Combustion Diagnostics

Title:“Combustion diagnostics of IC Engine”

Instructor: Dr. M.NAEEM

Group Member:

Fahad Noor (100678)Sheikh Saad Arshad (100679)Waqar Ahmed (100699)Syed Saad Ali (100693)Sohaib Imran (100696)Umar Iqtedar (100688)

Content:• Introduction• LIF diagnostic technique• LII diagnostic technique• PIV diagnostic technique• MIE Scattering diagnostic technique

Functional Chain of Engine combustion and Diagnostic tools:

LIF (Light Induced florescence)• Laser Spectroscopic Method for diagnostics of Engine

Combustion process.• Based on the Interaction between light and individual

molecules• Detects selective species of radicals and combustion

products.• Some applications

Nitrogen Oxide diagnostics, Temperature

Experimental Setup

• NOx concentration reduction using EGR at different crank angles.

Reduction of Oxides of nitrogen using EGR

New technology for quantitative measurement of soot volume fraction and primary soot particle size in engine exhausts

Laser optical measurement technique Soot produces by incomplete burning of hydrocarbons

LASER INDUCED INCANDESCENCE (LII)

Working of LII

Soot is placed within the laser beam pathHeated rapidly using a pulsed laser source up to

sublimation temperature.The collecting optics and photo detectors are used to

measure incandescence from soot particles.Analysis of incandescence signals to get information of

soot particlesLaser energy absorption process requires complex

analysis of nano scale heat and mass transfer.Laser heating is expected to affect soot form, shape or

structure.

Applicationthe LII instrument was installed in the trunk of a 2002

Volkswagen Jetta with a 1.9 liter TDI diesel engineancillary equipment consisting of a mini-tower PC and flat-

screen monitor, laser power supply, ejector pump and compressor to extract exhaust from the tailpipe

An OBD-II scan tool interface was used to access the vehicle and engine speeds

data set correlating time-resolved PM emissions with vehicle operating conditions i.e. Acceleration

Particle Image Velocimetry (PIV)

• Advanced laser-based measurement techniques.• Non-intrusive laser optical measurement technique

using laser-sheet flow visualization for research and diagnostics into flow, turbulence, microfluidics and combustion processes.

• Measure two or three components of velocity

PIV Principle

Advantage & Disadvantage

• Gives high degree of accuracy• Not requires Pitot tubes and other intrusive flow

measurement• High quantity information

• High speed data processing• Large number of image pairs

• Cannot perfectly follow due to high density of fluid.• z-axis is away from the camera.

PIV Modern Techniques: • Stereo PIV• Micro PIV• Nano PIV

Applications Optimization of in-cylinder flow processes in automotive

Internal Combustion (IC) engines Measuring flow over an aircraft wing in a wind tunnel. Measurements of blood cells suspension flow in a square

micro-channel Studying fluid mechanics in design. Flow in an artificial heart assist system

MEI SCATTERING

• WHAT IS MEI SCATTERING• HAPPENS IN LARGE SIZED PARTICLES SO HAS LESS DEPENDENCY

ON WAVE LENGTH

WORKING OF MEI-SCATTERING

Collecting lens

Non focal plane

Focal plane

Scattering angle

Lasersheet

Collectingangle

Droplet

FIGURE THE LASER IS THROWN TOWARDS THE FLAME OR THE EXHAUST AIR AFTER THAT THE PARTICLES ARE DEFLECTED TOWARDS CERTAIN ANGLE AND AS A RESULT OF THAT THE MASS OF EACH PARTICLE IS CALCULATED BY USING THE MIE SCATTERING INFOMETERY TECHINIQUE.GREATER DEFLECTION MEANS LESSER MASS.

USE OF MEI SCATTERING IN IC-ENGINE• It is used to check the amount of soot particles in diesel engine• It is used to check the content of mixture formed in engine it

gives optical diagnostics

• The shows the flame large size particles inside the flame. These results are then compared with results of LIF to give mean diameter ofParticles.

REAL LIFE APPLICATION OF MEI SCATTERING• MIE-SCATTENIG FINDS ITS APPLICATION IN Nephelometer (A

Device that measures particulate matter size distribution and concentration from combustion)

• Diesel Feedback Sensor Device that measures particulate matter mass emissions in diesel exhaust in “real-time”

Combustion analysis via CARS• Coherent Anti Stokes Raman Spectroscopy• A relatively new kind of spectroscopic technique• Two laser beams converted coherently into a high intensity

beam.• Useful for obtaining spectra of discharge gases, plasmas,

combustion and atmospheric chemistry.• This method gives qualitative analysis rather than quantitative.

Working

• Two high powered laser beams, along with dye laser beam, are focused together in a sample.

• A coherent beam of frequency ω3 = 2ω1–ω2 is generated in the medium.

• This frequency depends critically on the presence of molecular resonance of the medium at frequency (ω1 – ω2)

• As ω1 – ω2 is swept over the molecular resonance, the intensity of the beam at ω3

changes. Recording this intensity as a function of 2ω1 – ω2 constitutes a CARS spectrum.

Working

• By changing the frequency difference (ω1- ω2) to a particular Raman resonance, various molecules can be probed.• The energy of the scattered light

depends quadratically on the number of molecules and hence a measurement of the molecular density can be obtained. • Most often nitrogen is used as a

“thermometer molecule“.

Advantages of CARS

• The high laser-like directionality of signal emitted by interacting N2 allows for large distances between "emitter" and "receiver".

• This method can have errors less than 5% for temperatures, which is more satisfactory than most LIF results.

• It provides accurate temperature and species concentration in extremely hostile environments.

• Any Questions