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Metal Casting Technologies : March 2006
There are many technological changes that have been tested and proven that can reduce fuel consumption of the internal combustion engine and while each individual change may only reduce fuel consumption and emissions by one or two percentage points, in combination there is a potential for 25 to 30% improvement. It takes several years to develop and test new engine technologies and carmakers have been reluctant to introduce the improvements quickly for fear that increasing the 'sticker price' may make their vehicles uncompetitive. If the demand for fuel efficiency continues, it will force carmakers to introduce the changes because once they become standard in one model, others will be sure to follow. Vehicles are progressively becoming electrified as the engine becomes more and more matched to its other powertrain components. Electric power steering and braking as well as electric air-conditioning will progressively become the norm, enabling engineers to refine the engine improvements. Eventually, the all electric car will open the way to the fuel cell car. The fuel cell is widely seen by environmentalist and car companies alike as offering the most attractive long term solution but there are substantial technological challenges to be faced. Durability, cold start performance, power density and affordability issues have to be solved. Before the fuel cell is used widely in cars, however, we also have to solve the issuesd of availability of high-purity hydrogen produced and distributed safely without generating greenhouse gases, as well as a means of storing the hydrogen on-board the vehicle. The IEA report says "A transition to a near-zero-emissions transportation system will likely take three or four decades" and that means we'll be relying on oil and alternatives for many years to come. The fuel cell has the attraction of being small enough -- no larger than an internal combustion engine -- to be suitable as a source of on-board power. We already know the technology. Most carmakers have prototype cars at various stages of testing. I believe that buses will probably be the first to take up fuel cells widely because they operate in a confined range in cities. Storing hydrogen is much less of an issue than for cars. Early electric cars showed that having to store enough electricity to support an acceptable range wasn't practical. Batteries that could store sufficient electricity for a day's driving either weighed too much or cost too much. The hybrid car is the compromise using electrical energy as an assist to a smaller engine, and also capturing the energy that is freely available when slowing down or braking. Hybrids will grow in volume, reducing the cost penalty. Eventually, when clean hydrogen is available, fuel cell cars will be feasible. The hydrogen can be made using electricity from solar collectors or windmills or nuclear or other clean electricity sources. Most of the technologies supporting a fuel cell vehicle are the same as those for a hybrid vehicle. Batteries and capacitors will continue to improve, not just for automotive use, but for a very wide variety of applications, and it may well be that the improvements in battery technology will allow sufficient energy to be stored in batteries and capacitors for a day's driving. If this were so, a small internal combustion engine could be all that is needed to provide back-up power. In this case, it may not be worth the trouble of carrying the hydrogen on board. The plug in car would be the answer. Fuel cell technology will continue to attract massive investment anyway for base-load energy as well as for automotive applications. Alternative fuels are the short term opportunity. Australia has the highest acceptance of LPG and it becomes more attractive as oil prices rise. Ethanol is a useful means of stretching oil supplies but the plan for 350 million litres per year by 2011 only amounts to about one percent of our oil use. Even diluted to E10 we could use ten times as much. Natural gas too could be used to power many of our vehicles. Refinement of the internal combustion engine will continue, but will probably be concentrated on small engines. The sum total of resources devoted to making gasoline and diesel engines is so colossal that it would take a couple of decades to replace them all even if we started now, so, aside from the technology issues, it is easy to see that the internal combustion engine has many years of life left. Success of the all-electric car and the set-up time for hydrogen infrastructure are the factors that will most likely hold back mass production of hydrogen vehicles. Intelligent Transport Systems will happen anyway regardless of the other developments because we will always need to improve traffic flow. In summary, our oil-based future is uncertain. Global climate change is more widely recognised as a critical and very urgent issue. Affordable fuel cell cars & trucks are many years away. Alternative fuels will be needed for at least 20 years. Hybrid cars are a valuable contributor to reducing fuel use and emissions. Engines are likely to become smaller as they become more the 'top-up' power source. The all-electric car may answer all needs for city cars and may prove so attractive that carrying hydrogen around will be unnecessary. The transport dilemma is serious (but clean electrical energy is even more serious) We urgently need a roadmap to guide us to the best use of our unique resources and to a sustainable transport future. ● TECHNICAL FEATURE www.metals.rala.com.au 26