by Stuart Birch
European Editor, Automotive Engineering
A challenge for any automotive company is to produce vehicles that combine performance with economy. Cosworth, the British company famed for its racing successes, knows all about extracting every last kilowatt of power from an engine rather than every last kilometre from a litre of fuel.
But that is changing. Cosworth, which recently opened a new Emissions and Driveability Centre (EDC) for research and development, is broadening its automotive technology application to embrace wider aspects of engine design, research and development including advanced concepts that may provide exceptional fuel consumption figures.
A significant element of this work is the Merritt cycle petrol engine. Dr. Dan Merritt of Coventry University believes his concept which has a second, small piston in the cylinder head, shaped and driven like a valve has great potential . It may prove to have an economy potential superior even to a diesel.
Cosworth is working in collaboration with Merritt to develop an engine to demonstrate the principle. The decision to go ahead with the demonstrator engine came at the end of a year of research and development that saw the construction of a single-cylinder lean-burn 440 cc research engine. This is undergoing test work on a special dynamometer designed and built by Cosworth themselves. Merritt - specific systems which include electronic engine management are also being developed.
Although cast iron is being used for the research engine, if the concept enters production as a multi- cylinder power unit, aluminum would be used. While the engine would have applications for several types of vehicle, it would be particularly apposite for those being sold into emerging markets.
"No doubt this project will surprise those who know Cosworth for its racing and high-performance road car engines " says Cosworth's chairman Chris Woodwark. "However, facilities like our new EDC make Cosworth capable of taking such concepts through design, development, calibration and into production cost effectively."
The Merritt engine is just one of the projects being developed in the EDC where the company's design, engineering and manufacturing skills are being applied to prove a wide range of technology.
At the official EDC opening, Cosworth Engineering's managing director Rob Oldaker said, "Within a single facility we have an integrated data acquisition process covering both vehicle and engine testing." The ceremony was performed by Britain's Secretary of State for Transport, Sir George Young.
"Not only can we develop engines in vehicles but we can simulate on the engine in isolation, conditions of vehicle use such as gear-changes and warm-up. By eliminating much of the variation associated with vehicle testing, the development process can run faster and more accurately, bringing simultaneousengineering benefits to the entire process; time after time, the same conditions can be repeated."
As well as speeding the development process for new vehicles, and so cutting costs, the capability of the EDC will reduce the number of first-level prototypes needed - always a very expensive part of any vehicle programme.
The £3 million EDC brings to £26 million the investment in Cosworth - a division of Vickers plc - since early 1 995. The centre offers - even to customers not using Cosworth to design and manufacture an engine - facilities that include test cells and rolling roads with climate-control test capability spanning temperatures of minus 40 to +40 degrees C.
Together these reduce the need for motor manufacturers to take vehicles to remote areas of the world for on-road testing. That also means modifications can be made quickly and relatively easily and results are of a higher quality and more reliable, as human characteristics are avoided, claims the company.
This elimination of variation associated with on-road vehicle testing allows faster development bringing an added dimension to the simultaneous engineering process. Confidentiality is a vital part of Cosworth's business and technology philosophy, but as well as the Merritt engine, the company has given a glimpse of some of its other current research and development projects.
Among these is a system of port throttling with barrel throttles. These provide an individual throttle, close to the inlet valve, for each cylinder. Cosworth sees this as a route towards added engine efficiency and improved economy.
As legislation in many countries tightens further, the pursuit of reduced engine emissions is never ending, and Cosworth's research work also includes the investigation of techniques for improving cylinder-head cooling as a potentially effective means of reducing them.
Indications are that hydrocarbon emissions can be cut by about 10% while an added bonus is a slight improvement in power output . The company believes its precision cooling techniques could be easily integrated into current production engine designs.
But improved fuel economy, lower emissions and advancing technology must not create vehicles that are unpleasant to drive. No part of modern vehicle technology can be developed independently: it must integrate with the whole. It is a fact of which Cosworth is well aware.
"For all of us low emissions combined with excellent: driveability are vital requirements of any programme," says Rob Oldaker. Cosworth's new EDC has been designed to achieve those aims.