Chapter 3 presents specific information for the conversion of an air-cooled Volkswagen
engine (circa 1980). (See link at bottom)
It is understandable that people may want to use an older engine for this experiment. There is the risk, however, of problems
due solely to worn-out parts developing after the car is converted. It is important to be able to distinguish these from problems
that may be due to the ethanol or to an error in modification. So it is recommended that the engine selected for modification
be in the best condition possible.
The first question to consider in approaching engine conversion is whether there are
any materials in the fuel system or related systems that will be damaged by ethanol. It would be most unfortunate to pour
ethanol in your tank and have parts of the carburetor dissolve.
Metals commonly used in fuel systems are usually ethanol-compatible.
Magnesium is known to suffer severe corrosion when in contact with ethanol. Fortunately, it is rarely found in fuel systems.
Among non-metals, cork does not fare well with ethanol. Polyurethane and fiberglass-reinforced polyester have also been known
to deteriorate in ethanol. Avoid plastic fuel filters - the glass ones are preferable. Aside from these items, non-metal problems
with ethanol are unlikely.
Take your fuel pump and carburetor apart and clean them; soak them for a month in 180-190 proof ethanol. (If you can't afford
to have your car apart that long, pick up used parts from an auto wrecker.) Likewise, soak a fuel filter and a piece of fuel
hose. Agitate the container from time to time. When the time is up, look for pitting or corrosion of metals. Check non-metals
for softening, hardening, cracking, or change of size, shape, or weight.
If preliminary tests indicate materials problems, consult your local auto parts store, carburetor specialty shop, racing supplier,
or machinist regarding suitable replacements.
It may be that some fuel system parts will deteriorate slowly in service. Be alert for this possibility as you are running
the vehicle on ethanol. Also, impure fuel can cause unanticipated difficulties. Beware especially of overly acidic fuel (pH
less than 6)
It is also important to watch parts peripherally related to the fuel system that may be exposed to ethanol vapors, such as
vacuum advance diaphragms, automatic transmission modulators, and power brake assist units. Problems here are unlikely but
worth watching for.
Because ethanol is a dirt loosener, it will free dirt that has accumulated throughout the fuel system. For this reason it
is important to install a fuel filter before the pump, and another between the pump and the carburetor. Use the cleanable
type, and check it often in the first weeks of ethanol use.
Finally, note that ethanol spilled on the vehicle paint finish
may have adverse effects. Paint softening and wrinkling have been experienced in some cases.
The carburetor meters the flow of fuel to the cylinders and mixes the fuel with air. Because ethanol supplies less energy
per unit of volume than does gasoline, fuel-metering jets must be enlarged to allow the proper amount of fuel to pass.
There
are many carburetor designs in use, and it is not possible here to give specific directions for all. It will be necessary
for you to experiment in the context of the guidelines provided here.
Start by calculating the factor by which your jets must be enlarged. The formulas in Appendix B indicate that jet diameters
for gasoline should be multiplied by 1.27 for pure ethanol (200 proof). Most people, though, will be using 180-190 proof.
Unfortunately, the formulas do not seem to give accurate answers for hydrous ethanol. Start out about five per cent larger
than the figure you calculate.
Obtain a carburetor rebuild kit, which will include a detailed diagram of your unit. Clean and overhaul the carburetor since
you will have it apart anyway. Identify all fuel metering jets, including: main jet, pilot (idle) jet, and accelerator pump
nozzle.
Most jets are stamped with the orifice diameter in metric or English units. On a metric carburetor, a number such
as 120 means 1.2 mm.; on most U.S. units, 50 indicates .050 inch. There are exceptions; check with a carburetor shop to be
sure. Convert millimeters to inches by dividing by 25.4.
Multiply your jet sizes by the conversion factor. Obtain new jets of the proper size, if available, from a parts or racing
equipment supplier. Often they will not be available, and you will have to drill out the old jets yourself. Determine the
proper drill bit sizes from the chart in Appendix C. Obtain the bits and a pin vise from a tool supplier. Do not use an electric
drill. Carefully enlarge the jet, wash it, and blow it clean with compressed air.
Some carburetors incorporate a staging
adjustment for the accelerator pump. This controls the duration and quantity of fuel injection from the pump. In addition
to enlarging the nozzle, lengthening the pump stroke may help.
Because ethanol is 7 to 8 per cent heavier than gasoline,
it may be necessary to adjust the float setting to maintain the proper level of fuel in the float bowl. Otherwise the fuel
level will be too low. Bend the float up slightly or use a thinner gasket under the needle seat. As an alternative, find a
slightly heavier float.
On cars with automatic chokes, adjust the choke unit to a winter setting. When the engine is running again, adjust the idle
and mixture screws.
Carburetor modifications, especially jet sizing, will be a matter of some trial and error. With jets
it is better to start small and work up. If you go too far, you can buy a new jet and try again. You can judge your results
by comparing power and CO emissions with gasoline operation. Both should be similar. Power is also affected by other factors,
as we shall see.
Below 60-65 degrees F., ethanol will not vaporize sufficiently to form a combustible mixture. The simplest way to start a
cold engine is to inject a more volatile fuel into the intake manifold or carburetor. Gasoline and propane are good candidates.
Straight ether is not recommended, but there are ether formulations - used for starting diesels--in which the tendency of
ether to explode all at once is modified.
A gasoline cold-start system consists of the following components: Fuel tank. A one-gallon motorcycle tank will do. Install
it in the trunk where it is well protected in case of accident and away from engine heat. Secure it well.
Fuel line. A metal tube runs from the tank to the engine. Install it so nothing rubs against it. An in-line fuel filter should
be installed near the tank.
Pump. An electric or manually controlled pump should be installed in the line where convenient. You will need a switch or
other control on the dashboard. Beware of pumps not designed for gasoline, such as windshield washer pumps. The plastic and
rubber parts may degrade when used with gasoline.
Nozzle. Connect the fuel line to a small nozzle with an opening about the size of the accelerator pump orifice in the carburetor.
This nozzle can be installed in the air cleaner, pointing straight down the carburetor throat, or in the intake manifold.
A propane system is constructed as follows: Fuel tank. Buy a propane-torch kit, which includes the tank and a pressure control
valve. The orifice in the tube, after the valve, should be drilled out somewhat to allow an adequate flow of propane. Mount
it away from the engine compartment.
Control valve. Propane is stored at high pressure - over 200 psi - so a special electric
valve is required to control it. This is available from a valve supply shop. It is recommended that the valve be brazed to
the neck of the pressure control piece to insure against leaks. A switch on the dashboard, preferably with a warning light,
is wired in to activate the valve.
Fuel line. Tightly clamp a fuel hose to the electric valve and connect it directly to the intake manifold or carburetor in
a convenient place.
Note: With either the gasoline or propane system, inject fuel for just a few seconds, while starting
the cold engine. It will run on ethanol alone almost immediately.
Preheating engine coolant is an alternative approach. In engines that incorporate a water-heated manifold, a small electric
water heater installed as close to the manifold as possible will improve cold starting. Such heaters are often used on gasoline
engines in cold climates and are commercially available. Of course, you have to plug it into the wall and wait.
Improved spark quality, as discussed below, also aids in cold starting.
This is the link to Roger Lippman's book on converting your car to run on ethanol.
How Does Ethanol Fuel Differ from Gasoline? For more Information: * Fuel-Cycle Fossil Energy Use and Greenhouse Gas Emissions
of Fuel Ethanol Produced from U.S. Midwest Corn, by M. Wang, C. Saricks, and M. Wu (full paper, 457kb pdf)
|
| Ethanol-powered Le Mans race car, team Nasamax's DM139 LMP1 |
Suffolk, United Kingdom - July 28, 2004
The description might sound like a bad joke, but the DM139 LMP1, Judd V10 is fast and black and "green" all
over. So fast, in fact, that the Nasamax racing team placed 17th out of 26 cars to finish at this year's Le Mans 24 hour race
with the DM139, which runs entirely on bio-ethanol fuel. It was the second year the team qualified for international motor
sport race, but the first year the drivers took it to the line to become the first team to place with a car run on alternative
fuels.
"It's very interesting out there. There are people flying off all over the place, perhaps a few who are new to Le
Mans," night driver Werner Lupberger said.
The Kent, England based team has a core of experienced scientific and racing personnel who belong to an international
racing program designed to promote low-emission renewable fuels. Motor sport racing is a big industry and a big fuel consumer,
and not what many people think of as environmentally friendly.
Development partners for the green fuel venture are Applied Sciences Technologies (ASTEK) and Cosworth Racing. ASTEK is
a research and development company that specializes in renewable and sustainable technologies. They have developed technology
for the use of alternative fuels in internal combustion engines, and methods for the production of bio-ethanol from cellulosic
materials. Fuel for the DM139 engine is made from sugar beets and potatoes grown in Northern France.
Cosworth Racing is a division of the Ford Motor Company, and they designed, developed and manufactured the XDE engine
used by the Nasamax team. They are renowned for their Formula One engine development for teams such as Jaguar and Jordan as
well as for the WRC Rally program.
"This is the first time for years Cosworth Racing has been involved on a factory support basis in sports cars. It
also marks the first time we have used renewable fuel, bio-ethanol, in a racing engine and it is very exciting to be spearheading
this technology," said Nick Hayes, Managing Director for Engineering at Cosworth Racing.
Cars that qualify for the LeMans have to meet race regulations, so the Nasamax team had to work on ways to meet the regulations
while ensuring the DM139 could compete with the other cars in terms of tank capacity and fill rate during refueling. Bioethanol
fuel contains only 75 percent of the energy of the same volume in gasoline, so the car needed 135 liters of tank capacity
to carry more of their 200 proof fuel than a standard racecar.
Information on the team's Web site used a comparison of coffee and espresso to explain why a greater volume of ethanol
(coffee) is necessary to run the DM139 for the same amount of time as a car run with fossil fuels (espresso). An espresso
carries a certain amount of caffeine in a small quantity of drink, while regular coffee will carry the same amount of caffeine
but in a greater quantity of the drink. If caffeine intake were the goal, then a person would need to drink more coffee than
espresso. If fuel combustion is the goal, then a driver needs more ethanol because the efficient fuel burns up faster than
fossil fuels.
Engine performance with ethanol was everything the team could have asked for, but regular racing setbacks kept the car
from moving up any higher in the race ranks. Regular tire changes, a starter replacement and a persistent misfire made the
team lose laps.
"We lost time trying to find the misfire and eventually we had to just get on with it," McNeil said. "It's
frustrating as we know what lap time we could have had, and we know it would have put us safely in the top ten, even the top
six. However, these were the usual setbacks any car could have in racing, and we have still shown that this fuel can be competitive
in the top level of international motor sport. To do so with a new racing car to completely new regulations is also a major
achievement for the whole team. We will be back next year."
The three drivers completed a total of 316 laps around the 8-mile race circuit at Le Mans. McNeil estimated they lost
about 41 laps to pit stops for the misfire. Le Mans takes place every year in the Sarthe region south west of Paris, and has
always been a showcase for the debut of new technologies in the harshest competitive environment in motor sport. The 8-mile
circuit is a mix of permanent track and roads.
Information for this story courtesy of Nasamax public relations
Porsche
