What Are the Main Reasons for Excessive Vehicle Exhaust Emissions?
1 Answers
There are several reasons for excessive vehicle exhaust emissions: 1. Vehicle aging: If a vehicle has traveled more than 450,000 kilometers or has been in use for over 15 years, its components will show significant aging, poor contact, poor sealing, and insufficient pressure. 2. Failure of the three-way catalytic converter: The failure of the three-way catalytic converter is the primary reason for excessive vehicle exhaust emissions. The three-way catalytic converter is the most important external purification device installed in the vehicle's exhaust system. It converts harmful gases such as CO, HC, and NOx emitted by the vehicle's exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. When high-temperature exhaust gases pass through the purification device, the catalyst in the three-way catalytic converter enhances the activity of CO, HC, and NOx, promoting certain oxidation-reduction chemical reactions. CO oxidizes at high temperatures into colorless, non-toxic CO2 gas; HC compounds oxidize into water (H2O) and CO2; and NOx reduces into nitrogen and oxygen. These three harmful gases are transformed into harmless gases, thereby purifying the vehicle's exhaust. 3. Abnormal engine operation: The engine may experience issues such as misfiring, spark plug oil leakage, or oil mixing, causing it to run unevenly and weakly when the throttle is increased. 4. Dirty vehicle systems (intake system, exhaust system, fuel system): This situation usually occurs in relatively new vehicles, but the test results show excessive emissions or only slight exceedances by a few percent or fractions of a percent. This indicates that the vehicle's exhaust treatment system, including the three-way catalytic converter and oxygen sensor, is not significantly faulty. The cause of excessive emissions may be due to the three major systems (intake system, exhaust system, fuel system) being excessively dirty.
