How to solve the problem of only NO exceeding the standard?
3 Answers
If the NO in the exhaust gas exceeds the standard significantly, the first step is to clean the cooling system and the heat dissipation system, and even the lubrication system. Below are the relevant introductions about exhaust gas: 1. Control the flow of cleaning agent: The flow of cleaning agent should be controlled to the point where the engine idles with slight vibration as the best condition. If the engine vibrates severely during the cleaning process, the flow of cleaning agent should be reduced immediately. Some 4S shop technicians rush the process by injecting a large flow of cleaning agent into the engine quickly, which not only damages the engine but also reduces the cleaning effect. 2. Cleaning the three-way catalytic converter: The three-way catalytic converter should be cleaned and maintained every 30,000 kilometers, and those with the conditions can clean it every 10,000 kilometers. Under normal maintenance conditions, the service life of the three-way catalytic converter is between 150,000 kilometers and 200,000 kilometers before replacement is needed.
I've found that when only NO levels are exceeded, it usually indicates a faulty catalytic converter or an EGR system malfunction. Having worked on cars for many years, in such cases, I would advise the owner to first check if the oxygen sensor is malfunctioning or if the mass airflow sensor is clogged. Excessive NOx emissions are often related to the engine's air-fuel mixture ratio, and a diagnostic tool may be needed to read the fault codes and pinpoint the issue. If the catalytic converter is cracked or failing, it needs to be replaced; if the EGR valve is stuck, it should be cleaned or replaced. Using high-quality fuel can help prevent air-fuel ratio imbalances. It's advisable not to delay and to visit a professional repair shop promptly to avoid failing emission tests or causing further engine damage, which could be more costly. Regular maintenance can prevent such issues.
As a frequent driver, I get a bit nervous when only NO levels are exceeded, but the solution actually lies in developing good habits. Regularly ensure your vehicle is maintained on schedule, such as changing the oil and checking the air filter every 5,000 kilometers, which keeps the system running efficiently. Using higher-grade gasoline can reduce impurity buildup and prevent abnormal emissions. If you notice unusual exhaust smells or dashboard warning lights, don’t hesitate—immediately check the sensors and catalytic converter. NOx exceedance may stem from idling issues or fuel quality; occasionally driving at high speeds to increase RPM can temporarily improve the situation. In the long run, cultivating good driving habits is key—it saves money and hassle.
