Piezo PD System: New Information and Details

Hi,

Since there are repeated claims that VW intends to abandon the PD system, I would like to share some thoughts on this topic.

http://www.vw-mechatronic.com/produkt.htm
http://www.siemensvdo.de/de/pressarticle2004.asp?ArticleID=200411_007d

The Piezo PD injector has been in production since November 2004 and will first be introduced in the new Passat in the spring of 2005, and then in all other engines as well.
The advantage, in addition to the further increased injection pressure (2200 bar), is supposed to be improved controllability. This should finally give PD engines the smooth running characteristics of a common rail (CR) engine. Nevertheless, the advantages of PD engines (high torque) should not be lost.

Today, a major German newspaper published an article about the Piezo PD. Unfortunately, I haven't been able to find it online anywhere.

These piezo PDs should also fit perfectly into our high-pressure vehicles, right? Aren't there any test samples available?

These piezo PDs should also fit perfectly into our high-pressure vehicles, right? 8)Are there no test samples available?

Hello,
However, the control mechanism is certainly not 'suitable' or 'compatible.'
Piezo elements require higher voltages (several hundred volts).
And what benefit would they provide with a motor that isn't properly matched to them?
Best regards,
Günther.

Did you notice the ? It wasn't entirely meant to be taken seriously!!!

But what do piezo injectors really offer us? Sure, they provide cleaner vehicles. However, in my opinion, they introduce more vulnerability and, above all, higher costs in case of potential defects.

Is the 3.0 TDI engine in the Audi already equipped with that feature?

mullemaus wrote:

Is the 3.0 TDI in the Audi already equipped with that?

No sir... That's a CR engine.

6-cylinder PD engines are still not feasible (at least not in a cost-effective way).

joergs wrote:

... but what do piezo PDs really bring us? Sure, cleaner vehicles. But in my opinion: more susceptibility to failure and, above all, higher costs in case of potential defects.

I doubt that. Initially, piezoelectric elements will be expensive, but probably not in the long run. The manufacturing costs are likely to be significantly lower compared to solenoid coils. Piezoelectric elements offer much faster and more precise control compared to magnetic coils. Furthermore, the size of piezoelectric elements can be significantly reduced compared to magnetic coils, which simplifies cylinder head designs, especially for 4-valve engines. Piezoelectric elements are extremely stable with respect to temperature, which is very important in the engine compartment. I haven't yet figured out how it behaves on the MSTG side.

@bertil

The use of piezoelectric technology undoubtedly has advantages. This is a fact, and there's no arguing with it. However, overall, it seems that the conventional piezoelectric direct-drive systems are now under control, and they are also available at a very affordable price. But in the beginning, there were more than enough problems with those conventional systems. And that's exactly what I fear with Volkswagen's current approach. It's possible that there will be many issues before these 'things' become reliable and function stably, and potential customers might then switch to other systems and brands.

Hello,

Piezo injection control, with its advantages, is great. However, this technology already exists in some engines (e.g., the Audi V6). While PD (piezo direct injection) remains linked to a cam profile for fuel injection, it doesn't achieve the same flexibility as CR (common rail). VW will continue to use PD, but primarily because of the enormous investments already made in its development, production, and warranty services, which would otherwise be lost.

Best regards,
Albrecht.

joergs wrote:

That's exactly what I fear will happen with VAG's "banana politics" here as well.

I cannot and will not deny that. However, it's important to remember that Piezo CR systems were superior to their conventional counterparts from the very beginning.

Quote:

In the case of 3D printing, PD remains bound to a cam shape and does not achieve the same flexibility as CR.

The new system also addresses this issue more effectively. A pressure storage solution within the PD element (similar to the rail in CR systems) compensates for this disadvantage. Pre- and post-injection are also possible with the PPD system, just like with CR systems.