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Clarifying the impact of ETBE 8% blended fuel on current Japanese gasoline vehicles, under the Japan Clean Air Program II (JCAPII) we conducted exhaust emission tests, evaporative emission tests, durability tests on the exhaust after-treatment system, cold starting tests, and material immersion tests. ETBE 17% blended fuel was also investigated as a reference. The regulated exhaust emissions (CO, HC, and NOx) didn't increase with any increase of ETBE content in the fuel. In durability tests, no noticeable increase of exhaust emission after 40,000km was observed. In evaporative emissions tests, HSL (Hot Soak Loss) and DBL (Diurnal Breathing Loss) didn't increase. In cold starting tests, duration of cranking using ETBE 8% fuel was similar to that of ETBE 0%. In the material immersion tests, no influence of ETBE on these material properties was observed.

Emission regulations for diesel-powered vehicles have been gradually tightening. Installation of after-treatment devices such as diesel particulate filters (DPF), NOx storage reduction (NSR) catalysts, and so on is indispensable to satisfy rigorous limits of particulate matter (PM) and nitrogen oxides (NOx). Japan Clean Air Program II Oil Working Group (JCAPII Oil WG) has been investigating the effect of engine oil on advanced diesel after-treatment devices. First of all, we researched the impact of oil-derived ash on continuous regeneration-type diesel particulate filter (CR-DPF), and already reported that the less sulfated ash in oil gave rise to lower pressure drop across CR-DPF [1]. In this paper, impact of oil-derived sulfur and phosphorus on NSR catalyst was investigated using a 4L direct injection common-rail diesel engine with turbo-intercooler. This engine equipped with NSR catalyst meets the Japanese new short-term emission regulations.

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.

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.

Recently, as one of the effective measures for engine noise reduction, vibration damping steel sheets (VDSS) have been increasingly applied to engine oil sumps. This paper describes the formability of VDSS. Various factors closely related to drawability are considered. This study has been carried out in a production engineering process of manufacturing exceedingly deep, single blank sheet, oil sump for heavy-duty truck diesel engines. Some treatment of the surface of the VDSS was found to be a principal factor influencing deep drawability.

For the better understanding of nanoparticles observed on the rode side, adding to the emission test on the chassis dynamometer and engine dynamometer test, possible factors for formation of nanoparticles are investigated. As other possible factors, cold starting of transient test cycle, blow-by gas from heavy duty diesel engine without a positive crankcase ventilation, exhaust braking, and plume mixing of vehicle exhausts were investigated. Nuclei mode particles under the transient test cycles formed during fuel cut period, fuel enrichment period and idling period. Concentration of nuclei mode particles during the idling period are depends on exhaust temperature. The higher exhaust temperature courses the lower number concentration but variation range is within twice. Emission rate of nanoparticles from blow-by gas is one thousandth of tail pipe emissions rate and was found to be negligible.

The superior fuel economy of diesel engines compared to gasoline engines is favorable in reducing carbon dioxide (CO2) emissions. On the other hand, the reductions in nitrogen oxides (NOx) and particulate matter (PM) emissions are technically difficult, thus the improvement in the emission reduction technologies is important. Although the cooled exhaust gas recirculation (cooled-EGR) is the effective method to reduce NOx emissions, it is known to have durability and reliability problems, especially of the increased wear of piston rings and cylinder liners. Therefore, the degree of cooling and amount of EGR are both limited. To apply the cooled-EGR more effectively, the wear reduction technology for such components are indispensable. In this study, the negative effects of cooled-EGR on the wear are quantified by using a heavy-duty diesel engine, and its wear mechanism is identified.

JAMA-JARI has developed a biofidelic flexible pedestrian leg-form impactor (Flex-PLI 2004) by making several modifications to the Flex-PLI 2003 to improve usability, durability and biofidelity. Biofidelity evaluation for the Flex-PLI 2004 was estimated at the component level (thigh, knee, and leg individually) as well as at the assembly level (thigh-knee-leg complex), using an objective impactor biofidelity evaluation system based on a method developed by Rhule et al. to eliminate any subjective prejudice in an impactor biofidelity evaluation. Applying the biofidelity evaluation system to the Flex-PLI 2004, the average impactor biofidelity rank (IBR) score became 1.22 at the component level and 1.26 at the assembly level. These IBR scores mean that the Flex-PLI 2004 has good biofidelity at the component level as well as at the assembly level.

In order to reduce particulate and NOx emission from the direct injection diesel engine, most researchers have been expecting the utilization of higher injection pressure and injection rate for improvement of diesel combustion. In the case of pump-line-nozzle system, the injection pipe line is very important with regard to the high injection pressure. Namely, the pipe line must be able to resist not only high pressure but also cavitation erosion. In this paper, the effect of high injection pressure, injection rate and sharp cutting at the end of fuel injection are discussed along with cavitation phenomena on the injection pipe line. And durability tests on the pipe line system under high injection pressure using a test rig are also described. Regarding durability tests, several measures have been taken for the injection pipe. As a result, the authors have found that the best solution for the injection pipe is a composite pipe made with SUS and steel.

Environmental protection is now one of the most important social concerns in the world. In 1998, emission controls in the US required the reduction of NOx by 20% from the 1994 limit. Hino Motors has developed new J-series medium-duty diesel engines for trucks that meet the US 1998 emissions regulations. The engines comprise turbocharged and aftercooled 4- and 6-cylinder engines of the same cylinder bore and stroke. The engines feature a 4-valve system, OHC valve train design, centered nozzle arrangement, and an optimum combustion chamber design, which achieved uniform combustion. With these features, the maximum combustion temperature was decreased, and hence reduced the NOx, smoke, and PM emissions. A muffler integrated with a catalytic converter (catalytic muffler) was adopted to reduce PM emissions further. The engines with the catalytic muffler have successfully met the US 1998 emissions regulations.

To meet the strict emission regulations for diesel engines, an advanced processing device such as a Urea-SCR (selective catalytic reduction) system is used to reduce NOx emissions. The Real Driving Emissions (RDE) test, which is implemented in the European Union, will expand the range of conditions under which the engine has to operate [1], which will lead to the construction of a Urea-SCR system capable of reducing NOx emissions at lower and higher temperature conditions, and at higher space velocity conditions than existing systems. Simulations are useful in improving the performance of the urea-SCR system. However, it is necessary to construct a reliable NOx reduction model to use for system design, which covers the expanded engine operation conditions. In the urea-SCR system, the mechanism of ammonia (NH3) formation from injected aqueous urea solution is not clear. Thus, it is important to clarify this mechanism to improve the NOx reduction model.

1 To meet the Japan Post New-Long-Term (Japan 2009) emissions regulation introduced in 2009, The Hydrocarbon Selective Catalytic Reduction (HC-SCR) system for the NOx emission with a diesel fuel was chosen among various deNOx after-treatment systems (the Urea-SCR, the NOx storage-Reduction Catalyst and so on). The HC-SCR was adopted, in addition to combustion modification of diesel engine (mainly cooled EGR) as the New DPR system. The New DPR system for medium and light duty vehicles was developed as a world's first technology by Hino Motors. Advantages of the New DPR are compact to easy-to-install catalyst converter and no urea solution (DEF) injection (regardless urea infrastructure) as compared the Urea-SCR system.

This study employed a diesel particulate generator (DPG), with an installed engine oil injector for soot and ash accumulation in a diesel particulate filter (DPF). Ash was generated by engine oil injection into the diesel burner flame. The amount of soot accumulation per loading varied from 0.5 g/L to 8 g/L while ash accumulation amount per loading was maintained at 0.5 g/L. Initially, ash accumulation distribution in the DPF was visualized using X-ray computed tomography (CT). It was revealed that the form of ash accumulation changed depending on the amount of soot accumulation before active regeneration, i.e., a large amount of soot accumulation resulted in plug ash, whereas a small amount of soot accumulation resulted in wall ash. To clarify ash accumulation mechanisms, soot and ash transport behavior in DPF during active regeneration process was directly observed using a high-speed camera through an optically accessible D-shaped cut DPF covered with a quartz glass plate.

This work investigated the mechanism of oil dilution by post injection to remove accumulated particulate matter on the diesel particulate filter of diesel engines. We developed a model to simulate post injection spray under low ambient gas pressure conditions. The model can predict the quantity of fuel mass adhered on the cylinder wall. The adhered fuel enters oil sump through the piston ring and cause oil dilution. The fuel in diluted oil evaporates during normal engine operations. We focus on the mechanism of fuel evaporation from diluted oil. The effects of engine speed and oil temperature on the evaporation were investigated. The results showed that the fuel evaporation rate increases with increasing engine speed and oil temperature. Furthermore, we developed an empirical model to predict the fuel evaporation rate of diluted oil through regression analysis with measured data.

A fuel reforming technology using a low temperature oxidation was developed to improve a NOx reduction performance of HC-SCR (Hydrocarbons Selective Catalytic Reduction) system, which does not require urea. The low-temperature oxidization of a diesel fuel in gas phase produces NOx reduction agents with high NOx reduction ability such as aldehydes and ketones. A pre-evaporation-premixing-type reformer was adopted in order to generate a uniform temperature field and a uniform fuel/air premixed gas, and to promote the low temperature oxidation efficiently. As a fundamental study, elementary reaction analysis for n-hexadecane/air premixtures was carried out to investigate the suitable reformer temperature and fuel/air equivalence ratio for generation of oxygenated hydrocarbons. It was found that the reforming efficiency was highest at the reforming temperature around 623 to 673K, and aldehydes and ketones were produced.

Urea selective catalyst reduction (SCR) systems have a high NOx conversion rate because the ammonia formed by the hydrolyzing urea solution reacts with NOx efficiently as a reducing agent. Systems combining urea-SCR and a diesel particulate filter (DPF) have been adopted in heavy duty vehicles to meet the post new long term emissions regulations in Japan. This study examined the emissions reduction performance of these systems after 160,000 km. The emissions that were examined included both regulated emissions (NOx, PM, HC, and CO) and unregulated emissions. As a result, the cleanness of diesel emissions from a urea-SCR and DPF system was confirmed.

This study addresses the virtual optimization of the technical specifications for a recently developed Advanced Pedestrian Legform Impactor (aPLI). The aPLI incorporates a number of enhancements for improved lower limb injury predictability with respect to its predecessor, the FlexPLI. It also incorporates an attached Simplified Upper Body Part (SUBP) that enables the impactor’s applicability to evaluate pedestrian’s lower limb injury risk also with high-bumper cars. The response surface methodology was applied to optimize both the aPLI’s lower limb and SUBP specifications, while imposing a total mass upper limit of 25 kg that complies with international standards for maximum weight lifting allowed for a single operator in the laboratory setting. All parameters were virtually optimized considering variable interaction, which proved critical to avoid misleading specifications.

Ferrocene is used as an antiknock additive to replace lead alkyls. To clarify the influence of one metal additive, ferrocene, on engine, following experiments were carried out. The insulation resistance of spark plugs was measured, deposits in the engine were analyzed, and an exhaust emission and fuel economy tests were conducted using gasoline containing ferrocene. The deposit, which contained iron oxides, adhered to the combustion chamber, spark plugs, and exhaust pipe when the engine operated with gasoline containing ferrocene. When vehicles operated with gasoline containing ferrocene, fuel consumption increased and the exhaust temperature rose. In addition, an abnormal electrical discharge pattern was observed in spark plugs operating at high temperatures. Iron-oxide of Fe3O4 is changed into Fe2O3 under high temperatures. Discharge current flows in iron oxides including Fe2O3 because the conductivity of Fe2O3 increases at high temperatures.

DPR is a particulate-emissions reduction system that has been developed to reduce particulate emissions in production commercial vehicles and consists of a multiple fuel-injection system, an engine electronic control unit, and a DPR-Cleaner which includes an oxidation catalyst, a catalyzed particulate filter, and silencers. DPR performs active regeneration to accelerate the regeneration of the filter under engine operating conditions where regeneration by passive regeneration alone is not sufficient. Thus, DPR makes it possible to regenerate the filter regardless of the exhaust gas temperature and enables significant reduction of particulate in commercial vehicles to levels below 0.027 g/kWh under Japan's D13 mode operating conditions. The authors describe development results of the DPR.

Diesel Particulate active Reduction system (DPR) is a system that traps particulate matter in diesel exhaust gas with a particulate filter and actively regenerates the filter when PM accumulates to a specific level. In 2003, DPR was installed on Hino's light-, medium-, and heavy-duty diesel engines, and about 50,000 units of these DPR-equipped diesel engines are currently on the market. This paper reports results of further progress made on optimization of the active regeneration function of DPR. The goal of successful development of DPR is to optimally control the system under various engine-operating conditions to regenerate the filter without producing abnormal combustion of PM and to minimize the amount of unburned PM to keep the filter from clogging. To improve the control of DPR, the combustion phenomena of PM collecting on the filter were studied through visualization, and the factors influencing combustion were determined.