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I am thinking BLUE

October 27, 2008
Alternate Fuels Technologies, Inc

PROPANE FUEL ALTERNATIVE
While you are in the middle of converting your lawn mower to driverless operation, it would be patriotic of you to also convert it to one of the alternative fuel sources, to get away from gasoline. Pictured here are four different kits you could use to convert your robot's small engine to Propane. Conversion costs between $500 and $1,200 depending on what you already have. Small engines power the cybernetic exoskeletons that universities are building for DARPA. Their specification is right out of the book Starship Troopers by Robert A. Heinlein , not the movie version which does not feature the exoskeleton. In the book, troops can run faster, jump higher, and lift heavy loads, while wearing an exoskeleton. The exoskeleton in the book can walk itself and the operator back to the medical tent if the operator is injured or killed - which is not listed in the DARPA spec but people working on the real ones are considering that as a feature. There is an exoskeleton weight lifting contest promoted by several schools if you want to get involved. 



CNG - high
When people talk about compressed natural gas - the blue diamond, they mean the high pressure version, 2,000 psi to 3,000 psi. These are scuba tank like pressures and do not liquefy the gas. The gas is inhaled by the carburetor at very low pressures, measure in inches of water rather than pounds per square inch. The equipment is pricy but there is a low pressure, less expensive alternative that might work for you, if you have natural gas already piped to your shop. In California, PG&E charges approximately $1.40 per therm, equivalent to about $1.78 per gasoline gallon, for CNG used as a motor fuel. (Electric at $0.18 per gasoline gallon equivalent sure looks good, but this story is about Propane vs. CNG) 


CNG - low
The alternative, using lower pressure and less expensive equipment is CNG under 300 psi. One of the low-pressure Compressed Natural Gas systems used by a local steel shop as inexpensive cutting gas, which is typical of other low-pressure CNG systems is equipment is made by G-TEC. G-TEC Refuelers fill up to four Adsorbed Natural Gas cylinders to 275 psi, and then automatically shut off when finished. You can fill cylinders anywhere in your shop; no special cage or ventilation system is required. No permit or license required. Refueler 60 fills cylinders at 60 SCFH ($3,100) and Refueler 180 fills cylinders at 180 SCFH ($6,750).


BLUE CYLINDERS
These special blue cylinders are packed with adsorbent charcoal to store large quantities of natural gas at only 275 psi. There is no limit on withdrawal rates and G-TEC cylinders can be used in any position…standing straight up or lying on the side in a pickup truck. G-TEC cylinders use a standard CGA 510 fitting so you can keep using the regulators you already own. Best of all you can refill your own cylinders with a Refueler 60/180 or DM-60 Torch Booster/Refueler anytime from the natural gas line that your building is already connected to for heating.  No need to keep an expensive fuel gas inventory. G-TEC cylinders hold 130 cf ($590), 45 cf or 14 cf of natural gas. G-TEC Adsorbed Natural Gas cylinders are approved by the United States Department of Transportation and Transport Canada. Oh yes, the manifold to connect four cylinders up at one time to the compressor is $400.

PROPANE vs. CNG (low)
I have used and worked with both before. I like the idea that natural gas is already being distributed to nearly every building and you can fill your own tanks at home. It is very clean burning and can be used in place of gasoline in many applications. Before I recommend it to the Crown Golf Course as a replacement for the $35,000 worth of gasoline that they buy each season, I need to run the figures again, this time with actual quotes for actual part numbers I need to buy, plus shipping costs, and estimated delivery times. Whatever I find works best on paper, I will test in the spring by converting one mower to see the real world results. The results will determine if I convert the other 12 engines or not. These are the same mowers that I want to convert to driverless operation as soon as possible. Cutting the fuel cost in half would go a long way toward buying guidance system parts. 

GO ROBOTS !

Paul F. Grayson - Chief Engineer
AMERICAN INDUSTRIAL MAGIC, LLC
Racing to build technology that saves soldier's lives.
390 4-Mile Rd. S.
Traverse City, MI 49686-8411
(231) 946-0187, (231) 883-4463 Cell
pgrayson@aimagic.org
AIM: http://aimagic.org
Robot Club: http://tech.groups.yahoo.com/group/robotcluboftraversecitymi/
CE Magazine: http://www.controleng.com/blog/1180000318.html
pfg: (s),(l), tt

Posted by Paul Grayson on October 27, 2008 | Comments (0)