Tomas L

Why is that the issue?
No one has said that the DME gets a 0-5v signal.
Even if it did, it would not be a true TPS system in the sense that it would use the TPS signal as a primary factor in the fuel ignition calculation. If it did it would be an N-Alpha system and would not need an AFM/MAF (and it would not exist on a road car sold by Porsche).
The only reason I can think of where the extra info from a 0-5v TPS would be useful is for smaller corrections in special driving conditions and some emission fine tuning.

No back to the main issue, do you dare to comment on the load calculation questions?

jimbo1111

Don't take it to personal John. I'm just having a little fun. That's what it's all about. In fact I kind of like your key board demeanor.
All I have illustated is a product that's bin around for over 10+ years. The product has evolved some since then. It's proven and works well. I hope you don't feel as if I am bashing your business because am not. I think you guy's are on the right track and from the bottom of my hart . I hope that your business does well enough to stick around. Good luck.

Lorenfb

As I said before, the inputs to the DME are NOT a true TPS. So let's get technical
and not call them that, since we all like to be precise here, right?
Therefore, the 944 DME has switched inputs & not a TPS!

By-the-way, most/all later Bosch Motronic (DME) systems utilize a true TPS input
besides a MAF.

"To get load (torque) from the mass/time (energy/time) signal you have to multiply it with time. rpm is 1/time som if you take the flow signal (energy/time) and divide it with rpm (1/time) you get load (energy or torque)." - Tomas L -

1. Since Load = Torque = Energy = Mass then;
Load per unit time = Torque per time = Mass per unit time

2. Since the MAF provides a voltage output proportional to
mass air flow per unit time then:
MAF output voltage (0-5 volts) = Load per unit time
Then the input voltage to the DME (0-5 volts) from the MAF is the instantaneous
engine load value.

Therefore;
Load (instantaneous - dL/dt) = MAF (output - volts)

Tom M'Guinn

It seems we lack and agreed definition of "load" -- what is load?

On a related note, does the DME use an 8051 processor. I read that somewhere, but can't find an 8051 on the board. Is it in a custom chip? What clock speed?

Lorenfb

Yes, the 944 DME uses the 8051 u-p (N-Channel). It's the largest chip (40 pins) on the upper
circuit board. It runs at 6.0 MHz. The early 944 (015 box) uses the RCA u-p CMOS chipset
with multiple mask ROMs.

The basic 8051 DME design is used in;
1. BMW 535, 635, 735
2. Porsche 911 3.2
3. Porsche 928 later LH system

The key elements of the DME are:

1. 8051 u-p (u-code, run from EPROM, assembled/disassembled
using MSDOS DeBug or MS Intel Assembler)
2. EPROM, 32K(4K X 8, 24 pin)/64K(8K X 8, 28 pin), jumper selectable
3. A/D Converter - off-the shelf, NSC, Analog Devices, etc.
8 bit byte, key inputs - temp, AFM, idle switch & WOT
4. Ignition coil driver with current limiting, bipolar darrlington @ 25 amps
600 volts BVEO, high SOA - inductive switching, TO-3
5. Injector driver with injector multiple pulses per injector opening
& voltage clamp, Bosch custom I.C., bipolar darrlington @ 15 amps
100 volts BVEO, TO-220
6. Bipolar idle valve driver
7. +5.0 volt three terminal regulator, TO-220
8. Interdesign I.C. speed & reference signal shaper,
reference signal not needed once running, u-p counts ring teeth
9. Misc. bipolar 7400 & 4000 CMOS I.C.s
10. Misc. quad op amp & quad comparator I.C.s
11. fuel mixture & ignition timing adjustment switch, 8 position
12. O2 sensing uses simple quad comparator to drive u-p rich/lean

Bottomline: A very simple, inexpensive, & highly reliable design with very rare failures.

Note: Bosch, Ford, & et al used Intel u-ps versus GM which used a Motorola 6805 u-p
in the early u-p designed fuel/ignition systems. Both the Intel & Motorola u-ps were
either licensed or copied by European/Asian semiconductor manufacturers.

Tomas L

If you by true TPS mean that they divide the throttle angle in 256 (or whatever the digital resolution is) discrete positions, then yes they do.
If you by true TPS mean that they use the TPS signal as a primary factor in the fuel and ignition calculation, then no they don't.

And then load is calculated as load=MAF/rpm (or load=MAF x engine cycle time). Right?

Nope! Not in our generation of motronic.

Load is in this case a Bosch term. It's proportional to the amount of air the engine consumes each revolution (or cycle). It can also be regarded as an approximation of torque, or as MAPxVE.

Tomas

TurboTommy

Lorenfb,
This statement:
"Load = Torque = Energy = Mass"
is not correct and is the basis for screwing up the rest of your deductions.

Mass is actually "torque x RPM" (the actual air/time the engine is ingesting; which is also the horse power potential of the engine).

Therefore "mass" can not equal "torque/load".

Therefore the MAF signal to the DME is not the instantaneous load value.

Naplesguy06

What happened to this thread I wanted to hear the reply on the Atari 24 pin 32k and Nintendo 28 pin 64k Intel jumper selectable option,this is what all of the new MAF tuners have gone to 10 years later and wow an 8051 processor that has the clock speed of 6 hertz? You think they could have stretched for the 8080 that the Tandy COCO provided.?

Voith