Automotive Powertrain Tribology
Automotive powertrains experience inefficiencies that result due to the relative motion of the interacting components. Our research uncovers the key physical phenomena that generate and influence these frictional parasitic losses.
Improving the efficiency of automotive powertrains increases the vehicle range and power outputs. Our research studies the physical mechanisms that cause frictional losses and energy dissipation. Thus, our aim is to design powertrain components and systems in order to reduce the unwanted parasitic losses.
The research group works across a range of powertrain systems and components, such as transmission and differential gearing, shaft seals, radial lip seals, transmission rolling element bearing, as well as piston ring, piston skirt, valve-train and engine bearings in internal combustion engines.
Our research utilises a combination of multi-scale and multi-physics experimental work and numerical analysis. The efficiency of the interacting contacts highly depends on the coupled dynamics and tribological conditions at the contact and both aspects are carefully considered in any analysis. Experimentally, system and component level test rigs are used to determine frictional behaviour. These include:
- Engine test cell facilities
- Mini traction machine (MTM)
- Reciprocating tribometers
- Pin on disc tribometers
- Motored engines
- Motored transmisson sytems
- Gear Pair test systems
- High speed bearing test rigs
- Wet clutch rigs
Understanding the frictional behaviour is attained using a range of surface characterisation techniques for topographic analysis:
The Dynamics Research Group has completed numerous research projects with a variety of industrial partners in recent years. Key research projects and related outputs are summarised below:
- EPSRC-funded ENCYCLOPAEDIC national programme grant (EP/G012334/1) “Refinement of Engine in-cycle losses of Parasitic and Errant Dynamic Nature”. Some examples of published research from this project are:
- Tribodynamics of clutch system for engine-downsizing in heavy duty off-highway vehicles
- Tribology of piston compression ring conjunction under transient thermal mixed regime of lubrication
- On the Transient Three-Dimensional Tribodynamics of Internal Combustion Engine Top Compression Ring
- On the Effect of Transient In-Plane Dynamics of the Compression Ring Upon Its Tribological Performance
- Influence of In-Plane Dynamics of Thin Compression Rings on Friction in Internal Combustion Engines
- Transient elastohydrodynamic lubrication of rough new or worn piston compression ring conjunction with an out-of-round cylinder bore
- Direct measurement of piston friction of internal-combustion engines using the floating-liner principle
- On the boundary conditions in multi-phase flow through the piston ring-cylinder liner conjunction
- Transient tribo-dynamics of thermo-elastic compliant high-performance piston skirts
- Combined numerical and experimental investigation of the micro-hydrodynamics of chevron-based textured patterns influencing conjunctional friction of sliding contacts
- InnovateUK funded “Engine Based Driveline Disconnect for Downsizing” (102249). Examples of published research:
- InnovateUK funded “Eco Driveline – An increased efficiency driveline” (102257). Examples publications:
- The Dynamics Research Group is also involved in the EPSRC funded Centre for Doctoral Training (CDT) programme in Embedded Intelligence (CDT-ei)in collaboration with various industrial partners through the following projects:
- “Lubricant-Surface System Mitigation In-Cylinder Friction”. Example publications:
- “Tribodynamic Analysis of Bevel and Hypoid Gears”. Example publications:
- Transient analysis of isothermal elastohydrodynamic point contacts under complex kinematics of combined rolling, spinning and normal approach
- Lubricated loaded tooth contact analysis and non-Newtonian thermoelastohydrodynamics of high-performance spur gear transmission systems
- Lubricated loaded tooth contact analysis for spur gear pair
- “Elastohydrodynamic Lubrication in Piston-Ring Pack Assemblies”. Example publications:
- The Dynamics Research Group is involved in EPSRC funded Doctoral Training Partnership (DTP)programmes in collaboration with various industrial partners through the following projects:
- “Lubricant-Surface Interaction as a System”. Example publications:
- “Study of Radial Lip Seals for Automotive Transmission Systems”. (Ongoing) Example publication:
- “Tribodynamics of Ball CV (Constant Velocity) Joints”. (Ongoing)
- “Simulation of Transient Wear in Elastohydrodynamic Contacts of Gears”. (Ongoing)
- The Dynamics Research Group has also collaborated with various industrial partners through research as well as enterprise routes. Examples of projects and published work include:
- Performance of poly alpha olefin nanolubricant
- Inefficiency predictions in a hypoid gear pair through tribodynamics analysis
- On the effect of dlc and wcc coatings on the efficiency of manual transmission gear pairs
- Multiscale boundary frictional performance of diamond like carbon coatings
- Effect of teeth micro-geometrical form modification on contact kinematics and efficiency of high performance transmissions
- Heat generation and transfer in automotive dry clutch engagement
- Behaviour of rolling element bearings under ultra-high speed conditions of electrified powertrains.
- Laser treatment of metal surfaces for tribological enhancements.
- Application of solid lubricants in automotive powertrains.
- NVH refinement of electrified dual-clutch transmission for luxury passenger cars
- Numerical analysis of air foil bearings for high speed applications
- Characterisation of drivetrain tribology and dynamics using physical components.