Technology

This has me insanely curious as to where these are common and what are their emissions laws. Time for a trip down a rabbit hole.

I looked into getting one of these or converting my own car to be gasoline and methane about 15 or 20 years ago. Here's what I learned during that time. I don't know if any of this legal information is out-of-date now. During the really early days of bi-fuel cars, homebrew cars were very bad polluters because they'd skip the emmisions systems altogether. This changed when the law was put in place requiring catalytic converters on all cars that burned gasoline.

The challenge then with a bi-fuel car was you needed to build an emissions system that is compatible with two entire different fuels, with different combustion products. That is not a small challenge. This is fine for the gasoline side, however, there isn't really a catalytic converter for methane because the exhaust gasses were actually cleaner than exhaust from a gasoline engine even after passing through the catalytic converter. So there was no market to create a cheap methane catalytic converter because it would have been nearly useless. The law didn't care though and there was no exception for bi-fuel cars.

There WAS an exception in the law for methane only cars, which is why you could actually buy methane (CNG) cars from major manufacturers like the Honda Civic GX:

source

If you wanted to buy a used one of these, you can still find them and fill your CNG tank from your home's natural gas line.

Autotrader link showing Honda Civic GX for sale