A high performance and high versatility small-size diesel engine with a 95 mm cylinder bore (95 series) has been developed. The 95 series consists of 3, 4 and 6 cylinder models, and has two stroke-length (95, 115 mm) versions covering 2.02 to 4.89 liter swept volume in the 22 to 108 KW power range. The series has a DI and IDI combustion chamber, and a naturally aspirated and turbo charged version can be selected, depending on application requirements. The new engines are suitable for a wide range of applications such as prime-movers for construction machines, industrial vehicles, generators, ships, and trucks.The development objectives are light weight, small size, high fuel economy and low noise as well as high reliability and durability. These objectives have been achieved by various design features such as the optimized compact design of a linerless cylinder block of special alloy cast iron, an auto-thermatic piston, a noise-shield cover, and under-plate, etc.