The catalytic converter one of the most important components in your car. Commonly referred to as a “cat” by auto repair shops (or wreckers and recyclers), a catalytic converter is equipped between the muffler and the engine of your car. Although there is no standard shape or size for catalytic converters, they all have the same function. But before we talk about that, let’s take a look at how catalytic converters came to be, and how they became so valuable!
A Brief History of Catalytic Converters
The first patent for a catalytic converter was given to a French inventor named Eugene Houdry in 1952. Houdry had cut his teeth in the oil refining industry and as mechanical engineer, and it was in that line of work that he first researched how to scrub emissions from smokestacks. It didn’t take long for him to realize that his findings would have a wide range of applications, especially in automobiles and other small motorized equipment
The original converter was designed to scrub the primary chemicals that are emitted into the atmosphere during combustion, converting carbon monoxide into carbon dioxide and converted hydrocarbons into carbon dioxide and water. Although the design worked great on smokestacks, they only worked marginally well on industrial equipment using unleaded low-grade gasoline. Automobiles, however, were another story entirely. During Houdry’s time, cars ran on leaded gasoline, and the emissions from that kind of fuel made the original catalytic converters nearly worthless for automobiles.
However, everything changed in the early 1970s. The US passed the Clean Air Act in 1970 which required all vehicles to cut their emissions by a whopping 75% in only five years. One of the biggest objectives of the Clean Air Act was to require the switch from leaded to unleaded fuels, which was a huge opportunity for the catalytic converter. Without all of that lead coating and caking the ceramic substrate, catalytic converters became realistic for use on personal automobiles.
Then came the next evolution of the ‘cat’. Dr. Carl D. Keith, who at the time was working for the Engelhard Corporation, invented the three-way catalytic converter. This new design not only performed the same scrubbing functions as the original design, but it also converted nitrogen oxides into nitrogen and water.
The catalytic converter as we know it today had finally arrived.
So What Does a Catalytic Converter Do, Anyway?
Despite the fancy sounding name, their function is relatively simply. Basically catalytic convertors are designed to clean up all of the carbon monoxide, nitrogen oxides, and hydrocarbons that are emitted into the atmosphere during the combustion of petroleum fuels. The original models of catalytic converters employed a clever design of tiny ceramic beads attached to a steel mesh at either end of the converter; these pellets were then coated with specific catalysts that would transform these toxic emissions into less-harmful substances. The main catalysts used in the process are platinum (Pt), palladium (Pd), and rhodium (Rh).
As the exhaust passed through the original style of catalytic converter, it came into contact with all the different beads and then passed out the other end. Because of the large surface area of the beads, the majority of the toxic emissions would have been converted before leaving the tailpipe. And that meant less poisonous materials for us to breathe… Don’t your lungs thank you!
However, it quickly became evident that the bead design was inefficient. One of the main problems was that the beads shifted over time, reducing surface area and the productivity of the conversion. Also, over time the beads would wear down, eventually reducing (or even eliminating) the effectiveness of the convertor.
Because of this, the older style bead convertors were phased out in favor of a new type of catalytic convertor that instead utilizes a ceramic monolith substrate. This honeycomb-like structure has a ton of surface area relative to its size, which helps it convert noxious emissions even more efficiently. Newer models also use an ammonia derivative called urea to aid the process, and modern engines also go through a periodic hot cycle to burn away the soot accumulation on the substrate.
But Why Are They So Expensive?
Over the years, the emissions standards have gotten even stricter, and along the way, catalytic convertors have also been designed for diesel engines. But with all the demand for catalytic conversion, and increasing requirements for even greater efficiency, new catalytic convertors require even higher quantities of precious metals.
After all, precious metals like platinum are the catalysts that make the whole thing work, so as more catalytic convertors are demanded by the market, and as the catalytic convertors themselves require more and more precious metals, all that demand necessarily drives up the price.
According to a recent study conducted by Johnson Matthey Precious Metal Management, catalytic converters gobble up a ton of the earth’s precious metals. Over the last decade catalytic converters were responsible for 35-40% of the world’s demand for platinum, 50-70% of the total demand for palladium, and approximately 80% of the demand for rhodium.
An Entire Industry Is Born
As more and more people become aware of pollution, and as more individuals and companies start demanding better environmental regulation, the need for better and more efficient cleaning of emissions will continue to grow. Houdry probably had no idea that his humble invention in 1952 would give birth to a whole new industry! Not only is there sky-high demand for the convertors themselves, but there are also industries all over the globe that are dedicated to refining and recycling the substrate needed for these convertors.
And it’s not just refiners; there’s also huge demand for recycling centers to recapture precious metals that have spent. The normal life-cycle for a catalytic convertor takes it from your car, to an auto repair shop or a muffler shop, to an auto-wrecking yard, and then on to a recycling center. After processing at the recycling center, the core materials are then sent to the refineries where the precious metals are smelted down. After that, those metal return the market, and the cycle of reuse is complete!
Because they are finite resources, the value of precious metals is sure to remain high—but recycling is a key way to help meet demand without depleting our earth’s resources. With increasing governmental and popular concern for our ecosystem will ensure that the demand for catalytic convertors will also increase. As long as we all still drive our internal combustion cars to and from work every day, and as long as we burn fossil fuels in our power plants, catalytic convertors will remain an essential tool to help keep our skies clean.