Wartsila and ABB Turbo Systems are co-operating in a joint development programme for what is described as a new and groundbreaking application of two-stage turbocharging on large diesel engines. Two-stage turbocharging combined with advanced engine technology offers significant advantages in fuel consumption and engine emissions.

In the development programme Wartsila is focusing on developing advanced engine technology, which with the turbocharger, is able to reach the highest possible performance and become a cost-effective commercial solution for its customers. ABB Turbo Systems is delivering the turbocharging technology with defined performance in terms of airflow, pressure ratios and efficiency.

In the new engine design, two turbochargers are arranged in series to generate increased air pressure, airflow and a superior turbocharging effect. This results in an efficiency rating of up to 76%, which is extremely high. The increased air pressure, combined with the advanced engine technology, improves the engine output and power density by up to 10%. At the same time, both fuel consumption and CO2 emissions are reduced.

Further emissions reduction can be achieved with additional engine systems or by the use of exhaust gas after-treatment. A precise combination of fuel consumption levels and reductions in CO2 and NOx emissions can be selected through detailed systems configuration. Intelligent engine control allows optimum operation of the advanced engine design over the whole load range, and a significant reduction in NOx emissions can be reached. At high altitudes, 2-stage turbocharging technology guarantees the engine’s operational performance by compensating for the reduced air density.

The significant reductions in fuel consumption and emissions are the result of extensive joint testing of the 2-stage turbocharging system on the Wartsila engine at the company’s test facility in Vaasa, Finland, and the targets for the development programme have been successfully met. The two companies are planning to initiate a major pilot project with a customer in the near future.