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This paper proposes a new integrated chassis control (ICC) using a predictive model-based control (MPC) for optimal allocation of sub-chassis control systems where a predictive model has 6 Degree of Freedom (DoF) for rigid body dynamics. The 6 DoF predictive vehicle model consists of longitudinal, lateral, vertical, roll, pitch, and yaw motions while previous MPC research uses a 3 DoF maximally predictive model such as longitudinal, lateral and yaw motions. The sub-chassis control systems in this paper include four wheel individual braking torque control, four wheel individual driving torque control and four corner active suspension control. Intermediate control inputs for sub-chassis control systems are simplified as wheel slip ratio changes for driving and braking controls and vertical suspension force changes for an active suspension control.

This paper presents an adaptation method of equivalent factor in equivalent consumption minimization strategy (ECMS) of fuel cell hybrid electric vehicle (FCHEV) using hilly road information. Instantaneous optimization approach such as ECMS is one of real-time controllers. Furthermore, it is widely accepted that ECMS achieves near-optimum results with the selection of the appropriate equivalent factor. However, a lack of hilly road information no longer guarantees near-optimum results as well as charge-sustaining of ECMS under hilly road conditions. In this paper, first, an optimal control problem is formulated to derive ECMS analytical solution based on simplified models. Then, we proposed updating method of equivalent factor based on sensitivity analysis. The proposed method tries to mimic the globally optimal equivalent factor trajectory extracted from dynamic programming solutions.

The series-parallel hybrid electric vehicle(HEV), which employs a planetary gear set to combine one internal combustion engine(ICE) and two electric motors(EMs), can take advantages of both series and parallel hybrid system. The efficient powertrain operating point of the system can be obtained by the instantaneous optimization of equivalent fuel consumption. However, heavy computational requirements and variable constraints of the optimization process make it difficult to build real-time control strategy. To overcome the difficulty, this study suggests the control strategy which divides the optimization process into 2 stages. In the first stage, a target of charge/discharge power is determined based on equivalent fuel consumption, then in the second stage, an engine operating point is determined taking power transfer efficiency into account.

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”.

Supervisory control strategy of a hybrid electric vehicle (HEV) provides target powers and operating points of an internal combustion engine and an electric motor. To promise efficient driving of the HEV, it is needed to find the proper values of control parameters which are used in the strategy. However, it is very difficult to find the optimal values of the parameters by doing experimental tests, since there are plural parameters which have dependent relationship between each other. Furthermore variation of the test results makes it difficult to extract the effect of a specific parameter change. In this study, a model based parameter optimization method is introduced. A vehicle simulation model having the most of dynamics related to fuel consumption was developed and validated with various experimental data from real vehicles. And then, the supervisory control logic including the control parameters was connected to the vehicle model.

Due to technological evolutions and social demands, motor vehicles are requested to be enhanced in terms of occupant safety and comfort. As a result, many countries are reinforcing crash regulations and new car assessment programs. Automotive seats are essential parts for providing passenger safety and comfort and have become most important. Many automotive companies concentrate on optimization of the seat structure. This paper presents an overview of the recent evolution of the seat structures and gives a development procedure covering seat frame design, optimization and validation. Through the study, a competitive frame design is drawn as a case result and a design guideline and a standard development procedure is established

A technical approach to reduce NOx and to minimize the fuel consumption caused by the DeNOx aftertreatment system was introduced. The NEDC mode test of the HMC (Hyundai Motor Company) DeNOx system was done with a Euro 5 vehicle (ETW (Equivalent Test Weight) = 1,810 kg, 143 kW, 430 N⋅m), which resulted in that the Euro 6 legislation standards were met. The NOx and HC emissions were, respectively, measured to be 0.059 g/km and 0.087 g/km with the hydrothermal-aged catalysts, and CO₂ was increased by ≺ 4%.

This paper reflects an efficient and comprehensive approach for vehicle sound optimization integrated into the entire development process. It shows the benefits of early consideration of typical vehicle NVH features and of intensive interaction of P/T and vehicle responsibilities. The process presented here considers the typical restriction that acoustically representative prototypes of engines and vehicles are not available simultaneously at the early development phase. For process optimization at this stage, a method for vehicle interior noise estimation is developed, which bases on measurements from the P/T test bench only, while the vehicle transfer behavior for airborne and structure-borne noise is assumed to be similar to a favorable existing vehicle. This method enables to start with the pre- optimization of the pure P/T and its components by focusing on such approaches which are mainly relevant for the vehicle interior noise.

An integrated starter and generator (ISG) is a type of electric machine which is mechanically connected to an internal combustion engine (ICE). The ISG is intended to conduct important roles in the hybrid electric vehicle (HEV) such as engine start and stop. Since the HEV has frequent electric vehicle (EV)/HEV mode transition, rapid engine cranking and vibration-free engine stop controls are necessary. In the case of the engine stop, the ISG provides the negative torque output to the ICE which can rapidly escape from its resonance speed. However, the ISG torque is determined by engineering intuition, the amount of energy recovery is hardly considered. Dynamic programming (DP) is an effective solution to find optimal ISG control strategy to maximize energy recovery during engine stop transition. Even though DP is an offline algorithm, the result can be used as a reference to evaluate and improve an existing on-line algorithm.

The squeak noise generated during the moving of the door glass has a influence on the performance of vehicles felt by the consumer. In order to improve the noise, it is necessary to understand the principle of a friction vibration. In this paper, it is confirmed that the principle on the waist belt is most closely related to stick-slip and sprag-slip among various vibration characteristics. Stick-slip is expressed by energy accumulation and divergence due to difference in static and dynamic friction coefficient. Sprag-slip define instability of geometric structure due to angle of lips on the belt. In this paper, the physical model and the energy equation are established for the above two phenomena. Stick-slip can be solved by decreasing the difference of the static and dynamic friction coefficient. Sprag-slip is caused by the ratio of compressive and shear stiffness of the lips. The belt uses flocking to ensure durability, not coating.

Engine calibration on the powertrain test bed with transient mode is proposed with dynamic powertrain test bed having low inertia dynamometer. Automated ECU (Engine Control Unit) calibration system is completed with the combination of experimental design software, powertrain test bed, evaluation tools and their electrical interfaces. The process is composed up of the system interface definition, test design using DoE skill, test proceedings by step sequence of connecting systems, measured data collecting, mathematical model and optimization result extraction at the end. All the processes are automated by interfaces between the systems. Acceleration surge is minimized by proposed process by optimizing combustion control labels and tip in driveability is maximized by manipulating torque filter labels of EMS (Engine Management System) logic. Their detailed steps from the problem definition to the verification test results of improved design with vehicle test are presented.

It is common knowledge that body structure is an important factor of road noise performance. Thus, a high stiffness of body system is required, and determining their optimized stiffness and structure is necessary. Therefore, a method for improving body stiffness and validating the relationship between stiffness and road noise through CAE and experimental trials was tested. Furthermore, a guideline for optimizing body structure for road noise performance was suggested.

In order to achieve the proper automobile interior sound, the tailpipe noise of the exhaust system must be considered as a main contributor. This paper describes a study of the achievement of dynamic sound quality through exhaust system design. Firstly, we determined the vehicle's interior sound quality and established a target sound using a subjective assessment of 10 benchmark vehicles. The exhaust noise target is determined by means of transfer path analysis focusing on the noise source and how it's impacted by the muffler design. The exhaust system is commonly modeled as a combination of source strength and impedance. We obtained the source character by the wave decomposition method using two microphones and six loads ultimately leading to an optimized design of the inner muffler structure. Based on this study, we achieved dynamic interior sound and improved exhaust system performance.

In the early stage of vehicle development process, it is customary to establish a set of goals for each kinematic and compliance (K&C) characteristic and try to find out design variables such as the location of hard points and bushing stiffness which can achieve these goals. However, since it is very difficult to find out adequate set of design variables which satisfy all the goals, many engineers should rely on their own experiences and intuitions, or repeat trial and error to design a new suspension and improve old one. In this research, we develop a suspension design process by which suspension K&C characteristic targets can be achieved systemically and automatically. For this purpose, design optimization schemes such as design of experiments (DoE) and gradient-based local optimization algorithm are adopted.

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.

The paper describes an engineering project carried out to optimize the crashworthiness of an existing passenger car for frontal crash using a procedure relying on numerical simulation. An optimization target is defined in terms of an ideal acceleration pulse at the seats anchors. The acceleration time history and structural members are scanned in parallel to correlate the local acceleration peaks to specific structural members. Members details are iteratively modified in order to alter the accelerations and get closer to the target.

Today, light connecting rods are vital to satisfying the demands of modern internal combustion engines. HYUNDAI Motor Company (HMC) has applied powder metal forged connecting rods instead of conventional hot forged connecting rods to obtain low product costs and to improve NVH characteristics and bearing reliability. Light connecting rods were developed through optimized design with high quality and low cost. Notably, the mass of a powder metal forged connecting rod is 17.7% lighter than that of a conventional hot forged type connecting rod, and its crank end is 22.5 % lighter than that of a conventional type connecting rod. Light connecting rods result in reduced crankshaft mass, so the mass of the main moving parts can be reduced. With this mass reduction, bearing reliability and NVH characteristics can be enhanced.

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.

A body joint is one of the most major factors affecting the overall body stiffness in a body system. Thus, in order to optimize the body system, the joint must be also optimized. In order to optimize a body joint, it is necessary to first identify the efficiency of the joint itself. Then, the joint stiffness targets for each joint must be set by analyzing the interaction between joint stiffness and overall body stiffness and the function of the joint in terms of vehicle performance. Finally, an optimal joint structure should be designed with an optimal design methodology. In this study, an optimal methodology for the joint stiffness and design is introduced. Based on this research, an optimized joint design for each joint was applied to the new SUV model resulting in a lightweight body with a required body stiffness.

The electrical power system is the vital lifeline to most of the control systems on modern vehicles. The demands on the system are highly complex, and a detailed understanding of the system behavior is necessary both to the process of systems integration and to the economic design of a specific control system or actuator. The vehicle electric power system, which consists of two major components: a generator and a battery, has to provide numerous electrical and electronic systems with enough electrical energy. A detailed understanding of the characteristics of the electric power system, electrical load demands, and the driving environment such as road, season, and vehicle weight are required when the capacities of the generator and the battery are to be determined for a vehicle. An easy-to-use and inexpensive simulation program may be needed to avoid the over/under design problem of the electric power system. A vehicle electric power simulator is developed in this study.