Atmospheric pressure

Hello Jose As you say the marker's precion if it affects the start of an engine since the highest height is lower the oxygen content in a certain mass of air) therefore you will need a greater volume or mass of air to get the air, oxygen, fuel, for a good combustion, for a good combustion, for a good combustion, what does not happen at sea level, for that. ECU reads the indicators of the flow, èste measures temperature, flow and air mass, with these parameters it starts the injection, therefore increases or decreases the injection and can avoid the exesive pollutant pollution, it has and as it is at great height you have a fuel excess in the excess of oxygen that you need so that the combustion is produced by the spark Heat, and because it happens after a long time, it


becomes

Hi Jose.
I understand that your punctual question is what is the compression measure at 4,000 meters above sea level taking into account the density of the air at that height, that is, what percentage is lost with respect to the sea level?
And it is true that my table is illegible, I correct it:
R ---- T-ºC ---- p-bar ---- pr-bar ---- pt-bar
12 ---- 665 ---- 27 ---- 25 to 27 ---- 20
14 ---- 700 ----- 33
---- 28 to 30 ---- 23 16 ----
731 ---- 40 --- 46 ---- 34 to 39 ---- 28
20 ---- 786 ---- 54 ---- 39 to 44 ---- 31
22 ---- 810 ---- 60 ---- 44 to 50 ---- 35
The meaning of the symbols if it is clear. Luck.
Miguel

Hi Jose.
I have been investigating that the issue aroused my interest since I was not sufficiently aware, for that I advise me with the son. We are clear that the pressure-highness ratio is proportional: at greater height, lower pressure- applying a rule of three we will have:
170- 95 over 50-4200 is equal to .018 bars. That is, for each meter high it is lost .018 bar. Being turbocharged can have some relationship that I consider will be minimal because air density would also affect turbo. Luck.
Miguel

As you ascend the amount of oxygen therefore decreases combustion in these conditions are not favorable to obtain complete combustion.

For me that everyone is getting too complicated, they are asking about the compression and this is generated by the engine and what you are thinking about is how it affects the engine and what affects it depends on the amount of oxygen in the air not on the amount of air. The amount of air is the same what is different is the amount of oxygen, to me when I studied they taught me that there are places on sea level where it is a rule that vehicles have turbo due to the lack of oxygen in the air. Air and oxygen are 2 different things, as well as atmospheric pressure and compression also for that reason should not be affected the measurement of compression at the height that the measurement is taken, but in the manuals the atmospheric conditions to which the compressions must be measured will be specified.