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The rotary engine was conceived by Felix Wankel in Germany in 1926 with the first functional prototype not actually running until 1957 – this was largely due to the Second World War and the fragmented post-war Germany.
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Mazda’s Renesis rotary engine can be seen here with the basic stages of rotation illustrated. |
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Mercedes-Benz (DaimlerChrysler) believe that fuel cell vehicles offer the best options for sustainable vehicle propulsion. Since the 1990s, DaimlerChrysler and its affiliated companies have developed and demonstrated hydrogen and fuel cell technology for automotive applications. Researchers and engineers have been working toward practical implementations of this technology since the early nineties. DaimlerChrysler presented its first fuel cell concept study for the NECAR series in 1994. Since then, 20 different vehicle prototypes with fuel cell drives have been developed and tested. The vehicles range from the Mercedes-Benz A-Class and the Jeep Commander to the NEBUS.
In 2001, DaimlerChrysler presented the “Natrium†(the Latin word for sodium), which demonstrated an innovative and unconventional method for storing hydrogen: on board a minivan, hydrogen was generated directly from a white salt – sodium borohydride.
In May 2002, the NECAR 5, running on methanol travelled 3000 miles across the US to prove the technology to the World at large. Practical use came in 2004 when the first F-cell, based on the Mercedes-Benz A-Class began use under normal conditions around the world. Additionally, bus and commercial vehicle fuel cell vehicles are in operation in many countries.
The A-Class lent itself well to use as a fuel cell vehicle. It is believed that the A-Class was originally intended to house electric propulsion and was hence designed with space below the passengers. This space is utilised in the NECAR for the fuel cell system components – especially energy storage in the form of hydrogen tanks and batteries.
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Basic computer systems have been used in cars for several years. Most recently, they have been used to offer more advanced on-board information systems. Central processors have for some time been used to control engine management – ensuring smooth running, good fuel efficiency and performance. They have, however, performed relatively simple tasks and are not safety critical.
More advanced use of information technology in cars will lead to an increase in user-orientated systems. Systems will continue to be developed to control and manage the mechanical elements of a vehicle – such as engine, suspension and braking – but the most noticeable changes will take place inside.
Displays & Interfaces
One area of vehicle intelligence that has already raised its head above the parapet is that of user interfaces. It is now possible to display all the information a driver or occupant may want without the use of three-dimensional analogue displays. Above and beyond that, it is now possible to cater the information that is displayed to the particular preferences of a user and to further vary that according to changing conditions – such as traffic, weather, time of day etc. It is envisaged that information relating to specific traffic conditions could be relayed to a driver in motion. Such systems would not only indicate congestion problems but perhaps warn of large numbers of pedestrians, accident black spots, approaching emergency vehicles – even opportunities for refuelling should the tank be empty.
Importantly for designers, the manipulation of displays and interfaces will allow the use of new aesthetic concepts, the simplification of dashboard forms and the ability to incorporate a large number of controls into small areas.
Design considerations
- Controls can take the form of touch sensitive displays, allowing greater use of smooth surfaces.
- Using multi-mode and menu systems, digital displays can eliminate the need for dashboard space for every control.
- Using technologies such as E-Ink, it will be possible to place displays and controls over entire surfaces; this offers opportunities for 2D graphic aesthetics (like computer screensavers) to be developed as well as the creation of large interactive work surfaces.
Environmental Interaction
Many location based information systems are already available and use satellite positioning coupled with pre-stored data about certain locations as well as live traffic information. With the increase of wireless technology, and ultimately its ubiquitous presence, it will be possible for a vehicle to simply collect (and pass on) information as it moves through different areas.
Volvo’s Monitoring & Concept Center (VMCC) in California have produced what they believe is a feasible future transport product based upon an inline occupant configuration. The designers at VMCC envisage a sleek two-seat commuter vehicle which uses very little energy and rarely gets caught in traffic.
| “Maybe it sounds over-the-horizon, but consumer trend research together with our conceptual design and engineering work shows we could deliver that vehicle before 2010,†says VMCC science officer Ichiro Sugioka. “Our competitors should be wary of the stuff we’re doing!â€The Tandem concept reflects the attitude the department have to vehicle design, looking forward to potential new ways to travel. Although much smaller and seemingly more delicate than traditional Volvos, the team at VMCC insist they can factor into the Tandem the level of passenger safety expected from the brand.
As Kolit Mendis, structures and safety engineering manager, explains: “We compensated the Tandem’s light weight with new occupant restraint concepts designed to handle frontal collisions with heavier vehicles. Also, the central positioning of Tandem occupants leaves ample room on either side to implement structural features mitigating the severity of side impacts. Our technical evidence is that Volvo would have no problem at all in delivering its traditional levels of driver and passenger safety.†|
| Lars Erik Lundin, VMCC general manager, says that for Volvo, meeting the challenge of sustainable mobility is about looking at designs and hybrid technologies (electric drive, alternative fuels, petrol or diesel derivatives) that will provide ‘maximized total efficiency of mobility with minimised environmental impact’.â€Our job is exploring the future and doing something really extraordinary,†says Lundin. “The Tandem was originally conceived as a vehicle to help solve the specific over-crowding and pollution problems of southern California, but we soon realized it taps into how people work, travel and think almost everywhere in the industrialised world nowadays.â€Strategic design chief Doug Frasher believes that the future will involve car buyers changing their thinking from one-car-fits-all to a scenario “where people own different cars for different reasons, just as we have different clothes for different social events, suits for work, and jeans for playâ€.
“We envisage a ‘family’ matrix of cars, starting with the commuting Tandem, that will spark a new paradigm in mobility, changing the way the world thinks about auto ownership in the same way the Sony Walkman did for the audio industry.†|
| Volvo’s thinking thinking is the result of ‘ethnographic’ research begun in 1998 into past and current trends among various consumer and other audiences, using techniques such as workshops, focus groups and customer panels. “We created a timeline stretching from 1900 until 2010 with the aim of profiling future customers and the world they’d be inhabiting by understanding how trends emerge,†said Benny Sommerfeld, business development manager. “The timeline pinpointed likely future values, needs, desires and aspirations.†|
The VMCC team believe that this type of design approach will become increasingly relevant in the future, with changes in the way people live and travel. Although very much a concept, the Tandem is not simply a design exercise. According to Geza Loczi, VMCC design director, the Tandem is “a real product still in its infancy that needs a lot of molding and tweaking to grow into a full-fledged finished product.â€
Fuel cells are largely envisaged as the most likely successor to the internal combusion engine (ICE) and are at advanced stages of development for use in motor vehicles. Fuel cells are not restricted solely to transport and can be used for power generation in a range of contexts. It is however, transport that is believed to hold some of the greatest possibilities for the technology.
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Background and History
The fuel cell was invented by Welshman Sir William Grove in 1839. It was his ‘gas voltaic battery’ that laid out the principles for modern fuel cells. Grove new that passing a current through water caused the separation of water into hydrogen and oxygen and hypothesised that the reaction could be reversed – thus creating an electric current. From his experiments, he created the first fuel cell. The term ‘fuel cell’ only came later in 1889 with Charles Langer and Ludwig Mond’s attempts to produce a working device.
In the 1960s, NASA used fuel cell technology to create electricity for spacecraft. Further development took place in the ’70s but it wasn’t until the 1980s that testing began in the automotive industry. In the mid ’90s, automotive prototypes were finally coming closer to practical use but the size of componentry was still a serious problem. Now, the size of fuel cell components has become manageable and testing is in advance stages.
The Principles of Fuel Cells
In the most basic sense, a fuel cell works in a similar way to a battery, changing chemicals from one form to another, generating an electric current as a by-product. The key difference is that whilst batteries hold energy to be released, fuel cells can generate energy only whilst they are supplied with fuel and air. The fuel used is typically hydrogen but can take other forms.
Unlike the combustion engine, a fuel cell has no moving parts making it far more efficient. Power is output as electric current which is passed to electric motors which in turn drive the vehicle. A combustion engine can actually only ever transfer a fraction of its input energy into motion; with substantial losses due to converting heat into mechanical energy. Toyota have stated that their conventional petrol engine offers a ‘tank-to-wheel’ ratio of 16% compared to their fuel cell vehicle which offers 48%.
In terms of vehicle design, fuel cells can now be packaged within relatively standard proportions.
The following components must be incorporated:
- Fuel cell stack
- Battery
- Electric motor(s) – depending upon your choice of drive configuration
- Hydrogen tank
- Electronic contol unit.
The Main Types of Fuel Cell
Proton Exchange Membrane (PEM)
PEM fuel cells are relatively small with a good power generation ratio for their size. These systems use a solid polymer membrane as the electrolyte and operate at low temperatures. The solid electrolyte means simpler production and longer life whilst low operating temperatures allow faster start-up and power increase responses.
Proton exchange membrane fuel cells are the choice for automotive applications due to the favourable performance they offer in a small package. All current automotive fuel cells use the PEM system.
More details on the PEM Fuel Cell
Others..
Alkaline
Alkaline systems need pure oxygen and hydrogen to work which makes them less versatile than other types of fuel cell.
Phosphoric Acid
Common for use in industrial power generation, they are typically used in static applications. With their high operating temperature, corrosive electrolyte and complex system, they are not appropriate for automotive roles.
Molten Carbonate
These systems are highly complex and use a molten electrolyte. This means the system operates at very high temperatures; this allows the process to take place without a fuel processor but it is only used in wholesale energy production applications.
Solid Oxide
These systems run at extremely high temperatures and can operate with far less pure fuels than other systems; their overall operation is relatively simple. Planned use as very large static power stations.
This section looks at the principles and design concerns associated with the most common form of automotive propulsion – the internal combustion engine as well as some of the less well know variants and alternatives.
The Internal Combustion Engine
The Wankel / Rotary Engine
The rotary engine was conceived by Felix Wankel in Germany in 1926 with the first functional prototype not actually running until 1957 – this was largely due to the Second World War and the fragmented post-war Germany.
Electric Motors
Electric motors were one of the earliest means of propelling autocars.
