A couple of decades ago, cars were one of the biggest causes for air pollution. And while decades later this is still party true, the amount of pollution gases they emit has been reduced to a very minimum. All the cars produced by every manufacturer need to pass emission tests in order for their products to become available on the market.
Some companies like Volkswagen cheated on those tests back a year ago or so, and as a result lost billions of dollars. The little miraculous wonder that’s responsible for reducing the pollution levels in the exhaust is known as the catalytic converter, or just cat.
The design of the catalytic converter allows it to clean the exhaust discharged from the cars. And as the engine burns fuel, it emits carbon monoxide, nitrogen and hydrocarbons into the environment. As the exhaust passes from the engine, through the converter, and eventually into the atmosphere, the converter silently does its job.
Earlier models used layers of ceramic beads packed tight at the end of the converter held in place by a steel mesh. The converter does its duty as the exhaust passes through the layer of pellets. A problem with these models was the gradual beads shifting, causing them to wear down and the effectiveness of the converter would be reduced or eliminated altogether.
Nowadays, most catalytic converters contain what’s known as monolithic substrate. The substrate is ceramic and is coated by platinum, rhodium and palladium. When you look into the converter the view through the substrate is similar to looking through a honeycomb. Filling the catalytic converter with the substrate exposes a max surface area to the exhaust gasses.
For the modern catalytic converter pattern, we have Eugene Houdry to thank. He was a mechanical engineer which developed the 2 and 3 chemical reaction designs. He successfully managed to convert two of the three chemicals into harmless gases – hydrocarbons and carbon dioxide. In the 70s car manufacturers had to cut on the emission of their products by 75%.
Part of the that transition was to begin transitioning from leaded fuel which had tetraethyllead, to unleaded gasoline. As the industry eliminated leaded fuel and cars began running on unleaded fuel, the converter was spared from lead coating, thus having it’s life expectancy extended immeasurably.
Not much has changed since then when it comes to catalytic converters, but some manufacturers try to push it a bit further every now and then. Nowadays, you can find high flow converters, high performance converters, designed to boost air flow to the engine, making it run smoother and performing better.