There are two ways of reducing emissions of conventional internal combustion engines. One is to make the power plant as efficient as possible, second – to capture some of its harmful waste. That is what catalysts are for, but they are expensive because of the usage of precious metals. Now Toyota managed to reduce the cost of its catalysts by reducing precious metal usage by 20 % while maintaining effectiveness of the device.
This was done thanks to the world’s first integrally-moulded Flow Adjustable Design Cell substrate. In essence, now cross-section of the catalyst is no longer uniform. It features higher density cells in the centre and lower cell density in the outer layers. This may look like a small achievement, but it is actually quite important, because catalysts are very expensive because of their precious metal content. Reducing cost while maintaining exhaust gas purification properties will allow investing into other technologies that could reduce carbon footprint of the cars even further.
Interestingly, not only does the new catalyst contain 20 % less precious metals, but it also is quite a bit more compact than the conventional one. Toyota says that there are no losses concerning gas flow either. Furthermore, a new manufacturing method was developed and now this reinvented device is the world’s first integrally moulded catalyst.
Conventional catalysts are made of ceramic honeycomb, covered with catalytic materials, like platinum, rhodium, palladium and other precious metals. The structure is quite uniform, but the problem is that the gas flow pattern is not. This means that the inner layers of the catalyst are working harder at purifying gas than the outer portions. Toyota reinvented the catalyst structure, making the inner portion of the device denser. This allowed for a more uniform flow of exhaust gas, which means that the entire catalyst is employed for the task of purifying the gas. Since it is more efficient, it can be smaller and that is where the savings come from.
Catalysts are needed for all internal combustion cars. They help reducing emissions without switching to hybrid systems. However, these precious metals are very expensive and the manufacturing methods of catalysts are less than perfect as well. Toyota’s new catalyst structure would be very difficult to manufacture using the conventional methods, which is why new integral moulding process is a huge part of the achievement as well.
Toyota says that company will continue looking for ways to improve catalyst design even further. This newly designed device will be available throughout company’s range very soon. The first car to get it is going to be Lexus LC 500h later this year.