A comparison of three ion sensing circuits in a homogeneous charge compression ignition engine

Tung M. Phan*, J. Hunter Mack, Ryan H. Butt, Robert W. Dibble

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The use of a spark plug ion sensor to detect combustion timing in a homogeneous charge compression ignition (HCCI) engine is a technique that could alleviate the need for pressure transducers, a more expensive alternative. One disadvantage of this approach is the difficulty in obtaining a strong signal at lower equivalence ratios. This article addresses and compares three ion sensing circuitries, namely a voltage follower, a notch filter circuit that removes the 60-Hz wall noise, and a notch filter whose output is coupled to a custom-built “integrator” circuit. The circuit optimizations are aimed at improving signal strength and reliability. The ion signal present in the combustion chamber is experimentally investigated in a 1.9-L Volkswagen engine, modified for HCCI operation and fueled with gasoline. Experiments are conducted across different intake temperatures, pressures, and equivalence ratios. It was found that the custom-built circuit provided the best ion signal strength and reliability.

Original languageEnglish (US)
Pages (from-to)1294-1306
Number of pages13
JournalCombustion science and technology
Issue number8
StatePublished - Aug 3 2017

Bibliographical note

Publisher Copyright:
© 2017 Taylor & Francis.


  • Circuits
  • Engine
  • Homogeneous charge compression ignition (HCCI)
  • Ion signal
  • Sensor

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


Dive into the research topics of 'A comparison of three ion sensing circuits in a homogeneous charge compression ignition engine'. Together they form a unique fingerprint.

Cite this