Effects of Negative Valve Overlap on HCCI Combustion and its use in the Control of HCCI Combustion Timing

• Author / Creator

  Schramm, Alexander E

• Homogeneous charge compression ignition (HCCI) combustion can produce higher efficiencies and lower emissions when compared to tradition spark or compression ignition engines. This study reports an experimental investigation into the effects of valve timings on HCCI combustion conditions. Using a single cylinder engine with state-of-the-art electromagnetic variable valve timing (EVVT) fully independent valves, a series of tests are conducted with varying negative valve overlap (NVO). The in-cylinder residual trapped by the NVO causes an advance in combustion timing, a shortening of burn duration as well as increase in load and increase in brake specific fuel consumption. Asymmetric valve timings are also investigated and show complex behavior with high sensitivity of combustion timing in certain operating ranges. Finally, these strategies are implemented as a set of feedback controllers including a proportional-integral (PI) controller and a feedforward with integral action controller. Both controllers have good tracking for step changes in combustion timing setpoint with the feedforward controller providing a rise time of just four cycles.

• Subjects / Keywords

  • Homogeneous Charge Compression Ignition
  • HCCI
  • NVO
  • Controls
  • Valve Timing
  • Negative Valve Overlap

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R32M3T

• 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.