The move from Tier 3 to Tier 4 Final diesel engines above 74 horsepower brought with it a whole grab bag of new components and systems – diesel particulate filters (DPFs), diesel oxidation catalysts (DOCs) and, finally, selective catalytic reduction (SCR), which involves a diesel exhaust fluid (DEF) dosing system and a DEF tank.
That’s a lot of hardware to hang on any engine block, not to mention all the sensors, fittings, brackets and weldments that go along with it. There is a trend underfoot now, however, that seeks to simplify this arrangement. We took a look at a handful of these devices at ConExpo.
A few years back, Cummins started talking about a single module arrangement that would put all the exhaust aftertreatment components into one streamlined device. Then last year at Bauma, the big construction equipment trade show in Germany, Cummins announced it would use the single module concept in its forthcoming Stage V diesel engines.
Cummins’ single module system for exhaust aftertreatment allows the company to do away with heat generating EGR systems.
The single module system combines a diesel particulate filter and selective catalytic reduction in one torpedo-shaped canister. According to the company, this cuts the size of the aftertreatment in half and the weight 30 percent. Passive regeneration keeps the DPF clean with no impact on equipment operation and no operator intervention.
American contractors got their first look at the system at ConExpo. Cummins calls this a “fit and forget” system. That means simplified installation for the OEM, and for the end user, it can reduce emissions almost entirely by passive means, requiring no work slowdowns or operator interventions. Cummins will use the system on engines ranging from 100 to 430 horsepower.
