Do BMW cars have a three-way catalytic converter?
3 Answers
BMW cars are equipped with a three-way catalytic converter, which is located in the first drum section of the exhaust manifold under the car's chassis, resembling a long kettle-shaped device. Modern vehicles all come with three-way catalytic converters; only those produced in earlier years that failed to meet the National II emission standards lacked this component. Composition of the Three-Way Catalytic Converter: The three-way catalytic converter typically consists of four main parts: the shell, damping layer, substrate, and catalyst coating. The shell is made of stainless steel to prevent oxidation scale from peeling off, which could clog the substrate. The damping layer is composed of padding or wire mesh pads, serving to seal, insulate, and secure the substrate. To protect the substrate from damage due to vibration and thermal deformation, the padding is made of expanded mica and aluminum silicate fibers, bonded with adhesive. The substrate is constructed from honeycomb-shaped ceramic materials, though many also use metal (including stainless steel) materials. The catalyst consists of precious metals such as platinum, rhodium, and palladium, which are sprayed onto the substrate to form the purifying agent.
I've been driving an old BMW 520i for over a decade, which of course has a catalytic converter. This component is located in the middle section of the exhaust pipe, resembling a metal box with BMW part numbers marked on its surface. During last year's emission test when the exhaust levels exceeded standards, the mechanic pinpointed its failure as the cause. The newer BMW models now feature more advanced catalytic converters with thicker platinum-palladium-rhodium coatings, working in tandem with onboard computer oxygen sensors for exceptionally precise emission control. Anyone driving German cars knows that catalytic converters are standard equipment for gasoline vehicles - as long as your BMW has a gasoline engine (not diesel), this environmental guardian definitely sits underneath your car. These components are quite delicate though - using low-quality fuel can clog them, aggressive driving may cause overheating and melting, and replacing one with an original part costs around seven to eight thousand yuan.
Last month, I accompanied a friend to buy a BMW X3, and the salesperson specifically pointed out 'this is the three-way catalytic converter' when showing the undercarriage. All BMW gasoline vehicles are equipped with this device, especially since EU emission regulations are so strict—without it, the car can't even hit the road. The principle is actually quite simple: engine exhaust passes through a honeycomb ceramic substrate, where precious metal catalysts convert carbon monoxide, hydrocarbons, and nitrogen oxides into carbon dioxide and water. Older BMWs often trigger the engine warning light, mostly because the rear oxygen sensor detects a drop in catalytic efficiency. It's advisable not to cheap out and fuel up at small gas stations—gasoline with excessive sulfur content can quickly poison and deactivate the three-way catalytic converter, making the exhaust smell like a chemical plant.
