• Title, Summary, Keyword: Fuel efficiency

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Sensorless Starting Method and Fuel Pressure Control of BLDC Motor for Fuel Pump of Vehicle (자동차 연료 펌프용 BLDC 모터의 센서리스 기동 및 연료 압력 제어)

  • Chang, Jin-Wook;Yoon, Duck-Yong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.2
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    • pp.114-121
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    • 2013
  • High efficiency operation is required for motors of vehicle to increase fuel efficiency due to the regulation of exhaust gas. This paper presents a control method of fuel pressure to increase fuel efficiency and a sensorless control method of BLDC motor to get higher efficiency than conventional brushed DC motor. Initial rotor position of BLDC motor is detected from current value that is occurred by test voltage pulse and rotor is accelerated by defined sequence to enter sensorless operation mode. The algorithm to control flow rate of fuel pump uses PI controller that is control motor speed to maintain the target fuel pressure commanded by ECU.

The development of High efficiency fuel processor for technical independence 5kW class fuel cell system (기술자립형 5kW 연료전지 시스템 구축을 위한 고효율 연료변환기 개발)

  • Lee, Soojae;Choi, Daehyun;Jun, Heekwon
    • 한국신재생에너지학회:학술대회논문집
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    • pp.123.2-123.2
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    • 2010
  • Fuel Cell cogeneration system is a promising technology for generating electricity and heat with high efficiency of low pollutant emission. We have been developed 5kW class fuel cell cogeneration system for commercial and residential application. The fuel processor is a crucial part of producing hydrogen from the fossil fuels such as LNG and LPG. The 5kW class high efficiency fuel processor consists of steam reformer, CO shift converter, CO preferential oxidation(PrOx) reactor, burner and heat exchanger. The one-stage CO shift converter process using a metal oxide catalyst was adopted. The efficiency of 5 kW class fuel processor shows 75% based on LHV. In addition, for the purpose of continuous operation with load fluctuations in the commercial system for residential use, load change of fuel processor was tested. Efficiency of 30%, 50%, 70% and 100% load shows 75%, 75%, 73% and 72%(LHV), respectively. Also, during the load change conditions, the product gas composition was stable and the outlet CO concentration was below 5 ppm. The Fuel processor operation was carried out in residential fuel cell cogeneration system with fuel cell stack under dynamic conditions. The 5kW class fuel processor have been evaluated for long-term durability and reliability test including with improvement in optimal operation logic.

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Maximum Efficiency Point Tracking Algorithm Using Oxygen Access Ratio Control for Fuel Cell Systems

  • Jang, Min-Ho;Lee, Jae-Moon;Kim, Jong-Hoon;Park, Jong-Hu;Cho, Bo-Hyung
    • Journal of Power Electronics
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    • v.11 no.2
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    • pp.194-201
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    • 2011
  • The air flow supplied to a fuel cell system is one of the most significant factors in determining fuel efficiency. The conventional method of controlling the air flow is to fix the oxygen supply at an estimated constant rate for optimal efficiency. However, the actual optimal point can deviated from the pre-set value due to temperature, load conditions and so on. In this paper, the maximum efficiency point tracking (MEPT) algorithm is proposed for finding the optimal air supply rate in real time to maximize the net-power generation of fuel cell systems. The fixed step MEPT algorithm has slow dynamics, thus it affects the overall efficiency. As a result, the variable step MEPT algorithm is proposed to compensate for this problem instead of a fixed one. The complete small signal model of a PEM Fuel cell system is developed to perform a stability analysis and to present a design guideline. For a design example, a 1kW PEM fuel cell system with a DSP 56F807 (Motorola Inc) was built and tested using the proposed MEPT algorithm. This control algorithm is very effective for a soft current change load like a grid connected system or a hybrid electric vehicle system with a secondary energy source.

Characteristics of Fuel Economy and CO2 according to Driving Pattern of Drivers (운전자간 드라이빙 패턴에 따른 연비·온실가스 특성)

  • Kang, Minkyung;Kwon, Seokjoo;Seo, Youngho
    • Journal of Institute of Convergence Technology
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    • v.6 no.1
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    • pp.13-16
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    • 2016
  • The purpose of this study is analysing the characteristics of vehicle fuel economy and greenhouse gase emissions according to driving pattern of drivers. Current fuel economy has not established on official test methods. The difference between actual fuel efficiency and specification fuel efficiency bring up consumer complaints and misunderstandings about fuel economy. Against this background, The country is progressing the study on influence of the fuel efficiency according to variety test conditions. This study analyze the driving pattern of the different drivers and influence of the fuel efficiency according to driving pattern of different drivers.

PERFORMANCE NEEDS OF TOMORROW'S DRIVELINE LUBRICANTS

  • Hong, Hyun-Soo
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.21-24
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    • 2002
  • There is a trend with driveline lubricants toward improved thermal stability, vehicle component durability and fuel efficiency. These improvements can significantly reduce vehicle operating costs and improve customer satisfaction. Of these improvements, the fuel efficiency is getting a substantial attention due to recent focus on $CO_2$ emission control in Europe, Japan and $CAF{\'{E}}$ requirement in U.S.A. Lower viscosity axle oils and transmission fluids are currently being evaluated as potential solutions since these lubricants tend to reduce the churning losses and can improve the fuel efficiency. However, these lubricants should provide adequate gear and bearing protection, while increasing the overall efficiency of the driveline components. In this paper, the development of new fuel efficient axle was discussed with the focus on the effect of base oils, additives, and viscosity modifiers on the fuel efficiency of driveline components.

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Reduction of Nitrogen Oxide by Fuel Staged Technology on the Combustion of Gasification Fuel (가스화 연료 연소시 단계적 연료주입 기술에 의한 질소산화물 저감)

  • Chae, Jong-Seong;Jo, Seon-Hui;Jeon, Yeong-Nam
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.2
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    • pp.107-116
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    • 1998
  • Coal gasification fuel has generally a lower calorific values than natural gas and also contains ammonia which is a main source of fuel NOx. Such a fuel is in need of the advanced technologies for the NOx reduction with higher combustion efficiency. Therefore fuel staged combustion was investigated for the fuel NOx control using a bench scale gas combustoi for the fuel NOx control. Parametric screening studies were performed with the variation of air ratio, retention length and reburning fuel. The NOx reduction efficiency was increased with an increase of total air ratio having optimum reburning air ratio differently, The Increased retention length of the reburning zone was preferable for NOx reduction. Hydrocarbonic reburning fuels like propane and butane were more effective for the NOx reduction efficiency than hydrogen fuel. The NOx concentration at exit was linearly increased according to the fuel-N the fuel.

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Rating of Agricultural Tractors by Fuel Efficiency (농업용 트랙터의 연료 소비 효율 등급화)

  • Kim, Soo-Chul;Kim, Kyeong-Uk
    • Journal of Biosystems Engineering
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    • v.35 no.2
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    • pp.69-76
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    • 2010
  • This study was conducted to develop an index of fuel consumption to rate agricultural tractors by their fuel efficiencies. The fuel consumption index consisted of two components: basic and operational indexes. The basic index is to consider an average amount of fuel consumed by engine when it transmits 20 and 100% of the rated power. The operational index is to consider the fuel consumed by tractor for typical field operations: plowing, rotavating, and the remains. The equations and procedures to obtain these indexes were proposed. The method and fuel consumption rate to classify tractors into 5 grades were also proposed. The best 15% of the tractor models were rated as the first grade, 20% as the second grade, 30% as the third grade, 20% as the fourth grade, and 15% as the fifth grade in order of fuel efficiency. Using the fuel consumption index, the classification was conducted on 143 tractor models tested at the National Institute of Agricultural Engineering from 2000 to 2007. The proposed 5-grade system of classification using the fuel consumption index could be used to rate the fuel efficiency of 20-100 kW tractor models produced over past 10 years in Korea.

A Study on the Solar Cell Charging Equipment for Hybrid Vehicle (Hybrid 자동차용 Solar Cell 충전장치에 관한 연구)

  • Kim, G.S.;Park, S.C.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.157-164
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    • 2011
  • Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.

Modeling of PEM Fuel Cell System-Sensitivity Analysis of System Efficiency with Different Main Operating Parameters of Automotive Fuel Cell System (PEM 연료전지 시스템 모델링-자동차용 연료전지 시스템의 주요 작동 변수 변경에 따른 시스템 효율 민감도 분석)

  • KIM, HAN-SANG;KANG, BYUNGGIL;WON, KWONSANG
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.5
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    • pp.401-410
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    • 2019
  • The operating conditions greatly impact the efficiency and performance of polymer electrolyte membrane (PEM) fuel cell systems and must be properly managed to ensure better performance and efficiency. In particular, small variations in operating conditions interact with each other and affect the performance and efficiency of PEM fuel cell systems. Thus, a systematic study is needed to understand how small changes in operating conditions affect the system performance and efficiency. In this paper, an automotive fuel cell system (including cell stack and balance of plant [BOP]) with a turbo-blower was modeled using MATLAB/Simulink platform and the sensitivity analyses of main operating parameters were performed using the developed system model. Effects of small variations in four main parameters (stack temperature, cathode air stoichiometry, cathode pressure, and cathode relative humidity) on the system efficiency were investigated. The results show that cathode pressure has the greatest potential impact on the sensitivity of fuel cell system efficiency. It is expected that this study can be used as a basic guidance to understand the importance of achieving accurate control of the fuel cell operating conditions for the robust operation of automotive PEM fuel cell systems.

Development of simulation model for fuel efficiency of agricultural tractor

  • Kim, Wan-Soo;Kim, Yong-Joo;Chung, Sun-Ok;Lee, Dae-Hyun;Choi, Chang-Hyun;Yoon, Young-Whan
    • Korean Journal of Agricultural Science
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    • v.43 no.1
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    • pp.116-126
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    • 2016
  • The objective of this study is to predict the fuel efficiency of an agricultural tractor. The fuel efficiency of the tractor during rotary tillage was predicted using numerical modeling. A numerical model was developed using Simulation X. Based on tractor power flow, numerical modeling consisted of an engine, transmission, PTO (power take off), and hydraulics. The specifications of major components utilized in the numerical model were the same as those of a 71 kW tractor (field test tractor). The load that was inputted for fuel efficiency prediction into the simulation model was obtained from a field test. Fuel efficiency predictions were conducted by comparing field test results and simulation results. In addition, it was performed by dividing the rotary tillage and steering section. Main results are as follows: first, t-values of engine torque were measured to be 0.31 in the rotary tillage and 0.92 in the steering section. Second, t-values of fuel consumption were measured to be 0.51 and 5.41 in the rotary tillage and the steering section, respectively. Finally, t-values of fuel efficiency were measured to be 1.72 and 40 in the rotary tillage and the steering section, respectively. The results show no significant differences with t-values of less than 5% in the rotary tillage. But, it shows significant differences in the steering section. Therefore, simulation for accurate fuel efficiency prediction requires a suitable algorithm or detailed design of the simulation model in the steering section.