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As CO2 legislation tightens, the next generation of turbocharged gasoline engines must meet stricter emissions targets combined with increased fuel efficiency standards. Recent studies have shown that the following technologies offer significant improvements to the efficiency of turbocharged GDI engines: Miller Cycle via late intake valve closing (LIVC), low pressure loop cooled EGR (LPL EGR), port water injection (PWI), and cylinder deactivation (CDA). While these efficiency-improving technologies are individually well-understood, in this study we directly compare these technologies to each other on the same engine at a range of operating conditions and over a range of compression ratios (CR). The technologies tested are applied to a boosted and direct injected (DI) gasoline engine and evaluated both individually and combined.

As CO2 legislation tightens, the next generation of turbocharged gasoline engines must meet stricter emissions targets combined with increased fuel efficiency standards. Promising technologies under consideration are: Miller Cycle via late intake valve closing (LIVC), low pressure loop cooled exhaust gas recirculation (LPL EGR), port water injection (PWI), and cylinder deactivation (CDA). While these efficiency improving options are well-understood individually, in this study we directly compare them to each other on the same engine at a range of operating conditions and over a range of compression ratios (CR). For this purpose we undertake a comprehensive simulation of the above technology options using a GT-Power model of the engine with a kinetics based knock combustion sub-model to optimize the fuel efficiency, taking into account the total in-cylinder dilution effects, due to internal and external EGR, on the combustion.

Polylactide (PLA), which is one of the most important biocompatible polyesters that are derived from annually renewable biomass such as corn and sugar beets, has attracted much attention for automotive parts application. The manufacturing method of PLA is the ring-opening polymerization of the dimeric cyclic ester of lactic acid, lactide. For the PLA composites including stereocomplexed with L- and D-PLA, we developed the unit processes such as fermentation, separation, lactide conversion, and polymerization. We investigated D-lactic acid fermentation with a view to obtaining the strains capable of producing D-lactic acid, and through catalyst screening test for polycondensation and depolymerization reactions, we got a new method which shortens the whole reaction time of lactide synthesis step. Poly(d-lactide) is obtained from the ring-opening polymerization of d-lactide. Also we investigated several catalysts and polymerization conditions.

Squeak and rattle (S&R) problems in body structure and trim parts have become serious issues for automakers because of their influence on the initial quality perception of consumers. In this study, various CAE and experimental methods developed by Hyundai Motors for squeak and rattle analysis of door systems are reported. Friction-induced vibration and noise generation mechanisms of a door system are studied by an intelligent combination of experimental and numerical methods. It is shown that the effect of degradation of plastics used in door trims can be estimated by a numerical model using the properties obtained experimentally. Effects of changes in material properties such as Young's modulus and loss factor due to the material degradation as well as statistical variations are predicted for several door system configurations. As a new concept, the rattle and squeak index is proposed, which can be used to guide the design.

An innovative design process is proposed to be applicable in the early conceptual design phase as a means of front loading design. The objective of the study is to minimize trial and errors in the detailed design phase and to shorten the overall design period. The process includes design optimization which is based on efficient modeling techniques. An integrated CAD/CAE modeling method and a simplified quality FE model are key factors in the course of effectuation. The conceptual modeling takes into account the adaptability of computer-generated models with the use of CAD/CAE integrated design environment. To achieve maximum efficiency in the repeated computations in optimization, an FE modeling approach is introduced in terms of simplicity and quality. The proposed FE modeling employs beam and spring elements to construct vehicle body models, which is targeted to produce an instant analysis result with a robust conceptual design at the incipient phase of development.

Light weighting is a critical objective in the automotive industry to improve fuel efficiency. But when redesigning parts for light weight, by changing from metal to plastic, the resulting design gives NVH issues due to differences in part mass and material stiffness. Many parts were not converted from metal to plastic because of NVH issues that could not be solved. Many engine parts such as cylinder head cover, air intake manifold, oil pan and etc. previously made of metal have since long been replaced with plastic. But timing chain cover has not been replaced because of the aforementioned issue. Sealing performance due to the dynamic characteristics of the application is another challenging factor. In this paper, the key aspects of the plastic timing chain cover as well as its advantage are presented.

Hyundai Motor Group launched a Continuously Variable Valve Lift (CVVL) engine in 2012. The engine is equipped with HMG's unique CVVL mechanism and is characterized by low fuel consumption, high performance and its responsiveness. The CVVL mechanism is based on a six-linkage mechanism and has advantages of compactness and durability. The engine is a 4 cylinder In-Line, 2.0L gasoline engine and is designed for a mid-sized passenger car. The engine increases fuel efficiency by 7.7% and the peak engine power by 4.2%. One of the most challenging issues in producing a CVVL engine is the valve lift deviations throughout the engine cylinders. The valve cap shim and set screw were designed to adjust the valve lift deviations. Cap shim thickness is chosen by measuring the valve top height, and shoe lift of the cam carrier assembly. The set screw is an auxiliary device to adjust the valve lift deviation.

Reducing unsprung mass of the car is a representative method to enhance the ride & handling performance and fuel efficiency. In this study, brake disc weight is reduced 15∼20% using a hybrid type material. The basis for this study is the separation of the friction surface and HAT(mounting part). Aluminum material is applied in the HAT for a light weight effect. Gray iron is applied in the friction surface section to maintain braking performance. Two types of joining between aluminum and cast iron are developed. One is the aluminum casting method utilizing a gray iron insert and the other is a bolted assembly method. Detailed structure, process and material are optimized using try-out & dynamometer experiments. The Reliability of this development is proved through durability (dynamometer and vehicle) testing.

Many high risks of failure in developing and applying new technologies exist in the recent automotive industry because of big volume of selling cars in a global market. Several recalls cost companies more than $ 100 million per problem. New technologies always have uncertainty in performing intended functions at various given conditions despite the fact that engineers do their best to develop technologies to meet all the requirements. Uncertainty of new technologies put companies into danger of failing in their business. Therefore, many companies tend to take interest in reducing risks from the uncertainty in technologies, but the increasing complexity of modern automotive technologies make it difficult to develop complete technologies. A new engineering methodology called SPEED Engineering was introduced to reduce the risks of new technology applications and to facilitate engineers to conceive innovative ideas dominating the market in the future.

Fuel cell vehicle is loaded with translating equipment, which converts chemical energy to electrical energy. The equipment has maximum power efficiency at a specific temperature when several operating conditions are met. To control the coolant temperature, the existing system uses a wax-type thermostat, which operates as the wax elements contracts and expands. However, there are several problems with the wax-type thermostat; it is impossible to measure real-time temperature and high pressure drop. To mitigate these problems, we developed a DC motor-driven 3-way valve that can control real-time temperature and low pressure drop. Application of the 3-way valve will improve fuel cell vehicle power and fuel efficiency.

We developed the hard IP (Instrument Panel) that is integrally over molded with a soft layer (TPO, Thermo Plastic Olefin) for the soft feeling and cost reduction. And also we produced the cost-effective PAB(Passenger-side Airbag) door system that had an in-mold tearseam and avoided competitors' patents simultaneously. The development procedure of this technology is; ① Material for overmolding ② Design optimization ③ Solving tool challenges. The reduction of process through integrally molding with soft material helped to accomplish a soft feeling on the IP and cost reduction at the same time. The deployment, head impact and heat aging tests were conducted and 5 patents were applied such as the optimization of the mold structure and injection condition.

Recently, in accordance with the increased interest of consumer in fuel efficiency due to the phenomenon of high oil price, complaints against actual fuel efficiency in the road in comparison with the certified fuel efficiency have been raised frequently. Especially in case of the hybrid vehicle which is highly popular for the reason of its high fuel efficiency compared with that of existing gasoline car, deviation in the fuel efficiency will be higher compared with that of gasoline car in accordance with the driving mode (downtown/highway), driver's driving style (wild/mild) and external environmental condition (gradient/temperature/altitude). To solve them, this paper developed a method so that the SOC (State Of Charge), EV/HEV mode transition point can be controlled variably in accordance with the driving mode, driver's driving style and external environmental condition by making the most of characteristics of hybrid.

The Eco-driving indicator is a colored lamp on a cluster to lead a driver to smoothen acceleration of a vehicle. Informed by the indicator, a driver learns how deep to push a gas pedal for a better fuel economy. The Eco-driving guide system outputs a vehicle fuel efficient state by the Eco-driving indicator. It is based on BSFC map, engine torque map, A/T shift pattern data, engine operation status and transmission operating status. With the Eco-driving guide system, vehicle fuel efficiency can be improved by 4∼26%.

Invisible Passenger-side Airbag (IPAB) door system must be designed with a weakened area such that the airbag will break through the Instrument Panel (IP) in the intended manner, with no flying debris at any temperature. At the same time, there must be no cracking or sharp edges at the head impact test (ECE 21.01). Needless to say, Head impact test must keep pace with the deployment test. In this paper, we suggested soft airbag door system that is integrally molded with a hard instrument panel by using Two-shot molding. First of all, we set up the design parameters of IPAB door for the optimal deployment and head impact performance by CAE analysis. And then we optimized the open-close time at each gate of the mold so that the soft and hard material could be integrally molded with the intended boundary. We could make the boundary of two materials more constant by controlling the open-close time of each gate with resin temperature sensor.

End-plates are highly stiff plates that hold together the components composing a fuel cell stack, i.e. Membrane Electrode Assemblies (MEAs), Gas Distribution Layers (GDLs) and bipolar plates, offering sufficient contact pressure between them. The proper contact pressure is required not only to improve energy efficiency of a stack by decreasing ohmic loss but also to prevent leakage of fluids such as hydrogen, air, or coolant. When a fuel cell starts in cold environment, heat generated in a fuel cell stack as a result of electrochemical reactions should not be used much to increase the temperature of endplates but to melt ice inside the stack to prevent ice-blocking and to increase the temperature near the three-phase-boundary on MEAs. However, to satisfy the high stiffness required, massive metallic endplates have been used despite their inferior thermal characteristics: high thermal conductivity and large thermal inertia.

An increasing number of cars which are being used to foster leisure and a convenient life for consumers are being outfitted with roof racks and/or cross bars. This trend of installing roof racks is partly for the function of carrying objects on the roof of the vehicle and partly as a way to affect the style and exterior look of the vehicle. Therefore, the application of roof racks and cross bars is becoming increasingly important in the automotive industry. Because of the expanding application of roof racks on vehicles, the challenge of reducing wind noise caused by exposed cross bars becomes the main issue in this field. For solving this problem, the cross bar shape is designed and evaluated in the development stage, and if there is a problem, it is re-designed and re-evaluated many times. This repetitive corrective action is called “trial and error”.

High pressure fuel injection systems, such as common rail (CR) systems and electronically-controlled unit injector (EUI) systems, have been widely applied to modern heavy duty diesel engines. They are shown to be very effective for achieving high power density with high fuel efficiency and low exhaust gas emissions. However, the increased peak combustion pressure gives additional structural stress and thermal load to engine structure. Thus, proper material selection and thermal analysis of engine components are essential in order to meet the durability requirements of heavy-duty diesel engines adopting a high pressure injection system. In this paper, thermal analysis of a 12.9 ℓ diesel engine with an EUI system was studied. Temperatures were measured on a cylinder head, a piston and a cylinder liner. A specially designed linkage system was used to measure the piston temperatures. A radio-tracer technique was also used to verify the rotation of piston rings.

Recently weight reduction is increasingly needed in automotive industry to improve fuel efficiency and to meet a CO2 emission requirement. In this paper, we prepared composite body panels for the lightweight vehicle based on a small passenger car. Fender, roof, door, side outer panel, and tailgate are made from hand layup using a glass/carbon hybrid reinforcement. Hood is made from low pressure sheet molding compound (SMC) to investigate feasibility of mass production. Both hand layup and low pressure SMC materials are newly developed and their physical properties are examined. CAE simulation was done for strength analysis and optimization of thickness for the body panels.

A new thermoplastic polyolefin with primerless adhesion to paint has been developed by polypropylene (PP) with α-olefin copolymers, mineral fillers and some additives. It can substantially reduce costs and environmental problems by eliminating primer treating operations, traditionally treated from trichloroethene (TCE). This new material exhibits unique solid-state texture that rubbery polymer component are typically dispersed in lamellar structure matrix. Versus conventional PP or thermoplastic olefin (TPO), it provides excellent brittle-ductile (BD) transition as well as paintability. Also it is expected to have a significant impact on interior parts as requirements for material change to an emphasis on light weight, lower cost, more efficient finishing.

Low-pressure molding compound (LPMC) is a new kind of composite material which can be used for automotive body panels. LPMC has similar mechanical properties compared to conventional sheet molding compound (SMC) but excellent moldability due to the different thickening system. In this paper, we prepared LPMC hood prototype for a passenger car using a low-cost tooling. Inner panel and outer panel were made of general-density- and low-density-grade LPMC, respectively, in order to maximize weight reduction maintaining surface quality. Physical properties containing tensile strength, flexural modulus, notched Izod impact strength of those samples were investigated. In addition, CAE simulation was also done for strength analysis of the hood assembly.