Gangselektive Drehmomentbegrenzung | Posts 16+

matthiasTDI96 wrote:

...Reducing torque in a diesel engine by retracting the electromagnetic valve is quick and relatively straightforward. In a gasoline engine, it's a bit more complex, and Bertil is certainly right about that. Because simply removing the EM value will lead to the problems mentioned.

Nevertheless, this happened within a few milliseconds.
The reason for this is that the preliminary control of the electromagnetic torque is performed directly via an alpha-n control, which uses the DK angle (alpha) as a function of the speed (n). It's just as responsive as a diesel engine, as it's directly linked to the driver's input.
Fine adjustments are made based on data from the air mass sensor and the lambda sensor.

Other types of control, such as pure lambda or LMM control, are no longer commonly used because they are too slow.

Quote:

A throttle valve doesn't destroy energy.

Yes!
In a way, Ulf is right. However, there is currently no better method available.
This loss is so small that it is negligible for the overall efficiency, especially where long suction paths exist downstream of the check valve. Things are different with a single-throttle system.

Ulf wrote:

...the desire to replace a working, but otherwise sloppy, solution with a (theoretically) better approach.

What do you want to do better?
The EM (electromotive force) is being retracted and is good, controlled by the DK (dielectric constant) angle. There's simply nothing better or faster available for gasoline engines.
The principle is the same as with a diesel engine. Turn off the gas.

The solution is neither sloppy nor bad!

Bertil wrote:

Ulf wrote: ...the desire to replace a working, but otherwise sloppy, solution with a (theoretically) better approach. What do you want to improve?

Avoid engaging the torque range that is never meaningfully usable, depending on the gear. For example, the desired WOT torque in 1st gear. Limit the torque to the specified 280 Nm instead of 350 Nm, so that less power is reduced (or, depending on the load and grip, nothing at all) through the intervention of the traction control system.

Hello everyone!

While perhaps less "constructive" – if one should even use that word in a thread like this, of course...

TDI-GTI-4-Motion wrote:

matthiasTDI96 wrote: I would have bet that you would be the first to interpret any selective limitation of something as a restriction of your free self-determination, disenfranchisement, or whatever. This is how one can be wrong. Typical Ulf, sometimes it's okay, sometimes it's not. If the limit were in place, the thread would now exist in a modified form, for every bet.

²

Best regards from Munich!

280 Nm is far too high. My Audi 80 with a 1Z engine also pulls off in first gear with its 203 Nm if I accelerate too quickly. So, the problem is much older than that. Perhaps the automotive industry isn't quite ready to disempower us yet?

hg
Herbert.

ulf wrote:

Do not even engage the portion of torque that is never meaningfully usable, depending on the gear. For example, limit the desired torque at full throttle (WOT) in 1st gear to the aforementioned 280 Nm instead of 350 Nm, so that correspondingly less (or, depending on the load and grip, nothing at all) needs to be regulated.

And to avoid further sources of error?
The risk is too high. Then, I'd rather do it this way.

Not even Bertil and Ulf can destroy energy.

I would like to have your problems.

Gang-specific torque limitations are applied when components...
in the powertrain, not achieving full power in the first or lower gears.
Hold on a moment.
Example: drive shafts, differentials, and the transmission itself.
The "driver" system (typically referred to as a "full-stack" system) already has an input parameter.
The component that allows you to adjust the desired level, which is generally called a "pedal" .
If the tires lose traction, release the accelerator!

Hello, (exPD90+TSI105) HSD136

Herbert wrote:

280 Nm is far too high. My Audi 80 with a 1Z engine, even with its 203 Nm of torque, will still pull in first gear, even if I accelerate too quickly.

This crucially depends on the vehicle's curb weight, the weight distribution/center of gravity, and the overall gear ratio (rpm -> km/h).
For the Polo, I only reach the torque limit of 280 Nm at a weight of 1670 kg and a rotational speed of 0.0086 rpm per km/h.

Actually, the following is completely incorrect:

ulf wrote:

If I remove the VA (vertical acceleration) relief limit of 5 m/s² from my calculation for the WRC Polo and only increase the weight per wheel from 18 to 20 kg, the calculated maximum acceleration in the 1st gear decreases. Acceleration from 7.25 to 7.0 m/s².

I had turned the wrong numerical setting, specifically the rim diameter in mm instead of the wheel weight.
A 2kg difference per wheel only changes the maximum possible acceleration by approximately 0.02 m/s².

ulf wrote:

Do not even engage the portion of torque that is never meaningfully usable, depending on the gear. For example, limit the desired torque at full throttle (WOT) in 1st gear to the aforementioned 280 Nm instead of 350 Nm, so that correspondingly less (or nothing, depending on the load and grip) needs to be regulated.

However, in mass production, the wishes of minorities are not taken into account, so you should simply accept that!
If you want it, make it yourself and be happy, but please don't spam the entire forum with these pointless "help requests."

I'm sorry if this sounds harsh, but this isn't helping anyone.

TDI-GTI-4-Motion wrote:

. . . please don't spam the entire forum with such pointless "help requests"

. Help request?
I wanted to know why the OEM... and that was already clarified in the initial responses.
The rest were your comments or questions to me, which I (courteously) answered .

Hmm, doesn't using significantly more energy to bring the turbo back up to speed after a throttle intervention become crucial in diesel engines, especially since they lack a blow-off valve function?

At least, after the adjustment, my 2.0 TDI engine would always experience a drop in torque before the turbocharger pressure built up again.

The TFSI system was noticeably more responsive in regaining traction after grip was restored.

I explain this by the fact that the tractor operates with significantly higher boost pressure, and the turbocharger, due to its size, is more sluggish.

In diesel engines, there is no throttle valve that completely closes when the engine is unloaded. Therefore, without a bypass valve, the boost pressure is not relieved through the compressor (as it would flow back in the direction of the compressor's rotation).

However, I would like to point out that a bypass valve on a diesel engine would indeed be useful in a single-stage turbocharging system, with high boost pressure and low engine speed, specifically to prevent turbocharger surge during deceleration.