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More stringent emissions regulations, fuel economy standards, and regulations are currently being discussed to help reduce both CO2 and exhaust emissions. Vehicle manufacturers have been developing new engine technologies, such as downsizing and down-speeding with reduced friction loss, improved engine combustion and efficiency, heat loss recycling, power-train friction loss recycling, and reduced power-train friction loss. The use of more efficient fuel economy 5W-30 engine oils for heavy duty commercial vehicles has started to expand since 2009 in Japan as one technological solution to help reduce CO2 emissions. However, fuel economy 5W-30 oils for use in heavy duty vehicles in Europe are mainly based on synthetic oils, which are much expensive than the mineral oils that are predominantly used in Japan.

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.

The friction pattern on the chamfers of sleeves and dog gears is a combination of peeling and adhesive wear caused by the formation and propagation of fine cracks. The effect of additional elements on wear were checked by making a test apparatus capable of performing evaluations on test pieces equivalent to those using actual parts. The results showed that the addition of B, Ti-Nb helped improve wear resistance. This is attributed to enhanced toughness and reduced peeling due to the formation of a texture. A 45% reduction in wear was achieved in actual parts tests on steel with added B, Ti-Nb.

Diesel engine has a good fuel economy and high durability and used widely for power source such as heavy duty in the world. On the other hand, it is required to reduce NOx (Nitrogen Oxides) and PM (Particulate Matter) emissions further from diesel exhaust gases to preserve atmosphere. The urea-SCR (Selective Catalytic Reduction) system is the most promising measures to reduce NOx emissions. DPF (Diesel Particulate Filter) system is commercialized for PM reduction. However, in case that a vehicle has a slow speed as an urban area driving, a diesel exhaust temperature is too low to activate SCR catalyst for NOx reduction in diesel emissions. Moreover, the diesel exhaust temperature becomes lower as a future engine has less fuel consumption. The purpose of this study is reduction of NOx emission from a heavy-duty diesel engine using the Urea SCR system at the low temperature.

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.

EPA 2010 emissions regulations - currently the strictest standards in the world - place particular emphasis on exhaust gas thermal control technology. The Burner System, a device developed to control exhaust gas temperatures, is the most effective means of raising exhaust gas temperature, as this system can function under any engine conditions, including low engine speed and torque. The Burner System begins operating immediately when the engine is started, activating the Diesel Exhaust Fluid (DEF) - Selective Catalytic Reduction (SCR) System immediately, because the Burner System is active, it enables the diesel particulate filter active regeneration under any engine operating conditions as well. This technical paper reports Burner System (ActiveClean™ Thermal Regenerator) development results.

The Advanced Safety Vehicle (ASV) project phase 2 was organized by the Japanese ministry of lands, infrastructures and transport in 1996 as a five year project. Hino Motors participated in the project and developed an intelligent truck “HINO ASV-2”. HINO ASV-2 was equipped with safety systems for accident prevention and accident avoidance, which were most effective in reducing accidents in freight transport. These intelligent systems aimed to reduce driving fatigue, minimize the chance of driver’s mistake, and prevent the occurrence of accidents. Human-machine interface, and front underrun protection device were also studied. Through the development of the ASV systems, the feasibility and basic functions of these systems were studied. Further development is necessary to implement the ASV systems in production vehicles.

Diesel particulate trap systems are one of the effective means for the control of particulate emission from diesel vehicles. Hino has been researching and developing various diesel particulate trap systems for city buses. This paper describes two of the systems. One uses a wall flow filter equipped with an electric heater and a sensing device for particulate loading for the purpose of filter regeneration. Another makes use of a special filter named “Cross Flow Filter” with an epoch-making regeneration method called “Reverse Jet Cleaning”, by which it becomes possible to separate the part for particulate burning from the filter. Both systems roughly have come to satisfy the functions of trap systems for city buses, but their durability and reliability for city buses are not yet sufficient.

Thai Hino Industries, one of Hino Motors Ltd.'s major overseas joint ventures, has been manufacturing trucks since it was founded over 20 years ago. During that time, Hino Motors, in cooperation with the Government of Thailand, has increasingly localized the production of vehicle component parts. Today, calculated by item, 45% of all such parts are produced by Thai Hino Industries and its local suppliers. As a result, Thai Hino Industries has grown into a company which makes significant contributions not only to the automotive industry but to Thailand's industrial sector as a whole. Localization of Thai Hino progressed from the transfer of vehicle assembly know-how, to the establishment of feasible guidelines for parts production localization, then on to the transfer of production engineering know-how for flexible manufacturing systems, and finally to the transfer of production engineering know-how for press dies.

The spark-assisted methanol engine has disadvantages like poor fuel economy especially at light load and low spark plug durability affected by combustion characteristics. Investigations of combustion characteristics of the spark ignition system and the autoignition system in the methanol engine and discharge characteristics of a spark plug are described in this paper. It is clear that effective autoignition was accomplished by increasing the compression ratio and adopting an EGR system in the spark-assisted methanol engine. This new improved methanol engine which is named HAMS achieved good fuel economy at light load, a low NOx emission and longer spark plug life. And a heat insulated piston with a stainless steel cap is being investigated for further improvement of autoignition combustion characteristics.

For the 1990's diesel engines, particulate control has been an important problem. The purpose of this paper is to discuss emission control needs for heavy duty diesel truck engines for the 1990's. This paper will focus on the factors such as fuel injection pressure and fuel properties which most affect particulate emission. The characteristics of diesel spray in the atmosphere and also actual combustion of a turbocharged and charge-cooled H.D. D.I diesel engine were studied as a function of injection pressure ranging from 50 to 150 MPa. Experimental results show that high pressure injection improves the atomization and air entrainment. Though Bosch smoke level, fuel consumption and combustion period decreased with the rise of injection pressure, particulate emission in EPA transient test cycle did not decrease dut to an increase of SOF.

A historical review of Japanese turbocharged diesel engines for heavy duty vehicles is described, and newly developed turbocharged diesel engines of HINO are introduced. The design features of these engines include new turbocharging technologies such as highly backward curved impeller for compressor blade, variable controlled inertia charging and waste gate. Laboratory and field test results demonstrated better fuel economy and improved low speed and transient torque characteristics than the predecessors. Several operational experiences, technical analysis and reliability problems are discussed.