PowerTech PVX and PSX 9.0L 56 kW (75 hp) and above engine models from John Deere Power Systems have received Interim Tier 4/Stage III B certifications. The engines were built from the PowerTech Plus Tier 3/Stage III A inline, six-cylinder engine platform, which includes cooled exhaust gas recirculation (EGR) for NOx control as well as an exhaust filter for reducing particulate matter. Engines feature full-authority electronic controls, a four-valve cylinder head, high-pressure fuel system, turbocharging, and an air-to-air aftercooling system. Both offer the company's cooled EGR and variable geometry turbocharger technologies for off-highway applications and maintain fuel-economy levels similar to Tier 3/Stage III A engines. EGR engines operate with ultralow-sulfur diesel as well as biodiesel blends. The PowerTech PVX 9.0L offers up to 224 kW (300 hp), while the PowerTech PSX 9.0L up to 317 kW (425 hp).