How can it be said that the environmental protection of the car after inspection is abnormal?

The treatment methods for checking the environmental protection of vehicles are as follows: overhaul the engine, clean, revive or replace the poisoned ternary purifier. Generally, after this procedure, you can basically reach the standard. There are many reasons why the environmental protection of vehicles is not up to standard, mainly CO, HC, NO, etc. The specific solutions are as follows: 1, CO, HC and NO all exceed the standard; If CO, HC and NO all exceed the standard, it means that the three-way catalyst and oxygen sensor of the vehicle are out of order. In this case, the three-way catalytic converter and oxygen sensor of the automobile should be cleaned and replaced directly if necessary. 2.CO and HC exceed the standard: If only CO and HC exceed the standard, it is generally that the air intake system of the automobile has failed, and there is also a problem of carbon deposition in the cylinder. In this case, it is necessary to clean up the engine carbon deposit and the air intake system of the car in time. 3. Only CO exceeds the standard: if only CO exceeds the standard, it is generally caused by insufficient combustion of fuel and mixture in the engine cylinder. In this case, check the air filter and spark plug, clean them in time, and replace them directly if necessary. 4.CO and HC exceed the standard, and the car emits a lot of black smoke when starting: This situation is generally caused by the serious wear of the engine cylinder, so it is necessary to replace the piston ring, cylinder head and other parts. Several methods to avoid exceeding the standard of automobile exhaust: 1, and clean up the carbon deposit in the engine on time. 2. Try to add high-quality fuel. 3. Replace high-quality fuel injectors and spark plugs.