Advances of Hino J-series Diesel Engines 2003-01-0054

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. The unique fuel injection characteristics such as pilot injection and multiple injections affect the reduction of NOx emissions and the reduction of combustion noise also.

In the case of 5-cylinder TI engine, the optimization of the exhaust system is very difficult because the exhaust gas pulsation from each cylinder interferes with the performance of the engine. In J07C-TI a no divided exhaust manifold and turbocharger was applied. It was the great compromise between low speed torque, emissions, fuel economy and cost. Another problem of 5-cylinder engine is engine vibration excited by unbalancing moment of the 1st and 2nd orders caused by oscillation masses. The rotational parts such as the crankshaft balance weights were carefully designed. Reduction of the engine vibration displacements of the 5-cylinder engine achieved a practical use compared with 4 & 6 cylinder engines.

New J-series engines had further progress in reliability, noise and installation ability, which is highly evaluated in current J-series engines.