An Innovative Retrofit Design for Energy Efficiency and Emission Reduction: MAN B&W Marine Engine Slide Fuel Injector

Abstract

The fuel injector is one of the most essential parts in marine diesel engines. For MAN B&W two-stroke engines, the conventional fuel injector, due to the existence of sac volume, can result in problems such as increased emission and fuel consumption and shortened service life of combustion chamber components. The MAN B&W marine engine slide-type fuel injector is a structural retrofit of conventional injectors, improving diesel engine combustion conditions, fuel efficiency, and emission reduction in hydrocarbon, NOx, smoke, and particulate matter by eliminating sac volume with patented technology. This study employed a comparative analysis approach to evaluate the performance of conventional fuel injectors versus slide-type fuel injectors in MAN B&W two-stroke engines. Data collection involved practical experiences, onboard operations, and analysis of fuel efficiency, emission reduction, and combustion improvement. The structural differences and operational advantages of both injector types were examined to assess the environmental benefits and economic implications of adopting slide fuel injectors. Recommendations for the gradual replacement of conventional injectors with slide-type injectors were based on empirical data and industry best practices. Slide fuel injectors obtain a reduction of about 75% of the HC emissions at all loads. The slide fuel injector significantly decreases the smoke emission level at low engine load, at 25% load. A reduction in PM of up to 50% has been confirmed, and slide fuel injectors can reduce NOx emission by approximately 15% on average. The smoke emission level at low engine load, at 25% load in particular, is greatly decreased by slide fuel injector. Slide fuel injectors, with a granted patent, are commonly used in marine low-speed engines due to their advantages.