- Carbon monoxide (CO) is the most toxic compound formed during engine operation, so its content in exhaust gases is measured. When a diesel engine is running, carbon monoxide is also produced due to incomplete combustion of fuel, however, in relatively small quantities (two thirds less than in a gasoline engine with a regulated catalytic converter!).
- Hydrocarbon (CH) is produced when the spark plug flame goes out on a cold engine. Hydrocarbon is mainly formed when the mixture is too rich or too lean. Diesel produces this compound in small quantities.
- Nitrogen oxides (NOx) are formed primarily because air consists of 3/4 nitrogen. Their proportion increases significantly at the high combustion temperatures at which diesel engines operate. Compared to a gasoline engine with a catalytic converter, a diesel engine produces approximately twice as many nitrogen oxides.
- Soot particles are typical for diesel engines, due to their operating principle. They consist of unburned hydrocarbons and ash. Soot formation increases with high engine loads and low engine speeds. The soot's ability to transport harmful hydrocarbon compounds is dangerous, which is why diesel engines have earned their reputation as engines with a heavy odor.
- Sulfur dioxide (SO2) is produced in small quantities due to the sulfur content of diesel fuel.
Exposure to harmful substances
- Carbon monoxide is dangerous when inhaled and can be fatal in enclosed spaces! In air, carbon monoxide reacts relatively quickly with oxygen to form harmless carbon dioxide (CO₂).
- Hydrocarbon compounds are a wide range of substances, from harmless to carcinogenic compounds formed during diesel operation, which can lead to cancer. In the air, hydrocarbon compounds combine with nitrogen oxides to form smog (poorly soluble exhaust gas clouds).
- Nitrogen oxides in certain concentrations lead to irritation of the respiratory system. When interacting with water, they form nitric acid (acid rain).
- Soot particles have the unpleasant property of absorbing harmful substances (possibly cancer causing) hydrocarbon compounds and transfer them into the atmosphere. Hydrocarbon compounds give diesel exhaust a heavy odor.
- Sulfur dioxide, interacting with oxygen from the air, forms sulfuric or sulfurous acid, both types of acids participate in the formation of acid rain. However, transport forms only 3% of sulfurous acids (SO 2).
Neutralization of exhaust gases
Fuel consists of carbon and hydrogen. When burned in an engine, carbon reacts with oxygen from the air and forms carbon dioxide (CO ₂). Hydrogen (H), interacting with oxygen (O ₂), forms water vapor (H ₂ O). One liter of fuel produces about 0.9 liters of water, which is not in its normal state due to the high temperature of the exhaust gases, but comes out of the muffler in the form of vapor. On a cold engine, especially in the cold season, white exhaust containing water condensate is clearly visible.
(Material taken from an online portal: RenaultBook.ru)
Although a diesel engine has a slightly different operating principle than a petrol engine, it also produces harmful substances.