The Catalytic Converter & Exhaust Gas Analyzers

Posted by David Anderson on

At Bridge Analyzers, we are proud to be able to say that the roots of our company are firmly embedded in the ground of emissions testing and performance tuning for forklifts, motorcycles, sports cars, and any other engine that burns fuel, whether the fuel type is diesel, gasoline, propane, LPG, or CNG.

Our customers use our series of Exhaust Gas Analyzers most often for performing emissions testing on forklifts, motorcycles, and sports cars, especially vintage cars and muscle cars that were around before catalytic converters came onto the scene en masse in the mid-1970s.

Before 1975— the year that the U.S. Environmental Protection Agency made catalytic converters mandatory— most cars were still run on carburetors and emissions were not a main concern for automotive manufacturers, the government, or drivers; but as the negative effects of pollution began to become more apparent and oil prices began to gradually rise, auto makers as well as government agencies such as the U.S.E.P.A began to look for ways to increase fuel efficiency and decrease emission levels.

One way to accomplish this goal was to move away from carburetors and towards fuel injection systems. Although more expensive than carbureted systems, fuel injection systems grew in popularity due to the fact that they decreased emissions while increasing fuel economy, while at the same time increasing engine power and performance. The automotive industry’s wide acceptance of fuel injection systems did a lot to reduce emissions and make the car driving experience more sustainable, but it wasn’t until the introduction of the catalytic converter in 1975 that sustainability really became one of the main goals of the auto industry.

The catalytic converter is a simple device that is mounted in the exhaust pipe. Its sole purpose is to convert ‘dirty’ exhaust such as hydrocarbons (HCs), carbon monoxide (CO), and nitric oxide (NOx) into harmless water vapor and carbon dioxide (CO2). Catalytic converters do this by super heating the ‘dirty’ exhaust molecules in the converter’s chamber and then exposing them to a catalyst — which is most often a mixture of precious metals such as platinum, rhodium, and palladium— at which point they, as if miraculously, become harmless water vapor and environmentally friendly carbon dioxide (CO2). The scientific name for the above process is a redox reaction, which is a combination of an oxidation reaction with a reduction reaction. In their article “How Catalytic Converters Work” Karim Nice and Charles W. Bryant summarize the discussion above saying, “The job of the catalytic converter is to convert harmful pollutants into less harmful emissions before they ever leave the car’s exhaust.” Their article is detailed and very good, and for those of you wanting to take a deeper dive into the science of how catalytic converters work, it is a great read.

Having discussed everything we have so far, let’s take some time to discuss our original topic of catalytic converters and their relationship with exhaust gas analyzers.

After fuel injection systems and catalytic converters became mainstream we found that most of our exhaust gas analyzer business dealt primarily with older carbureted cars, motorcycle performance tuning, and forklifts. For a while we assumed that mechanics and engineers that dealt with engines with catalytic converters simply did not need our exhaust gas analyzers as the catalytic converter had already done the magic of its redox reaction on the exhaust emissions. As we did more research and talked with customers about how they used our exhaust gas analyzers we realized that they were using it in more refined ways than we had envisioned. This was great news to us. They were not only using it to analyze exhaust gas but they were also using it as one of their preliminary diagnostic measures when dealing with OBD-II error codes, as well as using it as their primary way of getting real data for calculating catalytic converter efficiency. If you were curious, the OBD-II error code for catalyst system efficiency is P0420.

In future articles we will take a look at how some of our customers are using our exhaust gas analyzers, as well as go over how to perform a diagnostic test to determine catalytic converter efficiency.

Thanks for reading, and feel free to contact us with any questions you may have about our complete line of Exhaust Gas Analyzers. We’d love to hear from you.