Gubitak snage na većoj nadmorskoj visini

[Danko 184 Napisano Avgust 17, 2007]

Zna li neko kako izračunati procenat gubitka snage na određenoj nadmorskoj visini?

 

Sve što sam našao na netu je vezano za avionske motore, i mnogo velike visine, a ja bi da vidim računicu za npr 0, 500, 1000, 2000 i 3000 metara...

 

 

[Ribolovac 491 Napisano Avgust 17, 2007]

Odgovor ti je u baro senzoru .Kod automobila je zaduzen za merenje atmosferskog vazdusnog  pritiska u slucaju promene nadmorske visine vozila.

Ovaj podatak kompjuter obradjuje a znajuci procenat kiseonika za datu visinu regulise odnos vazduh gorivo.

Kada sve ovo lepo radi sasvim je sve jedno na kojoj smo visini... barem onima gde ima asvalta .

[Danko 184 Napisano Avgust 17, 2007]

Radi se o ATV-u... Naime bio sam pre par dana na servisu, i izmeđuostalog sam pričao sa serviserom o tome kako sam primetio da se ATV mnogo brže greje na planini, a on mi je kao odgovor dao da na planini zbog vazdušnog pristiska postoji gubitan snage i da motor mora da se tera na većim obrtajima da bi postigao istu stvar... Pa me živo zanima koliki je recimo gubitak snage na 2000 metara npr...

[RSVMillenian 228 Napisano Avgust 17, 2007]

Procenat snage zavisi od pritiska vazduha i nije uvek isti.  Evo jedan mali clanak doduse na engleskom: 

 

Let's start by noting air is the working medium of internal combustion engines, and the more air (mass of air) processed by the engine, the more power it will make. We also all know air density decreases with elevation, so engines lose power the higher they operate.

 

Let's also note supercharged and turbocharged engines are naturally aspirated upstream of the supercharger or turbo. In other words, we're still relying on something (atmospheric pressure) to drive the air into the blower or turbo.

 

So, the higher we go, the less power the engine makes unless something changes to process more air through the engine. As you noted, the naturally aspirated engine loses power because it can't process any more air — the engine can't magically grow displacement or increase rpm.

 

Likewise, a mechanically driven supercharged engine doesn't get any larger, doesn't rev any higher nor does the supercharger turn any faster. Therefore, the mechanically supercharged engine doesn't process any more air and begins losing power as it rises above sea level just as a naturally aspirated engine does. This effect is typically masked in automobiles because the supercharged engines have so much power at sea level that it's easy to use full throttle earlier and longer while driving in the mountains and not notice the difference.

 

The same is true of turbocharged engines, except for one thing. Turbocharged auto­motive engines are often fitted with relatively large turbos with excess capacity at sea level, plus a wastegate to limit turbo boost. Take such a car into the hills and the wastegate simply stays closed earlier and longer, and voilà, a sea-level air mass is forced into the engine. Well, it is until the engine's critical elevation is reached; that's where the turbo system runs out of capacity due to its sizing, or insufficient atmospheric pressure to feed it, and then only sea level or less power is possible.

 

The important point is a forced-induction system has to increase speed or have reserve capacity to maintain sea-level horsepower at altitude. This can be done with a mechanically driven supercharger if fitted with a transmission (once common on aircraft), or as we saw, more easily with a turbo. Likewise, some turbo systems are carefully sized to limit sea-level boost to a predetermined level and have no wastegate. Such engines cannot spin the turbo faster or earlier, and they lose power with elevation starting immediately. But again, they likely have so much power to start with, you can use more throttle earlier and not notice any drop for the first 2000 to 3000 feet of elevation.

 

[RSVMillenian 228 Napisano Avgust 17, 2007]

Evo nasao sam super link:

http://www.2-stroke-porting.com/altiden.htm

[lalajko 2024 Napisano Avgust 17, 2007]

Koliko se ja secam, za svakih 1000m se gubi 10% snage motora.

[aca-pn 6430 Napisano Avgust 17, 2007]

Valjda kad je redji vazduh bogatija je smesa - manje vazduha i isto benzina daje bogatiju smesu.

[Pedriic 1 Napisano Avgust 17, 2007]

Valjda kad je redji vazduh bogatija je smesa - manje vazduha i isto benzina daje bogatiju smesu.

 

Pritisak brale, nema sta da 'uvuce' benzin!

[AnteK 606 Napisano Avgust 17, 2007]

Valjda kad je redji vazduh bogatija je smesa - manje vazduha i isto benzina daje bogatiju smesu.

 

U pravu si, okrenulo mi se u glavi, brišem gluposti 

[aca-pn 6430 Napisano Avgust 17, 2007]

Valjda kad je redji vazduh bogatija je smesa - manje vazduha i isto benzina daje bogatiju smesu.

 

Pritisak brale, nema sta da 'uvuce' benzin!

Ne uvlaci benzin pritisak vazduha, nego vakuum koji klip napravi kad podje na dole. Tada je izduvni ventil zatvoren, usisni otvoren. Ne znam bese koji je to takt po redu

Inace, na vecim nadmorski visinama se gubi snaga zbog nedostatka kiseonika - manje kiseonika, losije sagorevanje.