Diesel Engine Cylinder Deactivation for Improved System Efficiency While Maintaining Elevated Aftertreatment Temperatures

Mrunal Joshi, Purdue University

Abstract

Diesel engines rely on aftertreatment systems alongside engine-based strategies to obtain maximum possible aftertreatment system efficiency in order to reduce emissions and achieve emission compliance. The efficiency of these aftertreatment systems is dictated by the aftertreatment temperatures during engine operation, with higher operating temperatures generally being associated with higher efficiencies. Conventional techniques to increase aftertreatment temperatures are frequently used during engine operation although they also incur a significant fuel consumption penalty. This thesis outlines the utilization of flexible valve actuation to identify and implement strategies such as cylinder deactivation (CDA) which, along with effective aftertreatment thermal management performance, also result in improved fuel efficiency. Specifically, cylinder deactivation has been studied as a strategy that can enable fuel efficient aftertreatment thermal management via reduction in effective displaced volume. Steady state results at 800 RPM/1.3 bar illustrate a 40\% lower fuel consumption with CDA as compared to conventional thermal management operation, which is due to the reduction in pumping losses with CDA. Moreover, CDA has also been demonstrated as a strategy capable of lowering the rate of cool-down of a warmed up A/T system via reduced exhaust flow rate and sufficient engine outlet temperature. Implementation of CDA as a fuel efficient strategy to maintain temperatures over the HD-FTP has been demonstrated to result in 3.4\% reduction in fuel consumption as compared to the conventional thermal management operation.

Degree

M.S.M.E.

Advisors

Shaver, Purdue University.

Subject Area

Mechanical engineering

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