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A Control System for Maintaining Passenger Cabin Air Quality

Chulalongkorn University-Thanin Wangsawangkul, Thiti Maneepipat, Nattapong Sukumdhanakul, Porpin Pungetmongkol, Prabhath De Silva
DENSO International Thailand-Pradit Mahasaksiri
  • Technical Paper
  • 2020-01-1243
To be published on 2020-04-14 by SAE International in United States
This paper presents a control methodology to maintain vehicle cabin air quality within desirable levels, giving particular attention to gaseous contaminants carbon dioxide (CO2) and carbon monoxide (CO). The CO2 is generated by the occupant exhalation while the CO is assumed to be ingested with the incoming fresh air. The system is able to detect and improve cabin air quality by controlling the recirculation flap of the ventilation system to control the amount of fresh air intake. The methodology is demonstrated in the laboratory using controlled experiments with a production level automotive HVAC (Heating Ventilating and Air-Conditioning) module. The results indicated that the designed control system can work automatically and control the CO and CO2 gas concentrations within acceptable levels.
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Study on Drowsy Driving Behavior from Driver Steering Pattern and Lane Offset Using Driving Simulator

Chulalongkorn University-Nuksit Noomwongs
Chualongkorn University-Pakpum Somboon
Published 2019-03-25 by SAE International in United States
Drowsiness has been one of the major reasons of road fatality over a decade because the effect of drowsiness is trying to shut down both mind and body. That means drivers are unable to completely control the car while trapped in an unconscious state. It will lead to a several number of casualties on road. In this research, two sets of people, partial sleep-deprivation and non-sleep-deprivation, are tested on the driving simulator. Two methods were used in this study to identify driver drowsiness. First, driving behavior focusing on steering pattern. And secondly, vehicle offset from the lane center. The tests were carried out on the designed scenarios in the Driving Simulator. The scenarios are such as following straight lane with vehicle along the road, following curve lane without other cars, car following on a single lane and following straight lane without other cars. From the results, there are significant results that can roughly separate drowsy driver from regular driver. The graph of both root mean square error with threshold or RMT and steering handling pattern…
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Effect of Slot and Chamfer Shape of Brake Pad on Mode Coupling

Chulalongkorn University-Sirapath Yeamdee, Thiti Bovornratanaraks, Chanat Ratanasumawong
Compact International (1994) Co., Ltd.-Meechai Sriwiboon
Published 2019-03-25 by SAE International in United States
In the present, one of the essential quality concerns in the automotive industry is brake squeal. Brake pad shape is one of the factors affecting to brake vibration and squeal noise. This research aims to study the effect of slot and chamfer shape on mode coupling through the Finite Element Analysis (FEA), impact hammer testing and performance test from dynamometer. The results can be used to develop geometry of the brake pad surface that leads to brake squeal reduction in the design stage. The natural frequencies and mode shape of brake components calculated by FEA are compared with the impact hammer testing to ensure the accuracy of the results. The FE results are also verified through the standard test with a dynamometer.
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Cabin-Ambient Air Exchanges and Their Relation to In-Vehicle CO2 Concentration

Chulalongkorn University-Tanawat Tessathan, Chutiphon Thammasiri, Prabhath De Silva, Rehan Hussain, Nuksit Noomwongs
Published 2017-03-28 by SAE International in United States
It is common for users of commuting passenger cars in Thailand to use the vehicle’s HVAC (Heating, Ventilating and Air Conditioning) system predominantly in recirculation (REC) mode. This minimizes the compressor work, thereby saving fuel, and reduces dust and odor infiltration into the vehicle cabin. The car windows are rarely opened for ventilation purposes, except for exchanges at service stations such as garage entrances and tollway booths. As such, there are few opportunities for fresh air to enter the cabin with the consequent accumulation of CO2 in vehicle cabins due to occupants’ exhalations being well documented. Field experiments conducted showed that the in-vehicle CO2 concentrations could reach up to 15 times that of the ambient concentration level during typical city commutes. Preliminary experiments were also conducted to quantify the air exchanges between the cabin and the ambient when the doors are opened for occupant egression. The results indicated that the amount of air exchange depends on the prevailing wind speed and direction, the number of doors opened, and the duration of the door opening.
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Road Surface Condition Detection in Bicycle for Active Safety Applications

Chulalongkorn University-Gridsada Phanomchoeng, Sunhapos Chantranuwathana
Published 2017-03-28 by SAE International in United States
Nowadays, the tendency of people using bicycles as the way of transportation has increased as well as the tendency of the bicycle accidents. According to the research of National Highway Traffic Safety Administration (NHTSA), National Survey on Bicyclist and Pedestrian Attitude and Behavior, the major root causes of bicycle accidents are from the road surface condition. Thus, this work has developed the system to detect the road surface condition. The system utilizes the laser and camera to measure the height of road. Then, with the information of the road height and bicycle speed, the road surface condition can be classified into 3 categories due to severe condition of the road. For the secure road, cyclists could safely ride on it. For the warning road, cyclists need to slow down the speed. Lastly, for the dangerous road, cyclists have to stop their bicycles. Also, the road surface condition information is useful for many active safety applications such as active warning systems to increase the reliability of the system and safety of cyclists.
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Sensitivity Analysis of the Total Cost of Ownership for Electric Feeder Bus Using Various Types of Energy Storage

Chulalongkorn University-Wachira Nilprapunt, Angkee Sripakagorn
Published 2016-03-27 by SAE International in United States
Urban Mobility is one of the most critical issues at the present. Public transport in connection with feeder bus system is proposed to be one of the main solution. Chulalongkorn University has a fleet of electric feeder bus in operation for a few years now. The fleet service is, however, to be improved because of current limitations in battery energy capacity and long battery charging time. This paper aims to examine the total cost of ownership (TCO) of the electric feeder buses using various types of energy storage. The results on the sensitivity analysis highlight the major parameters that exert strong influence in the TCOs. The fast charging system using supercapacitor battery bus shows the lowest TCO for the present bus fleet. The travel distance (km/year) and operational years were illustrated to be the top two parameters that exert major influence towards the TCO.
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A Study on Car Following and Cognitive Ability of Elderly Drivers by Using Driving Simulator

Chulalongkorn University-Thitsadee Ngernsukphaiboon, Sunhapos Chantranuwathana, Nuksit Noomwongs, Angkee Sripakagorn, Solaphat Hemrungrojn MD
Published 2016-03-27 by SAE International in United States
The world is aging rapidly. Many countries can already be categorized as aging or aged societies while a few are becoming super-aged societies. In Thailand as well as in other countries, traffic accidents caused by elderly drivers will continue to rise as a significant percentage of elderly people still prefer to drive. Accidents may be prevented with driving tests and screening methods for elderly drivers. However, it is also necessary to understand the effect of aging on driving ability. With this understanding, driver training, driver assistant systems, and improvements on infrastructure may be designed accordingly. Among various physical changes, cognitive ability of the brain is one of the most significant factors affecting driving ability. In this paper, correlation between various cognitive functions of the brain and car following skill of drivers are considered. Car following skill was chosen because rear-end collisions are some of the most frequent type of accidents in Thailand. Car following skill can be measured objectively by using time headway. Furthermore, car following experiments can be studied reproducibly and safely on a…
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Electrification of Public Transport with Fast Charging in Traffic Congested Cities

Chulalongkorn University-Thitipat Thitacharee, Angkee Sripakagorn
Published 2016-03-27 by SAE International in United States
The utility of energy efficiency and zero-emission of electric vehicles leads the way to electrify the urban public transport bus networks in many cities around the world. The purpose of this paper is to study the operational feasibility of transition the existing conventional combustion bus fleet to Electric bus fleet. The analysis is based on the data of the bus operation in Bangkok, Thailand. Traffic congestion as occurred in Bangkok is considered in the analysis. This research is focused on Fast charging technology of Electric vehicles. Instead of slow-charging overnight, Fast-charging is used during the regular layover time of the bus operation which is called Opportunity charging. The opportunity charging allows to extend the driving range of the electric buses which is a prominent problem of electric vehicles. The result stipulates the smallest number of batteries needed to meet the route requirement which come up with outstanding efficiency in energy consumption and more spacing of bus configuration. Rather than focusing on maximizing driving range, the outcome could lead to the optimization between on-buses energy storage…
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Driving Risk Rating for Driver Monitoring Based on Satellite Data

Chulalongkorn University-Natt Winitthumkul, Peerapat Phondeenana, Nuksit Noomwongs
Published 2016-03-27 by SAE International in United States
According to the recent study, Thailand has the 2nd most dangerous road in the world. Based on many researches, the driver is the main influencers of the traffic fatalities. Since the more dangerous the driver drive, the more chance of accident become. Therefore, driver’s monitoring system become one of the solutions that acceptable and reliable, especially for fleet management and public transportation.This paper’s goal is to find an algorithm that can distinguish driving behaviour based on cars’ acceleration and velocity, calling it as Risk Driving Score (RDS). The algorithm was tested by driving test by volunteers on highways with observers, who were told to rank the drivers in terms of driving risk from the 1-5 point. Meanwhile, the drivers were asked to drive in 3 different styles, normal, safety, and hurry. All drives were recorded by satellite and video data then filtered and used for the algorithm calculation. After that, the linear regression shows that there is a trend of driving score evaluated by algorithm and observers in term of linear equation with high correlation.…
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Vehicle Safety Monitoring System with Next Generation Satellite Navigation: Part 2 Excessive Acceleration Detection

Chulalongkorn University-Raksit Thitipatanapong, Sunhapos Chantranuwathana, Nuksit Noomwongs, Sanya Klongnaivai
Suranaree University of Technology-Pornporm Boonporm, Petch Wuttimanop
Published 2015-03-30 by SAE International in United States
The road accident is major concern around the world, so do Thailand. It is caused by three main factors: man, vehicle and infrastructure. The most important part that accounts the safety of vehicle is human. With experiences and careful driver, the accident could be diminished. So that the vehicle monitoring systems are the vital tools to screen out the inexperience or aggressive driver.In this paper, we state the problem about the dangerous driving behavior by monitoring lateral and longitudinal acceleration. For this purpose, the inertial measurement unit should be applied but it is inconvenient to install in the vehicle. Consequently, the vehicle monitoring system were developed based on novel consumer grade multi-satellite navigation receivers and were compared to Racelogic Video V-Box system in controlled condition tested track. The incidents were virtually detected and reviewed. The incident detection algorithm were proposed and tested alongside with receivers.As results, the vehicle lateral and longitudinal acceleration from all receivers were correlated with virtually count. With incident detection algorithm that cut off at 0.25g in both directions were detected and…
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