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Technical Paper

Study of Sealing Mechanism to Prevent Oil Leakage for the Thermoplastic Cylinder Head Cover

2007-04-16
2007-01-0566
Most of car makers nowadays produce Cylinder Head Cover with Thermoplastic to get the benefit of weight and cost reduction. The production of Cylinder Head Cover with Thermoplastic brings a number of benefits such as enhancement in productivity, design freedom, integration with other parts and reduction in weight. However, NVH characteristics, sealing performance issues possibly caused by design of cover and gasket and loss of properties of materials when used for long-term period still remain as critical tasks to be solved. Especially in case of car OEMs strongly insist that we have to meet their severe specifications requirements so as to satisfy their customers' growing demand. Sealing performance is one of the core factors, which require continuous effort and studies to meet the OEM's specifications.
Technical Paper

Development of High Wear Resistant and Durable Coatings for Al Valve Spring Retainer

2007-04-16
2007-01-1748
The use of light-weight materials in automotive engine components has increased in order to achieve better fuel efficiency and engine performance. In this study, Al alloy (AI5056) valve spring retainer can reduce a weight by 63% in comparison to steel and improve the upper limit of engine speed by about 500rpm. The Al valve spring retainer was fabricated by cold forging and coated with hard anodizing, DLC (diamond like coating), cold spray and thermal spray for better wear resistance and durability. We conclude that among these materials the DLC coating improves the wear resistance of Al valve spring retainer and has a sufficient durability after endurance testing.
Technical Paper

Influence of Tire Size and Shape on Sound Radiation from a Tire in the Mid-Frequency Region

2007-05-15
2007-01-2251
In this research, the influence of tire size and shape on sound radiation in the mid-frequency region was studied. First, the relationship between the structural wave propagation characteristics of a tire excited at one point and its sound radiation was identified by using FE and BE analyses. Then, by using that relationship, the effect of modifying a tire's aspect ratio, width and wheel diameter on its sound radiation between 300 Hz and 800 Hz was investigated. Finally, an optimization of the sound radiation was performed by modification of the tire structure and shape. It was found that most of a tire's structural vibration does not contribute to sound radiation. In particular, the effective radiation was found to occur at the frequencies where low wave number components of the longitudinal wave and the flexural wave first appear.
Technical Paper

A Study for Improving the Resistance to Fretting Corrosion of SCr 420 Gear Steel

2007-08-05
2007-01-3734
A study for improving the resistance to fretting corrosion of SCr 420 pinion gear was conducted. Fretting is the damage to contacting surfaces experiencing slight relative reciprocating sliding motion of low amplitude. Fretting corrosion is the fretting damage to unlubricated contacting surfaces accompanied by corrosion, mostly oxidation that occurs if the fretting occurs in air. Two kinds of conventional heat treatment and a newly designed one suggested for improving the resistance to the fretting corrosion of pinion gear were compared each other to find out what is the main factor for generating fretting corrosion phenomenon. Increased carbon potential at both the heating and diffusing zone and reduced time of tempering was found out to be a solution for improving the resistance to fretting corrosion of forged and heat treated gear steel. On the contrary, modified carbo-nitriding using ammonia gas has been getting worse the fretting corrosion problem.
Technical Paper

Solution for the Torque Steer Problem of a Front-wheel Drive Car with a High-torque Engine in Vehicle Development Stages

2007-08-05
2007-01-3656
This paper describes a torque steer reduction process for a front-wheel drive car with a high torque engine at the initial stage of vehicle development. Literature reviews for the reduction process and vehicle integration tradeoffs among chassis components, driveline components, and loading condition are included. Drive shaft angle and its stiffness, differential gear stiffness, and power train mount, and vehicle weight distribution are mainly considered. In addition, wheel alignment data such as kingpin offset, kingpin inclination, camber angle, ride height, and dynamic tire radius are also discussed to solve the torque steer problem. This paper introduces an example solution to improve the torque steer during vehicle development stage. In that case, the vehicle parameters should be considered the factors to achieve many requirements. In spite of that restriction of alteration, the result of improvement became better than that of its competitor.
Technical Paper

Design and Development of a Spray-guided Gasoline DI Engine

2007-08-05
2007-01-3531
Adopting the Spray-guided Gasoline Direct Injection (SGDI) concept, a new multi-cylinder engine has designed. The engine has piezo injectors at the central position of its combustion chamber, while sparkplugs are also at the center. The sparkplug location is designed so that the spark location is at the outer boundary of the fuel spray where the appropriate air-fuel mixture is formed. A few important operating parameters are chosen to investigate their effects on the combustion stability and fuel consumption. The final experimental results show a good potential of the SGDI engine; the fuel consumption rate was much less than that of the base Multi Port Injection (MPI) engine at various engine operating conditions.
Technical Paper

Theoretical and Experimental Flow Analysis of Exhaust Manifolds for PZEV

2007-08-05
2007-01-3444
As the current and future emission regulations become stringent, the research on exhaust manifold with CCC (Close Coupled Catalyst) has been the interesting and remarkable subject. To design of exhaust manifold with CCC is a difficult task due to the complexity of the flow distribution caused by the pulsating flows that are emitted at the exhaust ports. This study is concerned with the theoretical and experimental approach to improve catalyst flow uniformity through the basic understanding of exhaust flow characteristics. Computational and experimental approach to the flow for exhaust manifold of conventional cast type, stainless steel bending type with 900 cell CCC system in a 4-cylinder gasoline engine was performed to investigate the flow distribution of exhaust gases.
Technical Paper

A Characteristics of Particle Number Distribution for the Urea Solution Injection to Urea SCR System of Commercial Diesel Engine for an Emission Regulation

2007-08-05
2007-01-3455
While the request of diesel engine is recently increased due to its excellent fuel economy benefit, the regulation of emission becomes reinforced. The variety of method such as engine technologies and aftertreatment systems have been developed and applied to meet the criteria of regulation so far. One of recognizable technologies utilized in a heavy commercial vehicle is SCR system using urea solution as a reductant, which eliminates NOx. This paper includes the experiment of a diesel engine equipped with Urea SCR system, and its emission characteristic including particle is analyzed and evaluated against its regulation. This evaluation is performed for the diesel engine using ELPI(Electric Low Pressure Impactor) under the condition of constant engine RPM and load, and injecting urea solution to SCR system, particle number distribution of particle range from 7nm to 10μm was estimated.
Technical Paper

Analysis of Transient Thermal and Conversion Characteristics of Dual-Monolith Catalytic Converter with Palladium and Palladium/Rhodium Catalysts

2007-08-05
2007-01-3453
We used a one-dimensional monolithic catalyst model to predict the transient thermal and conversion characteristics of a dual monolithic catalytic converter with a Palladium only (Pd-only) catalyst and a Palladium/Rhodium (Pd/Rh) catalyst. Prior to the numerical investigation of the dual-catalyst converter, we modified the pre-exponential factor and activation energy of each reaction for both catalysts to achieve acceptable agreement with experimental data under typical operating conditions of automobile applications. We validated the conversion behavior of the lumped parameter model for each catalyst against different engine operating conditions. Two higher cell density substrates, Pd-only catalyst (600cpsi/3.9mil) and Pd/Rh catalyst (600cpsi/4mil), for faster light-off and improved warm-up performance are used in this study and the two monoliths has been connected without the space between monoliths.
Technical Paper

The Study for the Improvement of On-Center Feel with MTS Technique

2007-04-16
2007-01-0990
On-center feel is a multivariate problem that a performance is represented using put-together several sub-characteristics such as torque feedback, response, torque linearity, hysteresis, returnability, etc. For the improvement of a multivariate problem, multi objective optimization should be carried out. However each characteristic which ignores correlation between characteristics is usually optimized up to now. The objective of this research, Mahalanobis Taguchi System (MTS) technique is grafted to on-center steering feel to obtain the efficient improvement. MTS technique can optimize the unified on-center index which is generated in consideration of correlation between characteristics. In this research, first an effective value of MTS technique is verified with on-center steering feel which has the multivariate characteristic. Second, on-center steering feel is improved using MTS technique and Design of Experiments (DOE).
Technical Paper

Development of Accelerated Corrosion Test Mode Considering Environmental Condition

2002-03-04
2002-01-1231
Accelerated simulation of vehicle corrosion in a controlled environment not only involves large chambers for actual vehicle tests, but also requires careful consideration of interactions between various parameters given a short time period within which the test is bounded. A new corrosion durability test mode reproducing various field conditions using salt spray, climatic, sunlight simulation and cold chambers has been developed. Verification of the test mode is carried out using four actual vehicle corrosion tests correlated against used cars of Nort h America and Northern Europe. The process of new corrosion test mode is discussed along with the characteristics of the test chambers.
Technical Paper

Effects of VGT and Injection Parameters on Performance of HSDI Diesel Engine with Common Rail FIE System

2002-03-04
2002-01-0504
Recently, high speed direct injection (HSDI) diesel engines are rapidly expanding their application to passenger cars and light duty commercial vehicles in western European market and other countries such as Korea and Japan. These movements are strongly backed by the technological innovations in the area of air charging and high pressure fuel injection systems. Variable geometry turbine (VGT) turbocharger, which could overcome the typical weak point of the existing turbocharged engine, and the common rail fuel injection system, which extended the flexibility of fuel injection capability, became two of the most frequently referred keywords in recent HSDI technology. In this paper some aspects of VGT potential as a full load torque and power modulator will be discussed. Possibility to utilize the portion of full load potential in favor of part load emissions and fuel economy will be investigated.
Technical Paper

The Suspension of the Newly Developed Hyundai ELANTRA

2006-04-03
2006-01-1534
This paper introduces a newly developed suspension system for new Elantra model of Hyundai Motor Company which will be on the market this year. The new chassis of Elantra has been developed to give more driving pleasure and confidence to a driver. To achieve these driving targets, the suspension has been changed and finely adjusted to achieve better ride and handling performance compared with the previous generation. Especially, a new multi-link suspension which has two upper links has been developed. The kinematics and compliance characteristics have been contrasted to those of the previous model. Also, the crashworthiness and package efficiency has been considered without limitation of suspension performance. Based on the customer's voice of market, the suspension of new Elantra has tried to fit the all kind of the customer's demand.
Technical Paper

Performance Analysis and Valve Event Optimization for SI Engines Using Fractal Combustion Model

2006-10-16
2006-01-3238
On the basis of the newly-developed fractal combustion model, the engine-thermodynamic-cycle simulations were conducted with the 1D engine-cycle-simulation program AVL-BOOST for a passenger-car SI engine with a fully-variable valve train. Results of the simulations showed a good agreement with measurements for both full and part load at various engine speeds. On the basis of the thermodynamic model for the engine, the valve event optimization was carried out for both full and part load with a partial factorial DoE plan consisting of various valve event durations and timings. For each of the selected cases, an independent optimization for the ignition timing was performed to determine the minimum BSFC under a constraint on specified knock criteria. Satisfactory results for the valve event optimization were achieved.
Technical Paper

Tumble Flow Measurements Using Three Different Methods and its Effects on Fuel Economy and Emissions

2006-10-16
2006-01-3345
In-cylinder flows such as tumble and swirl have an important role on the engine combustion efficiencies and emission formations. In particular, the tumble flow which is dominant in current high performance gasoline engines has an important effect on the fuel consumptions and exhaust emissions under part load conditions. Therefore, it is important to understand the effect of the tumble ratio on the part load performance and optimize the tumble ratio for better fuel economy and exhaust emissions. First step in optimizing a tumble flow is to measure a tumble ratio accurately. In this research the tumble ratio was measured, compared, and correlated using three different measurement methods: steady flow rig, 2-Dimensional PIV (Particle Image Velocimetry), and 3-Dimensional PTV (Particle Tracking Velocimetry). Engine dynamometer test was also conducted to find out the effect of the tumble ratio on the part load performance.
Technical Paper

A Study on the Development Process of a Body with High Stiffness

2005-05-16
2005-01-2464
Design optimization of a vehicle is required to increase a product value for noise and vibration performances and for a fuel-efficient car. This paper describes the development process of a high stiffness and lightweight vehicle. A parameter study is carried out at the initial stage of design using the mother car, and a design guide with a good performance is achieved early prior to the development of the proto car. Influences of body stiffness based on the relative weight ratio of the floor and side structures are analyzed. Results show that bending and torsional stiffness has a significant effect on weight distribution ratio. Influences of the distribution of side joint stiffness are analyzed through numerical experiments. Results reveal that the stiffness difference between the upper and lower parts should be small to increase the stiffness of a body.
Technical Paper

Development of Fuel Consumption of Passenger Diesel Engine with 2 Stage Turbocharger

2006-04-03
2006-01-0021
High specific power, additional hardware and mapping optimization was done to achieve reduction of fuel economy for current engine in this study. 2 stage turbocharger with serial configuration was best candidate not only for high specific power at high engine speed but also for increase of low end torque for current engine. This increase of low end torque is important for development of transient characteristic of vehicle. DoE and efficient EGR Cooler was applied for optimization of fuel economy. DoE was useful for optimization of fuel consumption affected by various fuel injection parameters. This DoE was also efficient for matching optimal fuel economy after change of engine hardware. Performance improvement of engine with 2 stage turbocharger VGT was evaluated and additional development of fuel economy was performed in this study.
Technical Paper

Development of Fuel Cell Hybrid Vehicle by Using Ultra-Capacitors as a Secondary Power Source

2005-04-11
2005-01-0015
Hyundai motor company has developed a fuel cell hybrid vehicle that has ultra-capacitors as a secondary power source. The simulation of fuel cell vehicles allows the user to analyze various types of fuel cell systems and hybrid configurations before implementing into a real system and to reduce the development time and cost. Before implementing fuel cell vehicles, a fuel cell vehicle simulation model, that has component modularity and forward facing characteristics, was developed. The simulation model was used in designing the fuel cell hybrid vehicle to select component sizes and a hybrid configuration. The hybridization by using ultra-capacitors provided better fuel economy and power response than the hybridization by using batteries.
Technical Paper

Control of Diesel Catalyzed Particulate Filter System I (The CPF System Influence Assessment According to a Regeneration Condition)

2005-04-11
2005-01-0661
Environmental standards concerning Suspended Particulate Matter (SPM) are continuously becoming stricter. The light-duty diesel passenger car market is rapidly increasing due to performance improvements and the economic advantages of the diesel engine. To meet EURO 4 diesel passenger car emission regulations, regeneration experiments of a catalyzed particulate filter (CPF) system have been performed with 2.0L common-rail diesel engine. For effective regeneration of the CPF system, we investigated the effects of various regeneration conditions on the system. Conditions such as exhaust gas temperature, oxygen/hydrocarbon concentrations, gas compositions, etc. were investigated. We found that the regeneration efficiency was improved when the exhaust gas temperature increased to more than 700°C during CPF regeneration using engine post injection. An additional amount of post injection increased the exhaust gas temperature and residual hydrocarbon content.
Technical Paper

Improvement of Durability in HSDI Diesel Cylinder Head

2005-04-11
2005-01-0655
In order to cope with new exhaust emission regulations, automotive industry is interested in research and development of HSDI (High Speed Direct Injection) diesel engines with common rail systems. Since HSDI diesel engine operates under highly loaded condition due to increased power output, cylinder head of HSDI diesel engine is susceptible to high cycle fatigue cracks. In this study, FE analysis was used to find the mechanism of high cycle fatigue crack in the HSDI diesel cylinder head. In order to improve the durability of HSDI diesel cylinder head, the modifications of cylinder head and head bolt pre-load were investigated. Experiments were performed to prove the existence of residual stress created during the heat treatment of cylinder head. The results of experiments showed that residual stress can affect the durability of HSDI diesel cylinder head.
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