Kawasaki Heavy Industries’ (KHI) new type KG-18-T gas engine, equipped with German air management specialist, PBST’s two-stage-turbocharging ‘ECOCHARGE’ system, has recorded the world’s highest class power generation efficiency with Japanese standard city gas, according to a PBST release.

Designed for power applications, the KG-18-T’s ECOCHARGE solution consists of 1 × PBST TCX23 and 1 × PBST TCA66 turbochargers that have improved its power-generation efficiency by 1.5% compared to the previous generation of the engine, delivering a world-best class 51.0% in its output class.

KHI notes that the engine and turbochargers have passed a durability test and are now ready for serial production. The turbochargers themselves were inspected after the durability test with KHI reporting their condition as very good.

The ECOCHARGE principle optimally combines a low-pressure turbocharger – usually a TCT, TCA or TCR – with a high-pressure stage for which the newly developed TCX series was designed.

PBST ECOCHARGE offers increased turbocharging efficiencies, in comparison to single-stage turbochargers. This is mainly related to the intercooler – positioned between the low-pressure-stage and high-pressure-stage turbochargers – that significantly reduces the energy required to compress the intake air to high pressure.

The resulting, higher efficiencies have an instantaneous impact on the engine by advantageously increasing the air pressure over the cylinder during the scavenging process.

Additionally, greater charged pressure by two-stage turbochargers foster the reduction of NOx emissions through the Miller cycle, while the improved scavenging efficiencies provided by the ECOCHARGE system make the engine more fuel efficient.

The higher power-density generated by the ECOCHARGE technology presents the opportunity to choose between significantly boosting an engine’s power output or reducing engine size, all the while maintaining engine performance.

The ECOCHARGE system’s increased efficiencies and higher cylinder rating facilitate the use of a smaller engine with the same power output of a larger unit that employs traditional, single-stage turbocharging.

KHI’s senior manager four-stroke engine department and head of design department, Mr. Sakai, said: “Our new KG-18-T gas engine raises high expectations. This engine is the latest and most-efficient addition to our ‘Kawasaki Green Gas Engine’ series. The design is based on its previous models KG-18-V and KG-18… The newly developed two-stage turbocharging system improves power generation efficiency significantly resulting in the world’s highest class efficiency in this output range. Consequently, we are keenly awaiting to continue this engine’s success story.”

PBST’s vice president of sales & license turbochargers & exhaust-gas treatment, Ralph Klaunig, said: “Naturally we are very happy with this announcement since KHI is the very first Original Equipment Manufacturer in the medium speed segment to launch an engine with our two-stage turbocharging solution. PBST is a market leader within two-stage turbocharging, with more than 35 million operating hours recorded from over 2,000 units, and it is very pleasing that we can now add the world’s most efficient gas engine to our reference list.”