Is the Three-Way Catalyst Useful?
4 Answers
The three-way catalyst is useful. The main function of the three-way catalyst is to heat the catalytic converter using the exhaust gases emitted by the engine, then undergo a chemical reaction with the exhaust gases to convert toxic and harmful gases into harmless emissions such as water or carbon dioxide. How to determine the condition of the three-way catalytic converter: Visual inspection. Check the exterior of the three-way catalytic converter for any damage or discoloration. If there are scratches, cracks, etc., it is likely that the catalytic converter has been damaged. If there are noticeable gray spots in the center of the protective cover, severe discoloration, or purple marks on the shell, the catalytic converter may have suffered from overheating issues. Observe the engine's exhaust condition. Place your hand near the tailpipe outlet to feel the exhaust flow and check if the catalytic converter is clogged or if there are issues with poor exhaust flow. Another method is to open the air filter, remove the filter element, and observe if there is exhaust backflow during rapid acceleration, indicating poor exhaust flow. To test the condition of the TWC (Three-Way Catalyst), check if the secondary air injection pump is functioning properly. Use an infrared thermometer to assess. Compare the temperature difference before and after the TWC using an infrared thermometer. If the temperature difference between the inlet and outlet of the catalytic converter is less than 10°C, the TWC is likely damaged.
I really care about the environment, so I think the three-way catalytic converter is particularly important. It's installed in the exhaust pipe and can turn toxic gases in the exhaust into harmless substances. Pollutants like carbon monoxide and nitrogen oxides are converted into water and carbon dioxide after catalysis. With so many cars in cities nowadays, imagine how bad the air would be without this thing. Although it might get clogged after long-term use and affect performance a bit, it's a mandatory inspection item during annual vehicle checks, and replacing a faulty one can cost several thousand yuan. Overall, this technology makes driving much more environmentally friendly, and it makes perfect sense that the government mandates its installation.
Speaking of the three-way catalytic converter, I understand it's essentially a redox device. Inside, there's a honeycomb substrate coated with precious metals like platinum, rhodium, and palladium as catalysts. When exhaust gases pass through at around 400°C, chemical reactions occur: carbon monoxide oxidizes into carbon dioxide, hydrocarbons decompose into water, and nitrogen oxides reduce into nitrogen gas. The conversion rate can exceed 90%. However, it's crucial to avoid using leaded gasoline as lead can poison and deactivate the catalyst. Additionally, during cold starts when temperatures are insufficient, efficiency drops. While removing it might save some fuel, the resulting emissions would exceed standards, making it a clear case of the cure being worse than the disease.
I've been driving this car for eight years and had to replace the catalytic converter once, which gave me quite some experience. When the car was new, the exhaust had almost no smell, but later I often noticed a pungent gasoline odor. Upon inspection, it turned out the catalytic converter was clogged. The mechanic said frequent stop-and-go driving at low speeds tends to cause carbon buildup, and recommended occasionally taking the car on the highway to flush out the exhaust system. The replacement cost me 3,500 yuan, but it passed the annual inspection in one go and even reduced fuel consumption by a few tenths. Now I always avoid small-brand gas stations, fearing low-quality fuel might damage the catalyst. Actually, this device is like a water purifier - while filtering harmful substances, it also needs proper maintenance itself.
