Water heater

Hello fellow mechanics,

Unfortunately, I can't find any glow plugs for the water heater on my V6 TDI. Does anyone have a tip or suggestion for where to look next?

Regards,
René.

Hi Rene,

"Finally, Audi has used its common sense and decided to skip the glow plugs that Volkswagen is so fond of using."

You won't find any of those in the V6, at least not for everything from EU3 onwards.

Best regards,

bafische wrote:

da haben die AUDIs endlich mal ihr Hirn eingeschaltet und sich kurzerhand die Glühkerzen eingespart, die die VWler so gerne verbauen.

Hi Bavarian,

What do you find so bad about the idea of using water heating candles?

V6 TDI engines have a heater directly in the airflow, unless the vehicle has been updated with a factory-installed auxiliary heating system.

...there are also cars that aren't Volkswagens, namely mine.

Do the candles actually make a difference? When I think about how long my 5.2 kW auxiliary heater takes to run, I can't imagine that the estimated 500W of the glow plugs will really achieve much.

Well, I don't know why it's seen as such a negative thing.
When I start driving in temperatures like the last few days, at -10°C, I'm grateful for every degree that my coolant gets warmer.
On the other hand, the goal isn't to heat up the entire motor and interior with just 500 watts. If you want to be kind to the motor, it's best to wait a few kilometers before starting the heating system. Then, I think those 500 watts will make a difference in the smaller circuit. How many liters are in the smaller circuit? Is it 3.5 or 4 liters? A kettle can heat 1 liter of water to 100°C in just 1-2 minutes with 600 watts.

hi

Quote:

Ein Wasserkocher schafft mit 600W 1L Wasser immerhin in 1-2Min auf 100°C zu bringen.

na ja kommt drauf von welche Tem. vom 70° auf 100°C schon.

Normally, kettles have a power consumption of around 2000-2500W and require approximately 2 minutes to heat 1 liter of water from 12°C to 100°C (measured with a 2100W kettle).

But back to candles, I also think they can make a difference. I'm planning to do some tests soon with and without using a heater. The temperatures in the mornings have been around -3°C lately, so it's a good opportunity to test things out.

Regards,
voss

Okay, so I only have experience without: --> Extremely cold.
However, I also believe that these things won't necessarily change the world. Okay, they do consume a certain amount of power and draw energy from the alternator, so it's possible that they could have some impact, since the alternator draws its power from the engine...

I've decided to install a Webasto TT heater, and since then, I haven't been cold anymore... which I believe is the only truly effective solution against the cold.

There are only a few liters of coolant in the small cooling circuit. However, I believe that the mass of the engine absorbs much more thermal energy than the water does.

The specific heat capacity of water is much higher than that of aluminum or steel.

Specific heat capacity of the material in kJ/(kg·K).

Water: 4.187

Glycerin: 2.43

Aluminum: 0.91

Cast iron: 0.55

Therefore, the overall heat capacity of the engine is likely not significantly higher than that of the coolant alone.

wolfi_b wrote:

Specific heat capacity of the material in kJ/(kg · K). Water: 4.187 Aluminum: 0.91 Cast iron: 0.55 The total heat capacity of the engine is likely not as drastically higher than that of the coolant alone.

I believe:
Based on my gut feeling, I estimate the weight of a 1.9 TDI engine to be around 80 kilograms.
Assuming an average value of 0.7 kJ/(kg·K) for aluminum and cast iron, this results in 56 kJ/K for the engine.

With an estimated volume of 4 liters in the small circuit, the water has a heat capacity of approximately 16 kJ/K.

For me, a capacity that is roughly 3.5 times greater than the water's is already quite drastic...

ulf wrote:

Eine etwa 3,5-fache Kapazität des Motors gegenüber dem Wasser ist für mich schon drastisch . . .

I don't think so, considering the twentyfold difference in mass.

A comparison with and without [something] would be interesting. We could log the temperature for the first 15 minutes.
Since the heating is turned off above approximately 2200 RPM, you need to keep the engine speed relatively low (which is good practice anyway when the engine is cold).
Maybe it's only a difference of 5 degrees.

Probably, it won't make a significant difference during fast driving on open roads with normal engine load. But how does it behave in situations with very low engine load, such as in traffic jams or stop-and-go conditions? I imagine that the engine might not even reach its operating temperature for extended periods in very cold weather. In this way, at least a certain increase in temperature is guaranteed.
I still don't understand the justification for why this is being criticized. Is it about the electricity consumption, or just the minimal effect?

Hello.

Ich habe schon einen Vergleich gemacht - mit und ohne den Glühkerzen im kleinen Wasserkreislauf. Die Aussentemperatur betrug -5,5 Gard bei beiden Versuchen und das Auto ist jeweils 10 Stunden gestanden. Die 3 Glühkerzen funktionieren einwandfrei, was ich durch Anlegen von 12V überprüft habe. Als Versuchs dient eine 3 Kilometer lange Strecke, die leicht bergauf geht. Gefahren wurde mit Tempomat und einer Geschwindigkeit von 80 km/h im dritten Gang - entspricht ca 3000 rpm beim Passat AJM. Beide Mal gleichmässiges Beschleunigen der kalten Maschine bis auf die Nenngeschwindigkeit und dann den Tempomaten reingemacht. BeDuring the trip/journey. ohne den Glühkerzen im Kühlwasser hat die Nadel der Temperaturanzeige erst bei Kilometer 3,0 anfangen sich zu bewegen. Bei der Fahrt At kilometer 2.5, the glow plugs were activated in the coolant. Of course, this is only an approximate measurement, but it suggests a certain function – they certainly can't replace a separate heater. This was a simple test and should be interpreted accordingly. Someone still needs to take the trouble to perform a measurement using VCDS or the climate control system.
Regards,

hb2000

hb2000 wrote:

Bei der Fahrt ohne den Glühkerzen im Kühlwasser hat die Nadel der Temperaturanzeige erst bei Kilometer 3,0 anfangen sich zu bewegen. Bei der Fahrt mit den Glühkerzen im Kühlwasser war es bei Kilometer 2,5. Klar ist das nur eine ungenaue Messung . . .

Hi,

My experiences with the G3 AFN were similar.
"With the LEDs, I could see when and for how long they were active."
Depending on whether the ignition threshold was reached or not, I drove one morning with and another without the glow plug preheating system activated. The driving profile during the first few kilometers is practically always the same for me (speed, gear selection, almost empty roads, no traffic lights).
With the active candles engaged, the heating system started emitting a noticeable amount of warmth slightly earlier, even with (somewhat) lower outside temperatures. Looking back, it felt roughly equivalent to having about 5°C warmer weather outside, which resulted in the engine warming up more quickly.

It doesn't really matter for the whole story... but with candle heaters, you can at least defrost frozen windshields a little bit sooner.