The move is in response to concerns expressed by certain van makers that some of the turbos they’re employing at present just aren’t durable enough and are failing prematurely says CTT engineering director, David Green.
“The swing-vane variable-geometry turbos widely used are complex, have many moving parts and can have issues with binding, backlash and vane flutter,” he observes. “You’ve got 14 vanes rotating on an axis and they all wear.”
In response, CTT has come up with a sliding-wall variable-geometry design that Green says is less complicated — “it has a fixed nozzle with a sliding shroud” — and offers comparable performance. What’s more, unlike the swing-vane type, it can provide engine braking and diesel particulate filter regeneration.
Filter regeneration is possible because the turbo can be used to raise the temperature in the exhaust system significantly when the engine is idling. As a consequence there’s no need for additional dosing systems. Furthermore, Cummins has had ten years experience of this type of turbo design in its bigger engines.
Available to third parties as well as for use by Cummins itself, the new turbochargers were developed by an international team including engineers in China, India and Huddersfield.
Turbocharging specialist Holset Engineering was founded in the West Yorkshire town back in 1952. It was acquired by Cummins, which built over 600,000 engines worldwide last year, in 1973 and renamed Cummins Turbo Technologies in 2006. However, it still makes use of the Holset name.