This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The Turboexpansion Concept - Initial Dynamometer Results
Technical Paper
2005-01-1853
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
An expedient route to improving in-vehicle fuel economy in 4-stroke cycle engines is to reduce the swept volume of an engine and run it at a higher BMEP for any given output. The full-load performance of a larger capacity engine can be achieved through pressure charging. However, for maximum fuel economy, particularly at part-load, the expansion ratio, and consequently the compression ratio (CR) should be kept as high as possible. This is at odds with the requirement in pressure-charged gasoline engines to reduce the CR at higher loads due to the knock limit.
In earlier work, the authors studied a pressure-charging system aimed at allowing a high CR to be maintained at all times. The operation of this type of system involves deliberately over-compressing the charge air, cooling it at the elevated pressure and temperature, and then expanding it down to the desired plenum pressure, ensuring a plenum temperature which can potentially become sub-atmospheric at full-load. Due to the ability to support a high fixed CR, it is possible that an engine fitted with such a charging system could achieve fuel economy equal to or better than a Variable Compression Ratio unit, while permitting conventional engine architecture and assembly lines. The concept has been termed “Turboexpansion”.
This paper analyses some initial test bed results taken from an engine fitted with such a charging system, and discusses future development work intended to establish further the validity of the concept and hence its feasibility as a tool to facilitate aggressive engine downsizing. Additional theoretical analysis is presented which indicates constraints on the effectiveness of the system in terms of its sensitivity to the separate component efficiencies.
Recommended Content
Authors
Citation
Turner, J., Pearson, R., Bassett, M., Blundell, D. et al., "The Turboexpansion Concept - Initial Dynamometer Results," SAE Technical Paper 2005-01-1853, 2005, https://doi.org/10.4271/2005-01-1853.Also In
References
- Turner, J. Pearson, R. Kenchington, S. “Concepts for Improved Fuel Economy from Gasoline Engines” Int. J. Engine Res.
- Drangel, H. Bergsten, L. “The new Saab SVC Engine - An Interaction of Variable Compression Ratio, High Pressure Supercharging and Downsizing for Considerably Reduced Fuel Consumption” Aachen Colloquium October 2000
- Wallace, W. Lux., F. “Variable compression ratio engine development” SAE paper no. 762A 1963
- Krebs, R. Böhme, J. Dornhöfer, R. Wurms, R. Friedmann, K. Helbig, J. Hatz, W. “The new Audi 2.0T FSI Engine - The First Direct Injection Turbo-Gasoline-Engine from Audi” 25 th Vienna Motor Symposium April 2004
- Turner, J. Pearson, R. Parrott, A. “The Performance of a High Compression Ratio, High Speed Supercharged Engine” Global Powertrain Congress Dearborn September 2004
- Turner, J. Pearson, R. Bassett, M. Oscarsson, J. “Performance and Fuel Economy Enhancement of Pressure Charged SI Engines through Turboexpansion - An Initial Study” SAE paper no. 2003-01-0401
- Taitt, D. Garner, C. Swain, E. Pearson, R. Bassett, M. Turner, J “An Automotive Engine Charge-Air Intake Conditioner System: Thermodynamic Analysis of Performance Characteristics” Proc. Instn Mech. Engrs Part D
- Turner, J. Blundell, D. Bassett, M. Pearson, R. “The Impact on Engine Performance of Controlled Auto Ignition versus Spark Ignition with Two Methods of Load Control” Global Powertrain Congress Ann Arbor September 2002
- Chen, R. Turner, J. Blundell, D “The mechanism of an engine hybrid combustion concept with controlled auto ignition and spark ignition” Global Powertrain Congress Ann Arbor September 2003
- Chen, R. Turner, J. Blundell, D. “The Transition between controlled auto ignition and spark ignition” SAE paper no. 2004-01-0939
- Chen, R. Turner, J. Blundell, D. “Intelligent Coolant Control - A Potential Technology to improve Controlled Auto Ignition Combustion” Global Powertrain Congress Ann Arbor September 2004
- Turner, J Kenchington, S. Stretch, D. “Production AVT development: Lotus and Eaton's electrohydraulic closed-loop fully variable valve train system” 25 th Vienna Motor Symposium April 2004
- Tai C. Tsao T.-C. Levin M.B. Barta G. Schechter M.M. “Using camless valvetrain for air hybrid optimization” SAE Paper Number 2003-01-0038 2003
- Turner, J. Bassett, M. Pearson, R. Pitcher, G. Douglas, K. “New operating strategies afforded by fully variable valve trains” SAE paper number 2004-01-1386