Integration of an ORC Waste Heat Recovery with Electrification and Supercharging through Use of a Planetary Gear System for a Class 8 Tractor Application 2019-01-0229
A novel approach to the integration of turbocompounding, electrification and supercharging technologies was previously presented by FEV to reduce fuel consumption in a heavy-duty diesel engine. In the development of the ITES FEV applied a turbocompound turbine as the means for waste heat recovery. In a new approach a waste heat recovery expander is applied in place of the turbocompound unit. This configuration continues to provide a powersplit integration of the applied technologies, helping to achieve optimal management of power flow. As with the original ITES, this new approach delivers a reduction in both expense and space claim while improving the overall system efficiency in comparison to the independent implementation of each of these individual technologies.
As with the original ITES, the approach is enabled through the application of a planetary gear system. However in this configuration an organic Rankine cycle (ORC) expander is connected to the sun gear while the secondary compressor remains connected to the ring gear and the electric motor/generator is again connected to the carrier gear. The planetary gear system is equipped with a dry clutch and a band brake allowing flexibility in mechanical and electrical integration of the ORC expander, secondary compressor and electric motor/generator to the engine. The system provides the ability to do electrical integration of ORC expander when the turbine power output is low and mechanical/power-split integration when the turbine power output is high. At low engine speeds and high loads, the secondary compressor can provide power from the ORC expander or from the electric motor. Furthermore, the electric motor/generator can be used for regenerative braking as well as to provide torque assist to the engine when possible.
In a previous study, the ITES system functionality was validated through engine and vehicle drive cycle simulation utilizing the 48V motor generator unit for power split turbocompounding, power split supercharging, start-stop, regenerative braking and engine torque assist functionality using the ITES motor/generator unit. This study focuses on the simulation of the ORC expander equipped ITES system on an 11 liter six cylinder diesel engine applied in a heavy-duty class 8 tractor. The simulations demonstrate the ability of the ITES system to match the engine performance of the baseline 6 cylinder engine while providing benefit in fuel consumption when compared to independent integration of these technologies.
Satyum Joshi, Mufaddel Dahodwala, Erik Koehler, FNU Dhanraj, Michael Franke, Dean Tomazic, Jeffrey Naber
FEV North America, Inc., Michigan Technological Univ