Charged air cooling with vortex tube for a common-rail diesel engine

When vehicle speed is low, it is hard for the intercooler to cool the charging air owing to a reduction of the ram air effect. The performance of the vortex tube is not only independent of the vehicle speed but it is also independent of the ambient temperature. This benefit motivates a feasibility study of the vortex tube as a replacement for the intercooler in a diesel engine. In this study, the performance of a diesel engine with an intercooler was compared with that of a diesel engine with a vortex tube. The engine experimental results showed that the brake specific fuel consumption (BSFC) improved up to 3 per cent at 1750 r/min and 25 per cent partial load. The results also showed the soot (particulate matter) from the diesel engine equipped with a conventional intercooler was reduced up to 60 per cent at 1500 r/min and 25 per cent partial load when the vortex tube was used. As the engine speed increased, the intercooling with the vortex tube showed a similar performance, except at high speed and full load. This study demonstrates that the overall performance of the vortex tube makes it appropriate as a replacement for the intercooler, but the result also shows that the design parameters of the vortex tube need to be optimized to cover the whole operating range.