John J. Mooney: An Appreciation of Performance Directed Engineering Greatness

by Robert Kozak* (Atlantic Biomass/Advanced Biofuels USA) I was sad to see an obituary today for the great engineer John J. Mooney. Who was John J. Mooney you ask? He was the co-inventor of both the 2-way and the 3-way motor vehicle catalytic converter.

The “3-way cat,” as it is referred to by motor vehicle designers and engineers, was simply a genius level invention. The 3-way catalyst is a small metal container attached to the exhaust pipe downstream of the exhaust manifold and upstream of the muffler. It efficiently eliminates over 90-95 percent of a vehicle’s pollutants. If your vehicle has spark plugs and burns gasoline and/or ethanol, your vehicle has one. You can see it if you look underneath. Why is it there?

The Clean Air Act of 1970 stated that certain “criteria” pollutants that are in the exhaust of spark ignition internal combustion engines had to be controlled for health reasons. The critical three combustion pollutants were: oxides of nitrogen (NO and NO₂), carbon monoxide (CO), and unburned hydrocarbon fuel (C₆H₁₄). The Clean Air Act, however, did not specify how these pollutants were to be reduced. At the time some thought this was a mistake saying that private sector inventors could not be trusted. It was not a mistake. Rather it turned out to be a brilliant regulatory approach. By specifying a performance standard and not a control technology, the Clean Air Act opened the way for scientists and engineers to use their brains to devise the best solutions.

The problem that Mooney and his team had to solve was daunting. To simultaneously remove these three pollutants required two opposite reactions. Converting NO and NO₂ to atmospheric nitrogen (N₂) required removing oxygen (O₂), which is called a reducing reaction, while changing HC to water (H₂O) and oxygen (O₂) and CO to CO₂ required adding oxygen which is called an oxidation reaction. The simple version of these simultaneous reduction and oxidation equations is:

As you can see, 20 oxygen molecules are needed to drive the oxidation of a gasoline and a CO molecule while the reduction of NO₂ and NO only produces 3. This means two things. One, the NO/NO₂ molecular reduction reactions have to run 13.3 times for 1 HC and 1 CO oxidation reaction. Two, under the right temperature conditions, the addition of extra oxygen to the NO/NO₂ environment can cause the reaction to run in reverse producing NO₂ and NO₃ and depriving the HC and CO of sufficient oxygen to oxidize into non-pollutants. As Mooney said, solving the problem was more than finding a catalyst that would drive both reducing and oxidizing reactions. It was getting the flow just right.

“You had to look at things inside out and upside down. Nothing ever flowed perfectly.” he told the New Jersey Record newspaper in 2001.

By the mid-1980s the 3-way cat was achieving great results and almost looked like magic. (It wasn’t magic. It was just great science and engineering.) It was hooked into a computer-controlled feedback system that used input and output O₂ monitors and a series of actuators to modify fuel injector, timing, and air inputs to keep the air/fuel ratio coming into the cat within the range needed for both reducing and catalyzing reactions. The goals of the 1970 and 1977 Clean Air Acts were being met and the way was paved for more stringent regulations in the 1990 Clean Act Amendments. And, all this was achieved without the Clean Air Acts saying one word on how this would be done.

To finish, I have to add the unexpected benefits that came with the brilliant 3-way cat invention. The most important was that the catalysts used in the 3-way, platinum and palladium, did not work if lead was in the fuel. Lead had been used to raise fuel octane since the 1940s even though research had shown it was a major contributor to neural and brain damage. The need for unleaded fuel to keep the catalysts working led EPA to quickly ban lead as a fuel additive. This banning probably would not have happened anywhere nearly as fast without the 3-way. The number of lives this saved was easily in the thousands.

As the Washington Post obituary reported, “I feel my greatest contribution to the world was convincing countries to remove lead from gasoline,” he told the publication (Chemical Engineering Progress). “Lead in auto exhaust caused children in urban areas to lose up to 10 IQ points, and caused hypertension and serious heart problems for adults.”

Now ethanol, the same ethanol that’s safe enough to drink in beverages, replaces that toxic lead to provide octane.

The other benefits from Mooney's invention were improvements in vehicle performance and fuel economy. While the performance of vehicles equipped with the 1^st generation of non-catalytic emission control systems (1972-75) was abysmal, later systems that combined catalysts with computer controls revolutionized the industry. Fuel economy standards that seemed out of reach were achieved, often ahead of schedule. In addition, problems with unpredictable cold and hot starting disappeared. The spark ignition internal combustion, which many thought was headed for extinction in 1972, with 3-way cats became clean, efficient, reduced neurologic disorders, and achieved levels of performance in fully warranted production cars that were unheard of even in 1972 racing cars.

Thank you Mr. Mooney. And thank you to the US Congress and Nixon Administration that crafted a brilliant regulatory structure in the 1970 Clean Air Act. Let the government set the performance standards and let the scientists and engineers solve the problems. A return to that approach would certainly help our country in these trying times.

*Robert Kozak is the founder and President of Atlantic Biomass, LLC, and a co-founder of Advanced Biofuels USA. Having worked for about 40 years in the transportation, energy, environmental, and government relations industries and in enzyme development, he serves as a fuels/engines and policy expert for Advanced Biofuels USA. He can be reached at atlanticbiomass @ aol.com