Diesel Progress North American

Key to Cummins Tier 4 final engines is the company’s ability to develop and build its own aftertreatment systems.

external EGR (ceEGR) and DPFs on the two largest models.

For engines above 75 hp that enter Tier 4 final in 2014 and 2015, SCR joins the technology mix on some models with EGR and DPF technology used on other engines. There are also special Tier 4 final engine configurations for agricultural use. Wastegated, dual-stage and electronic turbochargers are also used, depending on the model and application.

is positioned in front of the SCR in the exhaust stream and efficient PM reduction is achieved with a catalytic coating, substrate and sizing that are tailored for the engine platform, the company said. The CCC is smaller than a particulate filter, a benefit for increasingly space-constrained installations, Cummins said. The CCC-SCR aftertreatment will be available in multiple configurations, including switchback, horizontal and vertical.

The new 675 hp top rating for the
QSX15 takes the Tier 4 final engine
75 hp above the Tier 4 interim top rat-
ing. The QSX12 engine also increases
power output for Tier 4 final with a new
top rating of 525 hp. The 12 L QSX
shares the same engine technology
and CPF-SCR aftertreatment system
as the QSX15. The integration of SCR
into the exhaust aftertreatment allows
the CPF to reduce the frequency and
duration of active regenerations below
1% of equipment operating time,
Cummins said, and it is also available
in multiple configurations.

DEUTZ

Deutz has detailed its Tier 4 final strategies graphically as shown in an accompanying illustration. The Deutz strategy for Tier 4 final includes one strategy for the engines below 75 hp that become compliant in 2013. In this range Deutz is relying on three turbocharged and one naturally aspirated models, all with diesel oxidation catalysts (DOCs), cooled

Deutz’s strategy for Tier 4 final by engine.
FPT

FPT Industrial said its “SCR Only” technology can meet the extremely stringent limits on NOx emissions by relying exclusively on the SCR system. FPT Industrial engines already meet the PM requirement of 0.02 g/ bhp-hr, the company said, without the use of EGR and a DPF.

The SCR system to meet Tier 4 final will utilize a separate DOC unit. The temperature of the DEF injection module located just after the DOC will be regulated by coolant from the engine.

The post-treatment system is composed of the SCR and the clean-up catalyst (CUC). The entire system is fitted with integrated sensors to control NOx and any excess amount of NH3 (ammonia slip) emitted. The use of this system allows NOx to be cut by more than 95%, FPT said.

To achieve these levels, the conversion efficiency of the catalyst must be significantly increased. This has been made possible because of the evolution of the engine management system, which controls the DEF dosing, and the thermal properties of the post-treatment system with extreme precision.

According to FPT, the Tier 4 final technology is an evolution of its existing Tier 4 interim solution already using SCR. Both Tier 4 interim and final offer no increased heat rejection over current Tier 3 engines, therefore the engine installation envelope remains the same. Thus Tier 4 final will be a “drop-in” the company said.