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Answers to our most frequently asked questions.

What is parSYNC®?

A: parSYNC® is an integrated PEMS device.  It is designed to be smaller, lighter, less expensive and easier to use than other PEMS equipment while maintaining comparable accuracy.

The parSYNC® CORE includes a sensor cartridge for Particle Mass/Particle Number.  The parSYNC® PLUS includes both a PM/PN senor cartridge as well as a GasMOD™ cartridge to detect the products of gasoline combustion.

How is parSYNC® easier to use?

A: Size – It is 26 cm x 20 cm x 15 cm and weighs approximately 4 kg.  The CUBE (Condensate Unit for Batch Emissions) is approximately 20 cm x 15 cm x 13 cm and weighs approximately 2.5 kg.  

Set-up – Set-up for a test usually takes approximately 10 minutes, including configuration and zeroing.  Many comparable PEMS take significantly longer to set-up and configure before beginning a test.

Cost – parSYNC® typically costs one-tenth of what other PEMS devices cost.

Which gases does parSYNC® PLUS track?

A: The parSYNC® PLUS has a GasMOD™ cartridge which can track CO2, NO, and NO2; in particular, parSYNC® PLUS can have full NOx speciation.  The newest configuration for gases is CO, CO2, NO, and NO2.  Full customization is available….just ask!

In the near future, additional sensors for monitoring hydrocarbons and NH3 will be available.

Does parSYNC® measure PM (particulate matter) and/or PN (particulate number)? If both are measured, how are the values determined?

parSYNC® PM/PN module measures PM and PN via a combination of three sensors whose output is pre-calibrated to an existing PN sensor via a proprietary software algorithm.  By using a flowmeter or an ECU/OBD device, mass flow can be obtained.  From these measurements, the data can be converted to mass density (e.g., grams/ml) or mass flow (grams/sec).

What are the three sensors which are used to measure PM and PN? Why use three sensors?

A: The three sensors contained in a PM/PN sensor cartridge are: ionization, opacity, and a laser-light scattering.  Each is sensitive to different sizes of particles.

  • The ionization sensor is most sensitive to finer particulates with sizes in the range of 0.01 to 1.0 µm.
  • The scattering sensor is most sensitive to coarse particulates with sizes in the range of 0.3 to over 10 µm.
  • The opacity sensor is sensitive over a wide range of particle sizes, from 0.1 to over 10 µm.

These sensors have been used in tandem before in coal mines and smoke detectors for many years for similar reason: they are sensitive to particles of different sizes.  Together, they are better able to detect a variety of different particles and particle types.  Their different sensitivity characteristics allow the PM/PN module of parSYNC® to detect different variations of the particles’ sizes.  Thus, the responses of the sensors can be integrated via a multi-plex processing system to provide an aggregate mass and particle count from the data.

See the computational note below for a more complete answer.

Is the PM data presented in terms of USEPA defined PM-10, PM-2.5 and PM-1 in micrograms/ meter3?
Based on specific customer requirements, particulate data output can be further developed for PM-10, PM-2.5 and PM-1.  Please request this when ordering your parSYNC® or parSYNC® PLUS.
Do the parSYNC® and parSYNC® PLUS take power from the vehicle being tested or can they operate on battery also?
A: The unit employs self-contained battery power; it can also utilize a vehicle’s standard DC outlet (if desired).  The standard batteries included with parSYNC® are:

  • Lithium Ion – (Swappable battery packs) 2 each
  • 12V DC nominal (12.6v – 10v), 4500 mAh

Working Time: 5-7 hrs (typical) , Recharge Time: 4-5 hrs

Are these electrochemical / infrared sensors and what is their average life span?
The specifications of the gas sensors are:

  • NO
    • 3-electrode Electrochemical 0-5,000ppm
    • Sensitivity drift: <5% signal loss/yr
  • NO2
    • 3-electrode Electrochemical 0-300ppm
    • Sensitivity drift: <2% signal loss/month
  • CO2
    • NDIR  0-20%
    • measures in CO2 absorption wavelengths 2.7-4.3 microns
  • Typical GasMOD™ lifespan 6-12 months (perhaps less, if used in an extremely hostile environment.)

 

In order to calculate mass (g/sec), flow rate has to be measured. I didn’t see a flow tube measuring flow rate in your file. Do you use ECU data instead?
The parSYNC® is designed to accept either flow measurements from commonly available flow meters (3DATX does not manufacture flow meters at this time), ECU data, or an engine sensor array.  These data are then combined with parSYNC® data to convert to grams/X.
What is the measured data rate and format type of result data to see the result data stream?
The maximum sampling / update rate of the parSYNC® hardware is 200 kHz; however, the sample rates per each pollutant is typically 4+ hz and averaged out to one data point per second.
In case of RDE testing, is it possible to have post processing? Does the processing follow Part 1065 or Reg 83?
Yes – post-processing can be accomplished, as well as on-the-fly monitoring.  The parSYNC® has been designed to follow Regulation 83, which is focused more on repeatability and accuracy, and allows for flexibility in sampling technique.  US regulation 40 CFR 86 Part 1065 (a-j) dictates specific sensor technology that is not conducive to a smaller lightweight design (such as parSYNC®).

However, the parSYNC® has been tested against 1065 equipment numerous times.  The available published results demonstrate that parSYNC® can provide an acceptable similar 1065 output with an R value in the range of .96 – .99, depending upon the pollutant.

You use two replaceable cartridges; one is the PM/PN cartridge and the other is GasMOD™. What are their normal life spans?

Under ordinary testing conditions for the parSYNC®, the PM/PN cartridge should last around 6 months, although this may not be true in a testing lane.  Even so, we have some cartridges that we have been using for almost 1 year.  The GasMOD™ cartridges should last approximately one year, again – depending upon the type of testing.

How is zero calibration performed?

Two methods can be employed: a simple field check utilizing commonly available “smoke in a can” or a match will ensure that the triple-phase particulate sensors are properly responding; 3DATX has also developed a precision calibrator/generator device – CA/GE Unit, which utilizes a pre-programmed or customized algorithm to employ a HEPA filter / Ambient / Particulate sequence designed to perform zero calibration.  We have found that the CA/GE Unit is most valuable to ensure proper calibration.

In case of accuracy test, linearity check would be necessary. Do you use a reference device for the calibration?
Yes – see above.
What other functions does parSYNC® have?
The output of the particle sensors can be displayed on a ternary plot.  The plot is then compared with that of a similar vehicle in relatively ideal condition.  The structure of this plot can be used to detect possible issues within the engine or exhaust system.
When I receive a parSYNC® device, will there be anything else with it?

Yes.  There is a CUBE (Condensate Unit for Batch Emissions) to trap excess water in the exhaust gases before the entering the parSYNC®.

Does trapping the excess water radically alter the output from the sensors?
With ideal behavior, not in theory.  In practice, there is probably some distortion, but nothing significant has turned up so far.
Because the Opacity Sensor, the Ionization Sensor, and the Scattering Sensor are used for measuring particulates, there will be a difference in sizing calculated by different techniques for the same particle. How then can the data of these three sensors be utilized together for arriving at the PSN (Particulate Synchronization Number)?
The multiplex parSYNC® outputs are combined using a fit algorithm that maps the three sensor outputs onto a conventional instrument output.  The fit model typically has the form:

CONC = f(VOt=-1, VOt=0, VOt=+1) + f(VSt=-1, VSt=0, VSt=+1) + f(VIt=-1, VIt=0, VIt=+1)

Where

CONC = the output of the reference method

VO = raw output voltage response from the opacity sensor

VS = raw output voltage response from the scattering sensor

VI = raw output voltage response from the ionization sensor

t =-1, 0, +1 are the sampling time increments relative to the measurement point

f(∙) is the fitting term.

Similar procedures are used by many other commercial 1065 PEMS systems to align the exhaust gas concentration and flow rate measurements when second-by-second mass emissions are calculated.  This step provides a significant improvement in particulate measurement accuracy and typically generates reference measurement agreements of the order of 95%.