15 Nov 2019


Discussions about the climate change controls a lot of the political debat in order how the clean up thee air. NOx, CO2 and Particulate Matter emissions have to disappear. Easier said then done. Cummins unveiled at Busworld in Brussels a new natural gas engine which promises to lower these emissions to close-to-zero.

Design enhancements to the Cummins L9N natural gas bus engine have achieved emission levels of Nitrogen Oxides (NOx) and Particulate Matter (PM), substantially below that of the Euro VI standard. The enige is specially suitable for high passenger capacity 12-to-18 metre buses to help improve air quality and lower the carbon footprint of fleets.

This new L9N engine is available with a 209 kW (280 hp) and 239 kW 320 (hp) with an peak torque of 1356 Nm at 1300 rpm. The L9N shares the same base engine platform as the Cummins L9 diesel.

The design improvements enable the L9N to reach the ideal stoichiometric combustion point faster than before, and then maintain that point more consistently across the engine operating speed range. As a result, the L9N has demonstrated the ability to lower NOx emissions by 80 percent below that of the Euro 6 standard of 0.46 grams per kilowatt hour (g/kWh). PM emissions reduction is equally impressive with levels over 90 percent lower than the 0.01 g/kWh standard.

The L9N reduces greenhouse gas emissions by around 15 percent lower than an equivalent diesel engine, when running on either compressed natural gas (CNG) or liquified natural gas (LNG).

Cummins emphasizes the L9N is fully compatible with operating on renewable natural gas (RNG), also known as biomethane, providing a carbon neutral or even carbon negative footprint for the bus equivalent to that of an electric battery system, depending on the source mix of the energy charge. “The enhancements made to the L9N align with effect date for the stricter Phase-D requirement of the Euro VI regulations, but we were able to go significantly beyond that to reduce emissions to exceptionally low levels,” said Ashley Watton, Cummins Director — On-Highway Business Europe.

The Three-Way Catalyst (TWC) aftertreatment, without AdBlue, has also been upgraded with a larger catalytic surface area and smarter logic for better low temperature control, helping to eliminate bus engine emissions during idle, cold starts or frequent stop-start operations. It requires no AdBlue injection, cleaning or scheduled maintenance intervention.

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