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PROPULSION UPDATE Wartsila Offers New Lew NOx Cembustien On Vasa 32 The Vasa 32 has been a popular engine throughout its 18 years on the market, and manufacturer Wartsila Diesel has reportedly lowered the unit's NOx emission. Recent requirements from the marine market concern limitation of NOx emissions. The NOx emission limitation proposed by the IMO for diesel engines onboard ships will, during the first phase, be related to engine speed. The proposed NOx emission level has been reduced 30 percent from the existing level recorded in a survey of existing ships in operation. Wartsila reports that its low NOx combustion technology is an alterna- tive to a solution which simply cuts NOx by retarding fuel injection, thus increasing the thermal load and sub- stantially increasing fuel consump- tion. The low NOx solution depends on many factors working together, but includes: •Anew piston has been developed for higher combustion pressure, because the maximum firing pressure has been increased by 10 bar to 165 bar. The higher maximum pressure is needed to handle the increased com- pression pressure and to provide greater thermal efficiency. The pis- ton is a composite consisting of a modular cast iron skirt and steel crown. •The stiff, bore-cooled liner is equipped with an anti-polishing ring in the upper end to eliminate the risk of bore polishing. •As a consequence of the increased cylinder pressure, the connecting rod was changed from a diagonally stepped, two-piece solution to a fully machined, three-piece design with a horizontally split, big-end bearing. The change provides greater safety at increased load and eliminates the need to interfere with the big end bearing assembly when overhauling the piston. The disadvantage is the increased number of parts. For more information from Wartsila Diesel Circle 95 on Reader Service Card IMS BFOC g/kWh) fi'lgfllRL^eflnHWBBBi m - nbmII % ilil NOx (g/kWh)15 SPECIFIC FUEL CONSUMPTION ISO Conditions, without engine driven pumps 3% tolerance P100% = 410 kW/cyl, n = 750 rpm Fuel: HFO 380 WV 32 WV 32 Low NO) 50 75 85 100 110 Load(%) SPECIFIC NOx EMISSION WV 32 WV 32 Low NO* 110 Load (%) • Long Predictable Life THE CLINE COMPANY is a custom engineer, designer and builder of universal drive shaft assemblies for marine vessels. We feature Cardan universal shafts and constant velocity shafts. Our main feature is composite tubes to reduce weight between the marine gear and the driven propeller or jet drive. We also supply the flexible coupling to reduce vibration from the fly wheel to the shaft assembly. We feature new Fawick, Eaton or Wichita clutches for marine propulsion. We have a tremendous inventory of spare parts for Wichita and Fawick clutches for marine drives. The Cline Company Mill Products Division P.O. Box 3307 Greenville, SC 29602-3307 Fax (864) 232-7828 1-800-235-6371 MARINE DRIVES FROM CLINE DELIVER... Design Flexibility for Naval Architects Higher Angular Capacities Low Maintenance Design Dependable Performance High Efficiency 12 Circle 216 on Reader service card Maritime Reporter/Engineering News
