Development of Low Pressure Exhaust Gas Recirculation System

Abstract

To comply with the IMO NOx Tier III regulations, we have developed a new and unique technology called “Low Pressure Exhaust Gas Recirculation (LP-EGR) system”. The LP-EGR system is a system which recirculates a part of low pressure exhaust gas emitted from an engine turbocharger outlet into a turbocharger intake after scrubbed by an EGR scrubber. We applied the integrated on-engine LP-EGR system into a commercial engine 6UEC45LSE-Eco-B2 aiming for onboard durability confirmation. The results showed that its NOx emission level was within the IMO Tier III regulations and that the increase of fuel oil consumption was approximately less than 1%. This was the first time in the world that the LP- EGR system installed into a marine low speed two-stroke diesel engine has satisfied the IMO NOx Tier III regulations.

Furthermore, we installed the system into a 34,000DWT bulk carrier, and we are currently checking its long-term durability through sea trial and commercial voyages. Now, the system has archieved about 400 running hours in total during commercial voyages. This was also the first effort that the LP-EGR system, which complies with the IMO NOx Tier III regulations, was installed into a marine low speed two-stroke diesel engine of a vessel that is actually operating at sea.