Hino Motors has developed the new K13C, a 12.9 liter six cylinder in-line, heavy duty diesel engine that provides superior fuel consumption, extra low noise and excellent driveability together with a lower exhaust emissions. The initial K13C engine, whose production began in 1986 and about 30,000 units have been produced, is recognized all over the world for its good reliability and fuel economy. The new K13C is using the basic design and manufacturing/assembly processes of the previous one but includes a common-rail type fuel injection system with enhanced electronic controls to meet future regulation and customer requirements. Major design changes consist of a new cylinder head, a new front gear train, a new air intake system, a new turbocharger, a new compression brake system and electronic control module.The optimization of the intake system includes a new intake port and an electronically controlled inertia charging system. The highly effective turbocharger in conjunction with the electronically controlled common-rail system leads to better fuel consumption and lower exhaust emissions.In order to reduce engine noise, the following measures were taken: reduction of the mechanical noise by a newly designed gear train, reduction of air-bone noise from the cylinder head cover and intake system by using isolating rubber, and the reduction of combustion noise especially at engine idle speed by means of pilot injection.For safer driving and better driveability on both expressways and normal roads, braking performance and starting ability have been improved. The braking performance has been increased by adopting a new compression brake system with an electronically controlled waste gate valve in addition to an existent exhaust brake. The starting ability at clutch engagement is also improved by the increased injection pressure obtained by the common-rail fuel system. Moreover, the new starting assist system was developed. The vehicle equipped with the new K13C has almost the same starting ability as a 20 liter naturally aspirated engine which is the most popular for dump trucks in Japan.