technical details of PD engines

[tboy]

Hi,

I am a recent addition to the Audi clan, having come from a very revvy Civic Type R. I have moved to an A4 TDI 130. I've seen some nice posts on other forums re: the Type R, and have a fairly good understanding of what's happening under the bonnet as the engine is performing, and I'm wandering if there is anyone out there who can tell me what goes on as you're revving the engine. Obviously there are various things going on at certain revs as you are driving hard (in particular there seems to be an extra bit of subtle thrust at between 3k and 4k revs)

Cheers,
T.

 

[imported_Hingy]

It's the turbo. /ubbthreads/images/graemlins/smile.gif

 

[tboy]

nah- I know it has a turbo! But thanks for the (only) response! What I was getting at was when you floored the Civic, there would be a varying amount of torque and power going through the wheels as you climbed the rev range, although I understand the Type R's power band could be desribed as fairly straight, which is something a lot of engine manufacturer's aim for. As you climb the rev range various cams with more agressive profiles would engage giving you more "lift"- I think that there were about four profiles in all. I was wandering if there was some resource I could check out on the web maybe that gives a descriptive explanation of the PD engines and how they work.

 

[jojo]

tboy, if you understand the Civic Type R's power delivery, you will know that the CTR achieves its high power output with the use of high revs, but in the process, it produces a low torque figure. With diesels, it's more about the torque in the midrange of the engine which gives you the push in the back around the 3-4k revs mark. Diesel engines require compression to provide the spark and runs a very high compression ratio, so does not require spark plugs, which is why they have a limited/short rev range. The PD system has seperate high pressure injectors per cylinder to give a finer spray(i think) to allow for a cleaner burn and more power in the process.

Thats about as technical I can get. /ubbthreads/images/graemlins/beerchug.gif