Having commenced testing in 2016, Hedemora Turbo and Diesel’s new HS7800 turbocharger is now officially part of its 2017 product portfolio. The product is the largest in the present range, designed for engines with airflow demands of up to 8.5 kg/s and output powers of up to 4,200kW per turbocharger. The first production units are built and awaiting engine installation but Hedemora has now announced a further new turbocharger, the HS6800, for which design work has already been completed.
“After announcing the HS7800 development in the 2016 edition of Worldwide Turbocharger Guide, we are now pleased that this new product has officially been added to our turbocharger range,” said Ernst Dahlin, Hedemora’s product development manager. “The HS7800 retains the capabilities of our existing HS products but we have been able to achieve significant increases in air flow capacities without increasing overall dimensions. This is also the case for the HS6800 turbocharger, which we will testing this year.”
The operating pressure ratio capability of the HS7800, at 4.5:1, matches that of the existing HS4800 and HS5800 products. Without the gas inlet casing fitted it has the same external dimensions as the HS5800 and, at 450kg it is very light, giving good vibration characteristics when installed on the engine bracket. The air-cooled radial turbine design is both simple and robust, with overall efficiency of the turbocharger being quoted at 68 per cent.
Close attention to aerodynamic and mechanical design has enabled Hedemora to improve many features of the product, including enhancing the compressor and diffuser. The HS7800’s diffuser is also based on a dual-row design that, along with the new centrifugal compressor, gives the turbocharger a wider compressor map. This is particularly important for variable duty applications and duties such as rail traction, enabling high levels of efficiency to be maintained over a range of conditions. To cater for the increased rotor axial loads resulting from the higher capacity, thrust bearing size has also been increased enabling bearing replacement intervals to be held at 24,000 hours.
Hedemora is also now well advanced with the development of the HS6800, which has been positioned between the HS5800 and HS7800 and is a drop-in replacement for the HS5800. Its aerodynamic design has been focused on widening the compressor map and, like the HS7800, it features new compressor and diffuser stages. With interfaces remaining identical to the HS5800, the changes have enabled air flowrate to be increased by approximately 20 per cent, giving the unit the potential to deliver charge air for engine outputs of up to 4,000kW per turbocharger.
Similar to other products in the family, the HS6800 has an operating pressure ratio capability of 4.5:1 and uprated thrust bearing capacity to maintain its reliability and service life. The axial turbine weight is less than 15kg, so inertia is low providing good response to demands for load changes. As with the HS7800, the turbine stage has retained the use of lacing wire to damp blade responses to exhaust gas pulsations and ensure durability in service.
Full analytical simulation work has already been completed and HS6800 components are now in manufacture. Testing is scheduled for August 2017 and this will be witnessed by representatives of an operator that has gained good experience with HS products and is planning to upgrade the performance of its in-service engines.
Seeing retrofit opportunities as well as new engine sales as commercially attractive targets, Hedemora offers flexible installation solutions for this purpose. The company designs bespoke gas casings that allow easy adaptation of its products to fit existing engine installations. Full retrofit kits are therefore available, allowing customers to easily replace older turbochargers with new HS products. The Hedemora engineering team provides full customer support for this work, analyzing engine data to ensure best matching is achieved and conducting on-engine tests to confirm turbocharger performance, or fine-tune the match to optimise engine power and efficiency.
Hedemora maintains its own development and test facilities and believes that its success with new product developments has been supported by close relationships with both customers and suppliers. The company is also making use of new manufacturing technologies to produce turbocharger parts. Designs are created using both Catia and Inventor software and use surface, solid, sheet metal and weldment modelling techniques. All critical components undergo comprehensive thermal and stress analysis to confirm their capabilities prior to designs being sealed and components manufactured.
Hedemora Turbo and Diesel is part of the Engenco of Australia, with HS turbochargers being manufactured and tested at the company’s headquarters in Hedemore, Sweden. The company is approved to ISO9001:2008 and ISO14001:2004 and, since 2012, has been certified by Turkish Lloyd for deliveries to Tülomsas. In 2016 approval was gained from the Russian Maritime Register of Shipping and the first turbochargers approved are now in service on a fishing trawler operating from Gran Canaria.