Biodiesel: Production, Benefits, and Uses

This forum has already had extensive discussions about the use of biodiesel. As a result of those discussions, I personally stopped using biodiesel.

Having had very good experiences with a 10% fuel mixture in the past based on engine performance, I've once again given in to temptation and filled up a few liters.

The engine runs noticeably smoother and subjectively has significantly more torque. I haven't yet performed any objective measurements, as the weather has been unpredictable and is distorting the performance readings.

Question: What are the arguments against adding approximately 10%?

Best regards,
Uwe.

Question: What arguments are there against adding approximately 10%?



...that Bosch only releases 5%

CU Gremlin.

Hello UWE,

I cannot confirm any increase in performance, but I can confirm a significantly higher fuel consumption when mixing it. (More than the theoretical increase in consumption of about 1% per 10% ratio).

What I can confirm is the noticeably smoother idle and the quieter operation of the machine at low load. I would also be interested in knowing the exact reason for this.

Even if Bosch only released 5%, I still wouldn't have any concerns with 10%. After all, many people have been running at 100% for years.

'If someone were to pass on the cost savings of blending biofuels to their customers, I would definitely go there to refuel. But BP/Aral are already among the most expensive, and why should I accept increased fuel consumption just for that?'

The 'silent effect' also occurs when using vegetable oil mixed with other fuels, but in that case, the consumption remains the same as if using only the other fuel, due to the higher energy content of the vegetable oil. (e.g., vegetable oil from Aldi or Lidl).

garth.brooks wrote:

I cannot confirm increased performance, but I can confirm a significantly higher fuel consumption when mixing. (More than the theoretical increase in consumption of about 1% per 10% ratio)

I will take the Ulf test and post the results here. However, it will take some time, as I first need to empty the tank.

garth.brooks wrote:

But BP/Aral is now adding it, and they are already the most expensive, so why should I accept a higher consumption?

Huh? I thought they mix things in France. Do Aral & Co. do that too?

garth.brooks wrote:

The "Leise effect" also occurs even when using a mixture containing pure vegetable oil, but in that case, the consumption remains the same due to the higher calorific value of the vegetable oil, resulting in no additional consumption. (Aldi-Lidl etc. oil)

I'm not comfortable with that. What if the liquid doesn't mix properly and a blob of it goes directly into the injection pump? Can we be sure that proper mixing will occur?

Best regards,
Uwe

Hi Uwe,
It's only when refueling that the mixing is potentially poor. However, because the fuel injection pump constantly delivers a higher volume of fuel than is actually needed for injection, there is a constant flow of fuel back to the tank. This continuous pumping action helps to...

1. The tank is clean, because any dirt immediately gets pushed into the filter.
2. Keep the ESP cold because it cools things down.
3. Make sure to mix the ingredients thoroughly.

PÖL and diesel mix quite well together - just give it a try. There are also many forums dedicated to discussing this topic.

It noticeably behaves differently, starting around 30-50%, especially when it's cold. I tried various things for a while, including warming up the ESP (Electronic Stability Program), but it doesn't really make a difference.

In Germany, to my knowledge, the addition of [substance] is now permitted, and Aral has announced that it will also do so. Whether this is currently the case is beyond my knowledge. (There was a topic about this in the forum a while ago.)

"When it comes to adding rapeseed oil or biodiesel to my fuel, it's not about saving money for me. What I appreciate is the way my engine runs. That's all that matters to me."

I've also looked into some of the relevant online forums and communities, but they all have completely different goals and interests than I do. So, I'm not really better off there either.

I've already driven about 80,000 km with 10-20% biodiesel in the tank. On one occasion, I filled the tank completely with biodiesel, and it didn't run well. There was very little torque, but the engine ran very smoothly. I started adding biodiesel by switching to regular gasoline. At the same time, I had installed a chip in my car, and I still had about 10% biodiesel in the tank. My car really took off like a rocket.

By the way, I tried the same thing with our PD (presumably referring to a specific product or system). I didn't notice any increase in performance, but the engine ran more smoothly, with less vibration and noise.

My question is: at what percentage of biodiesel in the tank are harmful effects possible? I've also heard that you shouldn't mix it at all...?

I can live with Bosch's approval of 5%. Maybe someone knows more details.

Best regards,
Uwe

Sure, here is the translation of the text from German to English:

"Additional question:"

What is the flow rate of the diesel pump? In other words, how long does it take for a full tank to be completely circulated?

Best regards,
Uwe

Okay, here's the translation:

'So, it says:'

'It (the wing cell pump) pumps 4.24 cm³ of fuel from the inlet to the interior of the VE pump per revolution.'

CU Gremlin.

Uwe wrote:

garth.brooks wrote: The "Leise effect" also occurs even when using a mixture containing pure vegetable oil, but in that case, the consumption remains the same due to the higher calorific value of the vegetable oil, so there is no additional consumption. (Aldi-Lidl etc. oil) I'm not comfortable with that. What if the liquid doesn't mix properly and a blob of it ends up directly in the injection pump? Can we be sure that proper mixing will occur?

Hello,

"The ESP doesn't mind; it's mechanically the same as the VE37 that I use in 4 cars with 100% rapeseed oil (or do you have a VP44? I can't quite remember what kind of car you have). With a DI engine, it's more dangerous that the injectors can become clogged, especially when it's cold, as the thick substance doesn't atomize properly and can then contaminate the engine oil, causing it to clump and clog oil passages. However, this shouldn't happen with up to 30% rapeseed oil in winter and 50% in summer. If you drive a lot of short distances or operate mostly at partial load, it's better to mix in a little less (10% or 30%). Our engines with swirl chambers run much better on rapeseed oil than on diesel."

Best regards, Uli.

'The ESP doesn't mind that, because it's mechanically the same as the VE37, which I use in 4 cars with 100% rapeseed oil.'


NO!

Your common rail diesel engines operate with injection pressures around 400 bar.

The elemental pressure within the VP is correspondingly low.
'Our DI pumps operate at 850-950 bar (1200 bar at the nozzle), and it becomes very critical in pure oil operation if it's not hot enough.'

CU Gremlin.

Gremlin wrote:

NO! Your common rail diesel engines operate with injection pressures around 400 bar. The elemental pressure within the VP is correspondingly low. "Our DI pumps operate at 850-950 bar (1200 bar at the nozzle), and it becomes very critical in pure oil operation if it's not hot enough."

Hi,

"We held a measurement event 2 1/2 years ago where we measured the pressure difference between the fuel and the test fuel ("aged" diesel) in the high-pressure section of the ESP (using a sensor instead of the central screw in the distributor head). The results showed that with cold fuel (20°C), the pressures were about 20% higher than those of the test fuel. If you consider this to be very critical, please let me know. I can't imagine that Bosch would design such a tight margin, leading to pumps failing significantly more often. I haven't heard of any TDI engines that have had their distributor plungers fail due to fuel issues (the engine speed of TDIs is simply more fuel-compatible than, for example, a VW bus, which already runs at 3800 rpm at 90 km/h). However, I have heard of TDI engine damage caused by fuel issues."
Hot oil (80°C) is, in terms of pressure, still approximately 10% higher than test oil.

Best regards, Uli.

Uli S. wrote:

... We already have cases of TDI engine damage due to sludge. ---

Why? What does the engine dislike about the oil?

Best regards,
Uwe.

Uwe wrote:

Uli S. wrote: ... We already have cases of TDI engine damage due to sludge. --- Why? What does the engine dislike about the oil? Best regards, Uwe

Hello Uwe,

I was away for a few days, so I'm just getting back to you now.
"DI injectors have nozzle holes that are more prone to carbon buildup than the nozzle tips found in older indirect injection (IDI) systems. Furthermore, they are much closer to the combustion chamber than IDI injectors. When the engine is cold, the thick fuel may not atomize properly (and even worse with carbon-clogged nozzles), and it can reach the cylinder wall. From there, the combustion pressure can force it past the piston rings into the oil pan. Over time, it polymerizes with the engine oil, forming clumps and a pudding-like mass, which prevents the oil from performing its functions properly, leading to potential damage such as bearing failure or piston seizure."
Depending on the route profile, driving style, and operating conditions, a diesel engine can also be successfully operated. Long distances, infrequent periods of very low load/idle, and few cold starts are beneficial.
In a chambered engine, it's not as crucial whether the fuel is completely atomized or not; the main thing is that a small portion ignites. The rest is then propelled at a tremendous speed into the main combustion chamber and burns there somehow. In any case, the problem of polymerization is not nearly as prevalent in chambered engines as it is in direct injection (DI) engines. Good injectors, of course, also improve combustion here, making cold starts easier and reducing smoke/the smell of fried food. For example, all four of our vehicles start easily at -12°C using 100% rapeseed oil (it hasn't been colder than that since we started using rapeseed oil), and after a short distance (1-2 km), they also run smoothly at idle. Only the van smells bad (thermostat is broken, so it doesn't get properly warm, and the engine is worn out).

Best regards, Uli.

Thank you, Uli, for the comprehensive answer.

I will definitely stick with using olive oil.

"However, I still decided to add some biodiesel and then objectively measure the performance. I assumed that this would give me higher engine power, as I had observed before. However, I'm still no wiser than before. I had filled the tank completely in Luxembourg (at 63 cents...). The engine ran very roughly. In Germany, I added 10 liters of standard diesel, and the engine suddenly ran much smoother. Then I did Ulf's test -> 5.3 seconds. After adding about 8% biodiesel, the expected difference in engine running didn't appear, and the acceleration test also didn't show any different values. The outside temperature was 20 degrees Celsius."

"Last night, when it got cold, I checked again, and it was still 5.3 seconds. My best results in cold weather were 4.7 seconds!"

Da scheint sich wieder mal mein LMM zu verabschieden. Ich kann leider keine Werte loggen, da ich nicht über die Soft- und Hardware verfüge. Hat das jemand im Rhein Main Gebiet für mich? HaEhnlein?

Wenn ich niemand finde, muss ich wohl auf Verdacht probeweise tauschen oder den Trick mit der Diode ausprobieren. Let's see...

Best regards,
Uwe.