Today, the 0.8L engine, boosted by Honeywell’s smallest-ever turbo, can be seen powering vehicles through the busy streets of India’s cities and towns, typically carrying goods from warehouses to local businesses. For Honeywell, boosting such a small engine created a whole new set of design and engineering challenges.
“The issues in developing a turbo for a 2-cylinder engine not only revolve around packaging but also around specific challenges linked to compressor surge, oil leakage, high vibrations and high thrust load due to engine pulsations. These issues are far more pronounced here than in a four-cylinder engine,” says Vijayan Asvathanarayanan, Director of Application Engineering for Honeywell Turbo Technologies in India.
This meant that Honeywell engineers had to approach the turbo design from a completely new angle.
“We came up with a totally new turbocharger that included a very small turbine housing with integrated manifold, and the smallest-ever compressor wheel developed by Honeywell. The higher relative thrust loads brought about by the pulsation of a bi-cylinder engine meant creating new concept thrust pads in the Z-bearing – vital if we were to be efficient in matching the turbo to the engine requirements.”
A high-efficiency, compact bearing was developed – and the design was so successful that it is now being extended to other turbo sizes as well.
The result of this intense engineering activity is a well-performing and reliable turbo fitted in the 2-cylinder OEM production engine since 2011, which is contributing to a remarkable 25% improvement in power over a non-turbo equivalent and to significant fuel efficiency gains and lower emissions.
Critically, the proven success paves the way for the roll-out of a new generation of turbocharged 2- and 3-cylinder diesel passenger cars and light commercial vehicles, particularly in emerging regions.