Science Inventory

Evaluation of Emerging Technologies on a 1.6 L Turbocharged GDI Engine

Citation:

Graham, C., R. Dennis, C. Caldwell, J. McDonald, J. Kargul, D. Barba, AND M. Stuhldreher. Evaluation of Emerging Technologies on a 1.6 L Turbocharged GDI Engine. SAE Technical Paper Series. SAE International, Warrendale, PA, , 15, (2018). https://doi.org/10.4271/2018-01-1423

Impact/Purpose:

The purpose of this work was to evaluate advanced, high-efficiency gasoline spark-ignition engine technologies that are expected to enter the U.S. light-duty vehicle market. These technologies include gasoline direct injection (GDI); advanced boosting systems; low-pressure-loop, cooled external exhaust gas recirculation (EGR); continuous variable intake valve lift (CVVL), and variable intake and exhaust valve timing (VVT). Engine dynamometer testing and engineering development was conducted using a PSA EP6CDTx base engine, adding developmental boosting and EGR systems, and calibrating engine control systems to minimize fuel consumption within the structural and knock limitations of the base engine platform. Engine dynamometer performance data and high-speed combustion data served also served as a basis for engine and vehicle model development in other EPA work. This work was conducted as part of the U.S. EPA's Light-duty Vehicle GHG Midterm Evaluation.

Description:

Low-pressure loop exhaust gas recirculation (LPL- EGR) combined with a higher compression ratio is a technology package that has been the focus of significant research to increase engine thermal efficiency of downsized, turbocharged GDI engines. Research shows that the addition of LP-EGR reduces the propensity to knock that is experienced at higher compression ratios [1]. To investigate the interaction and compatibility between increased compression ratio and LP-EGR, a 1.6 L Turbocharged GDI engine was modified to run with LP-EGR at a higher compression ratio (12:1 versus 10.5:1) via a piston change. The paper presents the results of the baseline testing on an engine run with a prototype controller and initially tuned to mimic an OEM baseline control strategy running on premium fuel (92.8 AKI). The paper then presents test results after first adding LP-EGR to the baseline engine, and then also increasing CR (using 12:1 pistons). As a final step, the 10.5 CR engine with LP-EGR was run on regular fuel (87.7 AKI) to verify that this configuration could be calibrated to maintain performance like the baseline engine running on premium fuel. To understand the effect of each technology and operating strategy combination on vehicle fuel economy, the various engine maps were compared in EPA’s vehicle simulation model (ALPHA) over regulatory drive cycles. This work was done in close collaboration with U.S. Environmental Protection Agency engineers as part of their continuing assessment of advanced light-duty automotive technologies to support setting appropriate national greenhouse gas standards.