Potential Fuel Economy Improvements from the Implementation of cEGR and CDA on an Atkinson Cycle Engine 2017-01-1016

EPA has been benchmarking engines and transmissions to generate inputs for use in its technology assessments supporting the Midterm Evaluation of EPA’s 2017-2025 Light-Duty Vehicle greenhouse gas emissions assessments. As part of an Atkinson cycle engine technology assessment of applications in light-duty vehicles, cooled external exhaust gas recirculation (cEGR) and cylinder deactivation (CDA) were evaluated. The base engine was a production gasoline 2.0L four-cylinder engine with 75 degrees of intake cam phase authority and a 14:1 geometric compression ratio. An open ECU and cEGR hardware were installed on the engine so that the CO₂ reduction effectiveness could be evaluated. Additionally, two cylinders were deactivated to determine what CO₂ benefits could be achieved. Once a steady state calibration was complete, two-cycle (FTP and HwFET) CO₂ reduction estimates were made using fuel weighted operating modes and a full vehicle model (ALPHA) cycle simulation. This paper presents the results from implementation of cEGR and CDA on an engine capable of Atkinson cycle operation.