Sommerschwaeche | Posts 32+

Hi,

However, in addition to the internal processes, there are also external factors that can influence performance. A climate control compressor, for example, can 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 acceleration after stopping at a traffic light is still present...



CU Gremlin.

Hello everyone,

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

Starting fuel temperature: approximately 28°C.

Approximately 50 km driving distance, mostly on country roads, with a brisk pace, ending in 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 lubricating oil, 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 and is heated further in the process. However, fuel cooling doesn't start until higher temperatures, I believe around 80 degrees Celsius. Does the 66 kW electric motor also have fuel cooling?

automatic operation only, 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 that the same engine with the same power output, right? 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 why they modify it on automatic transmissions, as those require more fuel. The lower emissions also mean that meeting Euro-3 standards is not compromised (since those standards 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 will continue to track this route, and if it gets really hot again and I happen to get stuck in traffic 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 clear trend towards reduced fuel efficiency is 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.