In this paper the methods applied to the Mazda 3.0 liter diesel engine for truck to reduce the size, weight as well as sound level, while improving the durability and reliability, are presented.
The Mazda 3.0 liter diesel engine was developed as the smallest in size and weight among all normally aspirated diesel engines of 90 PS or 3.0 liter class by means of incorporating engine accessory layout change, engine structure modification and material change.
To meet Japan’s stringent future noise regulations, efforts for noise reduction were focussed on engine modification aimed at reducing combustion and mechanical noises at the sources rather on an enclosure approach.
With the cylinder head with a new bolt pattern, modified combustion chamber, cylinder block of higher rigidity, expansion-controlled piston, modified piston cooling system, and fully balanced crankshaft, it has been made possible to reduce the sound level by 3–4 dBA.