iTurbo: Exhaust Energy Recovery in Low Carbon Vehicles by Intelligent Turbocharging

Lead Research Organisation: Imperial College London
Department Name: Mechanical Engineering

Abstract

Low Carbon Vehicles and challenging emissions standards are pushing the engine boosting system beyond the limits of current technology with the aim to aggressively downsize the internal combustion engine. This approach is one of the most promising engineering solutions to achieve a rapid, large scale decarbonisation of road transport. However, a detailed analysis of turbocharging options and matching techniques for the future gasoline and diesel engines is essential if we expect to meet the needs of heavily downsized engines and future hybrid power trains (including range extenders). The actual state of the art for downsizing has moved towards the introduction of more complex systems; such as double stage turbo system, a combination of turbocharger and volumetric compressor or electric assisted supercharger/turbocharger combination. These go well beyond the traditional optimization of single stage turbocharger. Energy utilisation can be improved in all these cases if the turbocharger design/selection is taken in the context of its true operating environment by carefully considering the unsteady flow energy contained in the exhaust engine stream. This proposal addresses recognised boosting needs in two fundamental manners. Firstly, it will propose methods for the treatment of turbocharger selection in the direction of enhanced energy recovery at present not embedded in the selection, matching and design process of engine technology. Secondly, it will investigate and propose the transfer to the automotive industry of the concept of active control in turbocharger operation by means of pulse matching techniques, developed in the Turbocharger Group at Imperial College London.iTurbo is focused on future air management strategies to make low carbon engine technologies harness the available exhaust energy in reciprocating engines. The state of the art in design and engine air management only makes use of the steady turbomachinery component maps, thus forcing the design, matching and eventual installation along lines of quasi-steady operation. Critically, such an approach does not harness the full energy potential contained in an unsteady flow. This study will therefore investigate the potential for a better selection of air management components (compressor, turbine, electric assisted, superchargers, etc) in view of the reality of a fully pulsating exhaust flow.One novel potential technology to be assessed in this study is the Active Flow Control Turbocharger (ACT) developed by the proposer's group. This technology has been the basis of an EPSRC grant and a Carbon Trust Incubator award; it still remains laboratory based and has not shown its potential at engine level. In this patented technology, a Variable Geometry Turbine (VGT) turbocharger system is tuned to follow the engine generated exhaust pulse by means of a fast actuated nozzle. It aims to make better use of the exhaust gas energy of the engine than in current VGT turbochargers. The appeal and ultimate transfer of this technology to the automotive industry will only be made possible once the predicted gains of engine performance are made apparent. It therefore needs the close collaboration and integration of turbocharger developers to ensure a clear commercial path for the technology implementation. In order to address this final need, the current feasibility study includes time for interactions with turbocharger developers and OEMs to explore the implementation of the technology in future development programs.

Planned Impact

The project's impact statement may be summarised as: * To achieve quantified reduction of CO2 emissions through the introduction of the Active Control Turbocharger (ACT) and the assessment of practical areas for further development prior to its implementation (reliability, serviceability and robustness). * To achieve a quantified reduction of CO2 emissions through improvements in engine/turbocharger matching through the reliable integration of flow unsteadiness into the design and selection process for turbochargers. * To develop closer relation between the OEMs and the turbocharger developers to address the key boosting technologies and unsteady considerations associated with their application in the light of the more complex systems proposed.
 
Description It is possible to adapt actively the operation of a turbo to an engine, thus making a better overall engine system efficiency and lower fuel consumption.
Exploitation Route They are leading to reconsideration of the turbocharger coupling to an engine by due consideration of engine pulses. The active control concept is under commercial consideration by a leading large engine European manufacturer.
Sectors Aerospace

Defence and Marine

Transport

 
Description Proof of concept
Amount £35,000 (GBP)
Funding ID N/A 
Organisation Imperial Innovations 
Sector Private
Country United Kingdom
Start 01/2004 
End 01/2006
 
Title 1D tools for turbos 
Description Allowed the prediction of 1D effects on turbochargers based on a wide set of experiments taken by Apostolos Pesiridis 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact Validated one Dimensional procedure applicable to many turbo/engine conditions. See publications 
 
Title VARIABLE FLOW-RESTRICTING TURBINE ASSEMBLY FOR A TURBOCHARGER, CORRESPONDING TURBOCHARGER ENGINE AND VEHICLE, AND OPERATING METHOD 
Description A variable flow-restricting turbine assembly for a turbocharger is disclosed. The assembly comprises a housing, a turbine mounted for rotation in the housing, and a variable flow-restrictor. The variable flow-restrictor comprises a first series of angularly-distributed flow-restrictor portions distributed around the turbine wheel and located in an exhaust flow path to the wheel, and a second series of angularly- distributed flow-restrictor portions distributed around the first series and located in the exhaust path. At least one of the first and second series is rotatable in the housing to vary the relative angular positions of the first and second series. The restrictor portions are arranged such that the first portions align with the second portions at each of a plurality of relative angular positions to open flow channels between the portions and such that they misalign between those positions to close the flow channels. 
IP Reference WO2014184542 
Protection Patent application published
Year Protection Granted 2014
Licensed No
Impact Rotation of the vane system to a change of the engine exhaust. Instead of an oscillatory response, this concept allows continuous rotation thus making it much easier to implement.