머신러닝을 활용한 시내버스 연비 운전 점수화 알고리즘 개발

김기복(Kibok Kim),이종화(Jonghwa Lee),박진일(Jinil Park) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

An eco-drive system was implemented on urban buses in Seoul. The system includes a shift indicator and the calculation of eco-drive score. With the implementation, 3,864 vehicles showed improvement in fuel economy by 12.1% annually. The eco-drive score indicates the degree of fuel economy of driving by monitoring acceleration and deceleration, timing of gear shift, accelerator pedal gradient, and coasting rate. During the annual operation, the eco-drive score showed discrepancy depending on the driving environment. This revealed the need to improve the linearity between fuel economy and the score. The eco-drive score was calculated based on OBD data, and external factors such as traffic environment and road conditions were not considered. In this study, the environmental factors of fuel economy were identified to supplement the eco-drive score. This is achieved by developing a machine learning fuel economy prediction model. The environmental factors are examined by assessing the contribution of each input variable (feature) of the fuel economy prediction model through SHAP-value. The driving start time, driving date, number of gear shifts per unit distance, and brake operation ratio during driving were set as the environmental factors of fuel economy. The measured fuel economy is normalized using the relationship between the average fuel economy and each of the environmental factor of the annual driving data. The eco-drive score is corrected in the range of 0.84-1.05 times based on the normalized fuel economy distribution of the equivalent eco-drive score. A corrected eco-drive score prediction model was developed, and the environmental factor of the fuel economy was used as the prediction model feature of the eco-drive score. The eco-drive score increased with an increase in the normalized fuel economy. The correlation between fuel economy and eco-drive score was 34% improved by considering the environmental factors of fuel economy.

ANALYZING UNCERTAINTY IN EVALUATION OF VEHICLE FUEL ECONOMY USING FTP-75

H. WI,박진일 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.3

Fuel economy is one of the major issues in the development of automobiles, along with performance and drivability. During a fuel economy test, the driver should follow the target schedule as closely as possible. However, it is impossible even for a skillful driver to completely follow the prescribed speed pattern; therefore, a speed tolerance, the extent to which violation of the prescribed speed pattern is permitted, is approved by the administrator of the test and has been used during fuel economy certification tests. Consequently, there is a difference in speed every time that a fuel economy certification test is conducted and therefore there is also a deviation in the certified fuel economy. Nevertheless, no research has been carried out into the deviation of fuel economy according to the observance of the target schedule by a driver. In this respect, this research aims to investigate the deviation of fuel economy which may take place during a fuel economy certification test. Fuel economy deviation is examined in three cases: driving at the highest or lowest speed in the defined range of speed tolerance, driving with the maximum or minimum tolerated acceleration, and driving with periodic variation from the prescribed speed. The periodic variation effects to the fuel economy deteriorated by more than 8%.

자동차의 주행거리 누적과 연비의 인과관계 분석 연구

노경완(Kyung Wan Rho),정환중(Hwan Jung Jung),심창호(Chang Ho Sim) 한국자동차공학회 2021 한국 자동차공학회논문집 Vol.29 No.6

The fuel economy of vehicles is the main concern for policy makers, vehicle manufacturers and consumers. Understanding the fuel economy of vehicles has important implications for fuel economy, greenhouse gas emissions and consumer information policies. Consumers need more fuel economy information to make informed decisions about their vehicle usage. This study seeks to satisfy our curiosity on whether fuel economy is closely related with cumulative mileage. The fuel economy data based on four different mileage conditions are measured by testing eight vehicles on two drive cycles (FTP-75 and HWFET) in accordance with the government test method to analyze and compare relationships between mileage and fuel economy. Statistical approaches with one-way ANOVA and paired t-test are used to verify causality between cumulative mileage and fuel economy. There is no mileage effect on vehicle fuel economy as shown in the one-way ANOVA results. The paired t-test analysis shows that fuel economy is minimally affected by cumulative mileage. However, it is difficult to ascertain if cumulative mileage can cause negative effects on fuel economy.

중대형 승합차의 차대동력계 시험과 시뮬레이션 방법의 연비 비교 분석 연구

정장호(Jang Ho JUNG),박현창(Hyun Chang PARK),김다은(Da Eun KIM),노경완(Kyung Wan RHO) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

The fuel economy of vehicles is very important for vehicle owners and affected by various kinds of factors. The fuel economy of the medium and heavy-duty vehicles(MHDV) is strongly influenced by weight factors such as payload or the number of passengers. However, there is not clearly determined method and procedure to measure fuel economy of MHDV on the chassis dynamometer with the exhaust gas analyzer in Korea. The United States and European countries have been using simulation programs to calculate the fuel economy of heavy-duty vehicles. Korea has been following the similar step to measure fuel economy of MHDV as well. However, there are pros and cons. The simulation program does not need the large amount of investment for test facilities, but the calculated results from the simulation could not include all the vehicle factors related with fuel economy. The purpose of this study is to compare the results acquired by the simulation program and the chassis dynamometer test. The study results show that the fuel economy from the simulation was up to 36.8% higher than that from the chassis dynamometer test. Because it is difficult to apply all the fuel economy influence factors of heavy-duty vehicles at the simulation program. Therefore it is more appropriat e to directly measure the fuel economy on the chassis dynamometer with the exhaust gas analyzer than to calculate it from simulation program to label fuel economy information on MHDV.

DEVELOPMENT OF DRIVER FUEL ECONOMY INDEX FOR REAL ROAD FUEL ECONOMY

Taehun Ha,Seonwoo Choi,Yoonwoo Lee,최회명 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.3

Although a 5-cycle testing was adopted to address the gap between the reported fuel economy from certification tests and fuel economy during real-world driving, the gap still remains and is difficult to be resolved without the consideration of the fuel consumption influencing parameters such as driver’s behavior, driving pattern and road condition. In this study, two types of driver fuel economy indices, the MAW (Moving Average Window) Power Ratio Index and the Constant Driving Index are newly defined to invent the index which can reflect the real-road conditions and simulate the realworld fuel economy. Both indices are defined as the ratio of actual driving to ideal (constant speed) driving in common but the former is based on the engine output and the latter is based on the work. Two types of indices are verified with 5-cycle testing results on chassis dynamometer. According to the verification, the MAW Power Ratio Index with window size of 60 seconds shows the highest correlation with the certified fuel economy and is the reasonable starting point of index for reflecting the real-road conditions.

웜업시 엔진 마찰이 차량 모드 연비에 미치는 영향

임건병(Gunbyoung Lim),위효성(Hyoseong Wi),박진일(Jinil Park),이종화(Jonghwa Lee),박경석(Kyoungseok Park) 한국자동차공학회 2008 한국 자동차공학회논문집 Vol.19 No.6

An improvement of vehicle fuel economy is one of the most important topic in automotive engineering. Lots of engineers make efforts to achieve 1% of fuel economy improvement. Engine friction is an important factor influencing vehicle fuel economy. This paper focuses on effect of engine friction on vehicle fuel economy during warm-up. A computer simulation is one of the powerful tools in automotive engineering field. Recently Simulation is attempting to virtual experiment not using expensive instruments. It is possible to presuppose fuel economy by changing the characteristic of accessories using CRUISE(vehicle simulation software). In this paper, fuel consumption at each part of the vehicle is analyzed by both of experiment and simulation. The results of fuel economy analysis on experiment substitute for Cruise to calculate fuel economy. The simulation data such as engine speed, brake torque, shift pattern, vehicle speed, fuel consumption level is well correlated to experiment data. In this paper, the change of warm-up time, faster or slower, through simulation is performed. As a result of the fast warm-up, fuel economy is improved up to 1.7%.

연료물성에 따른 경유 차량의 성능 및 에너지소비효율 연구

노경하(Kyeong-Ha Noh),이민호(Min-Ho Lee),김기호(Ki-Ho Kim),이정민(Jung-Min Lee) 한국유화학회 2018 한국응용과학기술학회지 Vol.35 No.3

점차 강화되는 배출가스 규제와 적은 연료로 많은 거리를 주행할 수 있는 고효율 자동차에 대한 요구로 에너지소비효율에 대한 관심이 점차 늘어나고 있다. 국내의 에너지소비효율은 도심주행모드와 고속 도로 모드를 주행하여 복합연비로 산정하고 5-Cycle 보정식을 이용하여 최종 에너지소비효율을 표시하고 있다. 에너지소비효율의 경우 카본발란스법에 의하여 산출되는데 이때 배출가스에 의해 계산이 됨에 따라 연소에 사용되는 연료는 자동차 성능과 에너지소비효율에 매우 중요한 역할을 하게 된다. 자동차 연료의 경우 국내에서는 석유 및 석유대체연료 사업법 품질기준에 따라 국내에 유통되고 있는데 정유사의 정제 방법이나 원유에 따라 품질 기준 내에서 물성 차이를 보일 수 있다. 일정 품질기준을 정하고 있음에 따라 연료별 큰 차이는 나지 않을 것으로 보이나 자동차의 성능에는 영향을 미칠 수 있어 그에 따른 연구가 필요한 실정이다. 따라서, 본 연구에서는 시중에서 유통되고 있는 연료 중 여름철에 판매되는 경유를 정유사 직영점을 통해 구매하였으며, 각 시료별 물성을 분석하고 그에 따른 에너지소비효율을 측정하였다. 에너지소 비효율의 경우 현행 경유 자동차의 에너지소비효율 산정식과 휘발유 에너지소비효율에서 사용되는 산출식을 이용하여 물성 적용에 따른 변화를 살펴보았다. 그 결과 시료별 밀도는 최대 약 0.9%의 차이를 보였으 며, 순발열량은 1.6%의 차이를 보였으며, 현행 에너지소비효율 산출 결과에서는 도심모드에서 약 1%, 고속모드에서 1.4% 차이를 보였다. 휘발유 산출식을 이용한 산출에서는 현행 에너지소비효율 산출때 보다약 6%정도 낮은 수치를 보였으며, 각 시료별 에너지소비효율은 최대 도심과 고속에서 최대 약 1.4%의 차이를 보였다. Increasing emissions regulations and demand of high-efficiency cars that travels a lot of distance with less fuel, there is growing interest in Energy Consumption Efficiency. Korean energy consumption efficiency compute combined Fuel Economy by driven city & highway driving mode and present final Energy Consumption Efficiency as using 5-cycle correction formula. Energy consumption efficiency is computed Carbon-balance-method, when used burning fuel play a key role in vehicle performance & Energy Consumption Efficiency. In Korea, vehicle fuel is circulate by Petroleum and Petroleum Alternative Business Act, there is property difference in quality standard because petroleum sector’s refine method or type of crude oil. It does not appear a big difference according to fuel, because it sets steady quality standard, it may affect the performance of automobile. Thus, in research We purchase a few diesel fuel which circulated in the market in summer season though directly-managed-gas station by petroleum sector, resolve property each of fuel, we compute Fuel Economy each of them. We analyze into change depend on applying for property as nowadays utilizing Energy Consumption Efficiency calculating formula of gasoline and diesel fuel. As result, Density each of sample fuel has a maximum difference roughly 0.9%, net heat value each of sample fuel has difference 1.6%, result of current Energy Consumption Efficiency each of sample fuel has a difference roughly 1% at city drive mode, 1.4% at highway drive mode. Result of use gasoline calculator formula shows less 6% result than nowadays utilizing Energy Consumption Efficiency calculating formula, each of sample‘s Energy Consumption Efficiency shows maximum roughly 1.4% result in city & highway drive mode.

수소연료전지자동차 연료소비율 평가기술 개발에 관한 연구

임종순,이현우,홍윤석,이광범,용기중,권해붕 한국수소및신에너지학회 2010 한국수소 및 신에너지학회논문집 Vol.21 No.3

Fuel consumption measurement of hydrogen fuel cell vehicle is considerably different from internal combustion engine vehicle such as carbon balance method. A practical method of fuel consumption measurement has been developed for hydrogen fuel cell vehicles. There are three method of hydrogen fuel consumption testing, gravimetric, PVT (pressure, volume and temperature), and mass flow, all of which necessitate physical measurements of the fuel supply. The purpose of this research is to measure the fuel consumption of hydrogen fuel cell vehicles on chassis-dynamometer and to give information when the research is intended to develop test method to measure hydrogen fuel economy.

EXPERIMENTAL ANALYSIS OF DRIVING PATTERNS AND FUEL ECONOMY FOR PASSENGER CARS IN SEOUL

Sa, J.-S.,Chung, N.-H.,Sunwoo, M.-H. The Korean Society of Automotive Engineers 2003 International journal of automotive technology Vol.4 No.2

There are a lot of factors that influence automotive fuel economy such as average trip time per kilometer, average trip speed, the number of times of vehicle stationary, and so forth. These factors depend on road conditions and traffic environment. In this study, various driving data were measured and recorded during road tests in Seoul. The accumulated road test mileage is around 1,300 kilometers. The objective of the study is to identify the driving patterns of the Seoul metropolitan area and to analyze the fuel economy based on these driving patterns. The driving data which was acquired through road tests was analysed statistically in order to obtain the driving characteristics via modal analysis, speed analysis, and speed-acceleration analysis. Moreover, the driving data was analyzed by multivariate statistical techniques including correlation analysis, principal component analysis, and multiple linear regression analysis in order to obtain the relationships between influencing factors on fuel economy. The analyzed results show that the average speed is around 29.2 km/h, and the average fuel economy is 10.23 km/L. The vehicle speed of the Seoul metropolitan area is slower, and the stop-and-go operation is more frequent than FTP-75 test mode which is used for emission and fuel economy tests. The average trip time per kilometer is one of the most important factors in fuel consumption, and the increase of the average speed is desirable for reducing emissions and fuel consumption.

EFFECTS OF FTP-75 MODE VEHICLE FUEL ECONOMY IMPROVEMENT DUE TO TYPES OF POWER STEERING SYSTEM

위효성,이용규,박진일,이종화,박경석 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.6

This paper focuses on fuel economy improvement according to the type of power steering system. Usually, a conventional power steering system is directly driven by the crankshaft of the engine with a belt, known as HPS (hydraulic power steering). However, there is some inefficiency with this system at high engine speeds. To improve this inefficiency, automobile makers have developed two power steering systems: EHPS (electro-hydraulic power steering) and MDPS (motordriven power steering) or EPS (electric powered steering). However, there has been insufficient study of effects of the type of power steering system on fuel economy. In this paper, the effect of the type of power steering system on fuel economy is studied experimentally, and calculations of the effect on vehicle fuel economy are presenting using computer simulation with AVL cruise software. The results demonstrate that a 1% vehicle fuel economy improvement can be achieved in a vehicle with an electro-hydraulic power steering system compared to a vehicle with a hydraulic power steering system. In addition, a 1.7% vehicle fuel economy improvement can be achieved using a full electric power steering system in a FTP-75 driving cycle. These results could be used to choose a power steering system.