The simulation-based investigation of the variable displacement engine is motivated by a desire to enable unthrottled operation at part load, and hence eliminate pumping losses. The mechanism modeled in this work is derived from a Hefley engine concept. Other salient features of the proposed engine are turbocharging and cylinder deactivation. The cylinder deactivation combined with variable displacement further expands the range of unthrottled operation, while turbocharging increases the power density of the engine and allows downsizing without the loss of performance. While the proposed variable displacement turbocharged engine (VDTCE) concept enables operations in a very wide range, running near idle is impractical. Therefore, the VDTCE is integrated with a hybrid powertrain to mitigate issues with engine transients and mode transitions.
The engine model is developed in LMS imagine.Lab AMESim using physics based models, such as thermodynamic cycle simulation, filling and emptying of manifolds, and turbulent flame entrainment combustion. A predictive model of the power-split hydraulic hybrid driveline is created in an third-party simulation tool. The integrated simulation tool is utilized to address design and control issues, before determining the fuel economy potential of the powertrain comprising a VDTCE engine and a hydraulic hybrid driveline.
