Measurement of actual CO2 mass emitted from a diesel engine

[AEW]

TL;DR

Looking for a method to measure the total CO2 mass or rate of emission of CO2 from a diesel engine used in a power generation station.

I was wondering if there is a method to measure the actual total mass of carbon dioxide (CO₂) emitted from a diesel engine used with a generator for power generation (https://www.cat.com/en_US/products/new/power-systems/electric-power/diesel-generator-sets/1000028914.html). Infrared CO₂ sensors, such as ENMET EX-6165 sensor, generally measure the gas concentration in parts-per-million (ppm), describing the amount of gas by volume of the air at a certain time and location, which is not what I am looking for in this application. Liquid flow sensors are already installed in the diesel fuel supply and return lines to determine the amount of diesel consumed by the engine, and hence the amount of carbon burned and CO₂ created, but I am looking to correlate these measurements with actual measurements of CO₂ mass produced at the output of the exhaust system.

The question can be formulated as how to measure the CO₂ emission rate from the engine exhaust system. A typical solution in practice would be to find a dedicated gas flow sensor and a monitoring system that accomplishes that.

Any idea on how to approach this problem would be greatly appreciated.

Thanks.

 

[russ_watters]

You can buy combustion gas analyzers but they give constituents not flow rates. But couldn't you just calculate it from fuel usage?

 

[Tom.G]

Another round-about method:

Todays cars use an MAF (Mass Air Flow) Sensor to measure intake air.

The basic operation is the sensor is a Hot Wire Anemometer, which combined with intake air temperature, and cross sectional area of the input duct yields enough information to calculate the MAF rate.

Combining the above data with the CO₂ concentration should yield your desired answer.

(I have not read any of these, but there are many results that look promising:
https://www.google.com/search?&q=how+measure+co2+emissions)

Cheers,
Tom

 

[tech99]

Another round-about method:

Todays cars use an MAF (Mass Air Flow) Sensor to measure intake air.

The basic operation is the sensor is a Hot Wire Anemometer, which combined with intake air temperature, and cross sectional area of the input duct yields enough information to calculate the MAF rate.

Combining the above data with the CO₂ concentration should yield your desired answer.

(I have not read any of these, but there are many results that look promising:
https://www.google.com/search?&q=how+measure+co2+emissions)

Cheers,
Tom

Air consumption is not useful for calculating CO2 from a Diesel engine because it does not have a throttle. Air is always fully open and not related to fuel mass.

 

[Tom.G]

Several years ago the State of California published a Request For Proposal (RFP) for pollution measuring equipment to be placed at freeway on-ramps. As I recall, the approach was a light beam (probably multiple Lasers) across the ramp and a wavelength selective detector for a differential absorption measurement. That is the same approach as those fingertip Pulse-Oximeters that measure pulse rate and blood O₂ saturation.

Edit: If you are in a country and/or state that has emission standards for vehicles, how about asking the government agency how they measure emissions. Here in the USA that information must be made public so the manufacturers can meet the standards.

 

[tech99]

I believe that calculating CO2 from fuel usage is very accurate.

 

[tylerkelley1980]

I’ve worked on emission testing setups for diesel engines, and getting accurate CO₂ mass values requires careful integration of exhaust flow rate and concentration data. Using a PEMS unit or combining a flowmeter with an NDIR sensor usually does the trick. Calibration is key. Also, correcting for ambient temperature and pressure helps ensure repeatable results under different test conditions.