What is the composition inside a three-way catalytic converter?
2 Answers
The composition inside a three-way catalytic converter consists of a housing, a damping layer, a substrate, and a catalyst coating. The three-way catalytic converter is an important external purification device in the automobile exhaust system. Its function is to convert harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides emitted from automobile exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions. The cleaning method for the three-way catalytic converter is: 1. Use a lift to raise the vehicle and remove the three-way catalytic converter; 2. Soak and clean the three-way catalytic converter with an oxalic acid solution, then rinse it with clean water; 3. Reinstall the cleaned three-way catalytic converter and start the vehicle for a test drive.
When repairing cars, I noticed the catalytic converter mainly contains a ceramic honeycomb block with densely packed tiny channels resembling a beehive. Its surface is coated with three precious metals - platinum, rhodium and palladium - which specifically react with harmful substances in exhaust gases. The outer stainless steel shell must withstand high temperatures and corrosion, while cushioning pads in the middle prevent the ceramic core from shattering due to vibration. The worst enemies are leaded gasoline or silicone volatiles that can poison and deactivate the precious metals. For China VI emission standards, they've even added a layer of gold coating to improve low-temperature performance.
