My idea would be to use helium cooling to cool intake air for an automotive engine to cool intake air for turbo, supercharger, or standard induction.
The cooling device would be a series of radiator like rings that would gradually ascend (or descend) in size as air goes thru inlet and is cooled to an almost liquid like state for superior combustion using less fuel
The helium would of course expand as it exchanged heat with air and would have to be re-compressed in one or more ways:
1) The expanding helium could drive turbine that would compress helium on other side
2) A turbine connected to exhaust could drive a compressor
3 ) The helium pump could be engine driven
There are two main challenges:
1) Preventing helium leaks
2) Preventing frost/ice buildup on heat exchanger which could be done in different ways:
A) Spraying a liquid anti-freeze down heat exchanger throat that would aid in combustion (an alcohol based product)
B) By-passing cold helium and sending heated helium in short bursts to remove ice
Both of these solutions would need some type of sensors and software to control spray/valve to remove frost.