BRAZIL'S ALCOHOL-POWERED CAR

>From Mother Earth News: Issue #66 - November/December 1980

http://motherearthnews.com/library/1980_November_December/Brazil_s_Alcohol_P
owered_Cars

BRAZIL'S ALCOHOL-POWERED CAR

Earlier this year, the Brazilian auto industry began marketing
alcohol-powered vehicles. But, surprisingly enough, fuel from farms isn't
new to that nation's motoring scene. In fact, a minimum of 5% alcohol has
been blended with the country's pump gasoline - though somewhat erratically,
because of variations in the sugar cane harvest - since 1931! And, as a
result of the nation's adoption of a "pro-alcohol" program in 1975, as much
as 20% of each gallon of auto fuel now sold in Brazil is pure ethanol.

The gasoline blends never affected the motor industry directly, because a
standard car needs no engine modification in order to burn such hybrid
fuels. But in light of the government's ultimate goal of replacing petrol
completely with 185-proof alcohol, Brazilian auto companies suddenly found
themselves faced with a major decision: either develop alcohol-powered cars
.. . . or lose much of their market.

THE SOLUTIONS

MOTHER's editors visited with representatives of General Motors and
Volkswagen of Brazil to determine precisely what the industry had done to
produce reliable ethanol-burning cars and trucks. Naturally, each factory
had its own way of satisfying the technical requirements set by its
engineers, but - predictably - the mechanical alterations themselves were
virtually identical for every motor manufacturer . . . which serves to
reaffirm the fact that alcohol fuel technology is now well beyond the "by
guess and by gosh" stage.

The automakers directed their attention toward eight areas of modification:

[1] Increasing the compression ratio. Since the "octane" rating of ethanol
is well over 100, engine compression can be raised to take advantage of the
fuel's antiknock qualities. Although the alcohol/ water blend is capable of
withstanding a 15-to-1 ratio, the factory-produced ethanol engines don't
exceed 10.5 to 1 . . . since costly forged components would be required to
do so, and because fuel mileage figures don't increase appreciably when
compression is raised to the upper end of the possible scale.

[2] Preheating the intake air. In order to help vaporize the alcohol, heated
air (up to 210°F) is taken from a jacket surrounding the engine's exhaust
manifold and directed into the air filter shroud. This flow is controlled by
a vacuum-sensitive valve that provides cooler ambient air - at wide open
throttle - to prevent ignition ping and deliver a denser fuel mixture charge
under acceleration.

[3] Heating the intake manifold. Again, this change helps alcohol fuel to
vaporize efficiently. In water-cooled engines, hot water is routed through
chambers in the manifold walls . . . in air-cooled models, the intake
"runners" are simply shortened to a minimum to reduce heat loss.

[4] Recalibrating the carburetor. Because the ideal air/fuel mixture for
ethanol is 9 to 1 (as opposed to 14 to 1 for gasoline), the main jet, idle
circuit, power valve, and - in some cases - the accelerator pump stroke have
to be modified to supply more fuel to the engine. (Certain carburetors must
also have their internal passageways bored.)

[5] Hardening the valve seats. Since alcohol doesn't contain the lubricating
elements that gasoline does (although the presence of water in the fuel does
help compensate for this lack), the engine's valve seats are
induction-hardened or fitted with stainless steel inserts. [EDITOR'S NOTE:
Cars built in the U.S. since the early 1970's are already so equipped, and
older cars "weaned" on leaded gasoline have likely absorbed enough lubricant
to provide a suitable cushion.]

[6] Modifying the fuel system materials. Ethanol, especially in the presence
of water, may cause eventual corrosion in various parts of a conventional
fuel system. To forestall that problem, the fuel tank and pump and
carburetor bodies are lined with a thin bronze coating in place of the
lead/zinc veneer which is normally applied at the factories.

[7] Making ignition changes. Because of the antiknock qualities of hydrated
alcohol, initial timing is advanced from 4 to 8° over normal settings. In
addition, the distributor advance curve is recalibrated . . . to take
advantage of the fuel's high "octane" during times of heavy acceleration. A
high-intensity ignition coil is also used - along with "hotter" spark
plugs - to help overcome the ethanol vapors' resistance to ignition.

[8] Constructing cold-start systems. Since alcohol's reluctance to vaporize
is accentuated in cool weather, the ethanolpowered vehicles are fitted with
starting aids for cold engines (which are used at temperatures below 55°F or
so). Direct gasoline injection down the throat of the carburetor is common
now, but alternative methods (based on increased fuel vaporization and
auxiliary heating) are currently being researched so that only one form of
liquid energy - alcohol -will be needed to operate the car.

Our test drive in an alcohol-powered Chevy sedan - despite our eager
anticipation - proved rather unexciting . . . not through any fault of the
car, but because the excursion was virtually no different from a spin in any
conventional automobile. And if it hadn't been for the slight, sweet odor
noticeable at the rear bumper, we'd never have known we were operating a
renewable-fuel-powered vehicle! The only drawback of such cars seems to be
that they use about 15 to 20% more fuel than their gasoline-powered
counterparts . . . though this increased consumption is offset by the fact
that Brazilian ethanol is about 30% less expensive than is the petroleum
derivative. On the positive side as well, the fledgling autos boast standard
warranties and maintenance schedules, and initial vehicle costs are in line
with conventional cars.

AND TO THE FUTURE?

Naturally, the Brazilian government is doing all it can - by monitoring
alcohol quality and offering reduced licensing taxes and easy credit terms -
to promote the purchase and use of the new models. But responsibility still
falls on the manufacturers to improve fuel economy and reduce exhaust
emissions (which, though already far below the levels spewed out by gasoline
engines in that country, still concern a growing number of ecology-conscious
Brazilians).

In the meantime, don't be surprised if you start to hear a lot more in the
coming months about what's being done in South America (and perhaps what
should be done in North America!) to ease the energy crunch!fs



.

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