Investigation of a ‘SCR-free’ system to meet the Stage IV and beyond emissions limits

In the emission power band above 55kW Kohler Engines have developed the KDI 3.4 litre engine to meet the Stage IV exhaust emissions limits using the Ricardo TVCS low soot combustion system plus DOC and SCR aftertreatment system, without DPF. For Stage IV, currently the 3.4 litre engine uses 2000 bar Denso Common Rail system with moderate EGR rates and requires a reduction in NO_x emissions of around 90% over the SCR system.