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As a result of the stringent noise regulations for heavy-duty vehicles, the use of shields and enclosures for engine compartment has been increasingly applied, but it is difficult for a conventional axial flow fan to provide the required airflow against higher resistance caused by such shields and enclosures. To solve this problem, a new, mixed flow fan (hereafter called MF fan) which is suitable for the higher resistance has been developed and this paper describes the development process of the MF fan. The design criteria of the MF fan were experimentally investigated with a test rig, and an optimum combination of design parameters were established. The airflow was improved approximately 6 % without any additional power loss in comparison with the conventional axial flow fan.

Diesel Particulate Filter (DPF) is a very effective aftertreatment device to limit particulate emissions from diesel engines. As the amount of soot collected in the DPF increases, the pressure loss increases. Therefore, DPF regeneration needs to be performed. Injected fuel into the exhaust line upstream of the Diesel Oxidation Catalyst (DOC), hydrocarbons are oxidized on the DOC, which increases the exhaust gas temperature at the DPF inlet. It is also necessary that the injected fuel is completely vaporized before entering the DOC, and uniformly mixed with the exhaust gases in order to make the DOC work efficiency. However, ensuring complete evaporation and an optimum mixture distribution in the exhaust line are challenging. Therefore, it is important that the fuel spray feature is grasped to perform DPF regeneration effectively. The purpose of this study is the constructing a simulation model.

Acidified 2,4-dinitrophenylhydrazine (DNPH) solution, or DNPH-impregnated cartridges are commonly used for the collection of automotive exhaust carbonyl compounds. There are some DNPH-carbonyl compounds in not in use DNPH cartridges and DNPH solution. Furthermore, concentrations of automotive exhaust carbonyl compounds are decreasing according to improvement of the purification technology for automotive exhaust. Automotive exhaust carbonyl compounds become to be difficult to be analyzed with DNPH collection method, because of these two reasons. It is thought that reliable analysis of acrolein in automotive exhaust is very difficult because concentration of DNPH-acrolein in extracted solution is not stable. Furthermore, it is found out that DNPH-acrolein in DNPH-cartridge is disappeared for short time storage in this research.

A current unmodified and modified engines with different amounts of thermal insulation have been used to generate data from which changes in bsfc, cooling loss, emissions, exhaust loss were determined. Since legislative requirement exists for allowable emission of NOx, fuel injection timing and other controllable factors were adjusted to maintain constant NOx emission except a test of influence on NOx emission according to the rate of heat insulation (adiabaticity). The effect of higher combustion temperature on the combustion phenomena is discussed.

Approximately 200,000 units of Hino J-series diesel engine were produced for 7 years. The J-series engines had a reputation all over the world for their performance, reliability, lightweight, and installation ability. They are composed of 4, 6 cylinders engines and unique 5-cylinder engine J07C. In 2002, newly modified J-series engines, which met the Japan 2001 noise emission regulations, were developed and J07C-TI, 5-cylinder TI engine, equipped with a common-rail fuel injection system was added in the J-series. Common-rail fuel injection system was equipped in order to achieve the emission targets in the future as well as to meet the current emission regulations. Achieving higher injection pressure level through the all engine speed, include excess low speed, was effective in reduction of PM emissions and in increasing of low engine speed torque drastically.

Hino Motors, Ltd. has added to its line of charge-cooled engines for heavy duty trucks a higher power version which is called EP100-II. To meet the recent customers' demands for rapid transportation with better fuel economy, this engine was developed on the uprating program for the original EP100 which was introduced in 1981 as the first Japanese turbo-charged and air to air chrge-cooled engine. EP100-II has the same displacement as the original EP100, 8.8 liters, and is an in-line six cylinder engine with 228kW (310PS)/2,100rpm (JIS) output that provides the world's utmost level specific output of 25.8 kW (35.1PS)/ liter. Also this engine achieved a maximum BMEP of 16.8 bar/1,300 rpm and best BSFC of 199 gr/kWh at 1,500 rpm. This paper describes the advanced technology for increasing horsepower and improving fuel consumption such as the so-called multi harmonized inertia charging system, the electronically controlled waste gate valve of turbocharger.

The goal of the present study was to develop a new legform impactor that accurately represents both the impact force (i.e., force between the leg and impacting mass)and leg kinematics in lateral impacts simulating car-pedestrian accidents. In its development we utilized the knee joint of the pedestrian dummy called Polar-2 (HONDA R&D) in which the cruciate and collateral ligaments are represented by means of springs and cables, the geometry of the femoral condyles is simplified using ellipsoidal surfaces, and the tibial meniscus is represented by an elastomeric pad. The impactor was evaluated by comparing its responses with published experimental results obtained using postmortem human subjects (PMHS). The evaluation was done under two conditions: 1)impact point near the ankle area (bending tests),and 2)impact point 84 mm below the knee joint center (shearing tests). Two impact speeds were used: 5.56 m/s and 11.11 m/s.

To improve the thermal efficiency of an engine, it is particularly important to reduce the cooling loss from the combustion gas to the combustion chamber wall, which constitutes a major proportion of the total loss [1]. Previous studies addressing cooling loss reduction attempted to use ceramic in place of the conventional aluminum or iron alloys, but this led to a reduction in the volumetric efficiency and increased smoke emissions. This was caused by the ceramics having both a low thermal conductivity and high heat capacity, relative to aluminum and iron. These characteristics cause the piston wall temperature, which rises during combustion, to remain high during the intake stroke, thus increasing the intake temperature and reducing the volumetric efficiency. This increases the smoke emissions [2].

The requirements for emission control, lower fuel consumption and higher engine output have changed the engine valve train system to 4-valve/cylinder and higher cam lift designs, and these changes make the cam/tappet lubrication conditions more severe than before. Under such a working condition, there is a high possibility that cam/tappet surface damages such as scuffing, pitting and wear may occur. Among the damages, the wear of cam/tappet is the most difficult to predict since the wear mechanism still remains unclear. To understand the lubrication condition and therefore, the wear mechanism at the cam/tappet contact, friction was measured with a newly developed apparatus. Measurement results showed that the lubrication condition between cam and tappet is predominantly in the mixed and boundary lubrication conditions.

In order to reduce diesel NOx emissions, aftertreatment methods including LNT (Lean NOx Trap) and urea SCR (Selective Catalytic Reduction) have been researched. One of the shortcomings of urea SCR is its NOx reduction performance degradation at low exhaust gas temperatures and possible emission of unregulated byproducts. Here, a new type of a urea-dosing device to overcome these shortcomings is studied. This dosing device actively produces ammonia without depending upon the exhaust gas temperature, and designed for onboard application. The device incorporates an electrically heated bypass with a hydrolysis catalyst. An injector supplies urea solution into the bypass. The bypass is heated only when thermolysis is needed to produce ammonia (NH3). The hydrolysis catalyst further assists in the production of NH3. The ammonia gas obtained is then mixed with the main exhaust gas flow.

In recent years, although experiment technologies on real engines and simulation technologies has been improved rapidly, the tribology contributing factors have not been quantitatively well evaluated to reveal critical lubrication failure mechanisms. In this study the oil film thickness of the main bearings in multicylinder diesel engines was measured, and the data was analyzed using response surface methodology, which is a statistical analysis methods used to quantitatively derive the factors affecting oil film thickness and the extent of their contribution. We found that the factor with the strongest effect on minimum oil film thickness is oil pressure. Lastly, as a verification test, bearing wear on the main bearings was compared under various oil pressure conditions. Clear differences in bearing wear were identified.