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This paper investigates the potential of using FEA poro-elastic Biot elements for the modeling carpet-like trim systems in a simplified setup. A comparison between FEA computations and experiments is presented for two layer (mass-spring) trim systems placed on a test-rig consisting in a 510×354×1.6 mm flat steel plate clamped in a stiff frame excited at its base. Results are presented for a given heavy layer with two different poro-elastic materials: one foam and one fibrous material. The investigations included accelerometer measurements on the steel plate, laser-doppler vibrometer scans of the heavy layer surface, sound pressure measurements in free field at a distance of 1 meter above the plate, as well as sound pressure in a closed rectangular concrete-walled cavity (0.5×0.6×0.7 m) put on top of the test-rig. Computations were carried out using a commercial FEA software implementing the Biot theory for poro-elastic media.

A premixed compression-ignited (PCI) combustion system, which realizes lean combustion with high efficiency and low emissions, was investigated and its effects and problems were ascertained. With PCI combustion, fuel was injected early on the compression stroke and a premixed lean mixture was formed over a long mixing period. The test engine was operated with self-ignition of this premixed lean mixture. From the results of combustion observation and numerical simulation, a need to prevent the fuel spray from adhering to the cylinder liner and combustion-chamber wall was identified. Consequently, an impinged-spray nozzle with low penetration was made and tested. As a result, an extremely low nitrogen-oxide (NOx) emission level was realized but fuel efficiency was detracted slightly. Also, the engine operating range possible with PCI combustion was found to be limited to partial-load conditions and PCI combustion was found to cause an increase in hydrocarbon (HC) emission.

Knock noise induced by automotive shock absorbers has serious influence on driving comfort and vehicle quality. Some research focusing on knock noise had been introduced in the past. However there is the unidentified phenomenon that has been unnoticed. This paper describes the new theory to clarify one of the unidentified phenomenon and proposes the equation for stability assessment which is useful on designing stage of development. First of all, the characteristics of the unidentified rod vibration of shock absorbers are investigated experimentally. Second, the new theory is established on the basis of the non-linear physical model with friction forces between piston and cylinder. This theory shows that the unstable vibration, so called the Self Excited Vibration, can be induced by not only friction property but also structure of rod and piston. Third, the equation for stability assessment, which is useful on designing stage of development, is proposed on the basis of new theory.

Three exhaust emissions, hydrocarbons, carbon monoxide and oxides of nitrogen, from the automotive spark-ignition engines are presently subject to regulatory control. Of these harmful pollutants, NOx emissions are the hardest to control under current status of emission control technology. Accordingly, exhaust gas recirculation (EGR) has been receiving continued efforts as one of promising NOx control. This paper reports the effects of EGR on the mechanism of NOx reduction and engine fuel economy, on the basis of research made in the following areas: (1). NOx formation in a combustion vessel. (2). Studies on EGR effects in a single-cylinder engine. (3). Effects of EGR on NOx and HC emissions and fuel economy.

Demands for Faster, safer, and more comfortable mobility under various road, weather and/or driving conditions have led to advanced engineering Features, such as 4WD, 4WS, and ABS. However, simple combination of these advanced components tend to induce the deterioration of the vehicle performance under certain conditions due to the interference among the related functions. This paper describes these conflicting areas and proposes newly developed integrated system in an effort to achieve the compatibility of each function among 4WD, 4 independent suspensions, 4WS, and ABS. The integrated system of these advanced engineering features has resulted safer and faster mobility in reasonably higher cost efficiency by the sophisticated system construction.

The purpose of this study is to explain the characteristics of homogeneous charge compression ignition. n-Heptane, which has the same cetane number as diesel fuel, was chosen for the fuel. A rapid compression machine was used to clarify the effects of air-fuel ratio, O2 concentration, and compression temperature on ignition delay and NOx emission. These investigations allowed the introduction of a formula for ignition delay.

It is generally known that the idling rattle in manual transmissions is caused by gear tooth portions that make repeated impact-generating vibrations in the backlashes. These vibrations result from rotational fluctuations of the flywheel induced by combustion in the engine. In the study reported here, the authors constructed an experimental setup using rotary encoders and a transient torsional angle converter that allowed the long-awaited direct measurement of impact-generating vibrations in the backlashes. Using this experimental result, the following ideas that the authors must pay attention for the numerical simulation are obtained. That is, transmission drag torque is to be input and treated as the offset value in the torque value of the torsional characteristics in the clutch disc, and coefficients of attenuation have great influence upon the calculation result.

The International Lubricant Standardization and Approval Committee (ILSAC) ATF subcommittee members have compared the two oxidation bench test methods, Aluminum Beaker Oxidation Test (ABOT) and Indiana Stirring Oxidation Stability Test (ISOT), using a number of factory-fill and service-fill ATFs obtained in Japan and in the US. In many cases, the ATFs were more severely oxidized after the ABOT procedure than after the same duration of the ISOT procedure. The relative severity of these two tests was influenced by the composition of the ATFs. The bench test oxidation data were compared with the transmission and the vehicle oxidation test data.

For compliance with stringent exhaust emissions regulation, a lot of the world's Heavy Duty Diesel Engines (HDDE) have been recently equipped with electronically controlled components, such as the Fuel Injection Equipment (FIE), Exhaust Gas Recirculation (EGR) system, Variable Geometry Turbocharger (VG). Flexibility of engine control has been increasing more and more with electronic control for low exhaust emissions and good performance. However, determination of the optimum combination of engine control parameters is extremely tedious, because an engine has so many parameters to be optimized and their interactions are complicated. Therefore, a Design of Experiments (DOE) method was used to optimize the engine control parameters, which effect emissions and performance, in a shorter time. After using this method, it was recognized that it was an effective method to optimize various engine parameters, and was very convenient for engine development.

A new state of the art DOC (Diesel Oxidation Catalyst) having superior light-off and exothermic activity for forced regeneration compared to conventional Pt base passive DOC, was investigated for LDD application. The DOC uses the latest Pt/Pd technology resulting cost effective DPF system. The newly developed DOC demonstrated improved catalytic activities from Pt only DOC in model gas or engine bench tests. In this study, DOC at early development stage showed excellent light-off activity in model gas and engine bench test compared to conventional Pt only DOC, however, it showed “extinction” phenomenon which is one of the deactivation mode while the post injection and it was observed when post injection operation was done at lower DOC inlet temperatures, e.g. below 250 C. Temperature profiles along diameter and length into DOC bed while active regeneration suggested extinction would be caused by fouling of supplied hydrocarbons derived from diesel fuel.

A new single-brick Ba + alkali metals NOx-Trap catalyst has been developed to replace a two-brick NOx-Trap system containing a downstream three-way catalyst. Major development efforts include: 1) platinum group metals selection for higher HC oxidation with potassium-containing washcoat, 2) alumina and ceria selection, and Rh architecture design for more efficient NOx reduction and 3) NiO to suppress H2S odor. Mitsubishi Motors' 1.8L GDI™ with this Delphi new NOx-Trap catalyst with H2S control achieves J-LEV standard with less cost and lower backpressure compared to the previous model. It is further discovered that incorporation of NiO into the NOx-Trap washcoat is effective for H2S control during sulfur purge but has a negative impact on thermal durability and sulfur resistance. Further study to improve this trade-off has been made and preliminary results of an advanced washcoat design are presented in this paper. Details will be reported in a future publication.

For fuel economy improvement by lean-burn gasoline engines, extension of their lean operation range to higher loads is desirable as more fuel is consumed during acceleration. Urgently needed therefore is development of emission control systems having as high NOx conversion efficiency as three-way catalysts (TWC) even with more frequent lean operation. The authors conducted a study using catalysts loaded with potassium (K) as the only NOx trapping agent in an emission control system of a lean-burn gasoline engine.

NO, OH, and soot in combustion flame produced from burning at high temperature and pressure diesel fuel spray issuing from a single-hole injection nozzle was measured by laser induced fluorescence (LIF) and laser induced incandescence (LII) methods. The LIF images of OH showed that OH radical, distributed in a band-like zone outside the region of the flame luminescence observed, would persist even after the extinction of flame luminescence. The LIF images of NO showed that NO was located slightly outside the flame luminescence zone and that its region was almost the same as that of OH and would tended to increase in the latter period of the combustion process. Also, the LII images showed that the formation of soot would take place near the flame central zone coincident with the flame luminescence zone.

Improving fuel efficiency often affects NVH performance. Modifying a vehicle’s design in the latter stages of development to improve NVH performance is often costly. Therefore, to optimize the cost performance, a Multi-Attribute Balancing (MAB) approach should be employed in the early design phases. This paper proposes a solution based on a unified 1D system simulation model across different vehicle performance areas. In the scope of this paper the following attributes are studied: Fuel economy, Booming, Idle, Engine start and Drivability. The challenges to be solved by 1D simulation are the vehicle performance predictions, taking into account the computation time and accuracy. Early phase studies require a large number of scenarios to evaluate multiple possible parameter combinations employing a multi-attribute approach with a systematic tool to ease setup and evaluation according to the determined performance metrics.

A resin cylinder head model was produced using a rapid prototype producing system. The resin model was used in the lost-wax casting process instead of a wax model. The casting molded by this method was as precise in both shape and dimensions as a casting produced using a metal mold. This paper describes the manufacturing process of cylinder head material using this method in detail.

Driving car means to control a vehicle according to a target path, e.g. road and speed, with some constraints. Human driving models have been proposed and applied for simulations. However, human control in driving has not been analyzed sufficiently comparing with that of machine control system in term of control theory. Input - output property with internal information processing is not easily measured and described. Response of human driving is not as quicker as that of machine controller but human can learn vehicle response to driving operation and predict target changes. Driving behavior of an expert driver and a beginner in an emission test cycle was measured and difference in target speed tracking was looked into with performance indices. The beginner's operation was less stable than that of the expert. Transfer function of the vehicle system was derived based on linearized model to investigate human driving behavior as a tracking controller in the system.

In this paper, emissions reduction technologies applied to high-speed direct injection (HSDI) diesel passenger car engines to meet the stricter exhaust emission legislation are described. To reduce smoke, the F.I.E. has been improved by using a radial-piston distributor pump which delivers fuel-injection-pressure up to 120MPa. Cooled exhaust gas re-circulation (EGR) system and increase in volume ratio of the combustion chamber has made it possible to increase EGR ratio and reduced nitrogen oxides (NOx) and smoke simultaneously. Furthermore, improvements in the oxidation catalyst activating temperature reduces PM at lower exhaust gas temperatures. As a result of applying these technologies, a clean and economical HSDI diesel engine for passenger cars, which complies with Japanese '98 exhaust emissions legislation and has better fuel economy than indirect injection (IDI) diesel engines (above 15%), has been developed.

The widening of the selectivity windows of a three-way catalyst under A/F ratio modulation was shown to result from retention of adsorbed species on catalyst surfaces and their subsequent reaction with gas-phase reactants. A reaction model was developed based on adsorption properties of CO, HC and NOx and by computer simulation, the conversion efficiencies of CO, HC and NOx under A/F ratio modulation were calculated. The calculated and experimental results were in good agreement.

Flows around a forward facing step and a fence are simulated on structured grid to estimate aerodynamic noise by using direct simulation. Calculated results of sound pressure level show quantitatively good agreement with experimental results. To estimate aerodynamic noise from 3D complex geometry, a simplified side mirror model is also calculated. Averaged pressure distribution on the mirror surface as well as pressure fluctuations on the mirror surface and ground are simulated properly. However, calculated result of sound pressure level at a location is about 20dB higher than experiment due to insufficient spatial resolution. To capture the propagation of sound waves, more accuracy seems to be required.

Recently, the evaluation of the thermal environment of an engine compartment has become more difficult because of the increased employment and installation of turbochargers. This paper proposes a new prediction model of the momentum source for the turbine of a turbocharger, which is applicable to three-dimensional thermal fluid analyses of vehicle exhaust systems during the actual vehicle development phase. Taking the computational cost into account, the fluid force given by the turbine blades is imitated by adding an external source term to the Navier-Stokes equations corresponding to the optional domain without the computational grids of the actual blades. The mass flow rate through the turbine, blade angle, and number of blade revolutions are used as input data, and then the source is calculated to satisfy the law of the conservation of angular momentum.