Low Carbon CarsThere has been a 25-year history of collaboration between the University of Bath and Ford Motor Company. During the 1990s, work focused on removing noxious fumes and pollutants. But for the last 10 years, the direction has been on fuel economy and cutting CO2 emissions.

This collaboration has resulted in improvements across the range of engines within everyday passenger cars, such as the Focus, Fiesta and Ka. For example, in terms of carbon emissions ratings, Ford now offer several A-rated models, producing less than 100g/km CO2, which simply didn’t exist three years ago.

With greater demand from both the car purchasing public, and tighter regulations, the challenge to produce safe, affordable, clean and increasingly environmentally-friendly cars is one which continues to be pursued at the University of Bath.

Current options for fuel efficiency

Electric cars struggle to meet the requirements of most buyers since their range is limited. Either a change in customer usage patterns or a significant breakthrough in battery technology will be needed if this issue is to be overcome. Until the grid is de-carbonised, the overall CO2 problem will remain. Hybrid power has a lot to offer, but their current fuel economy is not significantly greater than an equivalent diesel engine car. The plug-in hybrid is receiving considerable attention, but the grid issue still surfaces. Hydrogen as a fuel could be the ultimate solution, but issues with onboard storage and availability still need to be overcome.

Conventionally powered passenger cars, especially diesels using petrochemical fuel, are showing considerable fuel economy improvements with lower carbon footprints.

What further improvements can be achieved?

Professor Gary Hawley, University of Bath, said: “Passenger cars in the UK produce around 72 million tonnes of CO2 every year, but over the last ten years this has been gradually reducing through advances in engine technology, vehicle dynamics and greater use of lightweight materials in vehicles.”

The average CO2 emissions produced by new cars in the UK has fallen, year on year, from 189.9 g/km in 1997 to 149.5 g/km in 2009 - a reduction of 21.3%. So, what does this mean in relation to reduced CO2 from the total car population? Between 1997 and 2008, the number of cars on the roads in Great Britain has increased from 25.6 million to 30.3 million, and the total distance travelled has increased from 365.8 billion km to 401.7 billion km. The net effect is that CO2 has still fallen during this period of car growth and travel - from 75.4 million tonnes to 71.1 million tonnes [1].

The industry is well on its way to meeting EU regulatory targets of 130g/km fleet average by 2015, but the current rate of improvement must be maintained.

Prof Hawley commented: “A 1% improvement in fuel economy represents 750,000 tonnes CO2 saved each year, if applied to all passenger cars. Here at the University of Bath we are working to achieve a 10% fuel saving.”

Additional research

Research at the University of Bath has historically been conducted in collaboration with the Ford Motor Company, and more recently within two consortium projects funded by the Technology Strategy Board and the DTI. This research has focused on enhancing the fuel economy of diesel powered passenger cars and consequently, reducing CO2 emissions. A rigorous and precise approach has given a better understanding of the effects that engine cooling and lubrication systems have on vehicle fuel economy.

Dr Chris Brace, University of Bath, commented: “Engineering has to have an application – pure research is of limited value. We want to see the impact on the road. Once we’ve shown the potential here at the university, Ford can build our research findings into their own development. Academic research lives on in technical publications – but to see it out there in vehicles being used everyday is a very exciting outcome for us.”

Ian Pegg, Senior Research Engineer at Ford Motor Company in Essex, is equally enthusiastic: “Working with the University of Bath, we can look at things differently. In industry, it’s very easy to get stuck in a rut and take things for granted, but the academics will challenge and investigate measurable benefits. Sometimes, for example if we have a negative finding, we will come out with an in-depth knowledge of why it doesn’t work, and can therefore focus on chasing benefits in a different area.”

So, what have been the outcomes of this ongoing work?

Improvements have been made to the layout, operation and control of vehicle engine cooling systems. The impact of these modifications has led to a fuel economy saving of up to 2%.

The heart of an engines lubrication system is the oil pump – the design and construction of which has barely changed since engines were first developed. The work on new designs has validated and quantified fuel economy savings of up to 3%.

The work undertaken on assessing different formulations of lubrication oil has significantly enhanced knowledge on the interaction between lubricating properties and fuel economy. This knowledge is being fed into the next generation of lubricating oil formulations which will deliver a 1% fuel economy saving.

Laying the groundwork for future generations

It is clear that no one technology or modification will significantly enhance fuel consumption and reduce CO2 from passenger car engines. The research has shown that the accumulation of a number of small but measurable improvements can deliver significant impact. Progress is made through a complete understanding of the theory and practice of the detailed working of the engine, and the ability to assess the effects precisely in an experimental setting. These specialisms have been developed at the University of Bath so we are able to act as a valuable partner to Ford in the appraisal and development of new technologies to feed into production vehicles.

The work undertaken at the University of Bath has a very high impact due to its relevance to every internal combustion engine powered vehicle sold in the UK –and is laying the groundwork for future generations of ‘affordable’, low carbon, passenger car vehicles.

Refs

1 The Society of Motor Manufacturers and Traders New Car CO2 Report 2010, available at http://www.smmt.co.uk/wp-content/uploads/sites/2/New-Car-CO2-Report-2010.pdf.

2 Review and analysis of the reduction potential and costs of technological and other measures to reduce CO2-emissions from passenger cars (contract nr. SI2.408212), Final Report of the project carried out by TNO, IEEP and LAT on behalf of the European Commission (DG-ENTR). Available at http://ec.europa.eu/enterprise/sectors/automotive/files/projects/report_co2_reduction_en.pdf