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In recent years, since the demands for comfortable operation and low fuel consumption are increasingly enhanced on the industrial machines, non-road engines as power sources on agriculture, landscape and construction applications are required to be achieved high power, low fuel consumption and low noise. Also, even for small engines, it is necessary to keep up with the trend of electronic control devices on these machines. Based on such backgrounds, we developed new non-road direct injection diesel engines with common rail system to satisfy those demands. This paper reviews the technologies to achieve the adoption of common rail system onto such small displacement industrial engines and to optimize the combustion system and injection characteristics.

In recent years, small diesel engines for industrial use are required to achieve still higher power output per engine size (high power density) and to have the performance to comply with stringent exhaust emissions standards as well. To meet these social demands and market requirements, there are various engineering tasks yet to accomplish. In this paper, two important technical issues have been focused, those are, combustion system improvement to enable lower exhaust emissions and higher power output than conventional models and new cooling system as a solution for increased heat load issue accompanying the progress of high power density. Firstly, for combustion system improvement, the swirl adjustment technique has been developed that will optimize the swirl ratio for each engine application with different load and speed condition.

Hydraulic fluid (HF) specifications for mobile construction equipment called JCMAS HK and HKB have been established by the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA). The specifications are designated by two viscosity categories of single grade and multigrade. Each category has ISO viscosity grade (VG) 32 and 46. The JCMAS HK oils are recommended for use in hydraulic systems designed at pressure up to 34.3MPa(5000psi) and to heat hydraulic fluid up to 100 °C. These oils also provide wear control, friction performance, oxidation and rust protection, seal swell control and filterability performance. Two piston pump test procedures were developed to evaluate lubricating performance of these oils under high pressure conditions. The JACMAS HKB oils are classified as environmentally friendly oils due to the additional requirement for biodegradability.

In this paper, the features of V3300 heavy-duty diesel engine series and the technologies to achieve the concepts are introduced. V3300 series is the vertical water-cooled 4 cycle IDI diesel engine for agricultural and industrial use. Its output is the highest in our company's IDI diesel engines. V3300 series was developed based on the concepts of our conventional series (low vibration, low noise, clean exhaust emissions and good fuel efficiency). V3300 series adopts 3 valves system for the first time in agricultural and industrial diesel engines. This 3 valves system is composed of 2 intake valves and 1 exhaust valve per cylinder. V3300 series also adopts the new combustion system which succeeded to the KUBOTA's original combustion system. The volumetric efficiency, the fuel efficiency and the exhaust emission performance are improved by these systems. The comfort level is achieved by reduction of the vibration and the noise by adoption of the built-in balancer.