Wie funktioniert das Twincharger-System im Golf GT? | Posts 16+

It's clear that VW wouldn't install a part equivalent to a climate compressor coupling. The required drive power for a compressor should be significantly higher. Even with numerous climate control activations, the number of gear changes a TSI coupling needs to perform over the lifespan of a car would be many times greater than what a climate compressor would do. Therefore, as Roger says, all that's left to do is wait and see what everyday use reveals. Perhaps it will run completely smoothly this time, which would be well-deserved after the G-Lader era, a period that many don't like to remember, although the problem was elsewhere.

To be honest, I haven't seen water pumps with couplings before. I believe BMW was the manufacturer. Electric pumps are on the horizon, which should offer excellent controllability.

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It is clear that Volkswagen would not have installed a part equivalent to the A/C compressor clutch. The required power for a compressor should, of course, be significantly higher.

Hello Matthias,

I don't think the motor-compressor itself will demand more from the coupling than the refrigerant compressor. The only difference might be the number of switching cycles, which could be higher. The motor-compressor only needs to compress air into the intake manifold, which is already at a slight vacuum, and therefore, in my opinion, will operate with a much lower inrush current than the refrigerant compressor, which is working with a medium under high pressure. I also see the power requirements of both compressors as being in a fairly similar range. Furthermore, the engine-driven compressor only needs to cover about half of the engine's speed range, because, unlike the air conditioning compressor, it disengages at a speed of over 3,000 rpm.

@Aron:
That's encouraging. I'm not biased about this, but I'm very curious to hear about long-term experiences. As always, when VW does something completely new, anything can happen.

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In gasoline engines, the superchargers are even switched off at higher speeds (in the 206 RC, for example, at 6000 rpm, because the supercharger would likely break down at 7500 rpm).

VW implemented it in a similar way. The compressor is deactivated via the Motronic, at least at high engineload, even in diesel engines. It can even be deactivated during acceleration if you give it more than about half throttle. You can see this clearly in the compressor shut-off conditions displayed on the Climatronic control panel.

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Meanwhile, even the water pumps are being integrated, and it's working

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Even if the mechanical issue were resolved (?), the power output of a water pump would likely be negligible compared to a climate control or engine compressor, so it should be relatively easy for the clutch to handle.

@Jochen:
What does the climate have to do with the radio? Active power amplifier cooling ?

Hi Roger,

Okay, I wasn't referring to the moment when the compressor needs power to start up. It's already clear that it engages gently; it just needs to get its rotating mass moving at that moment. I meant the power that the compressor receives from the crankshaft via the belt, and therefore also through the clutch, when delivering its maximum force. That power is likely more than what the air conditioning system needs. I don't know exactly how much power an air conditioning compressor requires, but it's probably around 5 kW. A compressor that needs to provide approximately 1 bar of overpressure at 3000 engine revolutions per minute has to handle 1.4 liters of volume, which means 1500 times 1.4 liters with 1 bar of overpressure... now I need to calculate whether this claim is accurate.

In gasoline engines, the superchargers are even switched off at higher speeds (in the 206 RC, for example, at 6000 rpm, because the supercharger would likely break down at 7500 rpm).
VW implemented it in a similar way. The compressor is deactivated via the Motronic, at least at high engineload, even in diesel engines. It can even be deactivated during acceleration if you give it more than about half throttle. You can see this clearly in the compressor shut-off conditions displayed on the Climatronic control panel.


What kind of cheap compressor did Peugeot install?
The practice of reducing the load on the compressor at full load has become standard in order to improve the acceleration performance of passenger cars. Here, the extendable water pump, just like the switchable D+ terminal of the alternator, is designed to utilize the entire drive power for acceleration at full throttle, without powering any auxiliary components.
Here, the Americans are leading.
They may not be allowed to drive much faster than walking speed , but they want to reach that speed as quickly as possible, so they are using every possible means.

I haven't seen compressors being shut down due to overspeeding in my climate tests yet. Maybe we just weren't fast enough .





@Jochen:
What does the climate have to do with the radio? Active power amplifier cooling ?

One could also imagine...
Actually, nothing, but in modern vehicles, the radio has the ability to access the Comfort-CAN bus and, theoretically, read data.
In the field of climate science, there's one of those unusual connections:
In the Touareg, the steering angle is read and evaluated by the Climatronic system.
The larger the changes in steering angle, the greater the cooling capacity inside the vehicle.
The reason for this is:
Based on the numerous steering movements, it suggests a sporty driving style, which also results in greater physical exertion. This causes the driver to further heat up the interior, which is something one wants to avoid.


Best regards, Jochen.

@Matthias:

Calculation error: With each revolution (4-cylinder, 4-stroke engine), one cylinder must be filled, which is one-quarter of the total displacement = 3,000 RPM x 350 cc.
Don't forget that the turbo is already contributing significantly .

Jochen_145 wrote:

What kind of cheap compressor did Peugeot install? The practice of reducing the load on the compressor at full load has become standard in order to improve the acceleration performance of passenger cars. Here, the extendable water pump, just like the switchable D+ terminal of the alternator, is designed to utilize the entire drive power for acceleration at full throttle, without powering any auxiliary components. Here, the Americans are leading. They may not be allowed to drive much faster than walking speed , but they want to reach that speed as quickly as possible, so they are using every possible means. I haven't seen compressors being shut down due to overspeeding in my climate tests yet. Maybe we just weren't fast enough .

The compressors need to be the same, pressure-regulated. However, the French also regulate the evaporator temperature, and when there's a low cooling demand, they reduce the refrigerant pressure or cycle the compressor down. The compressor itself only limits the piston stroke when the refrigerant pressure is reached. Therefore, at partial load, the refrigerant pressure can only be reduced by switching the compressor off. All of this is now also controlled by characteristic maps (*grumble*).

But let's get back to the topic...

"I would actually prefer a different type of magnetic coupling for a larger mass like a large-volume compressor used for forced induction. It could potentially be implemented similarly to a small torque converter, perhaps with some hydraulics, but that would likely increase the cost. I'm still curious about how they solved it; it's probably a very large vibration damper." Perhaps there's more information available.

Roger wrote:

@Matthias: Calculation error: With each revolution (4-cylinder, 4-stroke engine), one cylinder must be filled, which is one-quarter of the total displacement = 3,000/min x 350 ccm.

In my opinion, Matthias calculated it correctly - after 2 revolutions of the engine, all cylinders have completed their 4 strokes, and each has undergone an intake stroke ==> the full displacement volume has been drawn in. Similarly, after one revolution, half of the total stroke volume was drawn in.

Best regards,
Munch.

@Mampf:

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After 2 engine revolutions, all cylinders have completed their 4 strokes

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Think about it again . In a 4-stroke engine, a complete cycle, as the name suggests, takes 4 strokes. So, it took 4 revolutions of the crankshaft for all cylinders to complete one full cycle.

Therefore, in suction mode, roughly simplified, 1/4 of the stroke volume is required per revolution. However, on top of that, there is naturally the (which I shamefully omitted ) charging to 1 bar, so roughly speaking, half of the stroke volume is actually required per revolution. So, Matthias was, of course, right, even though his specification of 1,500 RPM was a bit confusing to me.

The question remains how much the compressor actually contributes to boosting at 3,000 rpm, as the turbocharger likely already has ideal conditions at that point.

@Matthias:
Were you able to roughly estimate the power output of the compressor without considering the turbocharger?

My post, as mentioned above, only appears when I re-enter it (as shown below). Otherwise, although it indicates that I wrote the last post, it appears on page 2 of 1 . I can only find this post by going through my name and my contributions, not directly through this post; in that case, only one page is displayed... I'm going to try to delete the text mentioned above.

Herr Antje wrote:

Roger wrote: @Mampf: Quote: After 2 engine revolutions, all cylinders have completed their 4 strokes . Think about it again . In a 4-stroke engine, a complete cycle, as the name suggests, takes 4 strokes. So, it took 4 revolutions of the crankshaft for all cylinders to complete one full cycle. Therefore, in suction mode, roughly simplified, 1/4 of the displacement volume is required per revolution. I actually think Mampf's explanation is better (aside from the terms "sauger" or "lader"). @Roger I'm sorry, I don't understand. Could you please rephrase your question? For me, "4 strokes" means 2 times the piston moving up and 2 times the piston moving down (assuming we're talking about one cylinder). A 4-stroke engine needs 2 revolutions (720°) to complete the cycle, while a 2-stroke engine only needs 1 (360°). Why does a gasoline engine, as a 2-stroke, receive a spark every revolution, while a 4-stroke engine receives a spark every other revolution, and not every fourth revolution (excluding combined ignition coils)? In 2 revolutions, each cylinder returns to its initial position, and each cylinder completes one cycle (4-stroke), but not every cylinder is at top dead center (TDC). Therefore, I am operating at half the displacement volume. However, in my example, the cylinders can breathe 100% freely, without any consideration for boost pressure or vacuum, as if they were naturally aspirated. I found something else.

http://www.nao-bbsdiez.de/motor/4takte/funktionsbeschreibung.htm{MARKER}

Okay, I'm giving up. For some reason, the system doesn't seem to want to accept my posts. Perhaps my post will appear above in some form, or maybe not .

EDIT:
There he is again...

Sure, here's the translation:

"EDIT: Again."
I will fix it again when a new post is written; then it should work.

@ Roger.

No, I find very little that is useful. The only thing I can figure out is the work required to generate the airflow. Otherwise, the fluid dynamics is quite complex, and I've always found gases to be boring... . Now, we just need to roughly estimate when the compressor will have the most work to do. Possibly in this system at approximately 2000 RPM. That's when the turbocharger will start to contribute significantly. The fact remains that the power consumption of the compressor is the reason for the shutdown; otherwise, we could have somehow run the thing in bypass. The only information I found so far, after only searching for 5 minutes, suggests (although the source is questionable) that the supercharger for a 200 Mercedes engine requires up to 22 kW of power. Since there are no specifications regarding capacity or other dimensions, this information is probably not definitive. I would expect a power consumption of over 8-10 kW, considering the amount of energy the turbocharger extracts from the exhaust gases to generate the necessary pressure.

The thing about the rotational calculation was ambiguous, point to Roger who explained it to me .

@Mr. Antje:

It's slowly dawning on me, thank you for the clarification: beats are not the same as revolutions ...
The thread was also temporarily invisible to me.

Perhaps an interesting question:
Shouldn't the compressor theoretically drive the supercharger as long as the supercharger hasn't built up any pressure yet?
Therefore, the loader should also start responding much earlier than the 3000 rpm mentioned above, right?

My envisioned layout currently looks like this:

The 21 comes standard with a relatively small Garrett T03 turbocharger. This is replaced with a larger T04 turbocharger, which then, of course, has all the known problems associated with larger turbochargers .
This is then compensated for by a G60 charger (Please, no discussion about G-chargers, as the available space is very limited, so unfortunately, no Mini or SLK equivalent fits .

Currently, the clutch is causing some headaches. I'll probably take one from a Mercedes, which, of course, raises the question of its durability again.
A more elegant solution would be a kind of reverse centrifugal clutch on the crankshaft stub that disengages the entire belt drive at 3000 RPM... But aside from the fact that such a clutch would probably be more suitable for a mechanical engineering doctoral thesis, all this stuff would probably fall apart after an hour anyway .

Perhaps one of these cute piggyback engine control units could handle the connection and disconnection without requiring much programming effort.

citronist

@Roger and Matthias
Who among you was right: 1/2 Hubrauch or 1/4?

Roger agrees with me, I agree with Matthias, and Matthias agrees with Roger. Guys, we're going in circles .

Matthias, I think the order of magnitude of the compressor's performance is different here, and more related to the rated speed, because in Mercedes engines, a turbocharger cannot take over the work required to reach the rated speed. Thank you for providing a house number for the power output; I hadn't found much information on that.

@citronist:
The turbocharger starts boosting much earlier than at 3,000 RPM. However, as you mentioned, the combination of a small-displacement engine with a relatively large turbocharger for high maximum power is, in terms of responsiveness, just as problematic as it was with the very first turbochargers of the old school: barely drivable; it's either nothing, then a sudden surge. Especially in the case of a gasoline engine with a relatively low air intake.

The art here was for VW to achieve a seamless transition from compressor to turbo operation. A significant amount of work was undoubtedly put into the mapping and control of both chargers. Contemporary tests indicate a virtually imperceptible transition in all operating conditions, which suggests that this has been achieved successfully.

When you're doing your renovation, be prepared for a significant amount of work in that area.

@Mr. Antje:

You are both right. You've left out the charging part, and I think Matthias already included that.

Okay, so as not to compound the confusion.

"I made it simple, Tom, because I assumed that the compressor needed to produce 1 bar of overpressure, meaning a total pressure of 2 bar. Therefore, I only halved the rotational speed." If you do the calculations correctly, the result should be the same. However, I just made a rough estimate and, for simplicity, I omitted the 1 bar of overpressure.

Roger, I understand that even if the Mercedes values are plausible, they cannot be directly transferred. After all, the supercharger has to generate pressure at 1.7 or 1.8 liters. However, not too much pressure... oh yeah, since we're probably all going to fail due to missing parameters.

I wanted to say that a motor compressor requires more power than a compressor used in air conditioning systems.
Roger added that the number of engagements of the TSI compressor coupling element exceeds that of a climate control compressor coupling. That's what logic tells me too.

Both Roger and I see this as a potential problem area within the TSI's day-to-day operations. Hopefully, we are wrong.

P.S.: If anyone has compressor performance data, knows how to obtain it, or wants to calculate it, I would really appreciate it if you could share accurate data with me.