Hampshire, has developed a computer-controlled engine that operates intermittently, driving a fixed-volume hydraulic pump/motor," (Lynch 66).Shown above, an ICE is no longer required to power a vehicle. In the November issue of Popular Science, a fuel delivery system was overviewed; developed by an Italian auto maker, it uses an existing gasoline ICE, but adapts the fuel tank and fueling port to accept propane, methane/natural gas, and gasoline. The tank can be running low on gasoline, and the car fueled with natural gas or vice versa! Natural gas is an alternative fuel with the added bonus of cleaner and more complete combustion and thus emissions of carbon dioxide and water as opposed to hydrocarbons. Natural gas does seem a promising alternative. Currently there are an estimated one million natural gas vehicles in service, many of them used by natural gas companies, as city busses, and 250,000 of them used in Italy alone (Birch, 26). A CNG (compressed natural gas) vehicle currently emits less toxic fumes than do gasoline powered vehicles. For comparison, a CNG vehicle emits 8 lb/Yr. "ozone precursors," (Derr, 31). CNG vehicles are one of the most viable alternative options in the U.S. due to our country's huge supply of natural gas which could power autos for decades to come (Reed, 74). Also, natural gas would be cheaper to purchase than gasoline (Moore, 92). As of 1999, there were an estimated 30,000 NG autos in use in the U.S. (Reed, 74) The natural gas option is certainly not without its drawbacks. The most significant drawback would be a retrofit of existing vehicles with high pressure tanks. Retrofit costs are estimated to be $1500 to $3000 by Gene Moore, a fleet manager in Sacramento, California (Moore, 92). New CNG vehicle cost, detailed by Kenneth Derr, CEO of Chevron, in a speech, and estimated by the the U.S. Department of Energy, is $2500 to $5000 more than a "conventional car," (Derr, 31). "Natural gas needs to be highly...
