Reciprocating engine deterioration at altitude

[kkanel]

Hello everyone,

Is anyone aware of how the output of turbocharged reciprocating engines deteriorates with the site elevation?
I am using std atmosphere figures and at 400 m the reduced air density will certainly lower the massflow entering the the cylinders, and I am wondering how engine manufacturers claim to maintain power output at higher elevations.

Regards

 

[pmover]

turbocharged engines are maintaining air mass flow rates at higher altitudes; thus, maintaining engine output power. basically, the turbocharger is compressing atmospheric air before entering the cylinder. there are altitude limitations and recommend obtaining performance data from engine mfg.

good luck!
-pmover

 

[taylorg]

kkanel,

The manufacturer will match the turbocharger to the conditions to ensure the best performance.
A good rule of thumb is that output will drop by 1% for every 100m increase in altitude, so you are looking at a 4% drop in output.
Hope that helps.

 

[kmpillai]

Hi Kkanel,
Some Turbochargers has got a mechanism called waste gate mechanism. At sea level it will by-pass most of the exhaust gases and when the altitude increases (atmospheric pressure drcreases)most of the exhaust gases will pass through the turbocharger turbine and turbocharger will give more mass of air so that to compensate the density reduction. So that constant power output is maintained throughout the altitude range specified.

KMPillai

 

[edryd]

Hi

Suggest you also check out ISO 3046/BS5514/DIN 6271.

Generally there is no derate for the altitudes you have

Ed

 

[ilan7]

At the level indicated (400m) you should not notice any different in the engin performances.
Some years ago I travaled for few weeks in Tibet at 4,700 meters and the car had to be adupted to the low air (we have to do it too...)