Dear Sir,

 

I'm an undergraduate. I'm doing a project regarding Vehicle Exhaust Gas Analyser. Can I use following type of sensors to detect exhaust gas levels ?

CO>>
http://www.ebay.com/itm/DC-3-5V-MQ-9-Combustible-Gas-Carbon-Monoxide-CO-Sensor-Module-MQ9-Detector-/300847030943?pt=LH_DefaultDomain_0&hash=item460be1629f

CO2>>
http://www.ebay.com/itm/Carbon-dioxide-sensor-Gas-sensor-module-/170969527732?pt=LH_DefaultDomain_0&hash=item27ce93f5b4

HC>>
http://www.ebay.com/itm/MQ-5-Gas-Sensor-module-for-Methane-Butane-and-Propane-Arduino-Compatible-/130711771878?pt=LH_DefaultDomain_0&hash=item1e6f075ae6

I must be thankful to you if u will reply soon.

Thank You.

It is difficult to answer your question without having some figures for the expected concentrations of these components in exhaust gases.

 

For example the CO sensor: it has a range of 10 - 1000 ppm. Under normal conditions, I would think this is the range you could expect from an exhaust, but if combustion is somehow incomplete, it could be a lot higher.

 

I suggest you look up some typical car exhaust gas compositions in Google, and compare that to the ranges give in the data sheets of the sensors.

 

Your HC sensor might be a little limited. It only seems to detect small alkanes and hydrogen. I am not sure what you can expect to find in an exhaust. I would hope that in a modern engine, concentrations of these components is near zero anyway.

 

p.s. A bit off-topic... but I am amazed how cheap these things are!