1. The temperature is too high

At room temperature, the three-way catalytic converter does not have the catalytic ability, usually the catalytic converter ignition temperature is 250-350 ° C, and the normal working temperature is generally 400-800 ° C.

2. Chronic poisoning

Catalyst is very sensitive to sulfur, lead, phosphorus, zinc and other elements, sulfur and lead from gasoline, phosphorus and zinc from lubricating oil, these four substances and their combustion in the engine after the formation of oxide particles are easy to be adsorbed on the surface of the catalyst, so that the catalyst can not contact with the exhaust gas, thus losing the catalytic effect.

3. Surface area carbon

When the car works at a low temperature for a long time, the three-way catalytic converter cannot be started, and the carbon smoke from the engine will adhere to the surface of the catalyst, resulting in no contact with CO and HC, affecting its conversion efficiency.

4. Exhaust deterioration

If the concentration and total amount of the components of the discharged waste gas pollutants are too large, such as the mixture is too strong, it will affect the catalytic conversion ability of the catalytic converter and reduce its conversion efficiency.

5. Oxygen transfer failure

In order to achieve the best exhaust gas catalytic rate, it is necessary to install oxygen sensors in the engine exhaust pipe and achieve closed-loop control. If the air-fuel ratio is large, although the conversion rate of CO and HC is slightly increased, the conversion rate of NOx is sharply reduced to 20%.