Bi-fuel vehicle - AbsoluteAstronomy.com

Bi-fuel vehicles are vehicle

Vehicle

A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....

s with multifuel

Multifuel

Multifuel, sometimes spelled multi-fuel, is a term applied to any type of engine, boiler, or heater or other fuel-burning device which is designed to burn multiple types of fuels in its operation...

engines capable of running on two fuels. On internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s one fuel

Fuel

Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

is gasoline

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

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

Compressed natural gas

Compressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill...

, LPG, or hydrogen

Hydrogen vehicle

A hydrogen vehicle is a vehicle that uses hydrogen as its onboard fuel for motive power. Hydrogen vehicles include hydrogen fueled space rockets, as well as automobiles and other transportation vehicles...

. The two fuels are stored in separate tanks and the engine runs on one fuel at a time, unlike flexible-fuel vehicle

Flexible-fuel vehicle

A flexible-fuel vehicle or dual-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 or methanol fuel, and both fuels are stored in the same common tank...

s ("dual-fuel"), that store the two different fuels mixed together in the same tank, and the resulting blend is burned in the combustion chamber

Combustion chamber

A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...

. Bi-fuel vehicles have the capability to switch back and forth from gasoline or diesel to the other fuel, manually or automatically.

The most common technology and alternate fuel available in the market for bi-fuel gasoline cars is Autogas (LPG), followed by natural gas (CNG)

Compressed natural gas

, and it is used mainly in Europe. The Netherlands or the Baltic states have a large number of cars running with LPG. Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

currently has the largest number of CNG vehicles, followed by Sweden. They are also used in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, where these vehicles are mainly used as taxicab

Taxicab

A taxicab, also taxi or 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

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

and Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. 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.

Vehicles

Aftermarket

Aftermarket (automotive)

The automotive aftermarket is the secondary market of the automotive industry, concerned with the manufacturing, remanufacturing, distribution, retailing, and installation of all vehicle parts, chemicals, tools, equipment and accessories for light and heavy vehicles, after the sale of the...

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

Factory bi-fuel passenger cars

Fiat Punto
Fiat Punto
The Fiat Punto is a supermini produced by the Italian manufacturer, Fiat, since 1993.-1st generation :Internally codenamed Project 176, the Punto was announced in September 1993 and launched in late 1993 as a replacement for the ageing Fiat Uno. The Fiat Punto was voted European Car of the Year...
Fiat Siena
Fiat Siena
The Fiat Siena is the four-door sedan version of the Fiat Palio, a supermini car especially designed for developing countries. The car is similar to Fiat Albea...

Tetrafuel, with a gasoline flex-fuel
Flexible-fuel vehicle
A flexible-fuel vehicle or dual-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 or methanol fuel, and both fuels are stored in the same common tank...

engine and natural gas (CNG)
Compressed natural gas
Compressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill...

.
Holden Commodore
Holden Commodore
The Holden Commodore is an automobile manufactured since 1978 by the Holden subsidiary of General Motors in Australia, and, formerly, in New Zealand. In the mid-1970s, Holden established proposals to replace the long-serving Kingswood nameplate with a smaller, Opel-based model...

dual-fuel (LPG/petrol)
Chevrolet Cavalier
Chevrolet Cavalier
The Chevrolet Cavalier was a compact automobile produced from 1982 to 2005 by General Motors. Built on the company's J platform, the Cavalier was one of the best-selling cars in the United States throughout its life.- Predecessors :...
Ford Contour
Ford Contour
The Ford Contour, and its rebadged variant, the Mercury Mystique, were compact 4-door sedans marketed from model years 1995-2000 by Ford Motor Company in North America...
Mazda RX-8 Hydrogen RE
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 engine is configured to run on either hydrogen or gasoline. This is the fifth Mazda vehicle to be fitted with a hydrogen Wankel engine...
Premacy Hydrogen RE Hybrid
Premacy Hydrogen RE Hybrid
The Premacy Hydrogen RE Hybrid is a 2007 bi-fuel version of the compact MPV Mazda5, in which the two-rotor Wankel engine allowes operation with hydrogen or gasoline...
Chevrolet SPARK BiFuel
VW Polo BiFuel (LPG/petrol)
VW Golf BiFuel (LPG/petrol)
Mazda 2 BiFuel (LPG/Petrol)

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

Natural gas

Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

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

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 turbocharger by central mixer.

Common conversion features

Substantial savings on operation costs
Practically no engine modification required
Non-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)

Compressed natural gas

or LNG (Liquid Natural Gas)

Liquefied natural gas

Liquefied natural gas or LNG is natural gas that has been converted temporarily to liquid form for ease of storage or transport....

for bi-fuel operations. Both are also mostly used for Generator sets

Electrical generator

In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

conversions, because the engine does not lose the output power.

In recent years biogas

Biogas

Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and kitchen waste can be converted into a gaseous fuel called biogas...

is being used. The biogas

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%.

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

Vehicles

Factory bi-fuel passenger cars

Diesel conversions

Low and middle speed conversion

High speed conversion

Common conversion features

Gas types used

What is a reachable diesel/gas ratio?

See also