325i stage 1 turbo ?????

[GeoffBob]

I feel the need for one of those books right know.

Then download this here

[eta]

Well that books is interesting. I have started all over again and I am making some progress. It's been a long time since I have done proper thermodynamics. I have started from the first law this time. Thanks for the pointers.

[GeoffBob]

Well that books is interesting. I have started all over again and I am making some progress. It's been a long time since I have done proper thermodynamics. I have started from the first law this time. Thanks for the pointers.

Eta, download and study this here

It's chapter 2 of Internal Combustion Engines by Ferguson & Kirkpatrick. For the rest you'll have to buy the book. 7.46MB worth PDF, so may take a while to download.

All the relevant equations required to model an engine are presented from first principles. Take the time to understand the PV diagrams for the Otto (constant volume combustion) and Diesel (constant pressure combustion) cycles. Now you will understand that to accurately model an engine you must model the combustion process with both pressure and volume as variables (neither is constant) which sits somewhere between the Diesel and Otto (the Dotto ) cycles. To do this you need to use something like a Wiebe function (as used in that paper you mentioned). The authors build a "Finite Heat Release" model using a Wiebe function and the other equations already introduced. The mathematics is heavy, but not impossible to understand. They then go on to present graphs of gas pressure and temperature as a function of crank angle. A temperature of 3000K at the height of compression is calculated! This falls to around the 1500K mark by the end of the power stroke. With heat loss to the chamber walls, the head and the manifold you can expect this to drop further.

They then go on to determine the thermal efficiency of the modelled engine as a function of spark angle and the results are quite informative. Overall results are, however, on the high side since the process is assumed adiabatic. Heat loss must be included to achieve realistic results.

All of the models presented by Ferguson and Kirkpatrick (including the "Finite Heat Release" model above) can be found here on the Colorado State Uni' website.

[eta]

Well I made alot of progess last night in that I modelled most of the cycle assuming an adabatic power stroke and compression stroke. I then found by reading that book that my results agree with the same simplistic model they presented. So at least my thinking is now straight. So now to take it to the next stage and factor in heat losses and changing volume for the combustion phase and refinement of the other inital assumptions that I have made.

I might do a thread when I have got a handle on this. For now back to some maths.

Also thanks for the links they really have helped alot.

[GeoffBob]

[GeoffBob]

I plan to use a TD04HL-16T from a Volvo T5 on my 2.7i (I picked one up second hand for £120). This turbo should be even more appropriate on a 2.5, although Geoffbob I am sure will chime in on this.

Eta, I just stumbled across this here

May be of use to you.

Seems your TD04HL-16T has a turbine wheel exducer diameter of 45.6mm, and inducer diameter of 52mm. The compressor has an inducer diameter of 43.4mm, and exducer diameter of 56mm. I'd need to know the A/R of your turbine housing to comment further (if you want me to).

[eta]

I'll have to take a look, tommorrow when its light again.

[eta]

Nothing about the A/R of the turbine housing is stamped on any housing. This is shame so short of dismatling the turbo I simply won't know.

That link is a nice find, thanks.

Anyway about to depart for the Isle of Skye.

[e301988325i]

This sort of thread is what makes the Zone IMHO. Zone Gold.