Is the PD engine dead?

[Husbandofstinky]

For many years VAG has continued to go its own way with the PD engine. I must admit I am not complaining about it as its been a very reliable and strong unit. However, as an ex PSA diesel user, I did feel that the PD engine was a little bit unrefined (harsh I know). Even the newer 2 litre PD engine sounds a
bit rough imo compared with the competition.

The long and short of it all is that VAG has steered away from it's PD mantra and has gone for the common rail unit with the new Audi A4. Personally I believe that this has always been the way to go but was impressed how VAG stuck with its PD system and went against the crowd. No one can deny that this system was succesful.

A bit of a dull posting I know, but it does indicate that VAG is moving away from PD to common rail. Whilst on holiday I did spend time reading some car mags and the A4 with its new 2 litre common rail diesel got very good write ups (especially the engine). This was deemed to be more powerful, more economical and more refined than the old 2 litre PD unit.

As this size and type of engine is common accross the whole VAG range, I would expect that it will eventually be used in Leon's as well as the rest of the VAG family.

More power, more economical, more refined. Can't be bad

Extreme apologies for this posting.. not exactly PMSL!

 

[lunalupi]

Whats the difference? In simple terms

 

[chris285]

considering the quoted figures for the performance on mk4 ibiza diesels i say they made the correct choice, i know they are only quoted but nothing else has come close to the performance and economy quoted

 

[muddyboots]

Whats the difference? In simple terms

Imagine, if you will, a gents toilet.

On the wall are 4 piss pots.

The "common rail" piss pots have one water tank above that feeds all 4.

The VW "PD" piss pots each have their own water tank above.

Now subsitute "piss pot" for injector, and "water tank" for fuel pump.

 

[T. Spark]

Imagine, if you will, a gents toilet.

On the wall are 4 piss pots.

The "common rail" piss pots have one water tank above that feeds all 4.

The VW "PD" piss pots each have their own water tank above.

Now subsitute "piss pot" for injector, and "water tank" for fuel pump.

You should have more time off work mate, that is by far the best explanation of a PD engine set up I have ever witnessed!

Classic...

 

[devonmikeyboy]

A bit of a dull posting I know, but it does indicate that VAG is moving away from PD to common rail.QUOTE]

Yes VAG has decided to kill off the PD engine and go with everyone else and produce common rail engines. Audi are putting a common rail diesel in the new TT as well. LINK

 

[lunalupi]

Imagine, if you will, a gents toilet.

On the wall are 4 piss pots.

The "common rail" piss pots have one water tank above that feeds all 4.

The VW "PD" piss pots each have their own water tank above.

Now subsitute "piss pot" for injector, and "water tank" for fuel pump.

Cheers, I can understand that!

 

[JamesL]

That is the best explanation of pd I've ever seen. Genius!

So are the 90 and 110ps tdi engines in the leon common rail or something even before that? I presume something before?

 

[Husbandofstinky]

Imagine, if you will, a gents toilet.

On the wall are 4 piss pots.

The "common rail" piss pots have one water tank above that feeds all 4.

The VW "PD" piss pots each have their own water tank above.

Now subsitute "piss pot" for injector, and "water tank" for fuel pump.

PMSL... I'll remember this whilst trying to explain to a client who just 'doesn't get it'. Been through this sort of layman term loop no end of times.

That's just got to be about the best one yet!!!

 

[sssstew]

That is the best explanation of pd I've ever seen. Genius!

So are the 90 and 110ps tdi engines in the leon common rail or something even before that? I presume something before?

no, they are rotary high pressure injection.

 

[AlpineWhite]

The move from PD to CR was only a matter of time.

 

[muddyboots]

Cheers, I can understand that!

By the way I wasn't suggesting you were familiar with gents toilets

 

[muddyboots]

I think I should refine the analogy slightly:

Imagine, if you will, a gents toilet.

On the wall are 4 piss pots.

The "common rail" piss pots have one water tank high up one the wall that feeds all 4 through various lengths of pipework.

The VW "PD" piss pots each have their own water tank built in.

Now subsitute "piss pot" for injector, and "water tank" for fuel pump.

 

[AlpineWhite]

But the common rail toilet can flush whenever it likes, the PD toilet is a bit more limited.

 

[muddyboots]

But the common rail toilet can flush whenever it likes, the PD toilet is a bit more limited.

Indeed, the PD toilet can only flush when you're stood in front of it.
The common rail toilet can flush whenever it likes.

Gotta be able to work a joke in here around the word "piston"

 

[Muttley]

I found this useful cutaway of a PD unit on another website.

The PD system uses separate cam to squish the fuel directly into the cylinder.

Conventional diesels have a single high-pressure pump driven off the engine (the cambelt in my TDI 110) which also does he fuel timing and distribution, delivering to each injector in turn.

Common-rail systems have a high-pressure fuel pump delivering unmetered fuel to all the injectors. The injectors have electronic valves that control fuel pulse timing and length.

PD delivers higher pressures than other systems, because there is NO high-pressure piping involved - the pressure is developed at the injector itself. Timing and quantity are set by the electronic valve at the side, which opens part way through the cam stroke.

Common-rail systems user very exotic injectors - it is the same technology as petrol injection, but at much higher pressures. Common-rail has the advantage that it is much easier to control and shape the injection quantities and timing, which is necessary to comply with increasingly strict environmental legislation.

 

[WaveyDaveyGravy]

Given the German's history of refusal to accept their idea is bad and taking 40 years to make it work properly (911), I'm amazed they're not persevering.

 

[Guinness]

muddy boots mate that description has genunnaly made my night, its by far the best explanation of common rail I have heard. But what has cracked me up more is the mind that just plucks that out of thin air.

 

[muddyboots]

But what has cracked me up more is the mind that just plucks that out of thin air.

I do worry about myself at times.

 

[Ant FR]

i'm not sure i would call a an HDI engine refined compared to a PD engine. Gutless was always the word that sprang to mind with most of the PSA engines ever brought out. Although i will say my brother has an amzing little Renault 19 ( its his workhorse car) and even on an L reg with 42k on the Clock ( i know it was a bargain 1 owner fromnew for £300 buy) it seems to have some low down urge, quite surprising considering its age. Anyway soory but in general the PSA lumps have been rough and noisey and always rather smokey.

The only real refined units i have ever driven are the Merc diesels and the beemer 2.0 and above diesels. I also keep hearing rave reviews about the latest Lexus diesel engines. Also the other desel i was surprised at was mates company car Mazda 6 170bhp diesel, proper little rocket in such a big car.

I think the real reason for VW moving to common rail is due to the increased need to control fuel injection more, even in the latest incarnation with piezo injectors ( which even VW have admitted were too expensive to use in the first place) they have been striving to get more efficient control over the fuel supply.; Common rail enables that and also the use of one fuel pump makes the unit a lot more efficent.

Another one to look out for is the new Subaru Boxer diesel lump. Amazing torque levels being created.

However i really rate the 1.9Pd lump, i honeslty think it single handedly transfformed the countries perception of diesel cars, if it was'nt for cars like the Gofl Gt Tdi 130 i doubt many of us would have opted for a fast diesel hatch like we all did.