Sommerschwaeche | Posts 32+

Hi,

However, in addition to the internal processes, there are also external factors. A climate control compressor can also require a significant amount of power, which is particularly noticeable during startup.

Except, of course, when it comes to Ulf ...

That's why I chose the option without air conditioning.

and the lack of power when accelerating from a stop at a traffic light is still there...



CU Gremlin.

Hello everyone,

Today, I also logged some values, specifically boost pressure and mass airflow. However, at the start and at the destination, I again checked the fuel temperature, with the following result:

Starting fuel temperature: approximately 28°C.

Approximately 50 km driving distance, mostly on country roads, with a brisk pace, ending with city traffic.

Target: Fuel temperature approximately 47°C (measured in an underground parking garage).

The fuel tank was approximately 50% full. The outside temperature was around 25°C.

As you can see, the fuel has heated up quite a bit, even though the last few kilometers were driven in city traffic. Now, if the air being drawn in is also quite warm due to the shimmering asphalt, and a longer standstill at a red light warms up the engine's low-temperature coolant, then we have three factors that contribute to a loss of power.

Regards,
Alex.

Hello,

And that was with the tank only half full! With a nearly empty tank, an even higher fuel temperature can be expected, because the smaller volume circulates more frequently through the system, leading to further heating. However, fuel cooling only activates at higher temperatures, I believe around 80 degrees Celsius. Does the 66 kW electric motor also have fuel cooling?

automatic, due to the larger pump.

btw: the measurement series will, of course, be continued .

CU Gremlin.

@Gremlin:

Why does the automatic transmission have a larger pump?
"Is it the same engine with the same power output, or what? It doesn't make sense to me at first glance."

Regards,
Alex.

We can only speculate about the 'why.'

The pump has a larger piston, and the nozzles have a smaller cross-section.

This results in a higher injection pressure for the same amount of fuel injected, which naturally reduces emissions and increases efficiency. It's probably for this reason that it's often implemented in automatic transmissions, as they require more fuel. The lower emissions also ensure compliance with Euro 3 standards (which consider emissions per kilometer), and the increased fuel consumption remains within reasonable limits.

I can't say for sure whether the cooler is necessary. I'll continue to log this route, and if it gets really hot again and I happen to get stuck in the city, we'll see what happens.

CU Gremlin.

Okay...

You can find the diagram for today's trip HERE.

conditions:

clima ECON 23°
Outside temperature: 9°C (rural areas), 11.5°C (urban areas).
A brief shower of about 10 minutes, with the road mostly wet.
Fuel level: 25%


Here again, the trend towards reduced fuel efficiency is clearly evident. Specifically, in stop-and-go traffic (which lasted a particularly long time this time), the intake air temperature steadily increases while the fuel temperature remains constant.
As traffic resumed, the charging air temperature quickly returned to its 'normal' level.

CU Gremlin.