Technology | Benefits | Limitations | References |
Direct Water Injection (DWI) | · Potential reduction of NOx by an amount of 60% · Can be applied for medium speed marine diesel engine | · Increase the fuel consumption by 2% to achieve the same output | [24] [26] [27] |
Exhaust Gas Recirculation (EGR) | · Low operating cost · Allows significant NOx reduction by an amount of 30% | · Cannot be employed at high loads because it will reduce the peak power output · Increase the creation of PM · Drop in engine efficiency | [32] |
Miller Cycle | · Increase the efficiency of the DE · Allows potential reduction of NOx by an amount of 40% - 60% | · High cost engine · Requires more maintenance | [28] [29] [30] |
Scavenge Air Temperature | · Reduce the number and size of exhaust ports · Allows a potential reduction of NOx by an amount of 60% | · Cylinder head complex · Requires periodical maintenance | [33] |
Selective Catalytic Reduction (SCR) | · Potential reduction of NOx by an amount of 95% · Relatively simple installation | · May suffer from erosion · High efficiency turbocharger is required to overcome the pressure drop · Require space for urea storage and a good surface for installation | [36] [37] [38] |