The transport industry is on the move. From hybrid helicopters to sleeker, more streamlined conventional vehicles, here are five innovation trends that might just drive the future of transportation.
"Simplify, then add lightness." Those are the words of the late Colin Chapman, founder of sports and racing car manufacturer Lotus. While the British automotive engineer was referring to his philosophy of racing car design, his views resonate in many modern designers' approaches to improving energy efficiency: replacing steel with lighter materials.
One recent example is provided by BMW's new all-electric city vehicle, the i3. It is constructed from aluminium and plastic reinforced with carbon fibre, which makes it 30-50% lighter than it would be if constructed from steel. The i3's light body helps offset the weight of the battery pack used to power the car and ensures that driving characteristics such as acceleration, braking and cornering are similar or superior to those of conventional cars.
Norbert Enning and Ulrich Klages are another pair of high-profile innovators in this field. The 2008 European Inventor Award finalists developed an integrated weight-bearing system constructed from aluminium that lends a car's frame maximum stability at minimum mass.
New methods of propulsion can also slash weight. For example, electric buses and trams using battery power alone have the disadvantage that they need a very large, heavy battery pack to cover an entire route. A lot of energy is wasted in accelerating and decelerating the mass of the vehicle.
The patented work of vehicle manufacturer Bombadier Transportation GmbH, marketed under the brand name Primove, addresses this issue through inductive power transfer - a principle already used in charging electric toothbrushes and other household devices.
Electricity running through an induction coil in the ground creates a magnetic field that produces a charge in a vehicle-mounted receiver. Wayside components along the coil that charge the vehicle are switched on only when the vehicle is directly above them. Without a heavy battery, the trams or buses are lighter, so much less energy is needed to move them.
Train aerodynamics used to be all about the front end. However, a team comprising René Blaschko, Alexander Orellano, Martin Schober and Andreas Tietze at Bombardier GmbH has patented an innovation that smooths airflow over the entire length of a train.
The invention uses a special bodywork surface treatment to create a larger number of small vortices of turbulence along the length of the carriages, rather than a few large ones. This helps the train slip through the air more easily and significantly reduces the wind noise it generates as it travels.
What's more, it increases passenger comfort and reduces noise disturbance for people and animals living along train routes.
Another key patenting trend affecting energy efficiency in transport, at least in terms of its future benefits for society, is rooted in design philosophy. Increasingly, designers are moving away from improving individual aspects of vehicles over the course of model life cycles towards completely redesigning vehicles to be more energy-efficient from inception.
European aircraft manufacturer Airbus provides a perfect example. The company is exploring the use of a patent secured by Graage Klaus of German manufacturer DBB Fuel Cell Engines GmbH to replace gas-turbine-based auxiliary power systems in future aircraft with ones based on hydrogen fuel cells.
The fuel cells will form an integrated system that generates electrical energy to power everything from the plane's air-conditioning and water systems to driving the wheels during taxiing.
The cells can even be used to replace the energy supplied by aviation fuel to the aircraft's engines during descent, when power output requirements are low. Doing so significantly improves the aircraft's design and makes energy efficiency and production of fewer harmful emissions a central design objective.
The KERS kinetic energy recovery system is an established technology for the recovery and reuse of energy created when a vehicle brakes. It is already used in Formula One and Le Mans series racing cars, and manufacturers such as Volvo are developing similar systems for passenger cars.
Less well known but equally innovative is a system designed by British inventor Dr Thomas Tsoi Hei Ma. He has developed an energy control assembly that allows power generated by acceleration and deceleration to be stored as compressed air in a tank rather than as electric power in a battery. The air is then transferred between the tank and the battery as needs dictate. It's a clean, light solution that works as part of a hybrid air and combustion engine, reducing energy consumption and CO2 emissions.
Moreover, the technology is taken seriously by automotive giants like France's Peugeot-Citroën. The company holds more than 80 patents in this area and intends to launch a range of hybrid air passenger cars by 2016, which could deliver fuel savings of up to 45% compared with conventionally powered vehicles.
It's not just the automotive industry that is investigating new ways to power vehicles. Another patent held by aircraft manufacturer Airbus describes an innovative way to power the flight of helicopters: an electrical engine supports the power provided by the main combustion engine to enable variable control of the speed of one rotor.
This allows energy consumption to be optimised depending on whether the helicopter is taking off, flying or landing. The system also stores excess electrical energy that can then be released to provide more power as needed.
Eventually, though, it may be possible for some aircraft to travel around the world without any kind of traditional engine power. That's the goal of Solar Impulse, a long-range solar-powered flight project developed by the Swiss Federal Institute of Technology in Lausanne.
The project team has created an aircraft with the same wingspan as an Airbus A340 airliner that uses the sun to charge lithium polymer batteries via 11 628 photovoltaic cells on the upper wing surface. The batteries power a 10 hp motor and a twin-bladed propeller. Excess energy is stored during the day so that the plane can also fly at night. The aircraft has already completed extensive test flights in Europe and the USA lasting up to 26 hours, and a round-the-world test flight is planned for next year.