Bi-fuel vehicles are
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...
s with
multifuel
Multifuel, sometimes spelled multi-fuel, is any type of engine, boiler, or heater or other fuel-burning device which is designed to burn multiple types of fuels in its operation. One common application of multifuel technology is in military sett ...
engines capable of running on two fuels. The two fuels are stored in separate tanks and the engine is able to run on one fuel at a time. On
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
s, a bi-fuel engine typically burns
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
and a volatile
alternate fuel such as
natural gas (CNG),
LPG, or
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
. Bi-fuel vehicles have the capability to switch back and forth from the gasoline to the other fuel, manually or automatically.
[ See definition in Glossary and Abbreviations] A related concept is the duel-fuel vehicle which must burn both fuels in combination.
Diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
s converted to use gaseous fuels fall into this class due to the different ignition system.
The most common technology and alternate fuel available in the market for bi-fuel gasoline cars is
Autogas (LPG), followed by
natural gas (CNG), and it is used mainly in Europe. Poland, the Netherlands and the Baltic states have many cars running with LPG.
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
currently has the largest number of CNG vehicles, followed by Sweden. They are also used in
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, where these vehicles are mainly used as
taxicab
A taxi, also known as a taxicab or simply a cab, is a type of vehicle for hire with a driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of their choice ...
s in main cities of
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
and
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. Normally, standard gasoline vehicles are retrofitted in specialized shops, which involve installing the
gas cylinder
A gas cylinder is a pressure vessel for storage and containment of gases at above atmospheric pressure. High-pressure gas cylinders are also called ''bottles''. Inside the cylinder the stored contents may be in a state of compressed gas, vapor ...
in the trunk and the LPG or CNG injection system and electronics. The conversion is possible because the gases can use the
spark-ignition
A spark-ignition engine (SI engine) is an internal combustion engine, generally a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug. This is in contrast to compression-ignition engines, t ...
of a gasoline engine.
Diesel conversions
A Diesel engine is a compression ignition engine and does not have a spark plug. To operate a diesel engine with an alternate combustible fuel source such as
Natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, a Dual-Fuel system used with Natural gas as the main fuel while
diesel
Diesel may refer to:
* Diesel engine, an internal combustion engine where ignition is caused by compression
* Diesel fuel, a liquid fuel used in diesel engines
* Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...
fuel is used for the ignition of the gas/air mixture inside the cylinder. In other words, a portion of diesel is injected at the end of the compression stroke, thereby maintaining the original diesel operation principle. (Running gas-only is possible, but requires more extensive modification.)
Dual fuel operation in this case means the engine uses two fuels (gas and diesel) 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
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
Standards
ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
) and high speed (between 1200 and 1800 RPM).
Low and middle speed conversion
Gas is injected into the cylinder inlet manifold by individual gas electromagnetic valves installed as close to the intake 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 intake 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
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 turbocharger by central mixer.
Conversion features and benefits
Benefits relating to conversion to bi-fuel vehicles include savings on operation costs, little to no engine modification of the existing vehicle and non-derated output power. Other benefits also include emissions reduction (due to different C/H atom ratio) and fuel flexibility.
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
Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a ...
is being used. The
biogas
Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a ...
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
Diesel may refer to:
* Diesel engine, an internal combustion engine where ignition is caused by compression
* Diesel fuel, a liquid fuel used in diesel engines
* Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...
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 non-combustible compounds such as carbon dioxide.
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.
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%. Generally, it is not possible to guarantee an exact diesel/gas ratio without a test being done after the conversion.
Vehicles
Aftermarket 'bi-fuel' and even 'tri-fuel' conversions are also available.
Factory bi-fuel passenger cars
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Fiat Punto
The Fiat Punto is a supermini car (B-segment) produced by the Italian manufacturer Fiat from 1993 to 2018, spanning over three generations. The third generation of the car was marketed between 2005 and 2009 as the Grande Punto, and between 2009 ...
*
Fiat Siena
The Fiat Siena is a subcompact car produced by the Italian manufacturer Fiat from 1996 to 2022. It is the four-door sedan version of the Fiat Palio, a supermini car especially designed for developing countries. It was introduced for the first ...
Tetrafuel, with a gasoline
flex-fuel
A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol fu ...
engine and
natural gas (CNG).
*
Holden Commodore
The Holden Commodore is a full-size car that was sold by Holden from 1978 to 2020. It was manufactured from 1978 to 2017 in Australia and from 1979 to 1990 in New Zealand, with production of the locally manufactured versions in Australia endin ...
dual-fuel (LPG/petrol)
*
Fiat Multipla
The Fiat Multipla (Type 186) is a six-seater car produced by Italian automaker Fiat from 1998 to 2010. Based on the Bravo/Brava, the Multipla was shorter and wider than its rivals. It had two rows of three seats, where its compact MPV competi ...
1.6 BiPower (CNG/petrol) and 1.6 BluPower (CNG)
*
Chevrolet Cavalier
The Chevrolet Cavalier is a line of compact cars produced by Chevrolet. Serving as the replacement of the Chevrolet Monza, the Cavalier was the second Chevrolet model line to adopt front-wheel drive. Three versions of the Cavalier have been sol ...
*
Dacia Duster
The Dacia Duster is a family of automobiles produced and marketed jointly by the French manufacturer Renault and its Romanian subsidiary Dacia since 2010. It is currently in its second generation, launched in the autumn of 2017. It is marketed a ...
BiFuel)
*
Dacia Logan
The Dacia Logan is a family of automobiles produced and marketed jointly by the French manufacturer Renault and its Romanian subsidiary Dacia since mid-2004, and was the successor to the Dacia 1310 and Dacia Solenza. It has been produced as a ...
BiFuel
*
Dacia Sandero
The Dacia Sandero is a subcompact car/supermini (B-segment) car produced and marketed jointly by the French manufacturer Renault and its Romanian subsidiary Dacia since 2007, currently at its third generation. It has been also marketed as the Ren ...
BiFuel
*
Ford Contour
The Ford Mondeo I (first generation) is a mid-size car that was produced by Ford, beginning on 23 November 1992, with sales beginning on 22 March 1993. It is also known as the Mk I Mondeo; the 1996 facelift versions are usually designated Mk II. ...
*
Mazda RX-8 Hydrogen RE
The Mazda RX-8 Hydrogen RE is a 2003 bi-fuel version of the RX-8 sports car, in which the twin-rotor wankel rotary engine is configured to run on either hydrogen or gasoline. This is the fifth Mazda vehicle to be fitted with a hydrogen wankel r ...
*
Premacy Hydrogen RE Hybrid
The Mazda Premacy Hydrogen RE Hybrid or Mazda5 Hydrogen RE Hybrid was a hydrogen powered hybrid car produced by Mazda. Later models were also called the Mazda Hydrogen RE Plug in Hybrid. The first car was unveiled in 2005, with an improved version ...
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Chevrolet SPARK
The Chevrolet Spark ( ko, 쉐보레 스파크, translit=) is a city car manufactured by General Motors's subsidiary GM Korea from 1998 to 2022. The vehicle was initially developed by Daewoo and was introduced in 1998 as the Daewoo Matiz ( ko, 대 ...
Bifuel
*
Volkswagen Polo
The Volkswagen Polo is a supermini car (B-segment) produced by the German car manufacturer Volkswagen since 1975. It is sold in Europe and other markets worldwide in hatchback, saloon, and estate variants throughout its production run.
History
...
BiFuel (LPG/petrol)
*
Volkswagen Golf
The Volkswagen Golf () is a compact car/small family car (C-segment) produced by the German automotive manufacturer Volkswagen since 1974, marketed worldwide across eight generations, in various body configurations and under various nameplates ...
BiFuel (LPG/petrol)
*
Mazda 2
, commonly referred to as simply Mazda, is a Japanese multinational automotive manufacturer headquartered in Fuchū, Hiroshima, Japan.
In 2015, Mazda produced 1.5 million vehicles for global sales, the majority of which (nearly one mi ...
BiFuel (LPG/Petrol)
*Mercedes-Benz E200-NGT BiFuel (CNG/Petrol)
*
Audi A3
The Audi A3 is a subcompact executive/small family car (C-segment) manufactured and marketed by the German automaker Audi AG since September 1996, currently in its fourth generation.
The first two generations of the Audi A3 were based on the ...
g-tron
*
Audi A4
The Audi A4 is a line of compact executive cars produced since 1994 by the German car manufacturer Audi, a subsidiary of the Volkswagen Group.
The A4 has been built in five generations and is based on the Volkswagen Group B platform. The first ...
g-tron
*
Lada Vesta
The Lada Vesta is a subcompact car produced by the Russian car company AvtoVAZ since 2015. It was presented in August 2014 during the Moscow International Automobile Salon and went into mass production on 25 September 2015 in Izhevsk.
Bo Anderss ...
CNG (CNG/Petrol).
Factory bi-fuel pickups
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Chevrolet Silverado
The Chevrolet Silverado is a range of trucks manufactured by General Motors under the Chevrolet brand. Introduced for the 1999 model year, the Silverado is the successor to the long running Chevrolet C/K model line. Taking its name from th ...
*
Ford F-150
The Ford F-Series is a series of light-duty trucks marketed and manufactured by Ford since the 1948 model year. Slotted above the Ford Ranger in the Ford truck model range, the F-Series is marketed as a range of full-sized pickup trucks. ...
,
F250
See also
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Alternative fuel vehicle
An alternative fuel vehicle is a motor vehicle that runs on alternative fuel rather than traditional petroleum fuels (petrol or diesel fuel, petrodiesel). The term also refers to any technology (e.g. electric car, hybrid electric vehicles, Solar ...
*
Flexible-fuel vehicle
A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol o ...
(FFV or dual-fuel vehicle)
*
Hydrogen internal combustion engine vehicle
A hydrogen internal combustion engine vehicle (HICEV) is a type of hydrogen vehicle using an internal combustion engine. Hydrogen internal combustion engine vehicles are different from hydrogen fuel cell vehicles (which use electrochemical us ...
*
Multifuel
Multifuel, sometimes spelled multi-fuel, is any type of engine, boiler, or heater or other fuel-burning device which is designed to burn multiple types of fuels in its operation. One common application of multifuel technology is in military sett ...
References
External links
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