Emissions Tuning Fundamentals: Key Engine Emissions
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Key Engine Emissions
05.03
| 00:00 | The obvious place to start with an emissions tuning course is to get an understanding of exactly what emissions we need to be aware of and understand. |
| 00:07 | Whether you're running on gas, ethanol or diesel, the commonly measured emissions include CO which stands for carbon monoxide, CO2 which is carbon dioxide, CH4 which is methane and NO, usually referred to as NOx or NOx which is a grouping of emissions rather than a specific compound and includes oxides of nitrogen. |
| 00:31 | The two we're interested in are NO which is nitric oxide and NO2 which is nitrogen dioxide. |
| 00:38 | Lastly we have THC which stands for total hydrocarbons. |
| 00:43 | Regulators are interested in all of these gases because all of them either directly or indirectly impact the greenhouse effect. |
| 00:50 | There are some additional compounds that are also measured by some test systems, even though they generally aren't used to determine passing or failing results in the aftermarket. |
| 01:00 | These include N2O, commonly known as nitrous oxide, which is something you're likely familiar with spraying into an engine to add more power. |
| 01:08 | It's also a potential combustion byproduct created during moderate load incomplete combustion events so it's a heads up to investigate that area of operation. |
| 01:18 | Aldehydes such as HCHO which is formaldehyde can also be produced. |
| 01:24 | In addition to the items I've listed which are measured directly, a number of derived measurements are also commonly generated. |
| 01:31 | These include NMHC which is an acronym rather than a compound, standing for non methane hydrocarbons. |
| 01:38 | This is the total hydrocarbons value minus the methane value. |
| 01:43 | We also have HC plus NOx which is the total hydrocarbons plus the NOx content. |
| 01:50 | In addition to gaseous measurements, particulate matter or PM for short is another common test item. |
| 01:56 | Particulate matter causes a range of issues directly impacting human beings and other animals ranging from irritation of the eyes, nose and throat to more serious respiratory issues like asthma and heart health concerns. |
| 02:10 | Particulate matter emissions can be created by poured injected engines but they're more common on direct injected engines. |
| 02:16 | As a reminder, that's DI for short and DI systems are found in some gas and many diesel engines. |
| 02:23 | Unlike poured injected engines which offers fuel a much longer time and greater distance of travel for evaporation to take place before combustion, DI doesn't have that luxury. |
| 02:34 | Despite the assistance of much higher fuel pressures that better atomise the fuel, under some conditions direct injection can cause fuel to remain in liquid form prior to combustion. |
| 02:44 | Rich areas within the combustion chamber can also occur due to inadequate air fuel mixing. |
| 02:50 | Either situation can cause incomplete combustion, leading to a combination of fuel mix with combustion byproducts exiting the engine in liquid or solid form. |
| 02:59 | That non gaseous material is particulate matter. |
| 03:03 | You've likely seen a diesel engine that's heavily overfueled pumping out black smoke. |
| 03:08 | When emissions become visible to the naked eye like this, particulate matter is generally present. |
| 03:14 | On a gas engine you may have seen a haze from the exhaust or spatters of dark coloured material exiting the exhaust during dyno pulls and that also indicates particulate matter emissions. |
| 03:25 | This isn't to be confused with dirty water from condensation getting spit out of the exhaust during engine warm up though. |
| 03:32 | While looking at what comes out of the tailpipe by eye isn't sufficient to meet lab standards, if you can literally see emissions coming out the tailpipe under certain conditions, that might be an area where you can make the biggest improvement. |
| 03:45 | Beyond large particulate matter emissions, which should be avoided altogether, regulators currently tend to test for PM2.5 and PM10. |
| 03:55 | These names come from the maximum particle size each test is checking for. |
| 03:59 | PM2.5 testing observes particles 2.5 microns or less in size and PM10 is for particles 10 microns or less. |
| 04:09 | A micron is 1 1000th of a millimetre so these particles are understandably very small. |
| 04:15 | For most people though, a micron is not a particularly relevant measurement so for reference, the average human hair measures around 50-70 microns in diameter. |
| 04:25 | Particles under 2.5 microns are so small that they can't be seen with the naked eye. |
| 04:30 | I've mentioned less than 10 emissions in total and we'll focus on just a few of them because when it comes to emissions, regulators aren't trying to measure absolutely everything. |
| 04:40 | They've honed in on key emissions elements which they feel have the greatest environmental impact. |
| 04:47 | To recap this module, the key emissions we'll focus on in this course are carbon monoxide, carbon dioxide, methane and non methane hydrocarbons, oxides of nitrogen and particulate matter. |
