Innovative approach to reduce friction losses in turbocharger journal bearings

article in a collection out of WoS and Scopus

en

European and global regulations are putting pressure on the energy efficiency of machines. In high speed rotating machinery, higher efficiency can be achieved by eliminating mechanical losses. The mechanical efficiency of turbochargers is significantly influenced by the lubrication system and can be greatly improved by reducing mechanical losses in the journal bearings. The greater effect of reducing mechanical losses in the lubrication system is particularly noticeable at lower compressor speeds, when high performance is not yet achieved at the impellers. The main traditional tools used for lubrication analysis are approaches involving the numerical solution of the Reynolds equation. This innovative approach is based on a very general definition of the lubrication gap, the shape of which is then optimised. The innovative approach presented uses genetic algorithms to optimise the shape of the lubricating gap of hydrodynamic plain bearings under a variety of operating conditions. The result is a new geometry of the inner layer of the journal bearing, which achieves a load capacity comparable to the original series bearing, but with significantly reduced losses. To verify the innovative approach, engineering experiments were carried out on a test turbocharger. The experimental results prove the successful application of the innovative approach, with the resulting innovative bearing enabling a 20% reduction in mechanical losses in the lubrication system under preferred operating conditions. This also resulted in a 23% saving in oil flow through the lubrication system. The new bearing has also demonstrated sufficient durability for long-term testing of a turbocharged stationary internal combustion engine without significant risk of lubrication system failure.

European and global regulations are putting pressure on the energy efficiency of machines. In high speed rotating machinery, higher efficiency can be achieved by eliminating mechanical losses. The mechanical efficiency of turbochargers is significantly influenced by the lubrication system and can be greatly improved by reducing mechanical losses in the journal bearings. The greater effect of reducing mechanical losses in the lubrication system is particularly noticeable at lower compressor speeds, when high performance is not yet achieved at the impellers. The main traditional tools used for lubrication analysis are approaches involving the numerical solution of the Reynolds equation. This innovative approach is based on a very general definition of the lubrication gap, the shape of which is then optimised. The innovative approach presented uses genetic algorithms to optimise the shape of the lubricating gap of hydrodynamic plain bearings under a variety of operating conditions. The result is a new geometry of the inner layer of the journal bearing, which achieves a load capacity comparable to the original series bearing, but with significantly reduced losses. To verify the innovative approach, engineering experiments were carried out on a test turbocharger. The experimental results prove the successful application of the innovative approach, with the resulting innovative bearing enabling a 20% reduction in mechanical losses in the lubrication system under preferred operating conditions. This also resulted in a 23% saving in oil flow through the lubrication system. The new bearing has also demonstrated sufficient durability for long-term testing of a turbocharged stationary internal combustion engine without significant risk of lubrication system failure.

turbocharger; journal bearing; optimisation; pattern search; mechanical losses.

06.09.2023

Brno University of Technology, Faculty of Mechanical Engineering

Brno

978-80-214-6164-2

Scientific Proceeding KOKA 2023

1

20–20

1