• Transactions of the Korean Society of Automotive Engineers
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• 제21권1호
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• pp.92-98
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• 2013

There are lots of studies about hybrid electric vehicles (HEVs) because of the global warming and energy problems. Series and parallel HEVs are the common types of many developing hybrid vehicle types. Series HEV uses engine only as the generator for the battery but parallel HEV utilizes engine for driving and generating of the vehicle. In this paper, backward simulations based on dynamic programming were conducted for the fuel economy analysis of two different types of hybrid transit buses depending on driving cycles. It is shown that there is a relation between the type of HEV and the characteristics of driving cycles. Regarding the aggressiveness, the series hybrid bus is more efficient than the parallel system on highly aggressive driving cycle. On the other hand, the parallel hybrid bus is more efficient than the series system on low aggressive driving cycle. Based on this results of the paper, it is expected to choose more efficient type of the hybrid buses according to the driving cycle.

• Transactions of the Korean Society of Automotive Engineers
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• 제11권5호
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• pp.170-175
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• 2003

A control algorithm is developed for highly efficient operation of auxiliary power unit (APU) that consists of a diesel engine and a directly coupled induction generator in series hybrid electric Bus (SHEB). In a series hybrid configuration the APU supplies the electric power needed for maintaining the state of charge (SOC) of the battery unit in various conditions of vehicle operation. As the rotational speed of generator does not depend on the vehicle speed, an optimized operation of engine-generator unit based on the efficiency map of each component can be achieved. The output torque of diesel engine can be controlled by the amount of fuel injection, and the power converted from mechanical to electrical energy can be adjusted by generate control unit (GCU) using the decoupling vector control of torque and flux. As for the given reference of the generating power, the multiply of speed and torque, many combinations of operating speed and torque are possible. The algorithm decides the new operating point based on the engine efficiency map and generator characteristic curve. During the transition of operating points, the speed controller saturation is avoided using variable limit and filtering of generator torque reference. A test rig and SHEB consist of a 1.5L diesel engine and a 30kw induction generator are constructed by Hyundai Motor Company.

• Journal of the Korea Institute of Military Science and Technology
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• 제19권4호
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• pp.517-525
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• 2016

In this research, the effect of the pressure control of cooperative control system with regenerative brake for a military series hybrid-electric vehicle was studied. A cooperative control system with regenerative brake was developed to maximize regenerative energy from electric traction motors of the vehicle. However, the pressure control method of the system was modified to solve a time delay problem and it deteriorates the performance of the system. A Simulink model including the hybrid-electric components, the cooperative control system with regenerative brake, and the vehicle dynamics was developed and used to find a solution. The regenerative energy ratio with respect to the whole brake energy was increased in this research from less than 60 % to over 80 %.

• The Journal of the Korea institute of electronic communication sciences
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• 제13권2호
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• pp.443-448
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• 2018

Recently, Hybrid Electric Vehicle(: HEV) is in the spotlight to global warming caused by carbon dioxide and emission reduction. HEV consists of a combination of mechanical engine and electric motor system. The flow of energy required to drive a HEV depends on the driving conditions of the vehicle. In this paper, we study the contents of HEV education using real-time monitoring system. A real-time monitoring system consisting of hardware and virtual programs is used to simulate the overall operation of a HEV through simulations according to driving conditions and to explain how to learn through hardware.

• Journal of the Korean Society for Precision Engineering
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• 제29권7호
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• pp.770-777
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• 2012

This paper deals with the design and modal characteristics analysis of a drive-train for a paralleltype hybrid electric vehicle (HEV). The function of the drive-train system (DTS) in the HEV combines or divides the torque and velocity from the internal combustion engine along with the induction motor. The system consists of a compound planetary gear and unit's electromagnetic clutch to provide the operation modes such as Engine Only (EO), Electric Vehicle (EV), and Hybrid Electric Vehicle (HEV) modes. In order to investigate the characteristics of the velocity and torque flow for the system, dynamic models of the HEV with DTS are derived from the prototype DTS. The performance of the derived dynamic models is evaluated by both computer simulations and experiments according to each mode.

• Journal of Energy Engineering
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• 제20권1호
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• pp.1-7
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• 2011

The performance and life-cycle costs of electric vehicle(EV) and hybrid electric vehicle(HEV) depend inherently on battery packs. Temperature uniformity in a pack is an important factor for obtaining optimum performance for an EV or HEV battery pack, because uneven temperature distribution in a pack leads to electrically unbalanced battery cells and reduced pack performance. In this work, a three-dimensional modeling was carried out to investigate the effects of operating conditions on the thermal behavior of a lithium-ion battery pack for an EV or HEV application. Thermal conductivities of various compartments of the battery were estimated based on the equivalent network of parallel/series thermal resistances of battery components. Heat generation rate in a cell was calculated using the modeling results of the potential and current density distributions of a battery cell.

• Journal of ILASS-Korea
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• 제25권1호
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• pp.34-39
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• 2020

Automotive manufacturers are applying technologies for greenhouse gas reduction such as vehicle weight reduction, engine downsizing, direct injection technology, variable valves and transmission performance improvement to achieve the targets for enhanced greenhouse gas and fuel consumption efficiency. In this paper, compared and analyzed greenhouse emissions according to engine capacity, engine displacement, curb weight and sales volume of hybrid and internal combustion engine passenger vehicles. Hybrid emit 32~39% less greenhouse gas than internal combustion engines through the combined mode test method. Hybrid electric vehicle's curb weight was about 7% heavier on average for the same engine displacement, while greenhouse gas was about 36% lower. It was confirmed that in order to reduce the emission of pollutants of greenhouse gases as well as the air pollutants, it is necessary to expand the supply of eco-friendly vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• 제24권3호
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• pp.330-337
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• 2016

In this paper, component sizing and analysis of the novel plug-in hybrid electric vehicle powertrain configuration is conducted. Newly proposed powertrain configuration in prior study has an internal combustion engine and two electric motors. To optimize component size of the vehicle system and reduction gear ratio, component sizing methodology is proposed and conducted. Required power for vehicle's dynamic performance is calculated to decide minimum power requirement of powertrain component combination. Component size of engine and electric motor are optimized using vehicle simulation to maximize fuel economy performance. Optimized powertrain configuration and vehicle simulation results present validation of newly proposed vehicle system.

• Proceedings of the KIEE Conference
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.256-257
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• 2011

The development for Eco-friendly cars has been expanded as the concern about environmental pollution and a rise in gas prices. The Electric Vehicle(EV) and Plug in Hybrid Electric Vehicle(PHEV) are generally connected on distribution power systems to charge the traction batteries. The growing number of EV/PHEVs could have a effect on distribution power systems and result in overload of power utilities and power quality problems. In order to reduce the adverse effect on distribution power systems, the influence of electric vehicle loads should be evaluated. In this paper, the influence of electric vehicle loads is evaluated by using OpenDSS(Open Source Distribution System Simulator) according to the penetration rate of electric vehicle.

• Journal of ILASS-Korea
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• 제27권4호
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• pp.211-218
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• 2022

Recent vehicle regulations have become increasingly stringent in order to reduce greenhouse gases. Then not only movement to replace internal combustion engine vehicles with hybrid vehicles, but also studies of replacing internal combustion engine fuels with low-pollution fuels are increasing. In this study, the characteristics of a vehicle with LPG fuel engine and mild hybrid system is investigated. To avoid shortage of maximum power on LPG engine, a direct injection system of LPG is applied. In addition, P0 mild hybrid system is adopted to enhence the efficiency of the vehicle. The vehicle model is developed in order to predict fuel economy and CO2 emission of LPDi MHEV.