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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.

This paper analyzes low-speed pre-ignition (LSPI), a sudden pre-ignition phenomenon that occurs in downsized boosted gasoline engines in low engine speed high-load operation regions. This research visualized the in-cylinder state before the start of LSPI combustion and observed the behavior of particles, which are thought to be the ignition source. The research also analyzed pre-ignition by injecting deposit flakes and other combustible particulate substances into the combustion chamber. The analysis found that these particles require at least two combustion cycles to reach a glowing state that forms an ignition source. As a result, deposits peeling from combustion chamber walls were identified as a new mechanism causing pre-ignition. Additionally, results also suggested that the well-known phenomenon in which the LSPI frequency rises in accordance with greater oil dilution may also be explained by an increase in deposit generation.

One of the most significant current discussions worldwide is the anthropogenic climate change accompanying fossil fuel consumption. Sustainable development in all fields of combustion engines is required with the principal objective to enhance efficiency. This certainly concerns the field of hand-held power tools as well. Today, two-stroke SI engines equipped with a carburetor are the most widely used propulsion technology in hand-held power tools like chain saws and grass trimmers. To date, research tended to focus on two-stroke engines with rich mixture setting. In this paper the advantages and challenges of leaner and/or lean operation are discussed. Experimental investigations regarding the influence of equivalence ratio on emissions, fuel consumption and power have been performed. Accompanying 3D-CFD simulations support the experiments in order to gain insight into these complex processes. The investigations concentrate on two different mixture formation processes, i.e.

With the evolution of automotive features, larger flash program size has been required even at the local electronic control units (ECUs). As the flash programming data rate increases, Ethernet is adopted as a global data port from the external source. However, it can not be applied to the bus type network topology between the domain control unit (DCU) and the local ECUs, because it uses a peer-to-peer type network topology. On the other hand, high speed CAN-FD has been studied recently for this bus topology, but its data rate is limited at the range of several mega bps due to the signal waveform distortion caused by the multiple reflections at the non-terminated stubs. This paper describes a novel distortion cancelling for the bus topology as the pre-emphasis technique, in which the digital signal processing (DSP) compensates the complicated signal distortion caused by the multiple reflections.

This paper presents two newly developed technologies of optimizing impurity diffusion concentration for silicon semiconductor material and controlling internal stress of the top SiN (Silicon Nitride) layer on a membrane of a silicon substrate to apply them to the manufacturing process of MEMS (Micro Electro Mechanical Systems) type air-flow sensor chips. Until today, in MEMS-type airflow sensors, poly-crystalline silicon (poly-Si) and platinum were widely used as a resistor material of key functional elements on a membrane of air-flow-rate measurement portion. The functional resistors on the membrane are required to monitor high temperatures of about 300 °C and to perform the self-heating operations at that temperature range because of the suppression of contaminant deposition by means of evaporation or incineration.

The backward flow of the hot burned gas surrounding a diesel flame was found to be one of the factors dominating the set-off length (also called the lift-off length), that is, the distance from a nozzle exit into which a diffusion flame cannot intrude. In the combustion chamber of an actual diesel engine, the entrainment of the surrounding gas into a spray jet from a multi-hole nozzle is restricted by the walls and adjacent spray jets, which induces the backward flow of the surrounding gas. A new momentum theory to calculate the backward flow velocity was established by extending Wakuri's momentum theory. Shadowgraph imaging in an optical engine successfully visualized the backward flow of the hot burned gas.

This paper evaluates the effect of our new alternator concept for a conventional vehicle, which is able to generate electricity by storing kinetic energy of the vehicle in the high speed flywheel as rotation energy under deceleration. The alternator constructs a planetary gear device and multiple clutch-brakes perform CVT, alternator and high speed flywheel without an expensive electric device, mechanical CVT and vacuum pump. So it has high cost performance.

Higher pressure and higher precision are required for diesel fuel injection equipment in response to increasingly severe emissions control regulations. Market diesel fuels have become more diversified than in the past. Diesel fuel quality has also been changing, being affected by crude oil slate, extreme lowering of sulfur content, and diesel reformulated from heavy fuel oil, among other reasons. As a result of this, deposits thought to have a fuel origin have been observed within diesel fuel injectors in certain regions. Related changes in fuel injection quantity have also been observed. This paper determines injector deposit production mechanisms. It focuses on the structural changes of deposit causative substances by temperature as well as injector design change improvements to prevent deposits.

Stratified concepts offer a reduction of the scavenging losses of 2-stroke engines. STIHL has developed a stratified reed valve engine to comply with Phase2 emissions, introduced into the market in the new STIHL Cutquik™ TS 700. The engine with a displacement of 98,5 cm3 offers performance and product specifications that exceed its conventional predecessor. The results of the engine optimization process including flow simulation, concept evaluation and combustion process development are presented. The paper focuses on the design specifications of the air head carburetor and the specific layout of the reed valve scavenging process. Further, a cyclone type air filter system is presented. The engine today meets the FEL 72 g/kWh limit. The concept offers further potential to improve trapping and volumetric efficiency, enabling a power and torque increase as well as emission control for the future.

Unstable combustion and high cyclic variations of the in-cylinder pressure associated with low engine running smoothness and high emissions are mainly caused by cyclic variations of the fresh charge composition, the variability of the ignition and the fuel mass. These parameters affect the inflammation, the burn rate and thus the whole combustion process. In this paper, the effects of fluctuating fuel mass on the combustion behavior are shown. Small two-stroke engines require special measuring and testing equipment, especially for measuring the fuel consumption at very low fuel flow rates as well as very low fuel supply pressures. To realize a cycle-resolved measurement of the injected fuel mass, fuel consumption measurement with high resolution and high dynamic response is not enough for this application.

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.

The ejector is a fluid pump that recovers expansion energy, which is wasted in the conventional refrigeration cycle decompression process, and converts the recovered expansion energy into pressure energy. In the ejector cycle, the ejector helps to reduce power consumption of the compressor by using the above mentioned pressure-rising effect. Consequently, the ejector system can improve energy efficiency of the refrigeration cycle. In previous work, the ejector cycle was used to reduce power consumption in refrigeration cycles for a cool-box (a beverage cooling inside the vehicle) and refrigerated truck box. Both of these applications used the ejector to achieve refrigerant pressure/temperature below the vehicle cabin temperature. Now, the ejector has been integrated into the vehicle cabin evaporator to reduce power consumption of the refrigeration cycle for vehicle cabin cooling.

Down-sizing and dielectric insulation were required for the traction motors of hybrid vehicles. By utilizing the newly developed coil with thick resin insulation atop the conventional enamel film, the use of conventional inter-phase insulation paper was abolished. Furthermore, by adopting the stair-shaped coil structure and spiral winding configuration, the stator size was minimized. With the above technologies, the motor installation to smaller hybrid vehicles was realized, thus contributing to weight reduction of hybrid vehicles.

General analysis methods which are known as Transfer Path Analysis and Air borne Source Quantification have been extended to estimate forces of an air conditioner's parts and also clarify the path from air conditioner system. These results show noise transfer path to be improved. Originally, the existing methods are known to require considerable amount of time for the cause of complicated measurement to get analysis results. In the work of this paper, required measurement is simplified, and time reduction of 50% is achieved without critical decrease in analysis accuracy.

In recent years, vehicle cabin quietness takes a growing importance particularly related to the emergence of hybrid and electric vehicles and “Idle Stop system” vehicles. Demand for quieter car air-conditioner systems is increasingly important also, especially the reduction of the flow-induced noise from the HVAC. In HVAC systems, the rotating blower is one of the main noise sources and the digital solution for predicting and analyzing the blower aeroacoustic noise in the early stage of design is needed for developing a quieter blower. The target of this study is to develop and to validate a flow-induced noise predictive tool for a HVAC blower and to analyze the noise source. In this paper, a low-dissipation, transient, compressible CFD/CAA approach based on the Lattice Boltzmann Method (LBM) is used to predict simultaneously the flow and aeroacoustic radiation of two production blowers.

Increased interest in global warming requires rapid improvements in CO2 reduction efforts. The automotive industry is placing high importance on CO2 reduction technologies. Using Lithium-ion (Li-ion) battery pack Stop & Start (S&S) system with combined energy regeneration is an effective technology to reduce CO2 emissions. Power supply storage is very important for the S&S system. High charging acceptance, low weight, and compact size are required. A Li-ion battery is the optimal power supply that meets these requirements. It has high charge acceptance per weight. Furthermore, we developed simple system structure which eliminates the need for the DC-DC converter. By utilizing a Li-ion battery that has voltage characteristics similar to the Pb battery there is no need for a converter to make adjustments between the two power supplies. The Li-ion battery's range of capacity must be managed appropriately as overcharge and overdischarge causes extensive damage to the battery.

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 recent years, fuel consumption regulations are becoming more severe in every country in the world. Engine size reduction plus turbo is one of the solutions. Our turbo system has an intercooler which cools high temperature gas compressed by a turbocharger. The structure of the intercooler is a tank mounted on both sides of a heat exchanger. The tank connects to the heat exchanger and turbo system allowing EGR (Exhaust Gas Recirculation) gas through the heat exchanger in response to the tightening of exhaust gas regulations. Use of the LPL (Low Pressure Loop) system which refluxes EGR gas is expected to increase from now. Since EGR gas is characterized by high temperature, high pressure, and acidic condensed water, high fatigue strength at high temperature and acid resistivity is required. Therefore aluminum (Al) is generally applied for “intercooler tank” (hereafter referred to as “tank”).

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.