Characterization and Control of Cyclic Variability in a Gasoline/Natural Gas Dual-Injection Spark Ignition Engine

• Author / Creator

  Stang, Daniel A

• Reducing the cyclic variability of a gasoline/natural gas dual injection spark ignition engine using minimum variance control is the subject of this thesis. Cylinder pressure is used to calculate four combustion metrics, the standard deviation of which is used as an indicator of cyclic variability. Spark timing, fuel type, and engine speed are varied to characterize the cyclic variability of the engine. Location of peak pressure is found to be the best combustion metric for use as feedback in a closed loop controller. Using the location of peak pressure as an engine output and spark timing as an engine input, system identification is used to develop input-output models. Using the model, a minimum variance controller is developed which is able to reduce the cyclic variability by 1.4\% by changing the spark timing in response to the measured location of peak pressure. A detuned minimum variance tracking controller is designed to produce maximum power in changing operating conditions by using 16 crank angle degrees after top dead center as the location of peak pressure set-point. The detuned minimum variance controller is able to track and maintain the set-point under constant operating conditions and as disturbances such as, changing fuel type, addition of internal exhaust gas recirculation, and changing coolant temperature, are introduced into the system. The detuned minimum variance controller rejects these disturbances when experimentally tested and maintains optimal engine operating conditions.

• Subjects / Keywords

  • Cyclic Variability
  • Minimum Variance Control
  • Controls
  • Engine
  • GDI

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3QB9VD5C

• 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.