Selective Catalytic Reduction (SCR) and what it does for you

What is SCR?

If you are looking for a NOx reduction solution, SCR may be a suitable option. SCR is the catalysed chemical reaction that reduces NOx to water and nitrogen.

The process uses diesel exhaust fluid (DEF) as the reductant. DEF is injected into a tube where it mixes with the exhaust. The reactions take place as the DEF/exhaust mixture passes through the SCR catalyst.

Special considerations for using SCR

One unique aspect of an engine with an SCR system is that operators need to top-up the DEF on a periodic basis.

DEF consumption rates are determined by vehicle operation. For most light-duty vehicles, DEF refill intervals typically occur around the time of a recommended oil change or other scheduled vehicle maintenance.

DEF replenishment for heavy-duty vehicles and off-road machines and equipment will vary depending on the operating conditions.

What are the strengths of SCR?

• It’s a highly effective system for reducing NOx and is the primary technology within the industry to meet Stage IV/Tier 4 Final emission standards for the power band of 56-560 kW/75-750 hp engines
• SCR requires a second fluid – the DEF – and Perkins has developed systems to limit the amount of DEF consumption required in overall engine optimisation.