Toyota has introduced a new exhaust purifying catalyst that is smaller (approximately 20% less volume), and uses 20% less precious metal compared to conventional catalysts. The new technology will gradually make its way into new vehicle models, beginning with the Lexus LC 500h later this year.
The catalyst features the world’s first integrally-moulded Flow Adjustable Design Cell (FLAD) substrate, which has a different cell cross-sectional area at the inner portion compared to that at the outer portion.
The new FLAD substrate (developed by Toyota together with Denso) improves the uniformity of exhaust gas flow, allowing for the same exhaust gas purification performance as that of conventional catalysts while requiring less precious metal.
As the diagrams show, the newly developed FLAD substrate doesn’t result in an unbalanced flow of exhaust gas as compared to a conventional catalyst, where the flow of gas through the inner portion of the catalyst is faster, and at a higher volume than that through the outer portion.
Therefore, the FLAD substrate catalyst doesn’t require more precious metal at the inner portion of the catalyst, where the flowrate is greater, in order to maintain purification performance. The walls of cells within both substrates are washcoated with catalytic materials, like platinum (Pt), rhodium (Rh), palladium (Pd) and other precious metals.
This provides a catalytic effect, where harmful gases such as carbon monoxide (CO), unburned hydrocarbons and nitrogen oxide (NOx) are purified within the exhaust via oxidation-reduction.
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We can forget all this tech. 90% diesel cars still using super toxic Euro 2M (Euro 1.5) in Malaysia.
We can only dream of such tech
Most probably this new catalyst only works on gasoline engines emission control system, not diesel yet.
Some of the best engineering solutions are simple yet incredibly elegant.
In all flow in pipes, the fluid closer to the boundary layer at the wall moves at a slower speed compared to the middle. Velocity profile so to speak, where velocity at the boundary layer = 0
Thus closer to the wall, you don’t need that much catalyst as the fluid moves slower and thus spend more time around it. Thus reducing rate of reaction by reducing catalyst “volume” makes sense.
In the middle, the fluid moves much faster. Thus more catalyst is required to obtain a decent rate of reaction due to shorter exposure time.
By controlling catalyst density in view of the velocity profile is a very clever yet simple. Wonder why nobody thought of that.
Big companies look at how to reduce CO2 in their cars. Let’s have a look at proton shall we? Oh the designers are busy drawing DRL, 2 tone sport rims and engineers working on the 7th airbag. No one bothers abt emission and when Preve was launched, it cannot be sold in europe.!! Whats the point naming it Preve then, to proof?