New rig for friction studies

Researchers at Leicester University and Jaguar Engineering Centre are developing an engine-testing rig that will be used to study friction in automotive engines.

Researchers at Leicester University are developing an engine-testing rig that will be used to study friction in automotive engines, which is one of the main sources of inefficiency and energy loss.

Frictional losses occur in all automotive engines, primarily in the piston system, the valve-train and the engine bearings. The focus of the research work on the rig will be on valve train friction.

The facility is being developed as part of an on-going collaboration with the Jaguar Engineering Centre, Coventry. The rig uses a Jaguar 4.2L V8 engine cylinder head and can be driven at a range of speeds up to 1000rpm. It tests in the range of slow or idle speeds where engines suffer most friction and wear on start-up.

The valve-train in an engine is responsible for approximately 10% of the engine’s frictional losses at high engine speeds but is far more significant at low engine speeds. According to the Leicester team, this is an important area for controlling and reducing frictional losses.

The rig reportedly allows the frictional torque between a cam and tappet to be measured. It will allow engineers to investigate new materials, contact geometries or oil formulations, and is a versatile tool for looking at ways in which friction in the engine can be controlled.

Jaguar engineer Mr Dave Richardson said: ‘The modern car engine is a complex dynamic system; none more so than the cam-tappet interface where the properties of the components surface finish, the lubricant and additive chemistry, combine to keep the highly loaded surfaces apart.

‘Knowledge of the way the friction changes as the cam rotates allows engineers to optimise the design of components and lubricants, ultimately leading to savings in fuel used over the life of the vehicle.’