Search Results

Merging a CAE shape optimization system and a concept Taguchi method SN-ratio index, a robustness-focused automated shape optimization method has been developed. Applying this method to diesel intake ports, with mold position tolerance set as the error factor, SN-ratio was defined for swirl stability. As a result of the optimization provided by a multi-objective genetic algorithm, simultaneous improvement of flux, swirl rotation and SN ratio was achieved.

Previous studies have investigated the impacts of biofuel usage on the performance, drivability and durability of modern diesel engines and exhaust after-treatment systems including test work with different types, concentrations and mixtures of bio fuel components. During this earlier work vehicle fuel filter blocking issues were encountered during a field trial using various types of EN 14214 compliant Fatty Acid Methyl Ester (FAME) blended into EN 590 diesel. This paper summarises a subsequent literature review that was carried out looking into potential causes of this filter blocking and further work that was then carried out to expand on the findings. From this, a laboratory study was carried out to assess the increase in fuel filter blocking tendency (FBT) when various FAMEs from mixed sources were blended into EN 590 diesel at different concentrations, including levels above those currently allowed in the European market.

Knock in spark-ignition (SI) engines has been a subject of many research efforts and its relationship with high efficiency operating conditions keeps it a contemporary issue as engine technologies push classical limits. Despite this long history of research, literature is lacking coherent and generalized descriptions of how knock is affected by changes in the full cylinder temperature field, residence time (engine speed), and air/fuel ratio. In this work, two dimensionless numbers are applied to fully 3D SI conditions. First, the characteristic time of autoignition (ignition delay) is compared against the characteristic time of end-gas deflagration, which was used to predict knocking propensity. Second, the temperature gradient of the end-gas is compared against a critical detonation-based temperature gradient, which predicts the knock intensity.

The use of lead-free (Pb-free) solder and plating in onboard electronic components has accelerated rapidly in recent years, but solutions have yet to be found for the issues of whisker generation in tin (Sn) plating and crack initiation in Pb-free solder, despite widespread research efforts. Analysis of the whisker generation mechanism has focused on internal energy levels and crystal orientation, and analysis of the crack initiation mechanism in Pb-free solder has examined changes in the grain boundaries of Sn crystals.

The dissolution and exfoliation of chromium plating specific to Russia was studied. Investigation and analysis of organic compounds in Russian soil revealed contents of highly concentrated fulvic acid. Additionally, it was found that fulvic acid, together with CaCl2 (a deicing agent), causes chromium plating corrosion. The fulvic acid generates a compound that prevents reformation of a passivation film and deteriorates the sacrificial corrosion effectiveness of nickel.

The purpose of this study is to analyze the piston skirt friction reduction effect of a diamond-like carbon (DLC)-coated wrist pin. The floating liner method and elasto-hydrodynamic lubrication (EHL) simulation were used to analyze piston skirt friction. The experimental results showed that a DLC-coated wrist pin reduced cylinder liner friction, and that this reduction was particularly large at low engine speeds and large pin offset conditions. Friction was particularly reduced at around the top and bottom dead center positions (TDC and BDC). EHL simulation confirmed that a DLC-coated wrist pin affects the piston motion and reduces the contact pressure between the piston skirt and cylinder liner.

By using analytical techniques (FT-IR, TG-MS, ICP) and DFT calculations, the potassium (K) used as a storage component in NOx Catalysts can be analyzed. The results from this study show that the, K exists as K2CO3, and that the amount, molecular structure, and thermal stability of K2CO3 are different, depending on the support material (ZrO2, Al2O3, or TiO2). If the amount of K that interacts with the support to form an inactive complex oxide is decreased, the amount of K2CO3 and NOx storage is increased. The amount of the inactive K varies with the basicity of the supports. K2CO3 that exists in unstable structures on the supports can be easy to react with NOx to form the nitrate. So, the higher the quantity of unstable K2CO3, the higher the NOx storage capacity. Based on these results, a development guideline was proposed to improve the NOx storage performance.

Behavior of sprays formed by slit nozzle as well as swirl nozzles with the spray cone angle in the range of 40° ∼110 ° were studied in a constant volume N2 gas chamber. The fuels used are iso-pentane, n-heptane, benzene and gasoline. The ambient pressure and temperature were raised up to 1.0 MPa and 465 K, respectively. The injection pressure was mainly set at 8 MPa. Spray penetrates at an almost constant speed for a while after injection start and begins to decelerate at a certain point. This point was judged as breakup point, based on a momentum theory on spray motion, the observation of spray inside and the analysis of the spray front reacceleration which occurs under highly volatile condition.

Since the regulations of CO2 emissions have been tightened in each country recently, each automotive manufacturer has responded by bringing competitive technologies that maximize efficiency while promoting vehicle electrification such as xEV. Not only the efficiency, we need to meet or exceed occupant performance and comfort expectations. The climate control system expends a large amount of energy to keep a comfortable environment, having a significant impact on fuel consumption and EV driving range. Therefore, many manufacturers try to save energy and improve occupant comfort quickly by using not only the conventional convective heating by HVAC but also the conductive heating to heat the human body directly such as seat and steering wheel heater. In this study, a radiative heater, which is more efficient than a convective heating to warm anterior thigh and shin where a conductive heating cannot warm, was applied to vehicle.

To meet future stringent emission regulations such as Euro6, the design and control of diesel exhaust after-treatment systems will become more complex in order to ensure their optimum operation over time. Moreover, because of the strong pressure for CO₂ emissions reduction, the average exhaust temperature is expected to decrease, posing significant challenges on exhaust after-treatment. Diesel Oxidation Catalysts (DOCs) are already widely used to reduce CO and hydrocarbons (HC) from diesel engine emissions. In addition, DOC is also used to control the NO₂/NOx ratio and to generate the exothermic reactions necessary for the thermal regeneration of Diesel Particulate Filter (DPF) and NOx Storage and Reduction catalysts (NSR). The expected temperature decrease of diesel exhaust will adversely affect the CO and unburned hydrocarbons (UHC) conversion efficiency of the catalysts. Therefore, the development cost for the design and control of new DOCs is increasing.

Despite the fact that methanol is toxic to human health and causes serious damage to automobile engines and fuel system components, methanol-containing gasoline is becoming popular in some areas. Methanol demonstrates similar chemical properties to ethanol (which is already established as an additive to gasoline), so that it is difficult to identify methanol-containing gasoline without performing proper chemical analysis. In this study, we report a low-cost, portable, and easy-to-operate sensor that selectively changes color in response to methanol contained in gasoline. The colorimetric sensor will be useful for automobile users to avoid methanol-containing gasoline upon refueling.

This research investigates the influences of the injection timing, injection pressure, and compression ratio on the combustion and exhaust emissions in a single cylinder 1.0 L DI diesel engine operating with ultra-high EGR. Longer ignition delays due to either advancing or retarding the injection timing reduced the smoke emissions, but advancing the injection timing has the advantages of maintaining the thermal efficiency and preventing misfiring. Smokeless combustion is realized with an intake oxygen content of only 9-10% regardless of the injection pressure. Reduction in the compression ratio is effective to reduce the in-cylinder temperature and increase the ignition delay as well as to expand the smokeless combustion range in terms of EGR and IMEP. However, the thermal efficiency deteriorates with excessively low compression ratios.

Because of recent advances in steering control technology, steer-by-wire systems have continued to become more realistic. The principal issue for these steer-by-wire systems is considered to be promoting reliability through the construction of a design concept that can be utilized appropriately by drivers. This paper first describes the flow between the concept and system structure, and proposes a steer-by-wire system with a mechanical backup mechanism as one possibility. This paper also describes an investigation into its potential advantages using an experimental vehicle installed with the proposed system structure. The potential advantages of steer-by-wire are improved vehicle driving performance, vehicle maneuverability, and the feasibility of innovative packaging and design. In order to make improved maneuverability and design innovations compatible, it is critical to achieve steering characteristics that require little maneuvering angle.

Due to new CO2 regulations and increasing demand for improved fuel economy, reducing aerodynamic drag has become more critical. Aerodynamic drag at the rear of the vehicle accounts for approximately 40% of overall aerodynamic drag due to low base pressure in the wake region. Many studies have focused on the wake region structure and shown that drag reduction modifications such as boattailing the rear end and sharpening the rear edges of the vehicle are effective. Despite optimization using such modifications, recent improvements in the aerodynamic drag coefficient (Cd) seem to have plateaued. One reason for this is the fact that vehicle design is oriented toward style and practicality. Hence, maintaining flexibility of design is crucial to the development of further drag reduction modifications. The purpose of this study was to devise a modification to reduce rear drag without imposing additional design restrictions on the upper body.

Rubber is a thermosetting material and as such is generally considered difficult to recycle; therefore there is a demand for the development of rubber recycling technology to protect the environment and conserve resources. Some technologies exist to recycle vulcanized rubber, but none of these has high enough productivity to produce reclaimed rubber, and re-vulcanized rubber does not have the same properties as virgin rubber materials. Now a new recycling technology, called Shear Flow Stage Reactor, has been developed for rubber reclamation. This new technology has high productivity and can achieve the same properties as virgin materials. Automotive parts have been developed and are being produced with recycled Ethylene-Propylene-diene Rubber (EPDM) based on this new technology. The performance of the developed parts is the same as the parts made from virgin materials.

To resolve two major problems of conventional CFD-based shape optimization technology: (1) dependence of the outcome on the selection of design parameters, and (2) high computational costs, two types of innovative inverse analysis technologies based on a mathematical theory called the Adjoint Method were developed in previous studies for maximizing an arbitrary hydrodynamic performance aspect as the cost function: surface geometry deformation sensitivity analysis to identify the locations to be modified, and topology optimization to generate an optimal shape. Furthermore, these technologies were extended to transient flows by the application of the transient Adjoint Method theory. However, there are many cases around flow path shapes in vehicles where performance with respect to heat or concentration, such as the total amount of heat transfer or the flow rate of a specific gas component, is very important.

In recent years, GPFs (Gasoline particulate filters) have been installed in gasoline engines to comply with stricter environmental regulations in China and Europe. In particular, coated-GPFs having a catalytic purification function are required to have high conversion performances, high filter efficiencies in the sense of a high collection efficiency, and low pressure loss. It is not easy to design a filter that satisfies all these parameters. Experimental studies are being conducted, but it is costly to study in trial productions. In this technical paper, a GPF design optimization method will be proposed that combines multi-scale simulation, surrogate models by machine learning, and an optimization algorithm. By using this method, a GPF design that minimizes pressure loss while providing high conversion performance and particle collection rates that satisfy current regulations can be created.

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) technology since 1992, and finally “MIRAI” was launched in 15th Dec. 2014. An important step was achieved with the release of the “FCHV-adv” in 2008. It established major improvements in efficiency, driving range, durability, and cold start capability. However, enhancing performance and further reductions in size and cost are required to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs). TMC met these challenges by developing the world's first FC stack without a humidifying system. This was achieved by the development of an innovative cell flow field structure and membrane electrode assembly (MEA), enabling a compact and high-performance FC stack. Other cost reduction measures incorporated by the FC stack include reducing the amount of platinum in the catalyst by two-thirds and adopting a carbon nano-coating for the separator surface treatment.

This paper describes the development of a fracture finite element (FE) model for laser screw welding (LSW) and validation of the model with experimental results. LSW was developed and introduced to production vehicles by Toyota Motor Corporation in 2013. LSW offers superb advantages such as increased productivity and short pitch welding. Although the authors had previously developed fracture FE models for conventional resistance spot welding (RSW), a fracture model for LSW has not been developed. To develop this fracture model, many comprehensive experiments were conducted. The results revealed that LSW had twice as many variations in fracture modes compared to RSW. Moreover, fracture mode bifurcations were also found to result from differences in clearance between welded plates. In order to analyze LSW fracture phenomena, detailed FE models using fine hexahedral elements were developed.

Port fuel injection (PFI) injector and direct fuel injection (DI) injector clogging from deposits caused by poor fuel quality, is a concern in emerging countries. Then DI injector deposits are sometimes cleaned by injector cleaners in such situation. However deposit cleaners for PFI injectors have not been developed, because of the lack of research of PFI injector deposits. Through chemical analysis, this study showed them to be water-soluble deposits. Subsequently success was achieved in developing a new gasoline injector cleaner applicable to injector deposits in both types of injectors, through optimization of a surface active agent.