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Journal Article

Unregulated Harmful Substances in Exhaust Gas from Diesel Engines

The volatile organic compounds (VOC) from diesel engines, including formaldehyde and benzene, are concerned and remain as unregulated harmful substances. The substances are positively correlated with THC emissions, but the VOC and aldehyde compounds at light load or idling conditions are more significant than THC. When coolant temperatures are low at light loads, there are notable increases in formaldehyde and acetaldehyde, and with lower coolant temperatures the increase in aldehydes is more significant than the increase in THC. When using ultra high EGR so that the intake oxygen content decreases below 10%, formaldehyde, acetaldehyde, benzene, and 1,3-butadiene increase significantly while smokeless and ultra low Nox combustion is possible.
Technical Paper

Unregulated Emissions Evaluation of Gasoline Combustion Systems (Lean Burn / Stoichiometric DISI and MPI), State of the Art Diesel Aftertreatment Technologies (DPF, urea-SCR and DOC), and Fuel Qualities Effects (EtOH, ETBE, Aromatics and FAME)

In order to clarify future automobile technologies and fuel qualities to improve air quality, second phase of Japan Clean Air Program (JCAPII) had been conducted from 2002 to 2007. Predicting improvement in air quality that might be attained by introducing new emission control technologies and determining fuel qualities required for the technologies is one of the main issues of this program. Unregulated material WG of JCAPII had studied unregulated emissions from gasoline and diesel engines. Eight gaseous hydrocarbons (HC), four Aldehydes and three polycyclic aromatic hydrocarbons (PAHs) were evaluated as unregulated emissions. Specifically, emissions of the following components were measured: 1,3-Butadiene, Benzene, Toluene, Xylene, Ethylbenzene, 1,3,5-Trimethyl-benzene, n-Hexane, Styrene as gaseous HCs, Formaldehyde, Acetaldehyde, Acrolein, Benzaldehyde as Aldehydes, and Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(k)fluoranthene as PAHs.
Technical Paper

Truck Braking Standards and Regulations in Japan

This paper introduces the Japanese standards and regulations of automobiles with brakes as the central subject and clarifies the difference from those of Europe and USA by comparison. Further, this paper describes not only the application status of the standards and regulations in Japan but also the features of structure and performance of Japanese trucks that are designed and produced under such standards and regulations. It can be said that the Japanese trucks are comparatively simple in structure but are in a level equal to or higher than European and USA automobiles in respect of performance. Also in respect of the international harmonization, the internationalization of standards is being conducted in Japan on the basis of ISO and the internationalization for regulations is considered to be under preparation.
Technical Paper

Tractive Torque Steer for On-Center Stability1 Handling Augmentation with Controlling Differential Gear for Large-Sized Vehicles - A Comparison with Passive Read-Axle Steer

The running direction of a vehicle can be controlled by not only wheel steer but also torque steer. This paper introduces the tractive torque steer effect produced by a newly developed electropneumatic control system, the limited-slip differential for large-sized vehicles. This system enhances the vehicle's running stability and controllability by controlling the tractive force of the drive axle. The tractive force maintains a stable running course against disturbances such as road roughness and wind gusts, thereby enhancing the steering response and providing a better feeling of handling to the driver. The system also improves mobility. especially on low-μ roads. It is expected that a single axle equipped with this system will exhibit good performance comparable to that of tandem axle.
Technical Paper

The Wear Mechanism of Piston Rings and Cylinder Liners Under Cooled-EGR Condition and the Development of Surface Treatment Technology for Effective Wear Reduction

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.
Technical Paper

The Visualization and Its Analysis of Combustion Flame in a DI Diesel Engine

Since in-cylinder flame temperature has a direct effect on an engine's NOx characteristics, these phenomena have been studied in detail in a DI diesel engine using a newly developed method allowing the in-cylinder temperature distribution to be measured by the two color method. The flame light introduced from the visualized combustion chamber of the engine is divided into two colors by filters. The images of combustion phenomena using the two wavelengths are recorded with a framing streak camera which includes a CCD camera. The flame temperature is immediately calculated by a computer using two color images from the CCD camera. A parameter study was then carried out to determine the influence of intake valve number of the engine, and fuel injection rate (pilot injection) on the in-cylinder temperature distribution.
Technical Paper

The Study of Particle Number Reduction Using After-Treatment Systems for a Heavy-Duty Diesel Engine

To reduce ultra fine particle number concentration from a heavy-duty diesel engine, the effects of diesel fuel property and after-treatment systems were studied. The reduction of ultra fine particle number concentration over steady state mode using an 8 liter turbocharged and after-cooled diesel engine was evaluated. PM size distribution was measured by a scanning mobility particle sizer (SMPS). The evaluation used a commercially available current diesel fuel (Sulfur Content: 0.0036 wt%), high sulfur diesel fuel (Sulfur Content: 0.046 wt%) and low sulfur diesel fuel (Sulfur Content: 0.007 wt%). The after-treatment systems were an oxidation catalyst, a wire-mesh type DPF (Diesel Particle Filter) and a wall-flow type catalyzed DPF. The results show that fine particle number concentration is reduced with a low sulfur fuel, an oxidation catalyst, a wire-mesh type DPF (Diesel Particulate Filter) and wall flow type catalyzed DPF, respectively.
Technical Paper

The Study of NOx and PM Reduction Using Urea Selective Catalytic Reduction System for Heavy Duty Diesel Engine

To reduce NOx and Particulate Matter (PM) emissions from a heavy-duty diesel engine, the effects of urea selective catalytic reduction (SCR) systems were studied. Proto type urea SCR system was composed of NO oxidation catalyst, SCR catalyst and ammonia (NH3) reduction catalyst. The NOx reduction performance of urea SCR system was improved by a new zeolite type catalyst and mixer for urea distribution at the steady state operating conditions. NOx and PM reduction performance of the urea SCR system with DPF was evaluated over JE05 mode of Japan. The NOx reduction efficiency of the urea SCR catalyst system was 72% at JE05 mode. The PM reduction efficiency of the urea SCR catalyst system with DPF was 93% at JE05 mode. Several kinds of un-regulated matters were detected including NH3 and N2O leak from the exhaust gas. It is necessary to have further study for detailed measurements for un-regulated emissions from urea solution.
Technical Paper

The Study of NOx Reduction Using Plasma-assisted SCR System for a Heavy Duty Diesel Engine

To reduce NOx emissions from a heavy-duty engine at low exhaust temperature conditions, the plasma-assisted SCR (Selective Catalytic Reduction) system was evaluated. The plasma-assisted SCR system is mainly composed of an ammonia gas supply system and a plasma reactor including a pellet type SCR catalyst. The preliminary test with simulated gases of diesel exhaust showed an improvement in the NOx reduction performance by means of the plasma-assisted SCR system, even below 150°C conditions. Furthermore, NOx reduction ratio was improved up to 77% at 110°C with increase in the catalyst volume. Also NOx emissions from a heavy-duty diesel engine over the transient test mode in Japan (JE05) were reduced by the plasma-assisted SCR system. However, unregulated emissions, e.g., aldehydes, were increased with the plasma environment. This paper reports the advantages and disadvantages of the plasma-assisted SCR system for a heavy-duty diesel engine.
Technical Paper

The Spray Models and Their Influence on Ignition

The differences between spray models are investigated by comparing calculation results with experimental data. The calculations are performed using the KIVA-II code. The spray models TAB, which is the original model of KIVA-II, and the model developed by Reitz are calculated and compared. A semi-empirical spray model based on the TAB model is also formulated and compared with the other models. The penetration and droplet size distribution are compared with data from constant pressure bomb tests. The calculated ignition delay is compared with actual engine operating data- Each spray model has different characteristics influencing the atomization process. These differences result in discrepancies during the penetration, evaporation, and ignition.
Technical Paper

The Reduction of Diesel Engine Emissions by Using the Oxidation Catalysts of Japan Diesel 13 Mode Cycle

To reduce emissions from diesel engines, the effects of oxidation catalysts on the emissions reductions were studied. The effectiveness of several oxidation catalysts on both the regulated and unregulated emissions was evaluated. The oxidation activity of the catalysts was varied by changing Pt loading. The regulated emissions include particulate (PM), hydrocarbon (HC), and carbon monoxide (CO), and the unregulated emissions include benzene, formaldehyde, acetaldehyde, and benzo[a]pyrene (B[a]P). An 8 litter, turbocharged and aftercooled diesel engine was operated under the Japan Diesel 13 (D13) mode cycle for the evaluations. As the first step, evaluations were conducted with a commercially available JIS #2 diesel fuel (0.046 wt% sulfur). All the regulated and unregulated emissions except PM were reduced as the Pt loading (i.e. oxidation activity) increased. However, PM emissions were increased by the generation of sulfate when the Pt loading exceeded 0.2 g/l.
Technical Paper

The IP Filter, a DOC-Integrated DPF, for an Advanced PM Aftertreatment System (2): An Evaluation of Fundamental Performance

DPR consists of a multiple fuel-injection system, an electronic engine control unit, and a DPR Cleaner. The DPR cleaner is one assembly unit consisting of a DOC, a catalyzed DPF, and an exhaust silencer. Thus, DPR is a system developed to achieve healthy operation of a DPF with active regeneration regardless of engine operating conditions. The IP Filter was developed to improve the DPR cleaner by reducing the size of the unit and shortening the regeneration time. Both the DOC and DPF are integrated into one unit structure. The IP Filter has open-ended cells on the front face unlike a conventional wall-flow DPF. Instead, the plugs are positioned at the interface between the DOC and DPF. On the rear face of the IP Filter, plugs are installed at the same positions as those of a conventional DPF. The DOC substrate of the IP Filter is made of highly porous, straight honeycomb, the same as that of DPF.
Technical Paper

The Hino E13C: A Heavy-Duty Diesel Engine Developed for Extremely Low Emissions and Superior Fuel Economy

The Hino E13C was developed for heavy-duty truck application to meet Japan's 2003 NOx and 2005 particulate emissions standards simultaneously with significant fuel economy improvement. A combined EGR system consisting of an external EGR system with a highly efficient EGR cooler and an internal EGR system with an electronically controlled valve actuation device was newly developed to reduce NOx emissions for all operating conditions without requiring a larger engine coolant radiator. A Hino-developed DPR was installed to achieve extremely low particulate emissions at the tail pipe. Increased strength of engine structural components and a ductile cast iron piston enabled high BMEP operation at lower engine speeds and reductions of both engine size and weight. This paper describes key technologies developed for the E13C as well as the development results.
Technical Paper

The Development of Low Noise Engine on Hino New “H” Series

This paper introduces the details of a low noise design realized by fully utilizing the theoretical methods for the prediction of noise and vibration, applied to Hino's new “H07D” engine. In the development of this engine, the reduction of the vehicle interior noise was one of the highest priority aims. For this purpose, the influence of the engine noise on the vehicle noise was firstly investigated to identify the major noise sources. Then, making best use of noise prediction techniques (FEM, etc.), the noise radiation mechanisms were clarified and the components identified as major noise sources were re-designed. In these improvements, the theoretical techniques also predicted carefully the effect of design changes on the related components, including their installation in an engine as required. These procedures achieved a remarkable noise reduction of the engine by cost effective methods.
Technical Paper

The Development of High-Performance Viscous-Rubber Damper for Higher Boost Turbocharged and Charge-Cooled Diesel Engine

A newly developed viscous-rubber damper, which employed an innovative structure and a new heat resistant rubber, solved some tough problems. This paper dealt more closely with the features of the new viscous-rubber damper and the new calculation method for the viscous-rubber damper. This damper has been employed for Hino new K13C (K-II) higher boost turbocharged and air to air charge-cooled diesel engine, which has extreme severity on the torsional vibration.
Technical Paper

The Analysis of Combustion Flame Under EGR Conditions in a DI Diesel Engine

Since in-cylinder flame temperature has a direct effect on an engine's NOx characteristics, this phenomena has been studied in detail in a multi-cylinder DI diesel engine using a new method allowing the in-cylider temperature distribution to be measured by the two color method. An endoscope is installed in the combustion chamber and flame light introduced from the endoscope is divided into two colors by filters. The images of combustion phenomena using the two wavelengths are recorded with a framing streak camera which includes a CCD camera. The flame temperature and KL factor are immediately calculated by a computer using the two color images from the CCD camera. In the case of EGR, the test was conducted under 75% load conditions. The flame temperature was reduced according to an increase of EGR rate.
Technical Paper

Study on Exterior Idling Sound Quality Evaluation Method for Diesel Engine Trucks

In diesel engine trucks, the sound quality improvement as well as the noise level reduction is demanded because of their annoying exterior noise. The semantic differential method was applied to evaluate the sound quality of trucks. In order to improve the analytical accuracy, subjects who can evaluate the characteristics of sound quality were statistically selected among all the subjects. Comfortability and powerfulness were extracted as the principal components by using the data of the selected subjects. It has been clarified that the comfortability strongly relates to high frequency element ratio, high frequency level, etc. The powerfulness strongly relates to the Zwicker loudness.
Journal Article

Study of the Impact of High Biodiesel Blends on Engine Oil Performance

In Biodiesel Fuel Research Working Group(WG) of Japan Auto-Oil Program(JATOP), some impacts of high biodiesel blends have been investigated from the viewpoints of fuel properties, stability, emissions, exhaust aftertreatment systems, cold driveability, mixing in engine oils, durability/reliability and so on. This report is designed to determine how high biodiesel blends affect oil quality through testing on 2005 regulations engines with DPFs. When blends of 10-20% rapeseed methyl ester (RME) with diesel fuel are employed with 10W-30 engine oil, the oil change interval is reduced to about a half due to a drop in oil pressure. The oil pressure drop occurs because of the reduced kinematic viscosity of engine oil, which resulting from dilution of poorly evaporated RME with engine oil and its accumulation, however, leading to increased wear of piston top rings and cylinder liners.
Technical Paper

Study of 2-LEG NOx Storage-Reduction Catalyst System for HD Diesel Engine

A 2-LEG NOx Storage-Reduction (NSR) catalyst system is one of potential after-treatment technology to meet stringent NOx and PM emissions standards as Post New Long Term (Japanese 2009 regulation) and US'10. Concerning NOx reduction using NSR catalyst, a secondary fuel injection is necessary to make fuel-rich exhaust condition during the NOx reduction, and causes its fuel penalty. Since fuel injected in the high-temperature (∼250 degrees Celsius) exhaust instantly reacts with oxygen in common diesel exhaust, the proportion of fuel consumption to reduce the NOx stored on NSR catalyst is relatively small. A 2-LEG NSR catalyst system has the decreasing exhaust flow mechanism during NOx reduction, and the potential to improve the NOx reduction and fuel penalty. Therefore, this paper studies the 2-LEG NSR catalyst system. The after-treatment system consists of NSR catalysts, a secondary fuel injection system, flow controlled valves and a Catalyzed Diesel Particulate Filter (CDPF).
Technical Paper

Steer-Restoring Torque Controlled Driving Simulator for Developing Steering Road Feel

A driving simulator system for developing steering road feel has been developed. A new steering gear box or an electronic steering system is installed on the simulator and its road feel and control algorithm are developed according to the characteristics of any vehicle which has been programed into the engineering work-station. The vehicle model programed into the engineering work station runs according to the driver's operations, which are fed through the new steering system to be tested. The steer-restoring torque of the vehicle programed into the engineering work-station is produced by an actuator, and gives the impression through the new system of having been fed back from an actual road.