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What causes excessive NO emissions in exhaust?

4 Answers
ElisaLynn
07/28/25 9:50pm

The reasons for excessive NO emissions in exhaust include incomplete combustion in the engine combustion chamber, accumulation of large amounts of carbon deposits in the intake system and engine combustion chamber, and excessively high combustion chamber temperatures leading to emission exceedance. Below are specific solutions to address excessive emissions: 1. Use carburetor cleaner: It can dissolve the gum solidified on the surfaces of various carburetor components. Timely cleaning makes it relatively easy to remove. Currently, there are two types of carburetor cleaners on the market: domestic ones are cheaper but less efficient, while imported ones are more expensive but more efficient. 2. Remove dust: Take out the paper filter element of the air filter and knock off the dust on its surface or blow it clean with compressed air.

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LeGenesis
08/12/25 1:22am

There are many reasons for excessive NO emissions in exhaust. After years of repairing cars, I've seen it all. The most common issue is the aging or clogging of the catalytic converter. When this part fails, nitrogen oxides cannot be effectively converted. Poor engine combustion is another major cause. An imbalanced air-fuel ratio can lead to excessively high combustion temperatures, producing more nitrogen oxides. Additionally, a faulty oxygen sensor can send incorrect data to the computer, making it unable to control the fuel injection ratio properly. Improper ignition timing and severely worn spark plugs can also affect combustion efficiency. Poor maintenance, such as not changing the oil filter for a long time, can cause carbon buildup inside the engine, further worsening emissions. It is recommended that car owners regularly perform exhaust emission tests and fix any issues early to avoid being stopped and fined by the police on the road.

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JamesLee
10/01/25 2:58am

Last year during my vehicle inspection, I got a warning for exceeding NOx levels, which was quite frustrating. Later, it was found that the fuel injector was clogged. Poor fuel quality, sometimes even adulterated, leads to incomplete combustion and increased nitrogen oxides. If the catalytic converter is damaged, it basically needs to be replaced—expensive but necessary. Issues with the oxygen sensor or air-fuel ratio adjustment are common, especially in older cars with high mileage. Additionally, a faulty engine control module can mess with the emission system. I've learned that developing good habits is crucial, like cleaning the sensors every six months and using gasoline from reputable gas stations. Don't skimp on maintenance to save money, or you might fail environmental standards and risk serious car problems.

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MacElle
11/14/25 4:45am

Excessive NO emissions in exhaust gases severely impact air quality, primarily due to incomplete engine combustion or failure of the three-way catalytic system. Lower combustion efficiency leads to uncontrolled emissions, often caused by fuel injection malfunctions or faulty oxygen sensors. Older vehicles are more prone to such issues due to component wear. It is advisable to focus on regular maintenance, such as periodic inspections of the exhaust system. Environmental agencies conduct strict testing, and exceeding emission limits may result in fines and affect license plate renewal. This issue should not be underestimated, as reducing pollution benefits both individuals and the public.

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