Institution of Mechanical Engineers

Citation

(2002), "Institution of Mechanical Engineers", Industrial Lubrication and Tribology, Vol. 54 No. 2. https://doi.org/10.1108/ilt.2002.01854bac.001

Institution of Mechanical Engineers

Keyword: IMechE

Last November in London the British Institution of Mechanical Engineers ran a symposium entitled "Controlling Friction and Wear in Transport Powerplant". This was the first in a series of seminars being run covering Tribology.

The first paper was presented by Simon Edwards of Ricardo and gave an overview of the tribological implication of future automotive powertrains. It seems that the continual development of the internal combustion engine will create further contaminants for the engine and as well as creating higher mechanical and thermal stresses in the oil. Exhaust gas after treatments seen from the engine builders' viewpoint require the elimination of sulphur and phosphorus from the engine oil. However, at present this seems technically difficult if not impossible and it is clear that engine builders do need to understand more about sulphur and phosphorus compounds. It seems that engine builders have reverted to the bad scientific practice of defining performance in terms of chemical composition rather than, for example, defining what characteristics are desired in the exhaust gas. This debate will clearly be developed as a major issue for oil formulators. What is clear is that future powertrain development will create tribological challenges.

Dr Guangteng Gao described work that he and colleagues at Ford Motor Group have done concerning friction and cold starting of diesel engines. Current automotive diesel engines are rarely able to start reliably below 20°C but Ford require new engine designs to be able to start at 30°C. The work done has established a modelling situation that can predict friction and other cold start parameters. This leads to the starter motor and other start equipment requirements being clearly understood. The experienced gained using this prediction technique has created interest in the tribological aspects of the engine in attempts to reduce friction. Different types of cylinder bore honing and surface coatings in various parts of the engine are being evaluated. The workers reported that more accuracy is needed for this modelling technique but the initial results have been very fruitful. It will be very interesting to hear more on this subject in the future when more development has taken place.

Charles Bovington gave a review of the lubrication of automotive power plants. The basic functions of an engine oil were explained together with an insight into how these functions will change as engines are developed in the coming years. Again it was emphasised that both mechanical and internal loading of the lubricant will be increased as changes are made to surfaces and design of pistons and cylinders, bearings and of course extra exhaust gas after treatments. The presentation ended with the comment that changes taking place in power plants will require very close co-operation between engine designs, lubricant chemists and tribologists. The "zero sulphur and phosphorus" situation must be avoided in the future.

Francis Davis of the National Physical Laboratory gave the conferences a tribological tour of the internal combustion engine. This included a look at the different types of lubrication and frictional losses in an engine. Some thoughts on bearing design and positioning of the oil supply hole were presented together with details on the lubrication of piston and cylinder. Of particular interest was work done showing how attaching a cylinder head to an engine block actually caused distortion of the cylinder bores. The "tour" was completed by a roundup of the materials found in an engine.

Derrick Parker of Glacier Vandervell described how his company's computer modelling techniques were used to promote improved bearing designs. Amongst the many interesting points to emerge was how the film pressure inside a 'big-end' bearing was influenced by the design of the connecting rod. Again in this paper was a topic mentioned in others namely the distortion of engine components solely due to exposure to their normal operational temperature span. In this case main bearings were shown to change shape significantly between 20°C and 160°C. The paper concluded with a comparison between the computer modelling techniques and the other theoretical methods and actual measurements of oil flow versus engine speed to achieve full bearing lubrication.

Jonathan Leggett of Rolls Royce gave an interesting account of his work as a tribologist in the aerospace industry. It is clear that tribology is a very important factor in gas turbine engine development. The paper described many different examples of how surface finishes and coating were being developed to improve the life, reliability and economy of operation of the engines. One of the most interesting points was the development of abradable coatings for liners. In this case the liner must wear after contact with the turbine blade to allow a perfect fit but must not damage the blades or produce heavy debris. A very interesting paper illustrating the problems involved with a different type of powerplant.

After the papers were something a brief discussion followed and the papers authors were able to provide the audience with further insights into their experiences in powerplant tribology problems.

This symposium cannot be praised too highly. All levels of knowledge were catered for and all attendees left with new knowledge or a new perspective on an old problem.

Further conferences of this type will be held during 2002 and we will try to keep you advised of dates as they are announced. We do however recommend your attendance at what we believe will be an excellent series of events. The organisers should be congratulated on the quality of this event.