The marine transportation, such as the large-sized commercial tankers and cargo vessels, have been supporting the field of distribution in the world since olden times. Further, nowadays, attention is increasingly given to safer and more environmentally-friendly marine navigation. The marine engines falls into the field of the products that can be said as the representative products of Daihatsu Diesel, as they have been playing an active and important role in the "sea" of all over the world. Therefore, the products enjoy high reliability, and they have built up the achievements as the harmonized high-performance engines of a very high level, realizing the durability supported by matured technique, and also realizing the reduction of NOx, low noise, and less vibration among others, by fully taking into consideration the earthly environment as well as the preservation of work environment.