An Exciting Journey to Build the Tier 4 Locomotive

Last week, GE unveiled the Tier 4 Locomotive. The event culminates 7 years of exciting efforts by a global GE Transportation & Global Research team to develop an engine capable of meeting the emissions standards. With limits of 1.3g/hp-hr NOx and 0.03g/hp-hr PM, the Tier 4 standards require 76% and 70% reductions respectively from today’s levels. Those are big numbers that naturally require significant changes to current engine designs.

The Global Research team was an integral part of sorting through the technology palette of options to getting to Tier 4. Key question to answer was how much emissions reduction we could achieve with optimization of the combustion process. Any ensuing gap in emissions capability would have to be made up via exhaust aftertreatment. NOx reduction, for instance, could be accomplished with the use of Urea in an after treatment system; an option both we and our customers would like to avoid.

We were able to demonstrate with experiments performed in the single cylinder engine facility at the Global Research Center in Niskayuna that the NOx targets were realizable with the use of exhaust gas recirculation in conjunction with the optimization of other combustion parameters. Also, with the use of computer models of the integrated system, we were able to establish the key subsystem requirements as well as determine the necessary design changes to achieve these requirements. Cool thing is when the full scale engine was tested recently, the results came really close to our projections.

Tier 4 is almost out of the door; product launch is in 2015. We are not quite done yet. But this is certainly a good time to reflect on what has been an exciting journey for the team so far!

In the video below, I share a bit about reduce emissions in new Tier 4 locomotive. If you’d like to learn more, check out the GE Reports article.

– Wole


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