Due to the opposite reaction to combustion temperature, the reduction of either of the combustion products (NOX or PM) necessarily implies the increase of the other one. In order to further reduce NOX, as required by Euro VI, it is necessary to work on different combustion management and exhaust gas treatment system.
This means that Euro VI emission limits can be reached only through the use of SCR (Selective Catalytic Reduction), either with or without EGR. The use of an EGR system reduces the NOX emissions in the combustion chamber, through exhaust gas recirculation with a consequential increase in the production of particulate matter (PM) and a reduction in combustion efficiency. Furthermore, with high engine-out particulate emissions, a forced regeneration of the DPF is required.
FPT Industrial has chosen instead to increase the engine combustion efficiency to reduce the PM without using re-circulated exhaust gasses. While the remaining PM is reduced in the passive DPF, the NOX is reduced in the SCR system, while improving fuel consumption, HI-eSCR system performance and reliability. FPT Industrial’s HI-eSCR is able to reduce the NOX levels more than 95%.
The “SCR Only” technology sees the introduction of a new integrated approach that is the result of extensive research by FPT Industrial, research that has led to the creation of numerous significant patents.
HI-eSCR main components are:
- The Diesel Oxidation Catalyst (DOC)
- The Passive Diesel Particulate Filter (DPF) - only On Road application
- The AdBlue dosing module
- The AdBlue mixer
- The Selective Catalytic Reduction (SCR)
- The Clean Up Catalyst (CUC)
The whole system is fitted with a network of integrated sensors to control the NOX and any excess of NH3 (ammonia) emitted.
Exhaust gas flow coming from the engine enters the DOC, where NO is oxidised in NO2, which helps to reduce the PM in the subsequent passive DPF. The filter is automatically regenerated at lower temperatures compared to the active DPF used by our competitors. The ECU (Engine Control Unit), the brain behind the HI-eSCR system, checks, through sensors integrated in the exhaust, the amount of Water-Urea (AdBlue) solution to be injected in the exhaust pipe. To increase the durability of the injector, Dosing Module is cooled by the engine coolant.
The HI-eSCR after-treatment system adopts a catalyst converting NOx into Nitrogen (N2) and Water (H2O) thanks to the chemical reaction with a Water-Urea solution. In the end, the integrated CUC eliminates the remaining ammonia (NH3). The result is a reduction of NOx superior to 95%.