bi-fuel vehicle - wikipedia, the free encyclopedia

The Brazilian Fiat Siena Tetrafuel 1.4 is

the first bi-fuel car that runs with

natural gas (CNG) alternating

automatically with any of the typical

fuel blends used in flexible-fuel

vehicles, pure gasoline, or gasohol E25,

or just ethanol (E100). Shown below

are the CNG storage tanks in the trunk.

Bi-fuel vehicleFrom Wikipedia, the free encyclopedia

Bi-fuel vehicles are vehicles with multifuel engines capable of running

on two fuels. On internal combustion engines one fuel is gasoline or

diesel, and the other is an alternate fuel such as natural gas (CNG),

LPG, or hydrogen.[1] The two fuels are stored in separate tanks and the

engine runs on one fuel at a time, unlike flexible-fuel vehicles ("dual-

fuel"), that store the two different fuels mixed together in the same

tank, and the resulting blend is burned in the combustion chamber.

Bi-fuel vehicles have the capability to switch back and forth from

gasoline or diesel to the other fuel, manually or automatically.[2][3][4][5]

The most common technology and alternate fuel available in the market

for bi-fuel gasoline cars is Autogas (LPG), followed by natural gas

(CNG),[6] and it is used mainly in Europe. The Netherlands or the Baltic

states have a large number of cars running with LPG. Italy currently has

the largest number of CNG vehicles, followed by Sweden. They are also

used in South America, where these vehicles are mainly used as

taxicabs in main cities of Brazil and Argentina. Normally, standard

gasoline vehicles are retrofitted in specialized shops, which involve

installing the gas cylinder in the trunk and the LPG or CNG injection

system and electronics.

Contents

1 Vehicles

1.1 Factory bi-fuel passenger cars

1.2 Factory bi-fuel pickups

2 Diesel conversions

2.1 Low and middle speed conversion

2.2 High speed conversion

3 Common conversion features

4 Gas types used

5 What is a reachable diesel/gas ratio?6 See also

7 References

8 External links

Vehicles

Aftermarket 'bi-fuel' and even 'tri-fuel' conversions and are also available.

Factory bi-fuel passenger cars

Bi-fuel vehicle - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Bi-fuel_vehicle

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Low Speed Conversion

Fiat Punto[7]

Fiat Siena Tetrafuel, with a gasoline flex-fuel engine and natural gas (CNG).[8][9][10]

Holden Commodore dual-fuel (LPG/petrol)Chevrolet Cavalier

Ford Contour

Mazda RX-8 Hydrogen REPremacy Hydrogen RE Hybrid

Chevrolet SPARK BiFuel

VW Polo BiFuel (LPG/petrol)VW Golf BiFuel (LPG/petrol)

Factory bi-fuel pickups

Chevrolet Silverado

Ford F-150, F250

Diesel conversions

Because diesel engines are compression ignition engines, and lack spark plugs, to operate a diesel engine with an

alternate combustible fuel source such as Natural gas as the main fuel diesel oil is used for the ignition of the

gas/air mixture inside the cylinder (a portion of diesel oil is injected at the end of the compression stroke,

thereby maintaining the original diesel operation principle).

Dual fuel operation means the engine uses two fuels (gas and diesel oil) at the same time, as opposed to Bi Fuel

which would mean the engine could have the option of using either fuel separately.

There usually two type of conversions - low speed (below 1000 RPM) and high speed (between 1200 and 1800

RPM).

Low and middle speed conversion

How it works

Gas is injected into the cylinder inlet manifold by individual gas

electromagnetic valves installed as close to the suction valves as

possible. The valves are separately timed and controlled by injection

control unit. This system interrupts the gas supply to the cylinder during

the long overlap of the suction and exhaust valves (just typical for

slow-speed and medium-speed engines within the valve overlap

cylinder scavenging is performed). This avoids substantial gas losses and

prevents dangerous gas flow to the exhaust manifold.

This conversion is adjusted for low speed engines up to 1000 RPM.

System for conversion of industrial diesel engine to Bi-fuel operation by substitution of 70-90%

natural gas for diesel or HFO.Gas is injected directly before intake valve by high speed electromagnetic injector, one or two injector

per each cylinder.

High speed conversion


2 of 5 9/1/2011 10:13 AM

High Speed Conversion

How it works

Gas is mixed with air by a common mixer installed before

turbocharger(s). Gas flow is controlled by a throttle valve, which is

electronically operated by the special control system according to the

required engine output and speed. In order to avoid knocking of the

engine, knocking detector/controller is installed, thus enabling engine

operation at the most efficient gas/diesel ratio.

Suitable for all High Speed engines, 1200-1800 RPM.System for conversion of industrial diesel engine to Bi-fuel

operation by substitution of 50-80% natural gas for diesel.

Gas and air are blended behind air filter before turbochargerby central mixer.

Common conversion features

Substantial savings on operation costs

Practically no engine modification requiredNon-derated output power

Fuel flexibility: Possibility of bi-fuel or original pure diesel operations

Safe operations.Lower emissions

Longer engine life span, longer service and maintenance intervals

Gas types used

It is common to use CNG (Compressed Natural Gas) or LNG (Liquid Natural Gas) for bi-fuel operations. Both

are also mostly used for Generator sets conversions, because the engine does not lose the output power.

In recent years biogas is being used. The biogas composition and calorific value must be known in order to

evaluate if the particular biogas type is suitable. Calorific value may be an issue as biogas is derived from

different sources and there is low calorific value in many cases. You can imagine you have to inject sufficient

volume of gas into the cylinder to substitute diesel oil (or, better to say, substitute energy delivered by diesel

oil). If the calorific value (energy) of the biogas was very low, there is a need to inject really big volume of

biogas into the cylinder, which might be technically impossible. Additionally, the composition of the biogas has

to lean towards ignitable gases and be filtered as much as possible of uncombustible compounds such as CO2.

Associated gas is the last type of gas which is commonly used for bi-fuel conversions of generator sets.

Associated gas is a natural gas found in association with oil, either dissolved in the oil or as a cap of free gas

above the oil. It means it has almost the same quality as CNG or LNG.

What is a reachable diesel/gas ratio?

It depends on the technical state of the engine, especially of the injection system. The typical Diesel / Gas ratio

is 40/60% for the high-speed engines. If the operating output of the engine is constant and between 70-80% of

nominal output, than it is possible to reach up to 30/70% ratio. If the operating output is lower (for example 50%

of the nominal output) or if there are variations, the rate is about 45/55% (more of diesel is used). For Low

Speed conversions it is possible to reach the Diesel/gas ratio up to 10/90%.


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Generally, it is not possible to guarantee an exact Diesel/gas ratio without a test being done after the conversion.

See also

Alternative fuel vehicleFlexible-fuel vehicle (FFV or dual-fuel vehicle)

Multifuel

References

^ Diane Nassy. "Flexible Fuel Vehicles" (http://www.motorpoint.com.au/ffv-alternative.asp) . Motopoint.

http://www.motorpoint.com.au/ffv-alternative.asp. Retrieved 2008-08-24.

1.

^ "Glossary" (http://www.biofuelmarketplace.com/(S(mfsz0yfocwuc4lbg2lkdidel))/Anonym

/Glossary.aspx?Letter=1) . Biofuel Marketplace. http://www.biofuelmarketplace.com

/(S(mfsz0yfocwuc4lbg2lkdidel))/Anonym/Glossary.aspx?Letter=1. Retrieved 2008-09-01. See definition of Bi-fuel

Vehicle

2.

^ Dominik Rutz and Rainer Jansen (February 2007). "BioFuel Technology Handbook" (http://www.compete-

bioafrica.net/publications/publ/BioFuel_Technology_Handbook_1vs_WIP.pdf) (PDF). WIP Renewable Energies.

http://www.compete-bioafrica.net/publications/publ/BioFuel_Technology_Handbook_1vs_WIP.pdf. Retrieved

2008-09-01. See definition in Glossary and Abbreviations

3.

^ "Definition of Terms" (http://www.sugre.info/tools.phtml?id=686) . Sustainable Green Fleets.

http://www.sugre.info/tools.phtml?id=686. Retrieved 2008-09-01.

4.

^ "Glossary" (http://www.biofuelmarketplace.com/(S(mfsz0yfocwuc4lbg2lkdidel))/Anonym

/Glossary.aspx?Letter=5) . Biofuel Marketplace. http://www.biofuelmarketplace.com

/(S(mfsz0yfocwuc4lbg2lkdidel))/Anonym/Glossary.aspx?Letter=5. Retrieved 2008-09-01. See definition of FFV

5.

^ Alternative Fuels and Advanced Vehicles Data Center. "Natural Gas Vehicles" (http://www.eere.energy.gov

/afdc/vehicles/natural_gas.html) . US Department of Energy. http://www.eere.energy.gov/afdc/vehicles

/natural_gas.html. Retrieved 2008-09-01.

6.

^ "Fiat website" (http://www.fiat.com/cgi-bin/pbrand.dll/FIAT_ITALIA/carconfig

/carconfig.jsp?BV_SessionID=@@@@0974270220.1208873292@@@@&

BV_EngineID=cccdadedlljimjhcefecejgdfkhdfjh.0&modelKey=1885) . http://www.fiat.com/cgi-bin/pbrand.dll

/FIAT_ITALIA/carconfig/carconfig.jsp?BV_SessionID=@@@@0974270220.1208873292@@@@&

BV_EngineID=cccdadedlljimjhcefecejgdfkhdfjh.0&modelKey=1885. Retrieved 2008-04-22.

7.

^ Christine Lepisto (2006-08-27). "Fiat Siena Tetra Power: Your Choice of Four Fuels" (http://www.treehugger.com

/files/2006/08/fiat_sienna_tetr.php) . Treehugger. http://www.treehugger.com/files/2006/08/fiat_sienna_tetr.php.

Retrieved 2008-08-24.

8.

^ "Nouvelle Fiat Siena 2008: sans complexe" (http://news.caradisiac.com/Nouvelle-Fiat-Siena-2008-sans-

complexe-359) (in French). Caradisiac. 2007-11-01. http://news.caradisiac.com/Nouvelle-Fiat-Siena-2008-sans-

complexe-359. Retrieved 2008-08-31.

9.

^ Agncia AutoInforme (2006-06-19). "Siena Tetrafuel vai custar R$ 41,9 mil" (http://www.webmotors.com.br

/wmpublicador/Noticias_Conteudo.vxlpub?hnid=36391) (in Portuguese). WebMotor. http://www.webmotors.com.br

/wmpublicador/Noticias_Conteudo.vxlpub?hnid=36391. Retrieved 2008-08-14. The article argues that even though

Fiat called it tetra fuel, it actually runs on three fuels: natural gas, ethanol, and gasoline.

10.

External links

"Dual Fuel Organization" (http://www.dualfuel.org) . http://www.dualfuel.org.

"ComAp Conversion Kits Overview" (http://www.comapsystems.com/index.php?idpg=1&IDprod=103&IDbranch=30) . http://www.comapsystems.com/index.php?idpg=1&IDprod=103&

IDbranch=30. Retrieved 2007-12-12.

"Bi-fuel Power" (http://www.energetech.com/bi-fuel-info.pdf) (PDF). http://www.energetech.com


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/bi-fuel-info.pdf. Retrieved 2007-12-12."Conversions of Engines to Dual Fuel" (http://www.cesys.cz) . http://www.cesys.cz. Retrieved

2007-12-12.

"Dual Fuel Conversion Kits" (http://www.dualfuelconversions.com) .http://www.dualfuelconversions.com. Retrieved 2009-09-21.

Retrieved from "http://en.wikipedia.org/wiki/Bi-fuel_vehicle"

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bi-fuel vehicle - wikipedia, the free encyclopedia

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