(Condensate Unit For Batch Emissions) Chiller/Water Trap (Sample Conditioner); Technical Memorandum - 3DATX parSYNC User Manual

Minipems

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NDIR Carbon Monoxide (CO)

Measurement Range: 0-15%

Accuracy: ±0.02% absolute or ±3% relative

Repeatability: ±0.02% absolute or ±2% relative

7.3.4

C.U.B.E. – (Condensate Unit for Batch Emissions) Chiller/Water Trap (Sample Conditioner)

This sample conditioner/Water Trap weighs 1.5kg. The water trap collects condensation that forms within

the tailpipe sample line and utilizes the Peltier "thermoelectric cooling" effect to create an additional

condensation event to remove an additional amount of water

vapor prior to entering the parSYNC® (where the sample exhaust

is re-heated). The chiller method utilizes a significantly lower

amount of energy compared to traditional heated sample lines

(which attempt to keep all water in a gaseous form).

The unit ensures that water condensation does not occur within

the sensor's optics for the best instrument functionality.

Furthermore, ongoing tests have demonstrated that the

degradation of removed particulate is an insignificant amount that

can be accounted for in final data output via software.

The parSYNC® directly samples 2.5Liters/min from the engine exhaust, there is no dilution and thereby no

extrapolation of sensor values to full concentration. Thus, the small lightweight device can be comparably

responsive and accurate to a large PEMS device.

Moreover, the physics and chemistry are fundamentally identical to larger instrumentation. All the

sensors behave in roughly the same fashion, regardless of size, shape, orientation, and composition (as

large platforms). The only effective differences are relative accuracy, required volume, and

responsiveness of the system. Therefore, from a scientific perspective, the small, inexpensive sensors can

be comparably accurate with proper signal conditioning.

If the size of the device is potentially irrelevant to the overall accuracy of the device, what comparisons

can we draw? The smaller design enforces a direct measurement of the exhaust gases and particles that

does not happen with the current larger machines – the larger machines use dilutions, into which the

incoming air mixes before analysis. Hence, we can expect that the direct measurement is more volatile,

noisier, and more sensitive to external conditions; meanwhile, the indirect measurement smooths out the

data, tends to be less sensitive to exterior conditions and minor variations in the reading – but genuinely

useful, if transitory, sharp variations in output will be attenuated. (cf. parSYNC® versus DMM-3063

output.)

From a practical viewpoint, the more compact device permits greater flexibility in testing of multiple

vehicles numerous times under real driving conditions which are very difficult with even the best large

emissions testing devices (population statistics versus individual statistics). The portable device is only

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