Evaluation of SI-HCCI-SI mode-switching using conventional actuation on a CNG engine

• Author / Creator

  Boddez, Jason Bradley

• Homogeneous Charge Compression Ignition (HCCI) operation is desirable for its high thermal efficiency and low emissions of NOx and particulates. Difficulty with cold starting and maximum achievable speed/load highlight the desire for mode-switching to traditional spark ignition (SI) operation.

  Mode-switching between SI and HCCI is investigated using only actuation of throttle, CNG injector pulse width, and CNG injection timing on a single cylinder CFR engine. Open-loop control achieves a one cycle mode-switch between two adjustable IMEP levels. Sequences are repeatable as demonstrated by 10 mode-switches with the same inputs. Performance is evaluated using a developed mode-switch performance criterion (MSPC) by considering duration between steady-states of operation, smoothness of IMEP, and knock based on maximum rate of pressure rise. Comparing the results with subjective analysis (the current standard) reveals good correlation. Throughout development, mode-switching performance is shown to improve by a factor of 60.

• Subjects / Keywords

  • Conventional
  • Mode
  • HCCI
  • CNG
  • Combustion
  • SI
  • Engine
  • Switching

• Graduation date

  Spring 2011

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3701D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.