LLK: Sizes and Performance Levels (10th Edition)

Hello,

My engine (in its standard configuration) already produces up to 80°C of hot intake air at full load on the highway, even at an outside temperature of 13°C, while Rainer's A3 only needs to handle 50°C at an outside temperature of 19°C.
A difference of a "net" 36°C (at the same outside temperature)!

OK, the air-to-water heat pump charges with 0.3 bar more pressure than the air-to-refrigerant heat pump, but that doesn't necessarily mean a higher leaving water temperature: with a larger heat exchanger, a temperature of 50°C could also be achieved with the air-to-water heat pump.

So, are the intercoolers in Rainer's TDI generation now oversized, or were they "trimmed" in the 9N generation (or were the air ducts to the intercooler poorly designed, leading to misting before the intake, etc.)?

@ Motor experts:
Perhaps it would be helpful now if we could get some more detailed explanations about the internal motor consequences of different types of LLT (likely referring to "low-level training" or a similar concept).
Gremlin had already provided some keywords for that.

Quote:

- firing pressure. - thermal load - compressed drive power - thermal efficiency

delivered.

1.
Regarding thermal load: As far as I know, the LLT (likely referring to a specific method or technology) approximately "shifts" the entire operating cycle, including the exhaust gas temperature, in parallel, is that correct?

2.
The loader's power output could be reduced at lower LLT (Low Load Torque) if the air mass/stroke is not to be changed.
The logs from my altitude sensor show something different: high LLT (likely referring to a specific parameter) leads to lower boost pressure, possibly because of reason number 1, in order to prevent the temperature peaks from getting too high?

Unfortunately, I lack the background knowledge regarding ignition pressure and thermal efficiency. Could you please provide some guidance on these topics, as well as other aspects that are relevant to material stress and lifespan?


By the way, I once measured the dimensions of some LLKs.

-> The frontal area of the cooling fins, including the cooling ribs, on the 1997 AFN Golf 3 (81 kW) is 14 x 19 cm, and the oil cooler is 6.5 cm deep.
-> The volume of the cooling block is 1.73 liters.

-> Coolant reservoir in a 2001 ALH Ibiza (6K, 66 kW): Front dimensions 9 x 30 cm, depth 8 cm -> 2.16 liters.
The ASV-Ibiza, with its 81 kW engine, has the same type of automatic transmission fluid (ATF), as far as I know.

-> LLK (liquid cooling system) in the 2004 ASZ-Polo (96 kW): Front 18 x 20 cm, depth 6 cm. -> Also 2.16 liters, despite 44% more power than the ALH .
However, I believe that the larger frontal area of the ASZ-LLK is likely to have a (slightly) better effect on the LLK performance compared to the increased depth of the Ibiza.

It would be interesting to compare the LLK (Low-Temperature Combustion) parameters of the ARL engine with those of larger TDIs (2.5 l) -> could someone measure these?

Hi Ulf,

Let's ask a quick question: What's the actual difference between the 1Z/AHU and the AFN LLK engines in the VW Golf 3?

To the best of my knowledge, AFN has a different one.

m;

Here's another contribution to your statistics:
My 1Z's LLT max setting results in an overtemperature of 30-35 K above the outside temperature, which roughly corresponds to Rainer's measurements.

Hi,

Without specific dimensions: If you look at the design of the ARL, with its LLK (low-level cable) running across the front of the car, you'll see that it's significantly larger than the ASZ.
But remember, the larger the LLK, the greater the volume that the turbocharger needs to fill before the engine experiences boost pressure.

If that doesn't bother you, you could try the construction of a more powerful 1.8T engine by using two intercoolers connected in series }.

I can only talk about what's in the Skoda catalog right now.

LLK

1J0 145 803 F


MKB: AGU, AUM, AUQ, ARX, AGR, AHF, ALH, ASV, ATD


I'm not sure about ASZ either; unfortunately, my catalog doesn't go that far.

CU Gremlin.

LLK

1J0 145 803 F
AHF, ALH, AGR, AJM, AUY, ATD, ASV

1J0 145 803 E
ASZ

1J0 145 803 H
ARL

dieselmartin wrote:

Just a quick question: What's the actual difference between the 1Z/AHU and the AFN LLK engines in the Golf 3? The AFN, as far as I know, has a different

.
AFAIK, all G3 TDIs have the same oil level check, regardless of whether they are 90 or 110 horsepower.

Roger wrote:

But don't forget that the larger the LLK, the greater the volume that the charger needs to fill before the engine experiences pressure. If that doesn't bother you, you could try the construction of a more powerful 1.8T engine using two intercoolers connected in series.

If I'm going to do it, I'll stick with one large intercooler: The Ibiza Cupra (1.9 TDI with 160 hp) probably inherited the ARL principle -> one giant intercooler in the front of the car.
What fits in the Ibiza should actually also fit in the Polo...

What is the purpose of connecting two LLK devices in series ?
Double boost pressure loss compared to a single intercooler, and the second intercooler is less effective because the intake air is already pre-cooled, resulting in a smaller temperature difference compared to the ambient air.

If I were to do it, I would connect the intercoolers in parallel: this would halve the pressure loss and provide a better overall effect, because the charge air would flow into both intercoolers at a "fully hot" temperature!

1H0 145 805 A
1Z, AHU, ALE, AFN

1J0 145 803 H
ARL

It is intended for ARL, ASZ, and AXR (only Golf/Bora)... although I have never seen this plate cooler on the two weaker engines of the vehicle in question.

One more thought from me:

The charging capacity results from the product of the air intake volume flow and the pressure increase.

If the boost pressure is increased, then the pressure increase (by definition) and the volumetric flow rate increase, meaning that the turbocharger's performance increases approximately quadratically with the boost pressure (minus the change in air density due to heating).

With this nearly square-shaped increase in energy flow towards the motor, the liquid cooling system must now be completed.

Example AHF - ASZ: Boost pressure ratio 1:1.3 -> Turbocharger power ratio 1:1.69 with the same boost pressure ratio.

If the goal is to achieve the same level of throughput, the LLK would need to be approximately 70% more powerful.
The seemingly insignificant 25% volume increase of the LLK lamella block, for example, from AFN to ASZ, shows that the team consisting of developers and cost-cutters apparently tends to make compromises that lean quite heavily towards cost-cutting.

ulf wrote:

What is the purpose of connecting two LLK devices in series ? Double boost pressure loss compared to a single turbocharger, and the second turbocharger is less effective because the intake air is already pre-cooled, resulting in a smaller temperature difference compared to the ambient air. If I were to do it, I would connect the intercoolers in parallel: this would halve the pressure loss and provide a better overall effect, because the charge air flows into both intercoolers at a "fully hot" temperature!

It would be helpful to have some real-world data from a vehicle that has received a second low-voltage battery.
I have two LLK (likely referring to a specific type of liquid) lying around in my storage, but it's too much of a hassle to use them, especially since the silicone tubes are also very expensive.

What I still remember is that, for example, the Audi S3 has two LLKs, one on the left and one on the right.
It's roughly the size of an AFN. And the boost pressure in these vehicles is also incredibly high.

One more thought:

For example, the Pmax injection duration is approximately 36° KW for the AFN engine, but only about 22° KW for the ASZ engine.

This, in my opinion, results in an earlier termination of the afterburning cycle, which in turn generally keeps the exhaust gas temperature (EGT) lower.

This could potentially invite "Herr Rotstift" to interpret the LLK (Low Load Knock) aspect in the PD (Pre-Ignition Detection) system in such a (weak) way that the EGT (Exhaust Gas Temperature) remains at the "usual high" level due to a higher LLT (Low Load Torque) compared to VP (Variable Valve Position) engines .

The difference in LLT (Low Load Torque) between Rainer's AHF (which I'm now equating with the AFN) and my car, which is about 36 Nm at Pmax, would actually fit into this concept, wouldn't it?

@ Ulf:

I've read quite a few things in this thread that I feel I need to comment on.
The efficiency of an intercooler depends not only on its surface area and the external airflow, but the heat transfer from the charge air to the intercooler is also significantly influenced by the internal flow velocity.
Consequently, the heat transfer between the charge air and the coolant in the intercooler system deteriorates significantly when two intercoolers are connected in parallel.
In a series configuration, while there is a slightly higher pressure drop, the better heat transfer is maintained.

I would also be cautious about your volume-based size comparison, as the surface area of the heat sink fins is the determining factor, not the volume.
If the fin spacing of the liquid-cooled devices being compared is approximately the same, then this comparison can serve as a rough guideline; otherwise, it should not be used.

BTW: Does the ASZ actually meet the EU4 emission standard? If not, it might be due to the high LLTs (Low Load Torque) which increase NOx emissions.

Regards,
Alex.

donalexo wrote:

but the heat transfer from the charge air to the intercooler is also significantly influenced by the internal flow velocity. Consequently, the heat transfer between the charge air and the coolant in the intercooler system deteriorates significantly when two intercoolers are connected in parallel. In a series configuration, while you experience a slightly higher pressure loss, you still maintain the better heat transfer.

Hi Alex,

That completely contradicts my gut feeling.

Theoretically, when two identical parallel liquid cooling circuits are connected, the internal flow velocity is reduced to half.
That means the intake air remains in the intercooler for a longer time, and therefore has more time to release heat.
And yet, less heat should be released (per unit mass of air) .

What (apparently unknown to me) processes are responsible for this?

Quote:

Regarding your volume-based size comparison estimate, I would also be cautious, as the surface area of the cooling fins is the determining factor, not the volume. If the compared liquid cooling blocks have approximately the same fin spacing, then this comparison can serve as a rough guideline; otherwise, it cannot.

Okay, that's not what I was trying to express.

Quote:

By the way: Does the ASZ actually meet the EU4 emission standard? If not, it might be due to the high LLTs, which increase the formation of nitrogen oxides.

The ASZ only meets EU3 standards.

In EU4, it's called BLT and has practically the same upgrades as the 100 HP PD unit from EU3 that was carried over to EU4.
AGR water cooling, active AGR throttle valve, different PDE (positive displacement element), different catalytic converter, and, strangely enough, a different turbocharger - the reason for which remains unclear so far.

The LLK (likely referring to a specific component or system) of the BLT is, to the best of my knowledge, the same as that of the ASZ.

Just a quick question: What's the actual difference between the 1Z/AHU and the AFN LLK engines in the Golf 3?
The AFN, as far as I know, has a different .
AFAIK, all G3 TDIs have the same oil level check, regardless of whether they are 90 or 110 horsepower.

But don't forget that the larger the LLK, the greater the volume that the charger needs to fill before the engine experiences pressure.
If that doesn't bother you, you could try the construction of a more powerful 1.8T engine using two intercoolers connected in series.
If I'm going to do it, I'll stick with one large intercooler: The Ibiza Cupra (1.9 TDI with 160 hp) probably inherited the ARL principle -> one giant intercooler in the front of the car.
What fits in the Ibiza should actually also fit in the Polo...

What is the purpose of connecting two LLK devices in series ?
Double boost pressure loss compared to a single turbocharger, and the second turbocharger is less effective because the intake air is already pre-cooled, resulting in a smaller temperature difference compared to the ambient air.

If I were to do it, I would connect the intercoolers in parallel: this would halve the pressure loss and provide a better overall effect, because the charge air flows into both intercoolers at a 'fully hot' temperature!

Unfortunately, due to another llk, the overall volume on the printing side also increases, and consequently, the response time also increases, as this volume needs to be filled .

Quote:

Unfortunately, increasing the overall volume on the printing side through another llk also increases the response time, as this volume needs to be filled.

Okay, see the 3rd post from above .

Unfortunately, increasing the overall volume on the printing side through another also increases the response time, as this volume needs to be filled.

Okay, see the 3rd post from above .

Oops! I missed that!