What Causes Excessive NO Emissions in Exhaust?
2 Answers
Excessive NO emissions in exhaust can be attributed to the following reasons: 1. Incomplete combustion in the engine combustion chamber leading to an overly rich air-fuel mixture. 2. Accumulation of a large amount of carbon deposits in the intake system and engine combustion chamber. 3. Excessive combustion chamber temperature causing the exhaust emissions to exceed standards. More information about NO emissions is as follows: 1. NO emissions refer to nitrogen oxides, a type of brown, pungent-smelling exhaust gas that is produced in large quantities when the engine is under certain loads. 2. When the engine exhaust is first emitted, the NO present in the gas is less toxic, but it is easily oxidized into more toxic nitrogen oxides such as NO2. Once NOx enters the alveoli, it can form nitrous acid and nitric acid, causing severe irritation to lung tissue.
Regarding the issue of excessive NO in exhaust emissions, I usually pay more attention to car maintenance. Common causes include low engine combustion efficiency. For example, an imbalanced air-fuel ratio leads to a lean mixture, resulting in excess oxygen in the engine, which makes nitrogen oxides (NOx) more likely to exceed standards. When spark plugs are aged or severely carbon-fouled, ignition becomes unstable, combustion is incomplete, and emissions worsen. The three-way catalytic converter is a key component in controlling NOx. If it becomes clogged, fails, or wears out, its conversion function is significantly reduced. Another easily overlooked issue is when the oxygen sensor malfunctions, sending incorrect signals to the ECU, leading to improper adjustments. Additionally, frequent short-distance driving prevents the engine from reaching optimal operating temperature, reducing catalytic converter efficiency and increasing NOx emissions. Low-quality gasoline with high impurity levels can also exacerbate the problem. As vehicles age, components deteriorate, so regular inspections of these systems can prevent excessive emissions. Don’t wait until the annual inspection fails to take action—getting a test at a 4S shop is a safer approach.
