Reducing Diesel Engine Drive Cycle Fuel Consumption through Use of Cylinder Deactivation to Maintain Aftertreatment Component Temperature during Idle and Low Load Operating Conditions

Mrunal C Joshi,Gregory M Shaver,Dale Stretch,Alexander Taylor,Cody M Allen,Edward Koeberlein,Lisa Farrell,Kalen Vos,Dheeraj B Gosala,Matthew Van Voorhis,James Mccarthy

doi:10.3389/fmech.2017.00008

Abstract

Modern on-road diesel engine systems incorporate flexible fuel injection, variable geometry turbocharging, high pressure exhaust gas recirculation, oxidation catalysts, particulate filters and selective catalytic reduction systems in order to comply with strict tailpipe-out NOx and soot limits. Fuel consuming strategies, including late injections and turbine-based engine exhaust throttling are typically used to increase turbine outlet temperature and flow rate in order to reach the aftertreatment component temperatures required for efficient reduction of NOx and soot. The same strategies are used at low load operating conditions to maintain aftertreatment temperatures. This paper demonstrates that cylinder deactivation (CDA) can be used to maintain aftertreatment temperatures in a more fuel efficient manner through reductions in airflow and pumping work. The incorporation of CDA to maintain desired aftertreatment temperatures during idle conditions is experimentally demonstrated to result in fuel savings of 3.0% over the HD-FTP drive cycle. Implementation of CDA at non-idle portions of the HD-FTP where BMEP is below 3 bar is demonstrated to reduce fuel consumption further by an additional 0.4%, thereby resulting in 3.4% fuel savings over the drive cycle.

Highlights

Tailpipe limits for heavy-duty on-highway diesel engines in the United States are currently 0.2, 0.01, and 0.14 g/bhp-hr for oxides of nitrogen (NOx), particulate matter (PM), and unburned hydrocarbons (UHC), respectively (United States Environmental Protection Agency, 2010)
This paper demonstrates cylinder deactivation (CDA) as a competitive strategy to simultaneously reduce fuel consumption and maintain aftertreatment system temperatures via implementation at loaded idle conditions and at appropriate sections of the HD-federal testing procedure (FTP) where BMEP < 3 bar, thereby establishing CDA as an effective method to improve the trade-off between fuel consumption and tail pipe out NOx emissions
The results from four HD-FTP experiments are compared in order to demonstrate that: (i) tailpipe NOx reductions are possible via fuel-inefficient Six-cylinder A/T thermal management strategies, and (ii) similar tailpipe NOx levels are possible with notably lower fuel consumption through use of Half-engine CDA during idle for A/T stay-warm operation

Summary

Introduction

Tailpipe limits for heavy-duty on-highway diesel engines in the United States are currently 0.2, 0.01, and 0.14 g/bhp-hr for oxides of nitrogen (NOx), particulate matter (PM), and unburned hydrocarbons (UHC), respectively (United States Environmental Protection Agency, 2010). The aftertreatment system typically includes a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) system. The DOC converts UHC to carbon dioxide and water, the DPF traps PM, and the SCR system reduces NOx. The integrated aftertreatment system generally requires operating temperatures in excess of 200°C to work effectively, requiring the implementation of “thermal management” to reach, and maintain, desirable operating temperatures (Blakeman et al, 2003; Song et al, 2007; Charlton et al, 2010; Hou et al, 2010; Gehrke et al, 2013; Stadlbauer et al, 2013)

Methods

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Conclusion