy is an open problem. In this article, a novel approach to the integration of VLC within light-emitting diode (LED) drivers is proposed through the replacement of freewheeling/blocking diodes with light-emitting devices termed a light-emitting commutating diodes (LECDs). In this manner, communications and illumination can be provided using a simple, cost effective design while employing no additional components. The subtle change of LED driver control signals facilitates the transmission of data from LECDs while simultaneously supporting illumination functions. Lighting controls such as dimming are maintained and combined with modulation through the use of overlapping pulse position modulation (OPPM) and performance is quantified. Prototype buck and boost converters with LECDs are implemented and their efficacy is measured. Though current commercial LEDs are not intended for such signalling applications, we experimentally demonstrate their feasibility in this application and suggest methods to make such converters reliable. It is demonstrated that the addition of an LECD improves the efficacy of the luminaire as compared to conventional LED drivers while simultaneously enabling a VLC downlink.

/pdf/light-emitting-commutating-diodes-for-optical-wireless-2yyivbabrc.pdf

Light-Emitting Commutating Diodes for Optical Wireless Communications Within LED Drivers

With the advances in the technology of materials based on GaN, high brightness white light emitting diodes (LEDs) have flourished over the past few years and have shown to be very promising in many new illumination applications such as outdoor illumination, task and decorative lighting as well as aircraft and automobile illuminations. The objective of this paper is to investigate an active liquid cooling solution of such LEDs in an application of automotive headlights. The thermal design from device to board to system level has been carried out in this research. Air cooling and passive liquid cooling methods are investigated and excluded as unsuitable, and therefore an active liquid cooling solution is selected. Several configurations of the active liquid cooling system are studied and optimisation work has been carried out to find an optimum thermal performance.

https://hal.archives-ouvertes.fr/hal-00171358/document

Liquid Cooling of Bright LEDs for Automotive Applications

Experimental analysis on estimating junction temperature and service life of high power LED array

The automotive lighting industry is adopting compact cooling systems for high power light emitting diodes (HPLED) to overcome the heating issues in headlamps. Today, nano-particle based fluids are becoming popular as coolants as it is more effective than conventional coolant like water. The present work uses nano-fluid which is prepared using 100 percent ethylene glycol with 35 nm spherical shaped alumina nanoparticle with 1 percent volume concentration for HPLED cooling system. Using a custom made copper tube heat exchanger, experiments were conducted to study the performance of the cooling system using nano coolant and double distilled pure water as second coolant and results were compared. A popular Indian SUV headlamp that uses a halogen bulb was chosen for the study as it has space to accommodate the cooling system. Experiments were conducted by operating the HPLED at its maximum power and by varying the coolant flow rate. The performance of headlamp is studied by means of the light intensity measured at 49 test points on the floor surface and temperature measured at various points like LED junction and heat exchanger input and output. The junction temperature influences the light intensity of the LED. Lesser the junction temperature more will be the light intensity. It was found from the results that the junction temperature reduced by 26 percent with the help of the nano-fluid based cooling system. It is also found that the light intensity improved by 30 percent when the nano coolant was circulated at 0.3 m/s.

Liquid cooling system for a high power light emitting diode of an automotive headlamp and its effect on light intensity

The improved benefits of the general light emitting diode (LED) attracts the automotive lighting industry and as a result many of the higher end cars today are fitted with LED headlight in place of halogen and xenon bulb based headlights. The advantages include higher operating efficiency, compactness and improved bulb life. In this research, a comparison between the halogen and LED based headlight systems was carried out by focusing on their temperature distributions and light intensity illumination. For this purpose, headlights of SUMO Victa, a Multi Utility Vehicle (MUV) from TATA Motors is used. A LED bulb assembly was fabricated using SMD LEDs which was retrofitted into the Victa headlamps by replacing the original halogen bulb. To dissipate the heat produced by LED, a heatsink fabricated from copper sheet and fitted with copper powder was used. LED bulbs are fitted around the heatsink to effectively remove the heat generated during LED operation and control the junction temperature. To evaluate the performance of the fabricated SMD LED bulb and halogen bulb, experiments were carried out to capture the temperature distribution on bulb, inner and outer surface of headlight along with light intensity. The results clearly show that the LED bulb achieves higher light intensity, less power consumption and temperature distribution than a halogen bulb.

Investigation on light intensity and temperature distribution of Automotive's Halogen and LED headlight

https://iopscience.iop.org/article/10.1088/1757-899X/263/6/062056/pdf

Performance analysis of photoresistor and phototransistor for automotive’s halogen and xenon bulbs light output

The air filter is an important part in an automobile, with clogged air filters the engine may face a lot of problems. Filter clogging is an important problem but it is ignored. A lot of problems faced in vehicles are due to clogging of air filters. The objective of this study is to investigate and compare the effect of different stages of filter clogging on performance and emissions from engine. The experimental work has been carried out on single cylinder four stroke water cooled diesel engine. Readings were taken for five different stages of load, 0%, 25%, 50%, 75% and 100% load. Hypothetical situation of filter clogging is created by blocking the filter area in four stages 0%, 25%, 50% and 75%. Results show that BSFC and BTE both increase 10–20%. CO, HC and CO2 increase as max as 25% and NOx emissions reduce 7–16% for different filter clogging percentages.

A. Rammohan

Papers

Experimental analysis on estimating junction temperature and service life of high power LED array

Liquid cooling system for a high power light emitting diode of an automotive headlamp and its effect on light intensity

Investigation on light intensity and temperature distribution of Automotive's Halogen and LED headlight

Performance analysis of photoresistor and phototransistor for automotive’s halogen and xenon bulbs light output

Investigation of effect of air filter clogging on performance and emissions from engine