What is the composition of exhaust fumes from petrol and diesel engines?

In summary, conventional petrol driven internal combustion engines, such as those found in cars, typically emit N2, O2, CO2, and water vapor, with varying amounts of CO, SO2, NOx, and hydrocarbons depending on the air fuel ratio. Diesel engines, on the other hand, also emit N2, O2, CO2, and water vapor, but have higher levels of particulate matter, including soot, sulphur compounds, organic matter, and metals. The exact breakdown of these gases and substances varies depending on the engine type, purpose, and operation.
  • #1
Aquafire
49
1
In regards to two types of engines..

What gases (by percentage) are to be found in conventional petrol driven internal combustion engines, such as found in cars ?

What gases (by percentage) are to be found in conventioanl diesel driven internal combustion engines, such as found in trucks ?

I have tried to search for an accurate breakdown of the two, but ploughing through the internet has left me more confused than clarified.

So, if any of you guys knows for sure...then please help me out..

Thanks in advance..

Aqua

Ps...

Mods, if you feel that this thread should be in chemistry, feel free to move it...
 
Engineering news on Phys.org
  • #2
Depends quite a lot on the engine type, purpose, and how it's being run. This is a complex field, and (as you're probably aware), a huge amount of engineering work is done in this field.

In brief, there are thousands of different chemicals found in engine-out exhaust gases for both Diesel and petrol engines. The bulk of the gaseous emissions are made up of N2, O2, CO2, and water vapour (and maybe some CO). Typically, the N2 level will not change much before/after the combustion event. CO2, CO and O2 levels are all relative, and depend on the air fuel ratio. Lean operation will give high O2, moderate CO2, and low CO; where rich operation will give very low O2, moderate CO2, and very high CO.

Now, SO2, NOx and hydrocarbons are all pretty much universally present, but in very variable quantities (and these quantities are measured in ppm, rather than %). Sulphur compounds are a feature of sulphur in the fuel (which is why you now see low sulphur fuel), NOx is from atmospheric air, and is a feature of high peak cylinder temperatures; and HC are a result of incomplete combustion for whatever reason. Other components (notably alcohols and aldehydes) are present in smaller quantities still.

Diesel engines typically have high levels of particulate matter within the exhaust (as compared petrol engines). This particulate matter comprises of soot and sulphur compounds (from lube oil and fuel), all kinds of organic matter, and varying amounts of metals. Again, these are in tiny amounts compared with the main gaseous components.

Does this help?
 
Last edited:

What is exhaust fume composition?

Exhaust fume composition refers to the chemical makeup of the gases and particles emitted from the exhaust system of a vehicle or other combustion process.

What are the main components of exhaust fumes?

The main components of exhaust fumes are carbon monoxide, nitrogen oxides, hydrocarbons, and particulate matter. These pollutants are produced as a result of incomplete combustion of fuel.

How do exhaust fumes affect air quality?

Exhaust fumes contribute to air pollution and can have negative effects on human health and the environment. They can also react with other pollutants in the atmosphere to form smog and acid rain.

What factors can affect exhaust fume composition?

The composition of exhaust fumes can be influenced by several factors, including the type of fuel used, the engine design, and the driving conditions. For example, a vehicle with a catalytic converter will produce lower levels of pollutants compared to one without.

How can we reduce the harmful effects of exhaust fumes?

There are several ways to reduce the harmful effects of exhaust fumes, including using cleaner fuels, implementing stricter emission standards, and using technologies such as catalytic converters and particulate filters. Proper vehicle maintenance and reducing unnecessary idling can also help reduce the amount of pollutants emitted from exhaust fumes.

Similar threads

  • Mechanical Engineering
Replies
6
Views
1K
  • Mechanical Engineering
Replies
11
Views
19K
Replies
25
Views
2K
Replies
13
Views
5K
Replies
14
Views
3K
Replies
3
Views
34K
  • Sci-Fi Writing and World Building
Replies
21
Views
851
  • Thermodynamics
Replies
2
Views
2K
  • STEM Career Guidance
Replies
2
Views
6K
  • Sci-Fi Writing and World Building
Replies
15
Views
3K
Back
Top