thumb|HCNG -CNG emission HCNG or H2CNG (hydrogen compressed natural gas) is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances.
thumb|HCNG -CNG emission HCNG or H2CNG (hydrogen compressed natural gas) is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances.
(regarding the acronyms in the above emissions chart:
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).