MAN announces C2-compliant L21/31 solution

The new legislation will introduce directive limits for nitrogen oxides (NO_x) and hydrocarbons (HC) emissions as well as particulate matter (PM) emissions. MAN ES noted that the limits are particularly challenging for type 2 marine engines with single-cylinder displacements of under 15 litres, and an overall power output of <2,000 kW. The company expects the introduction of C2 to grow sales of its small-bore, four-stroke MAN L21/31 engine type as a result.

The solution comprises a MAN L21/31 engine, fitted with a Selective Catalytic Reduction (SCR) aftertreatment solution to lower emissions of nitrogen oxides (NOx). The solution will meet the China Stage II PM emissions limits without the need for a particulate filter.

Finn Fjeldhøj, Head of Small-Bore, Four-Stroke Engineering, MAN Energy Solutions, said: “As soon as C2 came on the horizon, we realised it was an excellent opportunity for our MAN L21/31 engine, whose compactness, low fuel-oil consumption and power rating make it particularly suited to this segment. Extensive testing shows that it complies with C2 particulate-matter limits without needing a particulate filter, while an SCR system will be required to meet NO_x requirements. In practice, such an SCR system will be sparingly employed to optimise engine efficiency and limit after-treatment operational expenses. We are confident that this practical solution will win favour in vessels sailing Chinese inland-waterways.”

MAN Energy Solutions states that the L21/31 can fulfil classification requirements as both controllable-pitch-propeller (CPP) propulsion and genset applications. Based on recent research, MAN is already capable of pursuing the engine’s official emission certificates from the China Classification Society but is continuing to develop more advanced solutions with its licensees to further improve the environmental impact of the engine, while lowering customers’ operational costs.