Effect of Divided Exhaust Period in a High Efficiency TGDI Engine

Heechang Oh,Joonsik Hwang,Soohyung Woo,Dongwon Jung,Youngmyung Kweon,David Roth,Jerry Song,Jinwook Son

doi:10.3390/en14196343

Abstract

The divided exhaust period (DEP) concept was applied to a high-efficiency gasoline engine and its impact on various engine performance aspects were investigated. To this end, key design parameters of DEP components were optimized through 1-D engine simulation. The designed DEP components were fabricated and experimental verification was performed through an engine dynamometer test. The developed DEP engine shows suitable performance for electrified vehicles, with a maximum thermal efficiency of 42.5% as well as a wide sweet spot area of efficiency over 40%. The improvement in thermal efficiency was mainly due to a reduction in pumping loss. Notably, the reduction in pumping loss was achieved under high exhaust gas recirculation (EGR) flow conditions, where further improvements in fuel consumption could be achieved through a synergistic combination of DEP implementation and high dilution combustion. Furthermore, a significantly improved catalyst light-off time, uncharacteristic in turbocharged engines, was confirmed through a simulated cold-start catalyst heating engine test.

Highlights

IntroductionAs a strategy to meet the regulations, manufacturers are increasing the volume of battery electric vehicles and fuel cell electric vehicles [1,2]
Accepted: 26 September 2021Since the time that strict emission and fuel consumption regulations were initiated, automobile manufacturers have been trying to minimize CO2 emissions all over the world.As a strategy to meet the regulations, manufacturers are increasing the volume of battery electric vehicles and fuel cell electric vehicles [1,2]
0.12%, was used for fuel consumption measurement. Combustion characteristic indices, such as COV of gIMEP, combustion speed, and combustion phasing, were calculated through a combustion analyzer (INDISMART manufactured by AVL, Graz, Austria), which uses the in-cylinder pressure signal measured by piezoelectric pressure transducers (6056A manufactured by Kistler, Winterthur, Switzerland) with 0.1 crank angle (CA) resolution

Summary

Introduction

As a strategy to meet the regulations, manufacturers are increasing the volume of battery electric vehicles and fuel cell electric vehicles [1,2] In addition to these zero tail-pipe emission vehicles, hybrid electric vehicles (HEVs), which have both an internal combustion engine (ICE) and an electric propulsion system, are regarded to be the important solution for the cleaner powertrain technology and are expected to have larger market shares in the future [3,4,5,6]. The main concept is to replace large displacement naturally aspirated (NA) engines with smaller displacement boosted engines that meet the required power output performance This technology began to be actively deployed along with significant improvement of low-end torque (LET) through scavenging, Published: 4 October 2021

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