Contribution to the study of waste heat recovery systems on commercial truck diesel engines.
Doctoral thesis (2011)
Fuel price increase as well as future fuel consumption regulations lead truck manufacturers to further enhance the current powertrain. In such a context, two waste heat recovery technologies appear as ... [more ▼]
Fuel price increase as well as future fuel consumption regulations lead truck manufacturers to further enhance the current powertrain. In such a context, two waste heat recovery technologies appear as promising: the Rankine system as well as the thermoelectric generator. Both technologies are well studied within the past 30 years literature. After a reminding of truck boundary conditions, this thesis work defines a 0-D modeling done under the engineering equation solver for both systems (approaches enabling to define the working fluid for the Rankine system). Then, for both systems a commercial tool is used to further investigate the two technologies. For the thermoelectric generator this commercial tool, developed under Matlab, models a thermoelectric generator architecture (designed for mass production) developed in the frame of a research program. Parametric studies are done on the integration of a thermoelecric generator upstream the existing engine exhaust gas recirculation cooler. Main studies are done with $Mg_2Si$ and $MnSi$ as thermoelectric materials but other materials are also considered. A Rankine system design is presented and modeled under a well known commercial 1-D solver used within the automotive industry. Preliminary validations of the model based on supplier modeling data are presented as well as the modeling validation of the turbine component tested. Transient aspects are evaluated to better understand the behavior of the system and its bottlenecks. The amount of refrigerant in the circuit and the control schematic are also addressed. From these study, it appears that the thermoelectric generator technology is not yet mature for an integration into a long haul truck due too the low performance of thermoelectric materials. The Rankine system technology should handle a complete truck prototype testing to estimate its potential. [less ▲]Detailed reference viewed: 159 (17 ULg)