Hi,
I find this,
Coating the intake valves with a Vanadium catalyst seems to be the cure according to VW patent.
Does any one know if this was applied to Porsche valves and cats?

Read page 14
Patent number: 6866031 - Google Patent Search
Direct injection internal combustion engine
Patent number: 6866031
Filing date: Mar 8, 2002
Issue date: Mar 15, 2005

This is the summery by Markstudy(planet 9 forum)
BACKGROUND OF THE INVENTION
Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects

A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However, with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible.


SUMMARY OF THE INVENTION
To this end, the invention provides that, in an internal combustion engine of the type described above, a surface of at least the neck region of the intake valve is designed as a catalytic surface in such a way that it counteracts the information of carbon deposits.

This has the advantage that the formation of carbon deposits on the intake valves, which could impair the Carbon deposits are prevented by designing the surface to be microporous or antiadhesive and to consist, for example, of Cr—C—N in a coating thickness of especially 5 /urn. The 5 mechanism of action here is a suitable surface tension that counteracts carbon deposits.

To prevent the accumulation of carbon deposits, the surface is designed to be chemically inert towards predetermined elements, especially towards C, H, O, and/or N, and 10 consists, for example, of TiZr—C—H—N—O or TiAl— C—H—N—O, for example, in a coating thickness of 5 /urn. The mechanism of action here is saturation of the surface with certain elements, which then are not deposited.

To remove carbon deposits, the catalytic surface consists, for example, of Pt or vanadium nitride (VN). It is especially advantageous to provide an oxidized coating of, for example, vanadium pentoxide. An especially good catalytic effect due to a large surface area is achieved by making the surface microrough.

Additional features, advantages and advantageous refinements of the invention are specified in the dependent claims and are described below with reference to the examples

 

Great Tech post. I would imagine that this would be a must on any DFI engine.