Engine manufacturers have started unveiling technical solutions to meet a further step in off-highway diesel engine emissions regulation planned by the European Union.

Under current European and U.S. regulations, particulate matter limits determined by mass have been driven down by a remarkable 99% from EPA Tier 1 levels. EU Stage V rules will target ultra-fine particulate emissions, which are considered the most harmful to human health, by setting limits on the number of particles emitted.

The new EU-only regulations are expected to be phased in by engine power bands over 3 years starting in January 2019. The EPA has given no indication it will adopt the same measure, but future EU-spec engines may become standard if ag vehicle OEMs want to avoid the complication of supplying engines to different specifications in two major markets — Europe and North America — where emissions rules currently are pretty much identical.

One thing is known — using a diesel particulates filter (DPF) is the only way to meet the EU’s proposed limits defined by particle number rather than mass. 

Some engine makers, such as Cummins, Deere and Perkins, already use filtration among measures to meet EPA Tier 4 Final and EU Stage IV rules. But AGCO Power, FPT Industrial, JCB Power Systems and MTU are among those who have chosen combustion tuning and selective catalytic reduction (SCR) to avoid using a DPF, which adds cost and often has a servicing requirement.

Although the regulations have yet to be formally established, engine manufacturers have pushed ahead with solutions. Deutz already has DPF options in anticipation of the Stage V limits as an addition to the SCR system on 4.1-liter and larger engines and the diesel oxidation catalyst on 2.9- and 3.6-liter sizes.

OEMs using the EcoFit Single Module solution unveiled by Cummins for heavy-duty and mid-range engine applications are promised easier exhaust treatment integration. The module is up to 60% smaller and 40% lighter than today’s combined SCR and DPF systems, it says.

FPT Industrial says a particle filter will replace part of the SCR catalyst in its next-generation HI-eSCR system. Together with a lack of exhaust gas recirculation (EGR), this will help maintain the after-treatment installation flexibility available with the manufacturer’s Tier 4 Final engines.

Perkins highlights its experience as an early adopter of DPF technology and is confident that its low temperature regeneration system — to periodically remove accumulated deposits from the filter material — can be applied to Stage V engines while remaining “invisible” to the operator and without interfering with the machine’s duty cycle or work load.

Germany-based MTU, a division of Rolls-Royce Power Systems, says the EU Stage V requirements and further improvements in fuel efficiency will be among priorities for product development.