What are the reasons for excessive NOx emissions in cars?
2 Answers
The reasons for excessive NOx emissions in cars: 1. Clogged fuel lines or fuel injectors, or insufficient fuel injection, which leads to excessive oxygen content in the engine. This results in insufficient CH and CO emissions to reduce NOx, causing the vehicle's exhaust emissions to exceed standards. 2. Failure of the three-way catalytic converter to catalyze the chemical reactions of CH, CO, and NOx, leading to excessive exhaust emissions. Mechanical faults in the engine can cause excessively high temperatures in the cylinders, generating large amounts of NOx and also resulting in excessive vehicle exhaust emissions.
When a vehicle experiences excessive NOx emissions, it is usually related to the combustion process. High combustion temperatures during engine operation cause nitrogen and oxygen to combine, generating more nitrogen oxides. A common cause is an aged or faulty three-way catalytic converter, which is designed to effectively convert pollutants but loses efficiency due to carbon buildup or clogging. The EGR (Exhaust Gas Recirculation) system is supposed to lower combustion temperatures and reduce NOx production, but if the valve gets stuck or the control system malfunctions, emissions can easily exceed limits. Poor fuel quality may also lead to incomplete combustion, as low-grade gasoline affects the air-fuel ratio. Neglecting long-term maintenance, such as a clogged air filter, can disrupt intake balance and worsen emissions. I recommend checking the condition of the catalytic converter and sensors during each routine maintenance service. Replacing aging parts early can prevent excessive emissions. Ensuring the vehicle operates under normal load and avoiding aggressive acceleration at high speeds can also help control emissions.
