Sensor for Incylinder Gas Temperature Based on H2O Absorption Spectroscopy and Applied an HCCI Engin

1
Sensor for In-cylinder Gas Temperature Based on
H2O Absorption Spectroscopy and Applied an HCCI
Engine
Chun Lan, Scott T. Sanders
Sensor system applied to HCCI engine
Suppercontinua wavelength

• A single color (1064 nm) enters the
  supercontinuum generation fiber, but a broad
  spectrum emerges
• By carefully choosing the fiber length and
  dispersion, we can select the fiber providing the
  highest power in our 1330 nm 1380 nm wavelength
  range of interest (50 m Corning LEAF fiber)

• Merits of Homogeneous Charge Compression Ignition
  (HCCI)
• Utra-low emissions and Particulate Matter
• High thermal efficiency
• Most challenge of HCCI
• Combustion control HCCI (HCCI is a combustion
  process governed by chemical kinetics)

• Overcome challenge by
• Absorption spectroscopy technology
• Objectives
• Design the sensor system
• Measure the H2O mole fraction and temperature
  immediately

Detector
Io
(around)
50/50
Oscilloscope
Io
I
HCCI engine
(through)
Detector
Absorption Spectroscopy Theory
Fiber Bragg Gratings

• FBG fiber Bragg grating
• each Fiber Bragg grating is designed to reflect
  one color of light (e.g., 1342 0.05 nm)
• the fiber Bragg gratings are based on modulation
  of the refractive index of the fiber along the
  direction of light propagation the resonant
  wavelength is reflected back towards the source

Experiment Results

• provides gas temperature every 16.6 ms ( 0.3
  CAD at 3000 rpm)
• laser operation and fiber coupling to engine are
  both user-friendly
• gas temperature can be viewed directly in the
  laboratory there is potential to provide a
  real-time voltage proportional to gas temperature
• system runs using LabVIEW software
• H2O mole fraction information is also provided
• the sensor works over the entire range of HCCI
  combustion conditions

Temperature K with crank angle
k v f (? ,T,P)
Water fraction with crank angle
FBG Wavelength choice
Sensor system design
color burst as a function of wavelength
wavelengths chosen to align with
absorption features of H2O
Future work

• all-fiber system no purge gas required, no
  alignment screws need
• entire system currently fits on a 0.3m x 0.9m x
  0.2m-high space, can be reduced in size if needed

• Improve the sensor system
• Develop to provide a real-time voltage
  proportional to gas temperature

• Test in different engines