From cryogenic cold treatment processes, to xenon headlights and refrigerant gases, our industry is a pivotal participant in the auto industry, as Rob Cockerill explores.

When most of us are making our way to work in the mornings all around the world, little do we realise we’re stepping on the gas quite so literally.

We’re all aware of the fuel, ‘gasoline’ or power consumed by our cars at what is sometimes a considerable expense. Readers of gasworld will also be aware of the fundamental involvement of industrial gases where energy and fuel production is concerned.

Perhaps what isn’t so obvious is the evidence of gases throughout the very DNA of the vehicle, ranging from air conditioning systems to chassis production and emissions testing.

According to the International Organisation of Motor Vehicle Manufacturers, around 73 million vehicles were manufactured around the world in 2007, at a 5.7% production increase compared to the year prior.

Of these 73 million cars, gases are prevalent throughout production and gasworld explores some of these areas in this Focus Feature.

Basic structure
At the very heart of the vehicle concept are both the engine and the structure itself, the chassis and the collective components that comprise the car.

Evolving from the basic metallic framework of yesteryear, the modern car is a moulded mesh of metalwork, plastics and carbon fibre to form the lightest, safest, most durable and efficient machine.

Besides the role of welding and cutting gases involved in the uniting of the various components and chassis, these components are the subject of a key application of gases themselves, that of heat treatment.

Heat treatment enables automotive component manufacturers to achieve the much-strived for physical properties and microstructure.

Heat treatment solutions are applicable to both ferrous and non-ferrous metal components, as well as the autoclaving of plastics and other composite materials such as carbon fibre – both products of petrochemical processes.

The annealing of ferrous metals uses a nitrogen-based atmosphere of hydrogen and hydrocarbon methanol to provide a protective environment for the heat treatment of metals, which are heated to a specific temperature to allow internal stresses to relax before again cooling.

Similarly, the annealing of non-ferrous metals requires atmospheres of nitrogen and hydrogen mixtures, though the use of the more expensive hydrogen appears minimised when possible and atmospheres vary where specialist applications are involved.

In contrast to heat treatment comes cold treatment, processes to ensure the durability and reliability of components. Modifying micro structures and optimising quality of performance, cold treatment serves as a considerable consumer of liquid nitrogen to deliver high wear resistance of metallurgical components.

The use of nitrogen is also found in the carburising of steel products and autoclaving of plastics and composite materials. Carbon-nitrogen mixtures are utilised for carburising steel components to produce a hard structure after quenching, while nitrogen is often used to autoclave as a safe and more inert alternative to compressed air.

Autoclaving uses elevated temperature and pressure to ensure sterility and the removal of air from a product or material.

Carbon fibre composites for selected Boeing aircraft are also though to be ‘cured’ in large autoclave devices.

Thought to be in the ‘age of composites’ by many, the goal for decreased weight to combat vehicle emissions and improve fuel economy is driving this demand for composite materials in the vehicle manufacturing market.

Innovative new autoclave process technologies, using gases such as liquid nitrogen are seen as fundamental to delivering faster, more cost effective production of composite components.

Although of an entirely different nature, nitrogen is also favoured as an alternative to compressed air in the inflation of tyres. Its inert nature ensures a higher quality of inflation and lack of moisture or oxidation properties, with nitrogen molecules less likely to escape the inside of a tyre wall compared with traditional compressed air mixtures.

Oxygen permeates the complex tyre membrane around three times quicker than nitrogen, causing under-inflation, increased tyre wear, and reduced fuel economy.

Air conditioning
For those motorists fortunate enough to use an air conditioning system while driving, the comfort of their ride is enhanced by refrigerant gases.

No longer a novelty for just the luxury cars of the world’s roads, air conditioning systems are generally a common feature of most modern vehicles.

Comfortable ambient conditions achieved through the use of refrigerant gases in the installation and refill of air conditioning systems, such refrigerants range from HCFC’s and HFC’s to R-717 Ammonia, R744 (refrigerant grade CO2), and others.

The Linde Group’s BOC also offers a refrigerant recovery and reclamation service, capable of recovering refrigerant loss and allowing for cost effective compliance with environmental legislation.

Xenon headlights
Increasingly finding favour among the major vehicle manufacturers, xenon-based headlights provide an optimum lighting performance which both improves the quality of vision for the motorist and reduces visual glare for oncoming drivers.

Auto industry ‘experts’ are thought to believe that by the close of 2008, almost four out of every ten new cars in Europe will be equipped with xenon lights.

Xenon is utilised in a wide range of lighting applications, such as photographic flashes, stroboscopic lamps, solid-state laser devices, xenon arc lamps, plasma displays, and IMAX film projection systems. In vehicles however, this is still a relatively new concept and one that is motoring ahead through its functionality.

It’s thought that xenon lights produce on average at least 2.5 times more light than a typical halogen bulb, while only consuming around two thirds of the power in the process – adding a dimension of energy efficiency to the product’s functionality. The benefits are obvious: a motorist is able to see much more clearly and safely , with the vehicle itself operating with more for other functions.

As well as this sense of functionality, xenon lighting offers a comparatively longer shelf life and increased output than the standard, limited filament of halogen lamps.

The clear blue-white light produced by xenon provides an illumination far more representative of daylight than the yellow hue of halogen bulbs, maximising driver concentration and comfort, while it also appears to afford improved illumination and wider light distribution across the road.

Perhaps it is no small wonder that the majority of new developments in car front-lighting technology are based upon the implementation of xenon.

Enabling emission control
A fundamental requirement for maintaining a cars’ road vehicle is the stringent adherence to specified emission levels.

These are becoming ever more significant as the age of environmental awareness takes hold and emission reduction of all forms is urged.

Calibration gases and gas mixtures play a pivotal role here, as determinants of air quality and accurate emission levels.

High quality calibration gases, available at parts-per-billion (ppb) concentration, are capable of monitoring impurities such as nitrogen oxides (NOx), sulphur oxides (SOx) and volatile organic compounds (VOC’s) as greater accuracy is required for tightening legislation and environmental needs.

Cool new cryogenic applications
Just as greater environmental awareness is a sign of the modern times, so too is the use of many innovative new cryogenic technologies.

While cryotherapy is increasingly used as a treatment of stimulation and rejuvenation for the human body, Deep Cryogenic Treatment is becoming a popular performance enhancer for the inner workings and central energy system of the motor vehicle.

Optimising performance and product durability for the automobile arena, deep cryogenic treatment involves the use of cryogenics in a one-off permanent process that toughens both ferrous and non-ferrous materials.

The treatment, also known as Deep Cryogenic Tempering or Cryo Treating, toughens the chosen metallic material right through to the core and relieves most residual stresses, while also increasing resistance to wear, impact and fatigue.

Creating a denser molecular structure and compatible with other treatments such as Chrome and Teflon, the process is also seen as environmentally friendly and has been gaining significant popularity in the motor vehicle market for the many long-life and performance enhancing benefits it brings to a whole variety of under-the-bonnet components.

Subzero treatment of ferrous steels at around -80°C transforms retained austenite left by heat treatment processes to martensite, ensuring a material that’s up to four-times harder and with refined, improved properties.

Further deep cryogenic treatment at around -185°C further enhances these improvements, consuming liquid nitrogen for such deeper temperature levels.

The UK’s Frozen Solid is one such company committed to providing deep cryogenic treatment to the vehicle industry, as well as for audio applications, and the utility in motorsport and karting.

The company notes that the entire cryogenic service it deploys is computer-controlled, from the freeze-down to cryogenic temperature levels to the heat tempering phase, while its provision of liquid nitrogen is catered for by The Linde Group’s BOC – supplied from a 1,000 litre efficient storage tank provided by BOC Gas.

Driving force
With an abundance of usages within the automotive arena, it could be suggested that industrial gases are streets ahead in terms of optimising vehicle production and driver comfort.

Indeed, we’ve not even covered the use of specialty and electronic gases in the production and development of the vehicle’s electronic nervous system, nor in the field of in-car entertainment provided through built in stereo systems and CD players.

From exhaust emissions to alloy wheels, xenon headlights to air conditioning refrigerants, gases are fundamental factors.

The saying may go that ‘the car in front is a Toyota’, but we could also say that gases are providing the drive behind our motoring.