None of the leading alternative powertrain technologies are ready to replace our reliance on fossil fuels for mass-market vehicles in the near term. We must therefore focus clearly on improving the technology used in mass-market, fossil fuel-burning vehicles.
In recognition of this need, vehicle manufacturers are targeting engine downsizing as a primary technical approach. It is likely that most premium gasoline engines will be downsized within five years as is already the case for diesel engines; however, there is still more scope for downsizing.
The aim of downsizing is to use advanced air management techniques to deliver the performance of a large engine with the economy of a small engine.
None of the leading alternative powertrain technologies are ready to replace our reliance on fossil fuels for mass-market vehicles in the near term.
Obstacles such as poor transient response of the turbocharging system, inflexible and inefficient turbocharging devices and a lack of knowledge exchange between suppliers and end-users have delayed adoption of downsizing.
The use of turbocharging to facilitate engine downsizing has a very attractive cost to benefit ratio and can be employed across the entire product range. Downsized engines are more expensive than those they replace due to the higher technology costs involved, but they are significantly less expensive than the alternative low CO2 approaches.
Importantly, the materials and processes used are commonplace, meaning that mass production can reduce the costs involved. In addition, the fuelling infrastructure is already in place to take advantage of these developments, and the market appears ready to accept the products.
At today’s fuel prices, a driver who covers average mileage in the UK will be better off by around £400 (US$630) each year if they move from an average CO2 emitting vehicle (140.3g CO2/km in 2010, according to the European Environment Agency) to one emitting around 100g CO2/km.
Interestingly, the consumer could do this simply by moving from a gasoline vehicle to the equivalent diesel; however, evidence presented by sales of diesel cars is that only 50% of new car buyers are willing to pay the £2000 extra on the purchase price.
This shows that if improved hardware is to have real impact in the market it needs to be affordable. Downsizing has the potential to meet this requirement.
In the medium term, it is crucial to move the debate from the single issue of CO2 towards a more holistic view of sustainability. If we wish to retain our current road transport model, we must look towards sustainable vehicle technology.
Downsized engines are more expensive than those they replace due to the higher technology costs involved, but they are significantly less expensive than the alternative low CO2 approaches.
In this respect, the long term sustainability of electric or hydrogen vehicles is still unclear due to the limited resources consumed during manufacture, and the scarcity of renewable sources of electricity. Considerations of whole-life-impact suggest that a logical course of action is to facilitate improvements in today’s powertrains, which are built largely from inexpensive, abundantly available and easily recycled materials.
The potential for sustainable CO2 and cost savings through downsizing are significant. Added to this, time is short, and therefore it is imperative that the technologies selected can be developed quickly, using new and improved tools.
The opinions expressed here are those of the author and do not necessarily reflect the positions of Automotive World Ltd.
Dr Chris Brace is an automotive researcher at University of Bath’s Powertrain and Vehicle Research Centre
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