Control of Charge Dilution in Turbocharged Diesel Engines via Exhaust Valve Timing

[+] Author and Article Information
Hakan Yilmaz, Anna Stefanopoulou

Department of Mechanical Engineering,  University of Michigan, Ann Arbor, MI 48109

J. Dyn. Sys., Meas., Control 127(3), 363-373 (Aug 24, 2004) (11 pages) doi:10.1115/1.1985440 History: Received April 10, 2003; Revised August 24, 2004

In this paper we extend an existing crank angle resolved dynamic nonlinear model of a six-cylinder 12 l turbocharged (TC) Diesel engine with exhaust valve closing (EVC) variability. Early EVC achieves a high level of internal exhaust gas recirculation (iEGR) or charge dilution in Diesel engines, and thus reduces generated oxides of nitrogen (NOx). This model is validated in steady-state conventional (fixed EVC) engine operating points. It is expected to capture the transient interactions between EVC actuation, the turbocharger dynamics, and the cylinder-to-cylinder breathing characteristics, although this has not been explicitly validated due to lack of hardware implementation. A nominal low order linear multi-input multi-output model is then identified using cycle-sampled or cycle-averaged data from the higher order nonlinear simulation model. Various low-order controllers that vary EVC to maximize the steady-state iEGR under air-to-fuel ratio (AFR) constraints during transient fueling demands are suggested based on different sensor sets. The difficulty in the control tuning arises from the fact that the EVC affects both the AFR and engine torque requiring coordination of fueling and EVC. Simulation results are shown on the full order model.

Copyright © 2005 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Current external EGR applications: Venturi mixer, intake EGR throttle, variable geometry turbocharger, exhaust backpressure valve

Grahic Jump Location
Figure 2

Notations of control volumes and gas flows

Grahic Jump Location
Figure 3

Apparent fuel burn rate from experimental data and model prediction vs crank angle

Grahic Jump Location
Figure 4

Quasi-static in-cylinder pressure, valve profiles, and gas flows through valves (scaled) vs crank angle (°)

Grahic Jump Location
Figure 5

Steady state maps for in-cylinder burned gas fraction vs EVC

Grahic Jump Location
Figure 6

Steady state air to fuel ratio vs EVC

Grahic Jump Location
Figure 7

Steady state maps for mean torque vs EVC

Grahic Jump Location
Figure 8

Steady state inlet manifold pressure vs EVC

Grahic Jump Location
Figure 9

System identification results (Wf step up∕down, EVC step up∕down, respectively)

Grahic Jump Location
Figure 10

Bode magnitude plots in dB and rad∕s of the linear identified systems at 1600 rpm, 57 lb∕h with EVC 350° (solid line) and 395° (dash line).

Grahic Jump Location
Figure 11

Three control architectures based on different sensor sets

Grahic Jump Location
Figure 12

Bode plot for the ideal-cancellation controller (Ccanc solid line) and reduced-cancellation controller (Cred dash line)

Grahic Jump Location
Figure 13

Response of linear closed loop schemes: FFC in solid line, fbAFRdec in dash line, fbMAPred in dash-dot line, and conventional engine linear response with fixed EVC=404° in dot line. All graphs show deviations from the nominal values where linearization was performed.

Grahic Jump Location
Figure 14

Nonlinear full order closed loop system response for FFC in solid line, fbAFRdec in dash line, and fbMAPred in dash-dot line



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In