An overview of biodiesel in Asian countries and the harmonization of quality standards

Recently, biofuels have been actively introduced as transportation fuels in Asian countries. Common drivers to use biofuels are energy security, fuel diversification, and the reduction of greenhouse gases. In addition, some Southeastern Asian countries look forward to utilizing the abundant agricultural resources and providing stability for farmers. However, a compromised quality of biofuels could cause vehicle trouble, which is why the quality standard of the fuels is very important. On the other hand, the quality standard of biofuels differs from country to country and could cause vehicle trouble in some countries and not others. These differing standards may become an obstacle to trade. In this situation, the harmonization of the biodiesel standards in the East Asia Summit (EAS) region has been initiated by the ERIA biodiesel working group, in which members are the specialists from each country. This review summarizes the introduction of biofuels in this region and the recent activities regarding the harmonization of the fuel quality standard. Important background for this review is based on the results of the ERIA biodiesel working group meeting.     

Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h.     

Driver recognition of a run-over accident

If a driver passes over a pedestrian lying on the road and flees, it is considered a crime. In several cases, even if the driver fled and was arrested, he/she often asserts that they did not know that the victim was a human being. However, the investigation agency often believes that a driver can certainly recognize when he/she passes over a person. Accordingly, such cases frequently lead to disputes due to the lack of criteria for recognizing when a driver was involved in run-over accidents. In this study, tests were conducted both to identify if drivers can recognize whether their vehicles passed over a person and to examine how they feel at the time. A silicon dummy, which was manufactured to have the same characteristic as the human chest, was used in this study. According to the method specified in ISO2631, the vibration delivered to the driver was measured, and eighteen participants drove a vehicle over the silicon dummy to experience how the vibrations felt. When the passenger car for the test ran over the dummy at speeds ranging from 10 km/h to 60 km/h, all participants recognized the delivered vibration, and the VDV that was delivered to the participants ranged from 1.81 m/s ^1.75 to 2.38 m/s ^1.75. The participants thought that the object they drove over was a stone or a piece of wood. This indicates that the driver certainly can recognize the vibrations generated from passing over a human chest even though it feels like a solid object.     

A novel adaptive algorithm with an IIR filter and a variable step size for active noise control in a short duct

The intake system in an automotive engine has a short duct compared with that of the exhaust system. The filtered-x LMS (FX-LMS) algorithm has been applied to the active noise control (ANC) system in a short acoustic duct. This algorithm design is based on the FIR (finite impulse response) filter; however, it has a slow convergence issue due to a large number of zero coefficients. To improve the convergence performance, the step size of the LMS algorithm was modified from fixed to variable. However, this algorithm is still not suitable for the ANC system of a short acoustic duct because the reference signal is affected by the backward acoustic wave propagated from a secondary source. Therefore, the recursive filtered-u LMS algorithm (FU-LMS) based on the infinite impulse response (IIR) is developed to consider backward acoustic propagation. Generally, this algorithm has a stability problem. The stability issue was improved using an error-smoothing filter. In this paper, the recursive LMS algorithm with a variable step size and smoothing error filter is designed. This recursive LMS algorithm, the FU-VSSLMS algorithm, uses an IIR filter. With fast convergence and good stability, this algorithm is suitable for the ANC system in a short acoustic duct, such as the intake system of an automotive engine. This algorithm is applied to the ANC system of a short acoustic duct. The disturbance signals used as primary noise source are a sinusoidal signal embedded in white noise and the chirp signal, which has a variable instantaneous frequency. The test results demonstrate that the FU-VSSLMS algorithm has a superior convergence performance when compared with the FX-LMS and FX-LMS algorithms. The algorithm can be successfully applied to the ANC system in a short duct, such as the intake duct.     

Development of a fail-safe control strategy based on evaluation scenarios for an FCEV electronic brake system

This study presents a few fail-safe control strategies based on reliability evaluation scenarios for the electronic brake systems of green cars in several critical cases. CarSim and MATLAB Simulink were used to develop the FCEV model with regenerative braking involving EWBs and EMBs. The proposed reliability evaluation scenarios were simulated, and a few fail-safe control algorithms were verified using the proposed reliability evaluation scenarios with the developed FCEV simulation model. The reliability evaluation scenarios were developed using a combination of driving modes and FMEA results for these electronic brake systems.     

Design methodology to reduce the chest deflection in US NCAP and EURO NCAP tests

There have not been many studies on the factors that affect chest deflection, although the US NCAP thoracic injury criterion was recently shifted from the 3-msec clip to chest deflection. This study explored these factors and proposed a design methodology for the factors to minimize chest deflection. Because injuries can become severe if the driver crashes against the vehicle interior, this study also sought a solution using a penalty function to prevent crashes with the interior and minimize injuries. First, a MADYMO model was made to simulate US NCAP and EURO NCAP tests by one-to-one and stochastic verifications. Second, a sensitivity analysis was conducted to find the major factors that affect chest deflection. Lastly, the factors identified via the sensitivity analysis were optimized to propose design guidelines that helped vehicles receive high star ratings in US NCAP and EURO NCAP tests and helped minimize the possibility of hard contact between the driver and the vehicle interior by utilizing a penalty function and the Taguchi method.     

Adaptive neural network based fuzzy control for a smart idle stop and go vehicle control system

Idle stop and go (ISG) is a low cost but very effective technology to improve fuel efficiency and reduce engine emissions by preventing unnecessary engine idling. In this study, a new method is developed to improve the performance of conventional ISG by monitoring traffic conditions. To estimate frontal traffic conditions, an ultra-sonic ranging sensor is employed. Several fuzzy logic algorithms are developed to determine whether the engine idling is on or off. The algorithms are evaluated experimentally using various data gathered in real areas with traffic congestion. The evaluation results show that the method developed can reduce the chance of false application of ISG significantly while improving fuel efficiency up to 15%.     

Development of a control strategy based on the transmission efficiency with mechanical loss for a dual mode power split-type hybrid electric vehicle

In this study, a control strategy for a dual mode power split-type hybrid electric vehicle (HEV) is developed based on the powertrain efficiency. To evaluate the transmission characteristics of the dual mode power split transmission (PST), a mechanical loss model of the transmission (TM loss) is constructed. The transmission efficiency, including the TM loss, is evaluated for the dual mode PST. Two control strategies for the dual mode PST are proposed. An optimal operation line (OOL) control strategy is developed to maintain a high engine thermal efficiency by controlling the engine operation point on the OOL. A speed ratio (SR) control strategy is proposed to obtain a greater transmission efficiency by shifting the engine operation point when the dual mode PST operates near the mechanical points. Using the TM loss and the proposed control strategies, a vehicle performance simulation is conducted to evaluate the performance of the two control strategies for dual mode PST. The simulation results demonstrate that, for the SR control strategy, the engine efficiency decreases because the engine operates beyond the OOL. However, the transmission efficiency of the dual mode PST increases because the PST operates near the mechanical point where the PST shows the greatest transmission efficiency. Consequently, the fuel economy of the SR control strategy is improved by 3.8% compared with the OOL control strategy.     

Robust design optimization of suspension system by using target cascading method

This study presents the robust design optimization process of suspension system for improving vehicle dynamic performance (ride comfort, handling stability). The proposed design method is so called target cascading method where the design target of the system is cascaded from a vehicle level to a suspension system level. To formalize the proposed method in the view of design process, the design problem structure of suspension system is defined as a (hierarchical) multilevel design optimization, and the design problem for each level is solved using the robust design optimization technique based on a meta-model. Then, In order to verify the proposed design concept, it designed suspension system. For the vehicle level, 44 random variables with 3% of coefficient of variance (COV) were selected and the proposed design process solved the problem by using only 88 exact analyses that included 49 analyses for the initial meta-model and 39 analyses for SAO. For the suspension level, 54 random variables with 10% of COV were selected and the optimal designs solved the problem by using only 168 exact analyses for the front suspension system. Furthermore, 73 random variables with 10% of COV were selected and optimal designs solved the problem by using only 252 exact analyses for the rear suspension system. In order to compare the vehicle dynamic performance between the optimal design model and the initial design model, the ride comfort and the handling stability was analyzed and found to be improved by 16% and by 37%, respectively. This result proves that the suggested design method of suspension system is effective and systematic.     

SCR control strategy based on ANNs and Fuzzy PID in a heavy-duty diesel engine

The paper presents an innovative method combining artificial neural networks (ANNs) with Fuzzy PID to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. An ANN model was utilized to simulate the formation of NOx emissions under various engine operating conditions. Next, an effective closed-loop control strategy with a type of feedback known as fuzzy PID is adopted for on-line, real-time control of 32.5% aqueous urea dosing in the exhaust stream. The new strategy explores the benefits by simulation and testing in the environments of Matlab/Simulink and ESC/ETC, respectively. The notable achievement of considerable NOx reduction and an acceptably small NH3 slip is obtained based on this new, feasible and effective strategy.