Modern diesel engines, including those manufactured by Cummins, rely on advanced emissions control technologies such as Exhaust Gas Recirculation (EGR) and Selective Catalytic Reduction (SCR) to meet stringent environmental regulations. While these systems effectively reduce nitrogen oxides (NOx) and particulate emissions, they also influence engine component wear—particularly in fuel injection systems like the barrel and plunger in fuel pumps.
How EGR Affects Barrel & Plunger Wear
EGR systems recirculate a portion of exhaust gas back into the combustion chamber to lower peak temperatures and reduce NOx formation. However, this process introduces soot, acids, and contaminants into the combustion cycle, which can degrade fuel quality and lubrication.
Increased Abrasive Wear: Soot particles in recirculated exhaust gas can contaminate fuel, accelerating abrasive wear on the barrel and plunger.
Corrosion & Pitting: Condensed acidic compounds (from sulfur and moisture in exhaust gases) may lead to corrosion, reducing the lifespan of precision-machined components.
Higher Operating Temperatures: EGR can alter combustion dynamics, sometimes leading to increased thermal stress on fuel system parts.
The Role of SCR in Wear Rates
Unlike EGR, SCR systems do not directly interfere with combustion. Instead, they inject Diesel Exhaust Fluid (DEF, urea solution) into the exhaust stream to break down NOx into nitrogen and water. However, SCR-equipped engines often run hotter and with higher injection pressures to optimize efficiency, which can indirectly affect wear:
Higher Fuel Injection Pressures: To compensate for emissions compliance, engines may operate at elevated pressures, increasing mechanical stress on the barrel and plunger.
Fuel Contamination Risks: If DEF injectors malfunction, urea deposits or ammonia can enter the combustion chamber, potentially contaminating engine oil and fuel.
Mitigating Wear in Cummins Fuel Systems
To combat accelerated wear caused by EGR and SCR systems, maintenance and component quality are critical:
Use High-Quality Fuel & Additives: Clean, low-sulfur diesel and lubricity additives help reduce abrasive wear.
Regular Filter Changes: Efficient fuel and oil filtration prevent soot and acid buildup.
Upgraded Materials: Hardened coatings and precision-matched barrel & plunger sets improve durability in high-stress conditions.
Conclusion
While EGR and SCR systems are essential for emissions compliance, they contribute to increased wear in Cummins fuel injection components. Proper maintenance, high-quality fuels, and advanced materials can help mitigate these effects, ensuring longer service life and optimal engine performance.
By understanding these impacts, fleet managers and technicians can take proactive steps to protect critical engine components and reduce downtime.
Comments (0)