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A cooling fan is one of the primary components affecting the cooling performance of an engine cooling system. In recent years, with the increase in electric vehicles (EVs) and hybrid vehicles (HVs), the cooling performance and noise level of the cooling fan have become very important. Thus, the development of a low-noise fan with the same cooling performance is urgently required. To address this issue, it is critical to find the relation between the performance of the fan and the flow structures generated around it, which is discussed in the present paper. Specifically, a computational method is employed that uses unsteady Reynolds-averaged Navier-Stokes (URANS) coupling with a sliding mesh (SLM). Measurements of the P-Q (Pressure gain-Flow rate) characteristics are performed to validate the predictive accuracy of the simulation.

DENSO International America, Inc. and the University of Iowa-Operator Performance Laboratory (OPL) have developed a series of new Multi-Modal Interface for Drivers (MMID) in order to improve driver safety, comfort, convenience and connectivity. Three MMID concepts were developed: GUI 1, GUI 2 and GUI 1-HUD. All three of the MMIDs used a new Reconfigurable Haptic Joystick (RHJ) on the steering wheel and new concept HMI Dual Touch Function Switches (DTFS) device. The DTFS use capacitive and mechanic sensing located on the back of the steering wheel as input operation devices. Inputs from the new controls were combined with a large TFT LCD display in the instrument cluster, a Head Up Display (HUD) and Sound as output devices. The new MMID system was installed in a Lexus LS-430. The climate control panel and radio panels of the LS-430 were used as a baseline condition to which the new designs were compared.

ESL (Electric System Level) Design Methodologies enable us to design and verify various electrical behaviors of automotive electronics including automotive semiconductors on a simulator before hardware prototyping. It could facilitate the optimization of hardware structures, and shorten the total development period by reducing rework process. We propose the “ESL Design Methodologies for Automotive” to renovate conventional development scheme. ESL technology began to be used from the domain of digital consumer electronics. Regarding automotive electronics domain, however, we would not be able to adapt the same methodologies to automotive systems, which consist of many mixed-signal components. Also, another approach is required for the rising demand of safety design sort of functional safety.

Heat exchangers used as charge air coolers are repeatedly subjected to thermal strain, which may cause fracture. To predict the durability of heat exchangers, stress estimations using Finite Element Analysis (FEA) are effective. However, producing a detailed finite element model would require an enormous number of elements and excessive calculation costs. To resolve this problem, we focused on periodic tube-fin structures, considering actual and designed fin shapes, and applied a homogenization method to the fins. We then determined their homogenization elastic stiffness and verified it by conducting compression experiments and analyses using partial models consisting of laminated tube-fin structures. If fins are homogenized, it is important that homogenization be based on the actual fin shape. We then produced a finite element model of a charge air cooler assembly by using the homogenization element, and conducted analyses which simulated a thermal fatigue test.

In order to improve corrosion resistance and thermal efficiency of the air conditioner evaporator, a coating which provides hydrophilicity was formed over the chromate coating. In addition, there has been greater demand for air with fewer smells. This report describes the cause of “dusty odor” and a method to reduce it. The dusty odor is caused by a little corrosion of the substrate aluminum. Hydrophilic coating film dissolves little by little in condensed water, and substrate aluminum is exposed. A method to prevent the odor was developed by forming a coating giving hydrophilicity and durability to the evaporator surface.

As the demand for improved fuel economy increases and new CO2 regulations have been issued, aerodynamic drag reduction has become more critical. One of the important factors to consider is cooling drag. One way to reduce cooling drag is to decrease the air flow volume through the front grille, but this has an undesirable impact on cooling performance as well as component heat load in the under-hood area. For this reason, cooling drag reduction methods while keeping reliability, cooling performance and component heat management were investigated in this study. At first, air flow volume reduction at high speed was studied, where aerodynamic drag has the greatest influence. For vehicles sold in the USA, cooling specification tends to be determined based on low speed, while towing or driving up mountain roads, and therefore, there may be extra cooling capacity under high speed conditions.

Requirements for fuel economy improvement and reduction in the vehicles engine compartment have increased significantly in the pass years. Performances in radiators have driven changes in terms of compactness and weight reductions. By focusing on the air flow we have optimized the radiator fin and developed a high performance radiator. A similar performance was achieved using an 11mm core depth which has 30% weight reduction compared to a 16mm core depth. The purpose of this paper is to present a technical outline about fin optimization.

This study investigates the reduction of the Blade Passing Frequency (BPF) noise radiated from an automotive engine cooling fans, especially in case of the fan with an eccentric shroud. In recent years, with the increase of HV and EV, noise reduction demand been increased. Therefore it is necessary to reduce engine cooling fan noise. In addition, as a vehicle trend, engine rooms have diminished due to expansion of passenger rooms. As a result, since the space for engine cooling fans need to be small. In this situation, shroud shapes have become complicated and non-axial symmetric (eccentric). Generally, the noise of fan with an eccentric shroud becomes worse especially for BPF noise. So it is necessary to reduce the fan BPF noise. The purposes of this paper is to find sound sources of the BPF noise by measuring sound intensity and to analyze the flow structure around the blade by Computational Fluid Dynamics (CFD).

Improving the engine efficiency to respond to climate change and energy security issues is strongly required. In order to improve the engine efficiency, lower fuel consumption, and enhance engine performance, OEMs have been developing high compression ratio engines and downsized turbocharged engines. However, higher compression ratio and turbocharging cause cylinder pressure to increase, which in turn increases the demand voltage for ignition. To reduce the demand voltage, a new ignition system is developed that uses a high voltage Zener diode to maintain a constant output voltage. Maintaining a constant voltage higher than the static breakdown voltage helps limit the amount of overshoot produced during the spark event. This allows discharge to occur at a lower demand voltage than with conventional spark ignition systems. The results show that the maximum reduction in demand voltage is 3.5 kV when the engine is operated at 2800 rpm and 2.6 MPa break mean effective pressure.

In electronic products, the recently increasing thermal radiation demands higher thermal conductivity of polymer composites. However, inaccurate observation of the filler dispersion within the polymer does not allow for accurate quantification of Interface Thermal Resistance and subsequently the prediction of thermal conductivity. Therefore, optimum filler design could not be achieved. Firstly in this report, accurate stereoscopic filler dispersion was observed by FIB-SEM. Secondly, quantification of Interface Thermal Resistance could be achieved by thermal conduction analysis using filler dispersion model. Thirdly, this Interface Thermal Resistance enabled the prediction of the thermal bulk conductivity. Lastly, the prediction made above could be validated by comparison of predicted value to measured value. This result may lead to optimum filler design and thereby to the development of higher thermal radiation materials.