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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.

In recent years, emission regulations have been getting increasingly strict. In the development of engines that comply with these regulations, in-cylinder pressure plays a fundamental role, as it is necessary to analyze combustion characteristics and control combustion-related parameters. The analysis of in-cylinder pressure data enables the modelling of exhaust emissions in which characteristic temperature can be derived from the in-cylinder pressure, and the pressure can be used for other investigations, such as optimizing efficiency and emissions through controlling combustion. Therefore, a piezoelectric pressure sensor to measure in-cylinder pressure is an essential element in the engine research field. However, it is difficult to practice the installation of this pressure sensor on all engines and on-road vehicles owing to cost issues.

This paper introduces the advancement of Engine Idle Stop-and-Go (ISG, also known as Auto Engine Stop-Start) and Neutral Coasting Control (NCC) with utilizing Advanced Driver Assistance System (ADAS) and GPS. The ISG and the In-Neutral Coasting (also known as Sailing or Gliding) have been widely implemented in recent vehicles for improving their fuel economy. However, many drivers find them somewhat disturbing because they basically change behaviors of their cars from what they used to. This annoyance discourages usages of those functions and eventually undermines their benefit of fuel saving. In order to mitigate the problem, new ISG and NCC algorithms are proposed. As opposed to the conventional logics that rely only on driver’s pedal action, the new algorithms determine whether or not to enable those functions for the given driving condition, based on the traffic information obtained using ADAS sensors and the location data from GPS and navigation map.

Due to improvements in vehicle powertrain performance, friction material fade performance is becoming an important topic. For this reason, needs for studies to improve thermal characteristics of the brake system is increasing. Methods for improving the fade characteristics have several ways to improve the thermal characteristic of friction materials and increase disc capacity. However, increasing disc capacity(size) have some risk of weight and cost rise, and friction factor improvements in friction material tend to cause other problems, such as increasing squeal wire brush noise and increasing metal pick up on disc surface. Therefore, a slot disc study is needed to overcome the problems discussed previously. Currently, there is few research history for slot disc related to fade and metal pickup improvements.

The sliding surface of the brake friction material is not uniform but composed of random contact plateaus with a broad pressure distribution, which are known to closely related to the triggering mechanism of friction induced noise and vibrations. The non-uniform contact plateaus are attributed to the various ingredients in the friction material with a broad range of physical properties and morphology and the size and stiffness of the plateau play crucial roles in determining the friction instability. The incorporation of friction surface inhomogeneity is, therefore, crucial and has to be counted to improve the accuracy of the numerical calculation to simulate brake noise. In this study, the heterogeneous nature of the friction material surface was employed in the simulation to improve the correlation between numerical simulations and experimental results.

A vehicle simulation model is developed, validated and integrated into a closed-loop virtual driving environment using a state-of-the-art hexapod driving simulator. Thirty variant states are implemented and evaluated subjectively on steering and handling performance quality and quantity. Standard open-loop objective testing manoeuvres are simulated and performance metrics are calculated, allowing for a systematic cross-correlation process. Graphical analysis of the correlation metrics proves that chassis changes may accurately be felt through the simulator interface. It is proposed how obtained correlation models may serve for driver-feel optimizing target setting in early vehicle development stages, frontloading a great deal of costly prototype testing. System requirements are established and benefits and limitations are portrayed.

Currently, diesel engine-out exhaust NOx emission level prediction is a major challenge for complying with the stricter emission legislation and for control purpose of the after-treatment system. Most of the NOx prediction research is based on the Zeldovich thermal mechanism, which is reasonable from the physical point of view and for its simplicity. Nevertheless, there are some predictable range limitations, such as low temperature with high EGR rate operating conditions or high temperature with low EGR rates. In the present paper, 3 additional considerations, pilot burned gas mixing before the main injection; major NO formation area; concentration correction, were applied to the previously developed real-time NO estimation model based on in-cylinder pressure and data available from ECU. The model improvement was verified on a 1.6 liter EURO5 diesel engine in both steady and transient operation.

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. It is caused by the stick-sleep phenomenon at the lining and disc interface. Recently, the field claim of low frequency creep groan has increased. There are a lot of efforts to improve creep groan noise by means of modification of lining material. In this paper, Transfer path of creep groan noise was analyzed through ODS and TPA. Additionally the correlation between Source (Brake torque variation, Brake vibration) and Creep Groan Sound level was discussed. Finally countermeasure to Creep Groan noise was suggested.

In order to improve the fuel consumption ratio of the vehicle, a great deal of research is being carried out to improve air-conditioning efficiency. Increasing the efficiency of the condenser is directly connected to the power consumption of the compressor. This paper describes an experimental method of using an additional water-cooled condenser to reduce power consumption and decrease discharge pressure of the air-conditioning system. First, the principle of a combined cooling (water + air) method was evaluated theoretically. Next, experimental proof was conducted with the additional water-cooled condenser. The shape and structure is similar to the plate type of the transmission oil cooler used in a radiator. Through a number of tests, it was found that it is possible is to reduce power consumption of compressor by decreasing discharge pressure.

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.

A traffic situation is getting more complex in urban areas. Various safety systems of an automobile have been developed but fatal and serious accidents still can be made by driver's faults or distractions. The system supporting extend of driver's recognition area is going to be an important part of future intelligent vehicles in order to prevent accidents. In this paper we propose sensor fusion system based on a digital-map for driver assistance. The accurate localization of a host vehicle is achieved by a stereo vision sensor and a digital-map using polygon matching algorithm in urban area. A single-row laser scanner is used for tracking multiple moving objects. The coordinate transformation from sensor frame to global frame is performed to visualize the moving objects on a digital-map. An experiment was conducted in an urban canyon where the GPS signals are frequently interrupted.

It is necessary for vehicle horns not only to satisfy regulations on the sound level but also to fulfill various demands related with sound quality. For example, a disk type horn which is attached on most of small size vehicles has been required to improve its sharp feeling sound. However, the improvement of horn sound has been deterred mainly due to the deficiency of the understanding on how design factors are related with emotional judgments on horn sound. In addition, a proper CAE tool is not available in the process of horn design since it is difficult to describe multi-physical phenomena engaged with horns. The purpose of this study is to improve the sound quality of a disk type horn. In order to achieve this goal, firstly, acoustic characteristics of horns were obtained through a series of experiments. In addition, various sound quality metrics were examined in order to derive design factors affecting sound quality enhancement.

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.

A nano-sized PM and THC emission characteristics were investigated according to the fuel injection strategy such as a pressure and timing in the GDI engine. On the part-load condition, the particulate emissions exhibited a strong sensitivity to the injection timing. The fuel injection pressure also had a great association with the nano-particles and THC. A size of PM exhausted from the GDI engine located near 10nm on the part-load. In contrast, accumulation mode particles within 60 - 80nm mainly exhausted during the cold transient start phase. Increment of fuel injection pressure positively affected on the nano-particle and THC emissions during the start of the engine, as well.

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%.

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 model based control algorithm for the pressure control type CVT has been developed. First, a P-line is proposed from the steady state relationship between the primary and secondary pressure for the given speed ratio to predict the shift performance. The P-line shows the pressure difference from the steady state primary pressure to the maximum(or minimum) pressure available for the given secondary pressure. It is found from the P-line that the bigger the pressure difference, the faster the shift speed. Based on the steady state characteristics of the pressure control type ratio control valve(RCV), the model based control algorithm is proposed. In the model based control, ratio control solenoid valve(RCSV) control duty is supplied in the feedforward loop.

Generally, the widely used hydraulic control system in automatic transmissions is pulse width modulation (PWM) type. It consists in a PWM solenoid valve and a reducing type second stage valve, so called pressure control valve (PCV), to amplify pressure or flow rate. In this study, the mathematical models of the PWM solenoid valve and the PCV with moderate complexity are proposed. Then, their behavior is analyzed from the steady state characteristics. Finally, we find that there are good matches between the dynamic simulation results and the experimental data.

Hands-free stability, one of the handling characteristics of a vehicle, is a stability criterion evaluated in case of a driver's steering wheel release after a certain steering input during driving. During the development process, a hands-free-unstable vehicle needs many steering and suspension parts to be repeatedly tested to improve the performance. In this paper, CAE methods are proposed to investigate easily the influence of the steering and suspension design parameters on the hands-free stability. And the results of CAE methods were compared with the prototype vehicle test to verify the validity of the methods.