Nochmal: Ändert die Ladelufttemp. den Motorwirkungsgrad? | Posts 32+

Hello everyone,




Hello Uli,

In your mechanically controlled diesel engine, the summer performance issues might be related to the fact that you don't have a correction for the fuel injection quantity based on increasing fuel temperature. Modern EDC (Electronic Diesel Control) diesels compensate for the density difference by adjusting the injection duration using a special fuel temperature correction map (difficult word ). In other words, in your case: if the fuel temperature increases due to higher ambient temperatures and/or a low amount of diesel in the tank, the density of the diesel decreases. However, since only a certain volume is injected, the injected fuel mass decreases, and the power output decreases!

Best regards,

Hello Ben,

Quote:

In your mechanically controlled diesel engine, the summer sluggishness might be related to the fact that you don't have a correction of the injection quantity based on increasing fuel temperature. Modern EDC (Electronic Diesel Control) diesels compensate for the density difference by adjusting the injection duration using a special fuel temperature correction map (a difficult word ). That is to say, in your case: If the fuel temperature increases due to higher ambient temperatures and/or a low amount of diesel in the tank, the density of the diesel decreases. However, since only a certain volume is injected, the injection quantity also decreases, resulting in a decrease in power!

Basically, you would be right if I didn't use a pre-heater for the fuel and the engine. With a warm engine, the fluid entering the ESP is around 60°C in the summer and 55°C in the winter. I've adjusted the fuel flow so that when the engine is warm and running at full throttle, it only produces a very slight amount of black smoke. When the engine is cold, it smokes visibly, so you have to be a bit more careful with the accelerator pedal. However, I usually don't rev the engine when it's cold.
In the winter, I can increase the fuel flow slightly because the intake air temperature after the air filter is at most 25° above the outside temperature (so, at 0° outside, it's around 20°). In the summer, it can sometimes be as much as 35° above the outside temperature (so, 65°). With the winter setting, it smokes in the summer. This is all due to the air temperature, not the fuel temperature, which remains nearly constant.

Best regards, Uli.

Hello!

It's a known fact that air contains about 21% oxygen. So, let's say in a 1.9 TDI engine, there are 500 cubic centimeters of air per cylinder stroke.

Luft hat bei 21 Grad eine bestimmte dichte. bei höherer Temperatur dehnt sich luft aus. Also passen bei 100Grad Ladelufttemperatur nur noch z.B. 450cm rein. (Fragt mich nicht nach den ganuen werten, bin kein Physiker). Also LLK rein und Temperatur der Luft sinkt so auf 50 Grad. Also wieder 475cm Luft pro Hub. Logical??

This achieves an efficiency that is almost the same as what you would have in a cold start. (ALMOST, BUT NOT QUITE) --> See the search function 'SUMMER WEAKNESS'.

And anyone who's interested can calculate the expansion that occurs with a certain boost pressure (1 bar) and specific air temperatures.

However, according to Pascal's law, pressure distributes evenly in all directions. This means that even if I have longer travel distances, the pressure only lags behind by a few milliseconds.
The loader will likely take about 30 minutes to move a 500-meter hose, but the difference will be hardly noticeable if it's just a few centimeters longer.

Best regards.