Model Predictive Control of a Waste Heat Recovery System Integrated with a Dual Fuel Natural Gas-Diesel Engine

Abstract

Waste heat recovery (WHR) is a promising technology that uses the thermal energy from the exhaust gases of an internal combustion engine (ICE) to aid propulsion in vehicles. This paper presents a model predictive control (MPC) framework to minimize the fuel consumption of an automotive ICE by integrating it with a WHR system. To this end, a control oriented model of a WHR system is developed and then integrated to a control oriented model of a turbocharged dual fuel diesel-natural gas ICE. The ICE model is derived based on experimental data collected from a 6.7 liter Cummins ISB engine modified for dual fuel operation. The designed MPC framework optimizes the ICE combustion, turbocharger, and organic Rankine cycle (ORC) system in the WHR to minimize fuel consumption of the ICE. The designed control framework also allows to meet time-varying exhaust gas temperature constraints for after treatment system light-off requirements and diesel particulate filter (DPF) regeneration. The results show that the optimal operation of the WHR and the ICE reduces the fuel consumption of the ICE by 5.9%.