The exhaust gas recirculation system has been further developed by Hatz engineers to improve emissions. A pre-cooling section for the exhaust gas recirculation (EGR) significantly reduces the exhaust gas temperature before the EGR valve, thus protecting it from thermal damage and fouling. Additionally, an optimized EGR mixing nozzle is used. It evenly distributes recirculated exhaust gases and fresh combustion air to all cylinders.
In conjunction with the common-rail system, this solution ensures excellent exhaust gas quality, allowing the TIC models of the H-Series to be equipped only with a diesel oxidation catalyst (DOC) and to forgo the additional installation of a particulate filter. Yet the engines still significantly exceed the emission limits of EPA Tier 4 final and EU Stage V.