To meet increasingly stringent emissions regulations, John Deere has followed a carefully planned approach. They have systematically adopted new technologies and integrated them with their field-proven solutions to meet each regulatory Tier.
John Deere was the first engine manufacturer to widely commercialize cooled EGR and variable geometry turbocharger technologies in off-highway applications, introducing them with the start of Tier 3/Stage IIIA regulations. This process reroutes cooled exhaust gas back into the intake manifold, which reduces oxygen levels, lowers exhaust temperatures, and reduces levels of NOx.
John Deere’s straightforward PowerTech EWX 4.5L engines have 2-valves cylinder heads, high-pressure common-rail (HPCR) fuel systems, and full authority electronic controls. These engines use simple wastegate turbocharging to maintain transient response and peak torque in all operating conditions. The HPCR fuel system provides variable common-rail pressure and higher injection pressures up to 23,000 psi. It also controls fuel injection timing and provides precise control for the start, duration, and end of injection.
Wastegate turbochargers are designed to develop more airflow at lower engine speeds to improve low-speed torque. The wastegate control device bleeds off a portion of the exhaust flow at higher engine speeds. Wastegate turbos deliver improved transient response and higher peak torque without compromising engine envelope size.
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 through a continuous cleaning process called passive regeneration. Passive regeneration occurs during normal operating conditions when heat form the exhaust steam and catalysts within the exhaust filter triggers the oxidation of the trapped PM. If passive regeneration cannot be achieved due to low temperature, load, or speed, the PM is removed using active regeneration-an automatic cleaning process controlled by the exhaust temperature management system. In most cases, filter cleaning does not impact engine operation or require operator involvement.
The use of exhaust filters on engines requires the use of diesel fuel with a sulfur content of less than 15 ppm (ultra-low sulfur diesel or ULSD). John Deere engines operate efficiently with ultra-low sulfur diesel as well as B5 to B20 blends, providing optimal performance and fuel-choice flexibility.