Natural Gas for Automobiles

by Virgil Soule. 0 Comments

In their on-going search for a perpetual-motion machine, auto manufacturers are experimenting with all kinds of propulsion schemes designed to use less gasoline. The goal, of course, is to use no gasoline at all while still producing Interstate-highway performance for commuting.

High-performance electric cars that meet this requirement are in production and are on the horizon. The current drawback is that electrics are rather expensive.

Gasoline-electric hybrids like the Toyota Prius have been in production for ten years now. In the original Prius design still in production, the gasoline engine is the primary source of power. The electric side provides extra power for acceleration and hill climbing, which saves gas. On level ground or going downhill, the gasoline side charges the batteries. All of this is carefully balanced and the Prius delivers an honest 50 – 60 mpg.

Electric-gasoline hybrids like the Chevy Volt turn this around. The car is primarily electric and uses no gasoline at all for the first 40 miles. When the battery runs down, the gasoline engine kicks in to power the car and recharge the battery.

From a “green” point of view, the advantages of electric and electric-gasoline hybrids are debatable. Despite claims to the contrary, electrics do produce carbon dioxide. They just do it remotely at the generating stations producing the electricity they use. The electrical energy required to charge the batteries comes off a grid that is still mostly supplied by coal-fired power plants.

For about ten years now, car manufacturers have been experimenting with compressed air motors for propulsion. Instead of internal combustion, these motors use high-pressure air from a tank to produce power at the wheels. Like electric vehicles, compressed-air vehicles must return to an air compressor for a recharge every 40 miles or so. To overcome this limitation, the French company, Peugeot-Citroen, has developed a compressed-air/gasoline hybrid scheme. A gasoline-engine-driven compressor is included in the design to supplement air coming from the tank and also recharge the air in the tank.

From an engineering point of view, hybrid systems are kluges (rhymes with luge or rouge). They’re complicated, cobbled-together mixtures of machinery that work but not ideally so.

The modern gasoline engine is likewise inordinately complex. In the 1940s or 50s engines were simple enough that a 15-year-old kid could overhaul a Chevy, say, using simple basic tools. Kids cobbled together piles of Ford parts into hot rods that worked admirably well. Today’s hot rods must be built by expert mechanics so as to meet emissions standards.

In today’s engines, computers control engine operating parameters like spark advance and fuel-air mixture to optimize power output, fuel consumption, and emissions. The computer also controls transmission shift points for improved gas mileage. Despite all this, the engine still produces oxides of nitrogen, which must be broken down by a converter that uses expensive platinum as a catalyst.

We could return to the simpler, cheaper engines of the 60s and 70s simply by switching to a more elemental fuel, namely, methane or natural gas. Catalytic converters would no longer be required because natural gas engines only emit water and carbon dioxide. Fueling stations taking gas off a home’s natural gas supply have been marketed. Farm stores nationwide sell bulk propane and liquefied natural gas. As a fuel natural gas is equal or superior to gasoline.

With modern materials high pressure gas tanks can be fitted in where gasoline tanks are now placed. With careful engineering they can be made crashworthy.

Fork-lift tractors burning propane have been in use in factories and warehouses for decades. These machines can be safely operated indoors because they produce no carbon monoxide or other noxious gasses.

The Montgomery County Ride-on and DC Metrobus systems already have LNG-powered buses in service.

The potential for natural gas fuel is already being realized. The country is seeing the beginning of a boom in natural gas availability and price. The transition to methane-powered automobiles is simply a matter of marketing.



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