Cummins premieres Tier 4 Final engines

Cummins has taken the wraps off its new 503 kW QSX15 diesel engine, which complies with Tier 4 Final exhaust emissions laws due to come into force for new equipment in 2014. The company is augmenting its existing exhaust gas recirculation (EGR) and Cummins particulate filter (CPF) technologies with selective catalytic reduction (SCR) to achieve the final reduction in nitrous oxide (NOx) emissions.

The modifications to the engine have also seen power output increased by 56 kW compared to the Tier 4 Interim QSX15. Similarly, the Tier 4 Final QSX11.9's top rating of 392 kW is higher than its Tier 4 Interim predecessor.

"The QSX15 and QSX11.9 not only meet the challenge of near-zero emissions, but they are able to achieve this with higher power output and lower fuel consumption," said Jennifer Rumsey, Cummins' executive director for heavy duty engineering.

She continued, "The CPF-SCR ultra clean aftertreatment raises the threshold of what can be achieved in the trade-off between lower emissions and higher performance. This means we are able to realise the full power productivity of the QSX engines by precisely balancing emissions control between aftertreatment and engine combustion with cooled EGR."

Cummins says its new SCR system moves beyond the technologies currently in use in the market to achieve Tier 4 Interim compliance. The system incorporates a copper zeolite-based catalyst capable of converting 95% of the NOx passing over it to non-polluting gasses. The CPF meanwhile is retained to reduce particulate matter (PM) pollution, or black soot.