Quote:
Originally Posted by roflwaffle
The reason why I've shied away from similar in the past has been that a diesel generator tends to only weigh a hundred pounds or so less than a small diesel engine and transmission and puts out far less peak power with similar or less efficiency. That being said, since ya got it already, am efficiency hit really won't matter much on WVO.  I think this would be your best bet IMO from the POV of emissions.I know on straight propane they're pretty good, something like 1g/hp-hr for NOx+NMHC, which is similar to what gasoline passenger cars are at AFAIK. This is w/o any emissions systems that I know of. Since most emissions for a gasoline powered vehicle are during startup when cold, I imagine a LPG/CNG diesel or gasoline engine would be cleaner if tuned properly. As for propane injection, if it's anything like Hydrogen injection it's supposed to result in a larger drop in emissions, although I don't think it would be better than just LPG/CNG. |
All good points. I was amazed to find that the 100+hp VW TDI engine only weighed twice the 10hp diesel. Perhaps that would be the ultimate system, a small lightweight turbocharged diesel coupled to the transmission, with an electric motor assist and idle stop. You cut out the generator ineffeciency and weight, and reduce the peak requirements of the electrical system saving even more weight. Maybe next time.
"propane is about 91,000 Btu per gallon so its not less expensive esp. if you add road tax.
Does your generator have to run at a certain frequency?
Turbo gets more power from smaller engine but is only more efficient if you can use most of that power. What is the compression ratio of your engine? And are the pistons oil cooled?"
I guess in this situation I'm trading price for the ability to get away with little/no emissions system and still have a relatively clean exhaust. Hopefully I will only be using <1gal / 100 miles so I'm still doing much better than the 30mpg of gasoline I burn currently.
Frequency is totally unimportant for me, each pulse is just getting dumped into the buffer of the battery bank before being consumed by the motor. I guess higher frequency may be slightly more efficient, but pretty negligable.
I bought a generator head rated to make use of ~20hp engine, so every hp over the stock 10 I can make will be capable of becomming more watts for propulsion. I tried to find the compression ratio but I don't see it listed anywhere, perhaps the documentation I get with the engine will be more detailed. From looking at similar engines I would guess between 20:1 and 23:1