Gedimmtes Tagfahrlicht | Posts 32+

Hi,

"I also liked that, and I've been thinking about where I could possibly put another one. Then, this morning while I was having coffee, I did some calculations."

- I'm driving at a constant speed of 100 km/h, and the engine is running at approximately 3000 RPM.
- My engine only has an efficiency of 50% in this operating condition, but it's probably much better because all the drive losses are already factored in.
- The specific consumption is 230g/kWh. The specific gravity of the diesel is 0.85.
- The high beam headlights require a total of 200W (I forgot to change the bulbs after the last Paris-Dakar).

"With the lights on, I need 400W more from the motor, which is 92g/h or 0.108 l/h more fuel consumption. For this example, that means an additional 0.108 liters per 100km. That's 1.1% more fuel consumption for my car. That's probably lost within the measurement uncertainty."

Since I assume the extra consumption is negligible, I'll probably skip using TFL after all.
If I manage it, I'll try to measure the actual difference in consumption soon.

Have I overlooked something, or made a significant mistake?

Greetings,
dieter

dieter wrote:

The specific consumption is 230g/kWh. When the light is on, I need 400W more from the motor, which is 92g/h or 0.108 l/h more consumption.

If you're actually achieving such a high engine efficiency in the real world, then your numbers are correct.

However, the balance looks different in column traffic: Low engine load -> lower efficiency. Let's cautiously say that the generator needs 0.15 liters of diesel per hour.
With an average speed of 50 km/h, you will consequently experience an additional fuel consumption of 0.3 liters per 100 km.
For a TDI car with an assumed fuel consumption of 6 liters per 100 kilometers, that would already be a 5% TFL surcharge.


For me, the TFL hype is just a billion-dollar business for the state (fuel taxes), oil companies, and profiteers, all disguised under the guise of road safety.
Anyone who fails to see a car without its lights on during the day, especially in an area with a high accident rate, is either so blind or distracted that they would also crash into a vehicle with its lights on...

Hi Ulf,

Then we can have a good argument about it.
I actually already drive with my lights on outside of town. I learned about and appreciate this practice in Scandinavia.
I personally think the Finnish version is the best, but only when used with lights on outside of urban areas. However, I fear that wouldn't work, as people seem to be driving cars with their brains increasingly turned off.

Let's see if I can measure anything.

Greetings,
dieter

Check this out:

http://www.wkw.at/docextern/sgewerbe/igpfleger/e_mail_info/42_05/ECER87.pdf

Section 6-8 and Appendix 3.

I installed these (Hella, integrated into the air intake grille of the Golf IV bumper) two years ago (2 x 12V 6W parking light bulbs, BMW).
I believe they have saved me from several bad situations (from my perspective). In addition, I've had consistently pleasant interactions with the police, who have stopped me on multiple occasions and tried to fine me for "unjustified use of fog lights" (finding the inspection mark always takes the longest).

I think it's a good idea, but the only downside is that when everyone uses TFL, the motorcycles become less appealing.

LED lighting is better, but significantly more expensive, and the difference of about 5 watts per lamp doesn't really make a big difference. Also, the lamps don't fit (or don't fit yet).

http://www.hella.com/produktion/HellaDE/WebSite/MiscContent/Download/Autofahrer/Sonstiges/LSN_Deutsch2.pdf

S.17