Quote:
Originally Posted by MechEngVT
the lines would then be isoconsumption (?) lines.
To create such a chart you would have to perform multiple pulls at various loads. You would have to measure steady-state fuel flow at fixed speed/torque points. Every 500-1000 RPM would be good enough to start and it would take nearly forever. It looks like the chart posted has values every 250 rpm and 3 Nm or so.
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I suppose it should be iso-specific-consumption lines as they are all referenced to unit power production..?
On a dyno it's much easier to hold rpm constant and do sweeps through the load range vs trying to hold a load and sweeping through rpm. Data points every 500 rpm or closer would really be needed for accuracy.
If you figure on 500 rpm and 12 load points per speed, with engine stabilization for about 5 minutes per point, you're talking about 11 speeds * 12 points * 5 minutes = 11 hours of data acquisition after the engine is fully warmed up! yikes. You could probably get away with engine stabilization for only 2 or 3 minutes per point though.
More sophisticated dyno software can automatically map engine performance with a set it and forget approach. Let the engine run on its own, provided it doesn't hit any safety limits....