GenSet Pocket Guide - JOHN DEERE POWER SYSTEMS - #9

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16 17 PowerTech PVX Interim Tier 4 technology PowerTech PVX 4.5L, 6.8L, and 9.0L engines EPA Interim Tier 4 Exhaust filters These engines utilize a catalyzed exhaust filter that contains a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF). The DOC reacts with exhaust gases to reduce carbon monoxide, hydrocarbons, and some particulate matter (PM). The downstream DPF traps and holds the remaining PM. Trapped particles are oxidized within the DPF through a continuous cleaning process called passive regeneration. Passive regeneration occurs during normal operating conditions when heat from the exhaust stream and catalysts within the exhaust filter trigger the oxidation of the trapped PM. If passive regeneration cannot be achieved due to low temperature, load, or speed, then PM is removed using active regeneration — an automatic cleaning process controlled by the exhaust temperature management system. Engines below 130 kW (174 hp) use an in-cylinder dosing system for active regeneration, while larger engines use an external dosing system. High-pressure common-rail (HPCR) and engine control unit (ECU) The HPCR fuel system provides variable common-rail pressure and higher injection pressures up to 1,975 bar (29,000 psi). It also controls fuel injection timing and provides precise control for the start, duration, and end of injection. 4-valve cylinder head The 4-valve cylinder head provides excellent airflow by utilizing a cross-flow design (4.5L and 6.8L) and a U-flow design (9.0L). Variable geometry turbocharger (VGT) Varies exhaust pressure based on load and speed to ensure proper EGR flow. The combination of the cooled EGR and VGT provide low-speed torque, quicker transient response, higher-peak torque, and world-class fuel economy. Cooled exhaust gas recirculation (EGR) EGR cools and mixes measured amounts of cooled exhaust gas with incoming fresh air to lower peak combustion temperatures, thereby reducing NOx. DOC Exhaust Out DPF Fresh Air Compressed Air From Turbocharger Exhaust EGR Cooler VGT Injector* Air-to-air Cooler Intake Throttle Valve EGR Valve * For engines 130 kW (174 hp) and greater.