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In India, a hack conversion (not approved by government) costs about $200 in parts + labor (not including the tank). And yes they use a domestic gas tank (simil

by awa 17y ago

In India, a hack conversion (not approved by government) costs about $200 in parts + labor (not including the tank). And yes they use a domestic gas tank (similar to barbeque grill tank) kept in the trunk.

mmt 17y ago
It's important to note that LPG (liquefied petroleum gas, mostly propane) is very much not the same thing as CNG (compressed natural gas) from an engineering perspective. CNG tanks have to keep much higher pressures and are therefore quite a bit more expensive. As a previous commenter noted, $2k-$3k just for the tank is about right, at least for a new, light unit. If you're willing to go the solid steel route, you can probably still get something old and heavy [1] for under $1k, but good luck finding capacity at under $100/GGE (gasoline gallon equivalent). Lastly, there's the safety question. Currently, CNG cars have remarkably good real-world crash experience. I don't believe there's a single tank burst or fire in a collision [2]. I'd be curious to know if other countries, with more lax regulations, have as good safety statistics. TANSTAAFL LNG (liquefied natural gas) is also quite different from LPG. I've looked into it, if only as an emergency reserve fuel tank. Turns out that to store it indefinitely requires refrigeration (or, presumably, absurd amounts of insulation), else it'll boil off, escaping out the pressure relief valve installed in the tank for just such an eventuality. Fortunately, like a pot of water on a stove, it doesn't all boil off at once, so there's little risk of leakage if one always uses enough vapor to keep the pressure down. [1] To the tune of hundreds of pounds. This is less likely to be a concern for converting trucks, but I notice a fuel economy difference carrying just one adult passenger in my Civic GX. [2] I haven't looked this up in the last 3 years or so. Corrections/updates are appreciated. Edit: added paragraph on LNG.
- awa 17y ago
  http://www.business-standard.com/india/news/%5Ccng-conversion-to-help-autorickshaw-owners%5C/184257/ http://www.business-standard.com/india/news/%5Ccng-conversio... CNG conversion kits costs about Rs 20000 (approx $400) according to the above article
  - mmt 17y ago
    That's for autorickshaws, which are closer to a motorcycle than an automobile. The fuel economy quoted in the article (40km/kg) is around twice that of my Civic GX (30mile/GGE=30mile/5.660lb=30mile/2.567kg=51.5km/2.567kg=20km/kg), which is consistent with motorcycle numbers. They also quote an autorickshaw traveling around 100km per day. Since the Civic with an 8GGE tank has a 400km range, the autorickshaw tank would need to be 1/16th the size. Assuming tank costs are linear and a new 8GGE tank is $3k, that puts the rickshaw tank at under $190. I suspect the non-tank portion will also scale at least linearly with number of cylinders. Assuming a single-cyclinder motorcycle engine and 4 cylinder car, that runs the price up to $4k total, which, unsurprisingly, is still cheaper than here in the US but not by $10k.

by awa 17y ago

mmt 17y ago

It's important to note that LPG (liquefied petroleum gas, mostly propane) is very much not the same thing as CNG (compressed natural gas) from an engineering perspective. CNG tanks have to keep much higher pressures and are therefore quite a bit more expensive. As a previous commenter noted, $2k-$3k just for the tank is about right, at least for a new, light unit. If you're willing to go the solid steel route, you can probably still get something old and heavy [1] for under $1k, but good luck finding capacity at under $100/GGE (gasoline gallon equivalent). Lastly, there's the safety question. Currently, CNG cars have remarkably good real-world crash experience. I don't believe there's a single tank burst or fire in a collision [2]. I'd be curious to know if other countries, with more lax regulations, have as good safety statistics. TANSTAAFL LNG (liquefied natural gas) is also quite different from LPG. I've looked into it, if only as an emergency reserve fuel tank. Turns out that to store it indefinitely requires refrigeration (or, presumably, absurd amounts of insulation), else it'll boil off, escaping out the pressure relief valve installed in the tank for just such an eventuality. Fortunately, like a pot of water on a stove, it doesn't all boil off at once, so there's little risk of leakage if one always uses enough vapor to keep the pressure down. [1] To the tune of hundreds of pounds. This is less likely to be a concern for converting trucks, but I notice a fuel economy difference carrying just one adult passenger in my Civic GX. [2] I haven't looked this up in the last 3 years or so. Corrections/updates are appreciated. Edit: added paragraph on LNG.

awa 17y ago
http://www.business-standard.com/india/news/%5Ccng-conversion-to-help-autorickshaw-owners%5C/184257/ http://www.business-standard.com/india/news/%5Ccng-conversio... CNG conversion kits costs about Rs 20000 (approx $400) according to the above article
- mmt 17y ago
  That's for autorickshaws, which are closer to a motorcycle than an automobile. The fuel economy quoted in the article (40km/kg) is around twice that of my Civic GX (30mile/GGE=30mile/5.660lb=30mile/2.567kg=51.5km/2.567kg=20km/kg), which is consistent with motorcycle numbers. They also quote an autorickshaw traveling around 100km per day. Since the Civic with an 8GGE tank has a 400km range, the autorickshaw tank would need to be 1/16th the size. Assuming tank costs are linear and a new 8GGE tank is $3k, that puts the rickshaw tank at under $190. I suspect the non-tank portion will also scale at least linearly with number of cylinders. Assuming a single-cyclinder motorcycle engine and 4 cylinder car, that runs the price up to $4k total, which, unsurprisingly, is still cheaper than here in the US but not by $10k.