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Viewing 1 to 30 of 223
2017-03-28
Technical Paper
2017-01-0693
Seungwoo Kang, Wonkyu Cho, Choongsik Bae, Youngho Kim
This paper investigated the influence of injector nozzle hole number on fuel consumption and exhaust emission characteristics of diesel engine. The engine used for the experiment was the 0.4L single-cylinder compression ignition engine which is modified from an 1.6L four-cylinder automotive diesel engine. The fuel injection equipment were operated under 250MPa injection pressure. Three injectors with identical hydraulic flow rate with various combinations of the nozzle hole number(8, 9, and 10) and diameter(105 μm, 100 μm, 95 μm) were compared. The indicated specific fuel consumption and NOx emission of three injectors were on same level because of the identical fuel flow rates and similar in-cylinder pressure traces. Without EGR, the particulate matter(PM) emission were lower with larger nozzle hole number. However, the NOx-PM trade-off were similar at low oxygen concentration with high EGR rate.
2017-03-28
Technical Paper
2017-01-1222
Jeongwon Rho, Jeongbin Yim, Daewoong Han, Gubae Kang, Seongyeop Lim
The current sensor for motor control is one of the main components in inverters for eco-friendly vehicles. Recently, as higher performance of torque control has become required, the current sensor measurement error and accuracy of motor controls have become more significant. Since the response time of the sensor affects the motor output power, the response delay of the sensor causes measurement errors of the current. Accordingly, the voltage vector changes, and a motor output power deviation occurs. In the case of large response delay of the sensor, as motor speed increases, then difference between motoring and generating output power becomes larger and larger. This results in the deterioration of power performance in high-speed operation. The deviation of the voltage vector magnitude is the main cause of motor output power deviation and imbalance through the simulation.
2017-03-28
Technical Paper
2017-01-1553
Min Kyoo Kang, Jin Hong Kim, HyuckJin Oh, Wookjin Jang, Sangwoo Lee, Young Hwan Lee
This paper presents a transient nonlinear vibration analysis of a full-vehicle model. The full-vehicle model consists of a powertrain model, a trimmed body, a drive line, and front and rear suspensions with tires, and is driven by combustion forces and runs on a road surface. The fundamental purpose of the transient nonlinear full-vehicle simulation is to replicate customer’s experience in driving situation in the time domain and to understand real-time phenomena. By performing time-domain simulation, it is possible to capture nonlinear behavior of a vehicle such as preloads due to gravitational force, large deformation, and material nonlinearity which cannot be properly considered in the conventional steady state analysis due to intrinsic linearization process. In constructing a full-vehicle, validation process is essential. Validation process is applied with respect to the assembling sequence.
2017-03-28
Technical Paper
2017-01-0443
Yong Hyun Nam, Gwansik Yoon
The sound induced by a closing door is determined by the various components like door latch, door module, door glass installed within the door area. The key components vibrate due to the force from the closing door, and the combined vibration caused by the components determines the sound from the door. In particular, when the door is closed with the door glass down, the vibration and noise of the door glass are louder than those of any other component; this is called door glass rattle - attributed to the loss of the door glass support point. This study not only evaluates the rattle influence level of a door glass support but also introduces an approach to reduce glass rattle noise by using sealing components. 1. Study on Minimization of Vibration A jig was constructed to evaluate the level of influence of the rattle of a door glass support.
2017-03-28
Technical Paper
2017-01-1429
Sung Rae kim, Inju Lee, Hyung joo Kim
In motor-vehicle frontal crashes, occupants often suffer from the abdominal injuries when the lap belt excurses over the pelvic bone, commonly referred to as submarining. Especially, it is well known that the obese occupants frequently get injured caused by submarining due to out-of-position belt fittings. This paper aims to investigate the interaction between the pelvis and the lap belt during a frontal crash event. For this purpose, twelve sled tests on four obese female Post-Mortem Human Subjects (PMHS) and four sled tests on the Hybrid III 50th dummy were carried out. In each test, a 3D motion capture system was installed to track the movement of the pelvis and the lap belt. Moreover, the validated subject specific FE model scaled from the 50th percentile male GHBMC model to fit to obese female PMHS in prior study was also simulated.
2017-03-28
Technical Paper
2017-01-1567
Jaepoong Lee, Sehyun Chang, Kwangil Kim, Bongchoon Jang, Dongpil Lee, Byungrim Lee, Kyongsu Yi
This paper proposes a reference steering wheel torque map and a torque tracking algorithm via steer-by-wire to design the targeted steering feel. The reference steering wheel torque map is designed using the measurement data of rack force and steering characteristic of a target performance of the vehicle at sinusoidal and transition steering test. Since the target performance of the vehicle is only tested in nominal road condition, various road conditions such as disturbances and tire-road friction are not considered. Hence, the measurement data of the rack force of reflecting the road conditions in the reference steering wheel torque map have been used. The rack force is the net force which consists of tire aligning moment, road friction force and normal force on the tire kingpin axis. A motor and a magnetorheological damper are used as actuators to generate the desired steering feel using the torque tracking algorithm.
2017-03-28
Technical Paper
2017-01-1481
Kyung-bok Lee, Sanghyuk Lee, Namyoung Kim, Bong Soo Kim, Tae soo Chi, Do young Kim
Conventional EPS systems are operated by one type of steering tuning map set by steering test drivers before releasing to customers. That is, steering feeling can't change by other conditions such as road condions(low mu, high mu, unpaved roads) or some specific driving condtions(emergency braking/EPS fail modes/full gasing start). Those conditiions can't afford the drivers consistent steering feel and vehicle driving. This paper approached the techonology detecting those conditions by using vehicle sensors such as wheel speed/vehicle speed/steering angle/steering torque/steering speed and so on. After detecting those conditions and judging which one is the best steering feel and safe vehicle driving, EPS system automatically can be changed with the steering friction level and selection of steering opitmized mapping on several conditions. I believe that this technology can afford the customer "Joy of driving and fun to drive".
2017-03-28
Technical Paper
2017-01-0898
Jongwon Lee, Sedoo Oh, Kyung Sub Joo, Seyoung Yi, Kyoung-Pyo Ha, Seongbaek Joo
Abstract The engine indicated torque is not delivered entirely to the wheels, because it is lowered by losses, such as the pumping, mechanical friction and front auxiliary power consumption. The front auxiliary belt drive system is a big power consumer-fueling and operating the various accessory devices, such as air conditioning compressor, electric alternator, and power steering pump. The standard fuel economy test does not consider the auxiliary driving torque when it is activated during the actual driving condition and it is considered a five-cycle correction factor only. Therefore, research on improving the front end auxiliary drive (FEAD) system is still relevant in the immediate future, particularly regarding the air conditioning compressor and the electric alternator. An exertion to minimize the auxiliary loss is much smaller than the sustained effort required to reduce engine friction loss.
2017-03-28
Journal Article
2017-01-1634
Hui Sung Lee
When customers use a tailgate(or trunk), some systems such as power tailgate and smart tailgate have been introduced and implemented for improving convenience. However, they still have some problems in some use cases. Some people have to search for the outside button to open the tailgate, or they should take out the key and push a button. In some cases, they should move their leg or wait a few seconds which makes some people feel that it is a long time. In addition, they have to push the small button which is located on the inner trim in order to close the tailgate. This paper proposes a new tailgate control technology and systems based on acoustic patterns in order to solve some inconvenience. An acoustic user interaction (AUI) is a technology which responds to human's rubbing and tapping on a specific part analyzing the acoustic patterns. The AUI has been recently spotlighted in the automotive industry as well as home appliances, mobile devices, musical instruments, etc.
2017-03-28
Technical Paper
2017-01-1459
HangMook Kim, Jae Kyu Lee, Jin Sang CHUNG
Abstract During a new vehicle development process, there are several requirements for side impact test that should be confirmed. One of the requirements is the prevention of door opening during side impact test. Even though there are many causes for door opening problem, this study deals with inertia effect by impact energy. Until now, there have been two classical methods to prevent car door from opening in side impact. One is the increment of the inertia resistance by increasing the mass of the balance weight and the spring force. The other is the application of the blocking lever. Unfortunately, in spite of our efforts, the door opening problem occurs occasionally. Therefore, to improve the problem fundamentally, this paper proposes a new blocking lever mechanism that work similar to ball-point pen structure. The proposed mechanism fixes the blocking lever when the opening directional inertia force is applied to the door outside handle during side crash.
2017-03-28
Journal Article
2017-01-0388
Haeyoon Jung, MiYeon Song, Sanghak Kim
This paper proposes the Off-cycle credit alternative test methodology for Semi-transparent solar panel integrated on Automobile roof glass to achieve the CO2 credits from the Environmental Protection Agency (EPA) & the National Highway Traffic Safety Administration (NHTSA). Manufactures offer the option to put solar cells on the roof of a vehicle for reducing cabin ambient temperature. However, Hyundai Motors develops the semi-transparent solar roof with a controller to provide electric energy for vehicles. This electrical energy cannot be accounted for on the current EPA cycles either the two cycle test or the five-cycle test. Therefore, the manufacture has to establish the methodology based on solar system for vehicles. In order to improve the efficiency of our solar system and to calculate reduced CO2 emission, we studied useable solar energy in driving condition other than peak power in standard test condition(@ 25℃, 1Sun).
2017-03-28
Journal Article
2017-01-1302
Hyung In Yun, Jae Kyu Lee, Jae Hong Choi, MyoungKwon Je, Junhyuk Kim
Abstract A sliding door is one of the car door systems, which is generally applied to the vans. Compared with swing doors, a sliding door gives comfort to the passengers when they get in or out the car. With an increasing number of the family-scale activities, there followed a huge demand on the vans, which caused growing interests in the convenience technology of the sliding door system. A typical sliding door system has negative effects on the vehicle interior package and the operating effort. Since the door should move backward without touching the car body, the trajectory of the center rail should be a curve. The curve-shaped center rail infiltrates not only the passenger shoulder room, but also the opening flange curve, which results in the interior package loss. Moreover, as the passenger pulls the door outside handle along the normal direction of the door outer skin, the curved rail causes the opening effort loss.
2017-03-14
Journal Article
2016-01-9114
Hoon Lee, Delbert Tesar, Pradeepkumar Ashok
Abstract In order to design the in-wheel motor (IWM) for Electric Vehicles (EV), it is necessary to analyze the desired (expected) duty cycle at a higher performance level in order that the IWM becomes commercially relevant. The duty cycle may be representative of different segments of the customer base. Or, the individual customer may wish to have a set of IWMs that uniquely meet his/her measured “demand” cycle for a balance of drivability and efficiency. Questions then arise: How to measure the demand cycle of an individual? What 2 or 3 standard duty cycles should be offered as customer choices for their vehicle? Should the IWM represent multiple speed domains to enhance efficiency and drivability? Can the vehicle be updated rapidly 2 to 3 years after purchase? Etc. In this paper, we lay the groundwork to answer these types of customer questions for an EV with four independent IWMs.
2016-09-18
Technical Paper
2016-01-1917
Bongho Kim, Jeongkyu Kim, Kwang Yun Kim, Jung Hoon Woo
Abstract Creep groan noise occurs in a just moving vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure in-vehicle. It is the low frequency noise giving the driver a very uncomfortable feeling. Recently, the field claims regarding the creep groan noise are increasing. So far, creep groan noise has been improved by means of chassis modification the transfer system. But vehicle body the response system does not. In this paper, the effect between vibration characteristics of vehicle body, creep groan noise was analyzed. Then presented analysis method for vehicle body effect regarding creep groan noise.
2016-09-18
Technical Paper
2016-01-1928
ByeongUk Jeong, Sang Do Kwak, Cheol Ki Kim
Abstract Recently, upon customer’s needs for noise-free brake, carmakers are increasingly widely installing damping kits in their braking systems. However, an installation of the damping kits may excessively increase softness in the brake system, by loosening stroke feeling of a brake pedal and increasing compressibility after durability. To find a solution to alleviate this problem, we first conducted experiments to measure compressibility of shims by varying parameters such as adhesive shims (e.g., bonding spec., steel and rubber thickness), piston’s shapes (e.g., different contact areas to the shims), and the numbers of durability. Next, we installed a brake feeling measurement system extended from a brake pedal to caliper. We then compared experimental parameters with brake feeling in a vehicle. Finally, we obtained an optimized level of brake feeling by utilizing the Design for Six Sigma (DFSS).
2016-06-15
Technical Paper
2016-01-1770
Insoo Jung, Jaemin Jin, Dongchul Lee, Seunghyun Lee, Seungwook Yang, Kyoungdoug Min
Abstract This paper presents two closed-loop control methods for monitoring and improving the combustion behavior and the combustion noise on two 4-cylinder diesel engines, in which an in-cylinder pressure and an accelerometer transducer are used to monitor and control them. Combustion processes are developed to satisfy the stricter and stricter regulations on emissions and fuel consumption. These combustion processes are influenced by the factors such as engine durability, driving conditions, environmental influences and fuel properties. Combustion noise could be increased by these factors and is detrimental to interior sound quality. Therefore, it is necessary to develop robust combustion behaviors and combustion noise. For this situation, we have developed two closed-loop control methods. Firstly, a method using in-cylinder pressure data was developed for monitoring and improving the combustion noise of a 1.7L engine.
2016-04-05
Technical Paper
2016-01-1546
Dongpil Lee, Bongchoon Jang, Kyongsu Yi, Sehyun Chang, Byungrim Lee
Abstract This paper describes a reference steering feel tracking algorithm for Electric-Power-Steering (EPS) system. Development of the EPS system with intended steering feel has been time-consuming procedure, because the feedforward map-based method has been applied to the conventional EPS system. However, in this study, a three-dimensional reference steering feel surface, which is determined from current vehicle states, is proposed. In order to track the proposed reference steering feel surface, sliding mode approach is applied to second-order steering dynamics model considering a coulomb friction model. An adaptive technique is utilized for robustness against uncertainties. In order to validate the proposed EPS control algorithm, hardware-in-the-loop simulation (HILS) has been conducted with respect to a typical steering test. It is shown that the reference steering feel is realized well by the proposed EPS control algorithm.
2016-04-05
Technical Paper
2016-01-0508
Hyung Seok KIM
Abstract This study provides a tire puncture sealant including NR latex and acrylic emersion, which has a reduced viscosity at -40°C, and is also excellent storage stability at -40°C to 70°C, initial sealing performance. Also, this study provides device for sealing inflatable objects. 'One- Piece Tire Repair Kit' can reduce weight and operation steps.
2016-04-05
Technical Paper
2016-01-0492
Bokyung Kim
Abstract The present study focused on CrN-Cu nanocoatings composed of nano-meter grains with CrN, Cr and Cu functioning low-friction, anti-wear and heat resistance. The coatings were synthesized by hybrid PVD including metal arc source, magentron sputter source and ion-gun source. Although Cu has low hardness, the hardness of CrNCu is not declined because it was composed of below 20nm sized grains of CrN, Cr, and Cu. However, CrN-Cu had lower friction than CrN owing to Cu’s low shear strength. CrN-Cu films optimized using the Reaction Surface Method (RSM) showed the excellent tribological behavior and low coefficient of friction compared with DLC. The tribological properties of the Cr-Cu-N demonstrated superior wear resistance and low friction at normal and high temperature conditions. The CrN-Cu nanocoatings can be used for the downsizing automotive engines working at severe tribological conditions.
2016-04-05
Technical Paper
2016-01-1098
Jongsool Park
Abstract The market demands for CO2 reduction and fuel economy have led to a variety of new gear set concepts of automatic transmissions with 4 planetary gear sets and 6 shift elements in recent years. Understanding the relationship between the torque of clutch and brake and gear ratio in the design stage is very important to assess new gear set concepts and to set up the control strategy for enhancing shift quality and to reduce the heat generation of clutch and brake. In this paper, a new systematic approach is used to unify the relationship between torque and gear ratio during the gear shift for all multi-step planetary automatic transmissions. This study describes the unified concept model with a lumped inertia regardless of the specific transmission layout and derives the principal unified relationship equations using torque and energy analysis, which prove that the sum of brake torque is always gear ratio -1 in every in-gear.
2016-04-05
Technical Paper
2016-01-1112
Byeong Wook Jeon, Sang-Hwan Kim, Donghoon Jeong, Joseph Young-il Chang
Abstract In general, driving performance is developed to meet preference of average customers. But there is no single standardized guideline which can satisfy various driving tastes of all drivers whose gender, cultural background, and age are different. To resolve this issue, automotive companies have introduced drive mode buttons which drivers can manually select from Normal, Eco, and Sport driving modes. Although this multi-mode manual systems is more efficient than single-mode system, it is in a transient state where drivers need to go through troubles of frequently selecting their preferred drive mode in volatile driving situations It is also doubtful whether the three-categorized driving mode can meet complex needs of drivers.. In order to settle these matters, it is necessary to analyze individual driving style automatically and to provide customized driving performance service in real time.
2016-04-05
Technical Paper
2016-01-1236
Jun Yeon PARK, Hojoong Lee
Abstract One of the ways to improve the fuel efficiency of the HEV (Hybrid and Electric Vehicles) is to optimize automotive electric system. In order to achieve this, the LDC (Low voltage DC-DC Converter) variable voltage was controlled. Using the ADAS (Advanced Driver Assistance System) map, the charge-discharge behaviors of 12V lead-acid battery was predicted during driving so that, the battery could be charged efficiently. In this study, the feedback control system for 12V battery discharging was designed to compromise between the 12V battery SOC (State of Charge) and the driving conditions at different traffic points. In contrast to earlier approaches, this experimental result indicates that the LDC variable voltage control based on ADAS is able to reduce the LDC average output power by 17.1% therefore, increasing fuel efficiency and ensuring the durability of the 12V battery.
2016-04-05
Technical Paper
2016-01-1029
Jinsuk Kang, Byungchan Lee, Dohoy Jung
Abstract Charge boosting strategy plays an essential role in improving the power density of diesel engines while meeting stringent emissions regulations. In downsized two-stage turbocharged engines, turbocharger matching is critical to achieve desired boost pressure while maintaining sufficiently fast transient response. A numerical simulation model is developed to evaluate the effect of two-stage turbocharger configurations on the perceived vehicle acceleration. The simulation model developed in GT-SUITE consists of engine, drivetrain, and vehicle dynamics sub-models. A model-based turbocharger control logic is developed in MATLAB using an analytical compressor model and a mean-value engine model. The components of the two-stage turbocharging system evaluated in this study include a variable geometry turbine in the high-pressure stage, a compressor bypass valve in the low-pressure stage and an electrically assisted turbocharger in the low-pressure stage.
2016-04-05
Technical Paper
2016-01-1294
Jonggyu Kim, Pyoung Beom Kim, YoungChan Lee, Sunghee Jung, Byeong-Ug Choi
Abstract This study presents the NVH characteristics of a passenger vehicle with a three-cylinder engine and a Continuously Variable Transmission (CVT) and an optimization procedure to achieve balance between fuel economy and NVH. The goal of this study is to improve fuel economy by extending the lock-up area of the damper clutch at low vehicle speed and to minimize booming noise and body vibration caused by the direct connection of the engine and transmission. Resonance characteristics of the chassis systems and driveline have been studied and optimized by the experiment. NVH behavior of the vehicle body structure is investigated and modifications for refinement of booming and body vibration are proposed by simulation using MSC NASTRAN. Calibration parameters for CVT control are optimized for fuel economy and NVH.
2016-04-05
Technical Paper
2016-01-1532
Kyoungtaek Kwak, Seungwoo Seo, Randi Potekin, Antoine Blanchard, Alexander Vakakis, Donald McFarland, Lawrence Bergman
Abstract The purpose of this study is to develop a dynamic model that can accurately predict the motion of the door handle and counterweight during side impact crash tests. The door locking system, mainly composed of the door outside handle and door latch, is theoretically modeled, and it is assumed that the door outer panel can rotate and translate in all three directions during a side impact crash. Additionally, the numerical results are compared with real crash video footage, and satisfactory qualitative agreement is found. Finally, the simplified test rig that efficiently reflects the real crash test is introduced, and its operation is analyzed.
2016-04-05
Technical Paper
2016-01-1114
Jinsung Kim
Abstract A dry clutch induces judder phenomenon which is caused by variations in the vehicle load condition and frictional material properties. Such a problem may lead to the stick-slip limit cycle that results in undesired longitudinal vibrations of vehicles. To solve this problem, a vibration suppression control is proposed. The amplitude of vibrations is detected by the signal conditioning from the measurements with the transmission input shaft speed and the wheel speed sensors. Based upon this, a perturbation torque is applied additionally on the nominal launch controller to make the drive shaft oscillation vanish. It can be achieved by the control design without any extra hardware cost. Finally, experimental results confirm the effectiveness of the proposed mechanism.
2016-04-05
Journal Article
2016-01-0515
Jee Young Youn, Seok Hwan Kim, Yong Sun (Steven) Jin
Abstract Impact resistance of plastic underbody parts was studied using simulated injection-molded specimen which can be tested according to different types of material used, injection molding variants like position and number of injection molding gates, and features of ribs. Material applied was glass fiber reinforced polyamide which can be used in underbody parts. Test was performed using several combinations of injection molding gates and rib types. From the test result, optimal design guide for plastic underbody parts was determined. Also, new high impact resistant plastic material made of glass fiber reinforced polyamide 66 (PA66) and polyamide 6 (PA6) alloy was developed and the material properties useful for CAE were determined. As a case study, oil pan and muffler housing were designed following the optimal design guide and CAE. And the reliability of the sample muffler housing designed was verified.
2016-04-05
Journal Article
2016-01-1184
Kyoung-Ku Ha, Chang Ha Lee, Chi Myung Kim, Sae Hoon Kim, Byung Ki Ahn
Abstract The subject of this study is a centrifugal compressor for Fuel Cell Electric Vehicles (FCEV). Recently there is a growing interest in FCEVs since they are considered a realistic solution to environmental regulations for passenger cars to reduce emissions. Water vapor is the only byproduct of a reaction in the Proton Electrolyte Membrane (PEM) fuel cell stack which generates electricity with oxygen from the surrounding air and hydrogen from a fuel tank. Auxiliary systems called Balance of Plant (BOP) serve to provide air and hydrogen to the stack in a correct ratio. The compressor is one of key components of this system because compression of the intake air brings an increase in efficiency and power density of the FCEV. This paper presents the characteristics of a 10 kW class centrifugal compressor with an oil-free bearing system. It consists of a shaft, two airfoil journal bearings and a pair of thrust bearings.
2016-04-05
Journal Article
2016-01-1569
Kiho Yum
Abstract In this research, the influence of tire force and moment (F&M) characteristics on vehicle on-center steering performance was analyzed and then how to improve vehicle on-center performance was studied through controlling tire structure design parameter, tread pattern shape and tread grip characteristics. First, the relationship between vehicle on-center steering performance and tire F&M characteristics was identified by comparing vehicle steering measurements and tire F&M measurements. It was found that key factor of tire related with on-center performance is aligning torque at lower slip angles. As the aligning torque at slip angle 1° increases, on-center feel is improved. Second, the influence of tire design parameters on tire aligning torque was studied through F&M finite element (FE) analysis and measurement. It was found that the aligning torque at lower slip angle increases as stiffness of the tread and sidewall decreases.
2016-04-05
Journal Article
2016-01-1122
Hyungsouk Kang, TaeYoung Chung, Hyeongcheol Lee, Hyungbin Ihm
Abstract Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed.
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