Imperial celebrates its automotive research prowess
26 February 2013
Colin Smith takes a guided tour with Imperial College London academics to discover how their research is helping to shape the future of automotive design.
Turbochargers can reduce the size of an engine without compromising on performance, says Professor Martinez-Botas
The Department of Mechanical Engineering at Imperial has been at the forefront of research to develop the next generation of vehicles for more than 40 years. Researchers in the Department are working to improve combustion engines, advance hybrid motors and progress the way that cars are put together in an effort to make the next generation of vehicles safer, more economical and more sustainable.
For 30 years, Professors Yannis Hardalupas and Alex Taylor have been working behind the scenes on projects to improve the performance of combustion engine vehicles. They feel that ongoing refinements to the engine will enable it to maintain its dominance for many years to come.
Currently, their research involves investigating the effectiveness of new types of fuels such as bio ethanol and synthetic alternatives for use in combustion engines.
They are also looking at ways of modifying the diesel engine so that it can run on regular gasoline. Diesel engines are very fuel efficient but have high emissions, whereas gasoline engines are less fuel efficient, but have lower emissions. The researchers say making a diesel engine run on gasoline could improve their fuel efficiency and reduce harmful particulate emissions to zero.
Particulates from car exhausts currently cause smog that leads to approximately 25,000 preventable deaths in the UK each year.
Professor Taylor said: “Since the 1970s a lot of research has been devoted to improving the way that combustion engines perform to reduce their impact on the environment. We believe that we can still make them even cleaner and more efficient, which means that these engines could stay around for a lot longer than many people previously predicted.”
Another way to make combustion engine vehicles even more efficient, say researchers is to add a turbo charger.
“Turbo chargers aren’t just for petrol heads,” said Ricardo Martinez-Botas, Professor of Turbomachinery. “They provide a solution that can make the family car more sustainable.”
Turbo chargers work by sucking more air into the engine, which increases its power. It enables manufacturers to downsize an engine without compromising on their power or performance.
Professor Martinez-Botas has patented a system that uses exhaust gases to propel a high-performance turbine. This is coupled to a high-speed electrical generator, making use of energy that would otherwise go to waste. This technology would reduce the number of engine cylinders from six to four, while still enabling the engine to maintain its power as if it was a six cylinder unit. Professor Martinez-Botas says the technology could cut fuel consumption by up to 35 percent.
Other methods for improving fuel efficiency involve completely reconfiguring how car engines work.
Already becoming more prevalent on the road, hybrid cars combine a conventional combustion engine, which is more efficient over long distances, and batteries that power electric motors, which are more efficient for stop-start driving in city environments. Some engineers in the Department predict that these hybrid vehicles may become one of the dominant modes of transport in the future.
Dr Greg Offer, EPSRC Career Acceleration Fellow in the Department, said: “Hybrid cars could be the type of technology that completely transforms how we drive. However, more work needs to be done to understand how batteries function to improve the performance of these vehicles.”
Dr Offer is studying the electrochemistry of batteries to improve their effectiveness and longevity. In particular, he has developed a device that enables the physical conditions of the road to be simulated to test how batteries perform.
New industrial processes
Imperial researchers are not just carrying out work under the bonnet to make cars more efficient. They are also looking at ways to make the bodywork - which includes the chassis and frame - lighter. Jianguo Lin, Professor of Mechanics in the Materials Division, is working with industry to improve the processes for making chassis and frame components lighter, without compromising on strength.
Currently, the frame and chassis is made from steel, which ensures that passengers are protected from impacts should they be unlucky enough to be in an accident. However, these steel frames are heavy and reduce fuel efficiency. Professor Jianguo Lin has devised a method that will enable manufacturers to replace some of the heavier steel frame components withe lighter aluminium equivalents that are just as robust.
“Our method combines two processes in one where the aluminium alloy is heated and stamped into a shape to make a part. Heating the alloy makes it more malleable, which means that it can be formed into shapes that are much stronger,” said Professor Lin. Making the car frame lighter, Professor Lin says, could reduce fuel consumption in a standard vehicle by up to 23 percent.
Professor Lin has established a start-up company through Imperial Innovations, where to he aims to license this technology to automotive manufacturers around the world.
There are other ways of making the family car lighter and academics are also working with car makers to apply manufacturing techniques used in Formula One.
Of particular interest to researchers are composite materials, particularly carbon fibre reinforced plastics, which are used to make body parts for Formula Onen racing cars. However, these materials are currently expensive to produce.
Dr Ambrose Taylor, who is a Reader in Materials Engineering, is investigating new processes for manufacturing composite material so that it is more cost effective to produce. In particular, Dr Taylor is working on projects to increase the toughness and lower the cost of producing this material via improved manufacturing processes and through the use of nano-materials.
Dr Taylor said: “The humble family estate car could in the future have its roof or bonnet made from the same material that is used to build Formula One cars. Composite materials could help to make car bodywork lighter, while maintaining its strength and durability.”
Bonding, rather than welding, more car parts could also lessen the load say researchers. Adhesives are currently being used by manufacturers such as Aston Martin and Lotus; they can help reduce the overall weight of a car and improve fuel efficiency, as well as absorbing energy, making assemblies more shock resistant.
Working with adhesive manufacturers such as the German company Henkel, Dr Taylor is also carrying out evaluations of adhesives to determine their durability, as well as making improvements to their formula so that they can be produced at lower cost and last longer.
Tribology specialists at Imperial are currently working with SKF on ways to reduce friction and increase the reliability of wheel bearings. They are also working with the company Valvoline to design low friction oils for gear lubrication, and with energy giant Shell to develop lubricants that improve the efficiency of engines.
Professor Hugh Spikes, who heads the tribology group at the College, said: “A large proportion of the energy from fuel used in cars is ultimately wasted in the engine, the transmission, the tyres and even the windscreen wipers due to friction. Reducing friction is an important way to reduce fuel consumption of cars to make them more sustainable.”
The next generation
Future improvements to how cars perform will rely on the next generation of engineers being fully prepared for what industry requires, say researchers. That is why the Department is working on a range of student initiatives such as Imperial Racing Green (IRG). Professor Peter Cawley, Head of the Department of Mechanical Engineering, concludes:
“It is not enough to be world leaders in automotive research. We also need to be able to enthuse and prepare the next generation of engineers about the challenges and opportunities that lie ahead. That is why project such as IRG are so important. Thanks to the support of our academics, students get the opportunity to design, build and race their own low emission racing cars. This provides them with some of the valuable skills needed in their careers and prepares them for an industry that is moving towards a very low emission future."