3. DESIGN CONCEPT
3-1 RELIABILITY & DURABILITY
In order that RELIABILITY AND DURABILITY can meet the target, thermal stress is reduced by proper selection of material, parts outline and improvement in cooling. Moreover, maximum firing pressure at 20 MPa in design can provide much flexibility in adjustment for engines in commercial production whose maximum pressure is normally set at 16 MPa.
In this way, the engines are capable of maintaining adequate margin for stength under diifferent working conditions, and thus making it possible to realise long maintenance intervals as well as improving the reliability of components.
3-2 EASY MAINTENANCE & LOW MAINTENANCE COST
Marine type (holizontally split three-piece type) connecting rod makes it possible to leave crank pin bearing in tact after piston overhaul. It also reduces the piston pull out height.
Major bolts, such as, cylinder head, main bearing cap, and side ways frame, are hydraulically tightened so that correct tightening force can make the handling easy and improve reliability. In order to attain these targets, maintenance work is concentrated on one side of engine, thereby reducing the number of components by 30 to 40 percent.
3-3 ENVIRONMENTAL PROTECTION
Both low fuel consumption and low NOx emissions are achieved with best matched fuel injection and in-take/ exhaust systems. Low fuel consumption and low NOx emissions, these two factors are contradictory, however, the new DK series can clear the limitations to NOx emissions by IMO without influencing on the fuel consumption.
The level of vibration is further reduced from a half to a quater. The noise level can also be lowered by 3 to 4 dBA owing to robust engine frame with its double wall construction and optimumly controlled combustion pattern.
