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Frequently Asked Questions

Alternative Fuels

+Why use natural gas as a transportation fuel?

The world currently faces major challenges that are significantly impacted by transportation growth:

  • volatility of oil supply, costs, energy security, and the peak in global oil production
  • rising air pollution levels in the world's rapidly growing cities
  • increasing greenhouse gas emissions linked to global climate change

These oil supply, environmental and economic challenges are driving the rapid development of alternatives globally, including natural gas as a transportation fuel.

+Why use LPG as a transportation fuel?

As a vehicle fuel, LPG—otherwise known as propane or autogas—is relatively clean burning, easy to store and transport, has high energy content, and is widely available in many countries. LPG has a broad application of uses including home heating, agriculture, petrochemicals, and industrial as well as automotive. According to Navigant Research, approximately 9% of the global consumption of LPG in 2012 was used as an automotive transport fuel. Navigant Research indicates that in 2012, there were 1 million light-, medium- and heavy-duty vehicles converted to run on LPG in the world, including 449,000 vehicles in Europe. This is forecasted to grow to 1.4 million in new vehicle sales and conversions in 2020. While global sales of light duty LPG vehicles are projected to grow by 2.6% annually from 2014 to 2035, the Middle East and Africa will show faster growth at 4.7% CAGR. In North America, the annual growth rate of all LPG vehicle sales and conversions will average 4.7% between 2014 and 2035.

+What are the differences between CNG, LNG and LPG?

The fuel consumed in a natural gas engine mainly consists of methane, produced from fossil and/or renewable sources. This fuel can be stored either in a compressed or liquefied form.

Compressed natural gas (CNG) is natural gas that has been compressed into a high-pressure container for transportation or storage.

Liquefied natural gas (LNG) is natural gas that is liquefied by cooling to -160 °C (-260 °F) at atmospheric pressure. At that temperature, LNG occupies 1/600th the volume of natural gas at atmospheric temperature and pressure. The high energy density of LNG makes it useful for energy storage. LNG is stored in double-walled, vacuum-insulated tanks.

LPG is liquefied petroleum gas, a mixture of propane and butane liquefied at 15 °C and a pressure of 1.7 – 7.5 bar.

+What is biomethane / renewable natural gas (RNG)?

Biomethane, or renewable natural gas (RNG), provides a clean, easily controlled source of renewable energy from organic waste materials, replacing fossil natural gas with a sustainable carbon neutral fuel option.  It can be used as a 100% substitute for, or blended with conventional gas streams for use in vehicle engines.

+What is biogas?

Biogas is generated when bacteria degrade biological material in the absence of oxygen, in a process known as anaerobic digestion. Biogas is a renewable fuel, primarily a mixture of methane and carbon dioxide (CO2).

Landfill gas is biogas produced by organic waste decomposing under anaerobic conditions. The waste is covered and compressed mechanically by the weight of the material that is deposited from above. This material prevents oxygen from accessing the waste and anaerobic microbes thrive. This gas builds up and is slowly released into the atmosphere if the landfill site has not been engineered to capture the gas.

Biogas is normally rich in methane (about 65%) and impurities of hydrogen sulfide (H2S), CO2 and water. Technology is commercially available to remove H2S, CO2 and water contaminants present in the biogas and landfill gas through processing to produce high-purity natural gas (biomethane or RNG) suitable for vehicles.

+Where does biomethane come from?

Biomethane can be produced from a variety of sources, including:

  • Landfill gas
  • Solid waste
  • Municipal waste water
  • Agricultural manure
  • Forestry waste
  • Energy crops

+Why biomethane / RNG for transportation?

Transportation faces impediments to incorporating renewable and lower carbon energy into the fuel mix. Recent progress in generating lower-carbon sources of electricity have not been matched in the transportation sector.

Biomethane technology offers a pathway to diversity and decarbonize the transport sector:

  • Clean: Burns with the same low emissions as natural gas, with the lowest carbon-intensity of any transport fuel
  • Efficient: The readiness of biomethane production pathways to accommodate waste, mitigates land-use issues associated with biofuels production
  • Available: biomethane feedstocks can be found anywhere people are, and may provide supplemental income to feedstock owners
  • Adaptable: biomethane’s emissions benefits can be extended via blends with conventional gas without requiring any changes to the engine technology
  • Already here: The capture of biogas is already prioritized by environmental regulators

Alternative Fuel Vehicles

+Why natural gas vehicles?

Natural gas vehicles (NGVs) are among the cleanest, most practical solution for low-emissions transportation today. While other clean transportation technologies exist, natural gas vehicle technology offers similar performance  to conventional diesel and gasoline vehicles.

Stringent emissions standards for commercial transportation, together with concerns about volatile oil prices and oil supply security, are presenting economic advantages for natural gas vehicles. Governments around the world realize that natural gas or biomethane powered vehicles should be a major component of their transportation strategies. High transportation growth markets like China, India, and Brazil are driving the future energy picture for transportation, and they have been steadily increasing their natural gas use.

The NGV industry is a large and rapidly growing market. According to NGV America, as of February 2012 there were more than 15 million natural gas vehicles in use worldwide. The International Association of Natural Gas Vehicles projects that there will be more than 50 million natural gas vehicles worldwide within the next ten years, representing approximately 9% of the world transportation fleet.

One of the primary reasons for NGV adoption is the increasing price stability that natural gas has over petroleum-based fuels. We believe that rising demand for oil will result in ongoing price uncertaintly and/or fuel shortages, which will continue to create favourable market conditions for adoption of cheaper alternative fuels such as natural gas. As the relative price of diesel compared to natural gas remains higher, the incentive to switch becomes more attractive.

+What types of vehicles can use alternative fuels such as natural gas and LPG?

OMVL offers many alternative fuel components and systems that support a wide range of power requirements. Sold via our OEM partners, joint ventures and distributors, these products are well suited to a variety of applications from automotive and light industrial to urban and heavy-duty trucking.

+How do I make the best choice of vehicle: dedicated, bi-fuel or dual-fuel natural gas?

Light-duty vehicles typically operate in dedicated or bi-fuel modes, whereas medium- and heavy-duty vehicles operate in dedicated or dual-fuel modes.

A dedicated natural gas vehicle is one that only operates on natural gas. A bi-fuel vehicle is capable of running on natural gas (usually CNG) first, then if that tank runs empty, on gasoline. It allows the owner to use a clean, domestic, low-cost energy source as their primary fuel and (optionally) to have the security of gasoline as a back-up fuel.

Dedicated and bi-fuel spark-ignited natural gas engines operate on the same principles as the common gasoline (petrol) engine, the Otto cycle. Such engines are most commonly operated in a premixed mode with either lean burn or stoichiometric gas mixtures. Fuel (in this case natural gas) is drawn into the engine along with the intake air and ignited with a spark plug. The combustion process is characterized by premixed flame propagation typical for Otto (gasoline) engines.

In general, a dedicated vehicle will have more natural gas storage capacity and can travel longer distances on natural gas, which will result in larger fuel cost savings. However a bi-fuel vehicle may be a better option in areas where natural gas infrastructure is scarce, as it provides the security of gasoline when needed.

Dual-fuel technology enables a diesel engine to operate on a high proportion of natural gas. A dual fuel engine typically relies on conventional diesel engine hardware. Modifications to the base diesel engine allow operation with natural gas as well. Under dual fuel operation, natural gas is introduced at low pressure and mixed with the intake air. Diesel fuel is introduced directly into the combustion chamber near the end of compression stroke and is used to ignite a lean mixture of natural gas and air (i.e. no spark plugs are required). Since dual fuel engines are based on a diesel engine, it allows them to provide higher performance (torque and power) and efficiency on natural gas fuel as compared to a traditional spark ignited natural gas engine. Dual fuel engines are capable of reverting back to 100 percent  diesel operation over the entire engine operating range if required.


+How are Emer, OMVL and Valtek related to Westport?

Emer, OMVL and Valtek are all Westport companies which have their own brand identity.

+Where can I find OMVL products?

OMVL products are available in a number of countries worldwide, and availability depends on your location and requested product. Please contact us and we will help you find our products.

+Where are OMVL products manufactured?

For most markets (especially Europe, CIS, Middle East and Africa), OMVL products are manufactured in our own facilities in Brescia, Italy. In addition, we also have manufacturing facilities in Argentina and India through our joint ventures.

Dual-Fuel Systems

+What does "Dual-Fuel" mean?

In simple terms, dual-fuel can be defined as the simultaneous combustion of two fuels. In the case of the Westport Dual-Fuel System, natural gas is utilized in conjunction with diesel fuel to operate the engine. After conversion, the engine is able to operate on either 100% diesel fuel, or alternately, on a mixture of diesel fuel and natural gas (or other methane based fuels). At no time is the engine able to operate on natural gas exclusively.

+Will my engine have to be modified to operate on the Westport Dual-Fuel System?

No. The Westport conversion technology has been designed to allow for the in-field retrofit of diesel engines without the need to change or modify the engine design. The Westport conversion hardware is mounted externally on the engine and does not require modification of the engine or alteration of any critical engine structure.

+Will the system affect my engine warranty?

Most OEM engine warranty programs do not prohibit the use of aftermarket parts or technologies. Generally, OEM policy is that they neither recommend nor endorse aftermarket technologies; however, the use of these products does not automatically void the validity of the engine warranty. If the cause of an engine issue is unrelated to dual-fuel, the OEMs have historically honored the warranty and repaired the engine. Additionally, all Westport Dual-Fuel components that fail within the warranty period will be covered under the Westport Dual-Fuel warranty policy.

+Why can't the engine use 100 percent natural gas?

Because of the very high ignition temperature of natural gas (approximately 1,300 degrees Fahrenheit), sufficient heat is not generated during the diesel compression stroke to ignite 100% natural gas. As such, dedicated gas engines employ spark plugs and an ignition system to facilitate combustion of the air-natural gas mixture. In contrast, during dual-fuel operation, a reduced quantity of diesel fuel acts as the ignition source for the air-gas mixture; this process is often referred to as pilot ignition.

+Will my engine lose power after conversion to the Westport Dual-Fuel System?

Under normal circumstances, engines converted to Westport Dual-Fuel do not suffer any horsepower losses while operating in dual-fuel mode. Because the system maintains OEM compression ratio values and does not incorporate an air-throttling device, peak horsepower and efficiency levels of the converted engine remain on par with 100% diesel operation. In some circumstances, the engine may be de-rated in dual-fuel mode due to shortcomings in gas supply composition and/or quality.

+Will my engine run hotter on dual-fuel?

Westport Dual-Fuel technology has been designed to maintain OEM specifications for all engine temperatures including engine coolant temperature, oil temperature, exhaust gas temperature and intake air temperature. The dual fuel system replaces diesel fuel normally consumed by the engine with an equivalent quantity of natural gas, relative to the heat value of each fuel. As such, engine air-fuel ratios during dual fuel operation remain largely an "equivalent gallon" of natural gas is consumed resulting in similar engine fuel efficiencies.

Note: 1 gallon #2 diesel = 140 scf natural gas based on #2 diesel hhv.

+What about efficiency?

The Westport Dual-Fuel System replaces diesel fuel with an equivalent quantity of natural gas. This process results in the same net fuel burn vs. load as would be experienced during 100% diesel operation. For each gallon of diesel fuel displaced during dual-fuel operation, there is a corresponding consumption of approximately 140 cubic feet of pipeline quality natural gas (based on 129,000 btu/gallon # 2 diesel & 930 btu/scf natural gas). So for each gallon of diesel fuel displaced during dual-fuel operation, an "equivalent gallon" of natural gas is consumed resulting in similar engine fuel efficiencies.

Note: 1 d of natural gas = I liter # 2 diesel.

+What effect will the Westport Dual-Fuel System have on the durability of my engine?

Generally speaking, operation in dual-fuel mode has no negative effects on engine wear rates and durability. Because engine thermal loads are equivalent to 100% diesel operation, no excess wear of combustion chamber components (pistons, rings, valves, injectors, etc.) occurs. In addition, many users of the Westport Dual-Fuel System have reported positive benefits relative to engine wear including extended oil change intervals and extended time between overhauls. This is primarily the result of the cleaner burning characteristics of natural gas compared to diesel fuel.

+What are the economic benefits of operating on Westport Dual-Fuel?

Fuel cost savings resulting from operation in dual-fuel mode will vary according to the respective cost of each of the fuels. If there’s a significant cost differential between the cost of diesel fuel (per gallon, liter, etc.) and the equivalent quantity of natural gas (heat value basis) in favor of the natural gas, significant fuel cost savings would result. The closer the fuels are in price, the lower the fuel cost savings will be during dual-fuel mode. In addition to fuel cost savings, engine maintenance savings may also contribute to the economic benefit of dual-fuel operation.

R&D Tools


Advanced Modeling Environment for Simulations (AMESim) is a dynamic modeling system which applies the Bond Graph technique. It's used to develop a numerical model to define the behavior of the injector.

Injector behavior can be described in a one-dimensional geometry representation.

System design is based on the existing libraries: PNEUMATIC, SIGNAL, and MECHANICAL.

Boundary Condition for AMESim Simulation

AMESim Boundary Condition

Final Simulation Applied on CNG Component



Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. It is a renewable energy source and in many cases exerts a very small carbon footprint.

Biogas can be produced by anaerobic digestion with anaerobic bacteria, which digest material inside a closed system, or fermentation of biodegradable materials.

Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.

Biogas can be compressed, the same way natural gas is compressed to CNG, and used to power motor vehicles. In the UK, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel. It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio methane


The composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55% to75% methane, which for reactors with free liquids can be increased to 80% to 90% methane using in-situ gas purification techniques. As produced, biogas contains water vapor. The fractional volume of water vapor is a function of biogas temperature; correction of measured gas volume for water vapor content and thermal expansion is easily done via simple mathematics which yields the standardized volume of dry biogas.

In some cases, biogas contains siloxanes. They are formed from the anaerobic decomposition of materials commonly found in soaps and detergents. During combustion of biogas containing siloxanes, silicon is released and can combine with free oxygen or other elements in the combustion gas. Deposits are formed containing mostly silica (SiO2) or silicates (SixOy) and can contain calcium, sulfur, zinc, phosphorus. Such white mineral deposits accumulate to a surface thickness of several millimeters and must be removed by chemical or mechanical means.

Practical and cost-effective technologies to remove siloxanes and other biogas contaminants are available.  

For 1,000 kg (wet weight) of input to a typical biodigester, total solids may be 30% of the wet weight while volatile suspended solids may be 90% of the total solids. Protein would be 20% of the volatile solids, carbohydrates would be 70% of the volatile solids, and finally fats would be 10% of the volatile solids.

Biogas, if compressed, it can replace compressed natural gas for use in vehicles, where it can fuel an internal combustion engine or fuel cells and is a much more effective displacer of carbon dioxide than the normal use in on-site CHP plants.


All our products are developed, manufactured and tested in accordance with standards for LPG, CNG and LNG applications.

  • R67 : Approval of specific equipment for vehicles in the M and N categories, using liquefied petroleum gases in their propulsion system
  • R110 : Specific components of motor vehicles using CNG and/or LNG in their propulsion system
  • ISO15500 : Road vehicles – CNG fuel system components
  • UL : Safety certification for US market

+CFD Analysis

Computational Fluid Dynamics (CFD) Analysis within Westport group is developed with ANSYS FLUENT.

ANSYS FLUENT is a finite volume solver created for evaluating many aspects of 2D/3D flow models. It is currently an industry-standard for single/multiphase flows, combustion studies, fluid heat exchanges studies.

Case Study: High Pressure Flow Through a CNG Filling Valve

  1. The model is created in an integrated graphic ambient using data imported from designer's CAD system.
  2. The Meshing process is guided and analysed using automated algorithms.

  3. The boundary conditions and material data are specified in a pre-processor environment: it is possible to simulate the geometry in a wide variety conditions.
  4. The solver provides a solution for the simulation.
  5. The numerical solution is checked in order to evaluate its accurancy and coherency.

In the end, the graphical results are printed out using a sophisticated GUI: a variety of useful information could be extracted from the numerical database.

+Design of Experiments

Designs of experiments capabilities provide a method for simultaneously investigating the effects of multiple variables on an output variable (response). These experiments consist of a series of runs, or tests, in which purposeful changes are made to input variables or factors, and data is collected at each run.


Dimethyl ether (DME), also known as methoxymethane, is the organic compound with the formula CH3OCH3. The simplest ether, it is a colorless gas that is a useful precursor to other organic compounds and an aerosol propellant being researched as a future energy option. It is an isomer of ethanol.


One method of production is by dehydration of methanol:

2 CH3OH → (CH3)2O + H2O

The required methanol is obtained from synthesis gas (syngas). In principle, the methanol could be obtained from organic waste or biomass. Other possible improvements call for a dual catalyst system that permits both methanol synthesis and dehydration in the same process unit, with no methanol isolation and purification.

Both the one-step and two-step processes above are commercially available. Currently, there is more widespread application of the two-step process since it is relatively simple and start-up costs are relatively low. It is worth mentioning that there is a developing one-step liquid-phase process.

Application as Fuel

A potentially major use of DME is as substitute for propane in LPG used as fuel in household and industry.

It is also a promising fuel in diesel engines, petrol engines (30% DME / 70% LPG), and gas turbines. For diesel engines, an advantage is the high cetane number of 55, compared to that of diesel fuel from petroleum, which is 40–53. Only moderate modifications are needed to convert a diesel engine to burn DME. The simplicity of this short carbon chain compound leads during combustion to very low emissions of particulate matter, NOx, and CO. For these reasons as well as being sulfur-free, DME meets even the most stringent emission regulations in Europe (Euro V), U.S. (U.S. 2010), and Japan (2009 Japan). Mobil uses DME in their methanol to gasoline process.

DME is being developed as a synthetic second generation biofuel (BioDME), which can be manufactured from lignocellulosic biomass. Currently the EU is considering BioDME in its potential biofuel mix in 2030, the Volvo Group is the coordinator for the European Community Seventh Framework Programme project BioDME where Chemrec's BioDME pilot plant based on black liquor gasification is nearing completion in Piteå, Sweden


Finite Element Analysis (FEA) within the Westport group is developed with ANSYS Mechanical Desktop Environment.  ANSYS Mechanical Desktop is multiphysics simulation environment created for evaluating many aspects of 2D/3D models. It is currently an industry-standard for mechanics/statics/dynamics simulations.

Case Study: O-Ring Behaviour Under Heavy Load

  1. The model is created in an integrated graphic ambient.
  2. The meshing process allows the capture of every aspect of the physical process: the mesh is automatically analysed after the creation.
  3. The mechanical/thermal loads, pressures, supports, displacements, and forces can be set independently on the model. The entire load timing can be set in a wide range:
  4. Results analysis: Displacement
    1. Shutter duty full closed:
    2. Pressure (200 barA) effects

It's clear that the huge deformation amount is due to the very high pressure application on the round axys-simmetric gasket. Further analysis related to load and contact pressure between elements are possible.


Liquefied natural gas (LNG) is a liquid form of a gas. If you take compressed natural gas (CNG) and cool it down to -162 °C, you get liquid. It's known as a "cryogenic fuel."

Since LNG in its natural state takes up 1/600 of space compared to CNG, a vehicle can store more fuel onboard with a single LNG tank, compared to a set of CNG cylinders of the same overall volume.

LNG fuel has advantages when it comes to extended vehicle range. Although the LNG fueling network is currently under development in Europe, there are many "blue-corridor" projects crossing many countries, to give fleets greater fueling opportunities. For now, routes of LNG vehicles should be accurately planned in advance, to ensure a vehicle can be adequately fuelled on the road.

To get an amount of LNG fuel equivalent to diesel, The LNG tank(s) should to be about 1.8 times the size of the diesel tank: in other terms, you need 1.8 times the tank capacity of LNG, to reach the equivalent amount of fuel and range of diesel.

+Metal Replacement

The evolution of technology and a more competitive market push our research and development teams to improve, and to evolve so that our products are consistently becoming more efficient and reliable.

One example of our improvements is changing material, which means redesigning the product in for optimal function of new technology.

As an example, this injector illustrates our strategy. Our rail was historically made with an aluminum body, but we redesigned the injector and made the body in techno-polymer.

The advantage is it creates a lighter injector.

aluminum body polymer body

+Pressure Drop Simulation

Pressure drop simulation within Westport group is developed with CFD software.
A finite volume solver is applied for evaluating many aspects related to pressure drop. It is currently an industry-standard for single/multiphase flows.

Case Study: Pressure Drop in Injector Nozzle

  1. The model is created in an integrated graphic ambient using data imported from the designer's CAD system:
  2. The Meshing process is guided and analysed using automated algorithms.
  3. The boundary conditions and material data are specified in a pre-processor environment: it is possible to simulate the geometry in a wide variety conditions.
  4. The pressure drop is numerically and precisely evaluated: it is possible to account for the effect of very small design changes.

+Product Validations

Each new product or existing product modification needs to be validated to guarantee it conforms to its reference standards and functionality.

Westport Italy offers a complete range of laboratory equipment and test methods to completely validate our large range of products.

Validations are performed in compliance with national and international standards (UN ECE – ISO – UNI), and the test matrix is integrated with any customer's additional requests, but a complete product validation includes additional tests performed using internal specifications based on best practices.


SOLIDWORKS is solid modeling CAD (computer-aided design) software that runs on Microsoft Windows and since 1997 has been produced by Dassault Systèmes SOLIDWORKS Corporation.

SOLIDWORKS is currently used by over two million engineers and designers at more than 165,000 companies worldwide.

It allows the creation of intuitive solutions for all aspects of the design process; it's easy to use and in addition to part creation, it offers fully detailed drawings necessary for the generation of complex surfaces.

It includes also tools for performing stress and deformation analysis. It permits the complete definition of the designed model: thickness, radii, draft, markings and design according to customer needs and requirements.

+Test Report

Westport Italy’s Laboratory Quality System has a process that ensures each test is registered with a test report and results are checked from the reference manager.

Each test report refers to a reference project, customer or activity.

These reports are either a Passed/Not Passed test report or an evaluation test report.

There are different types of tests, such as:

  • Validation test report
  • Endurance test report
  • Functional test report
  • R&D test report
  • Claim analysis
  • 8D reports

This system traces all the activity performed in the laboratory, and directs the information quickly according to the reference project, customer or activity.