cuchulain
05-30-2009, 05:03 AM
Treating PHEV data
Fundamentally the distance travelled per tank data for a PHEV is made up of two contributions, as a hybrid using gasoline and as an electric car running off the battery.
S (distance miles) = (gallons of gasoline)(mpg gasoline) + (kwh of electricity)(miles per kwh)
Comparing Forces data over 5 tanks,
tank||dist. M||gas gal||elec. Kwh||blended mpg
5th|| 1691 || 10.16|| 323.7||166
4th|| 1053 || 8.57 || 174.4 ||122.9
3rd|| 1105.6||9.39 || 165.2||117.5
2nd|| 330.4|| 4.62 || 18.32||71.5
1st||1275 || 7.86|| 210.4||162
we can compare any two tanks and get 10 sets of simultaneous equations. Solving for mpg(gasoline) and mpkwh (electricity) we
Comparison||mpg||mpkwh
5th to 4th||45.9 ||3.78
5th to 3rd|| 57.7 ||3.41
5th to 2nd|| 58 ||3.4
5th to 1st|| 140 ||0.81
4th to 3rd|| 84.6||1.88
4th to 2nd|| 59.1||1.88
4th to 1st|| -1.87||6.12
3rd to 2nd ||58.1||3.39
3rd to 1st || 32.4||4.85
2nd to 1st || 55.7||3.98
Average ||59||3.48
Median || 57.8||3.41
Some of the comparisons are not valid, too close (tanks 4-3) or different efficiency (tank1 and tank5) but leaving all the data in the average does not change much.
Average gasoline consumption of 59mpg is pretty much what we would expect for the gen2 Prius after the battery is depleted. Electric consumption of 3.48 mpkwh, (AC 287wh/m) seems close to DC 200-250wh/m that we expect. Using this approach, when we get an EPA mpkwh, we should be able with the EPA hybrid mpg to rank PHEVs in terms of efficiency.
Good Luck
Andrew
Fundamentally the distance travelled per tank data for a PHEV is made up of two contributions, as a hybrid using gasoline and as an electric car running off the battery.
S (distance miles) = (gallons of gasoline)(mpg gasoline) + (kwh of electricity)(miles per kwh)
Comparing Forces data over 5 tanks,
tank||dist. M||gas gal||elec. Kwh||blended mpg
5th|| 1691 || 10.16|| 323.7||166
4th|| 1053 || 8.57 || 174.4 ||122.9
3rd|| 1105.6||9.39 || 165.2||117.5
2nd|| 330.4|| 4.62 || 18.32||71.5
1st||1275 || 7.86|| 210.4||162
we can compare any two tanks and get 10 sets of simultaneous equations. Solving for mpg(gasoline) and mpkwh (electricity) we
Comparison||mpg||mpkwh
5th to 4th||45.9 ||3.78
5th to 3rd|| 57.7 ||3.41
5th to 2nd|| 58 ||3.4
5th to 1st|| 140 ||0.81
4th to 3rd|| 84.6||1.88
4th to 2nd|| 59.1||1.88
4th to 1st|| -1.87||6.12
3rd to 2nd ||58.1||3.39
3rd to 1st || 32.4||4.85
2nd to 1st || 55.7||3.98
Average ||59||3.48
Median || 57.8||3.41
Some of the comparisons are not valid, too close (tanks 4-3) or different efficiency (tank1 and tank5) but leaving all the data in the average does not change much.
Average gasoline consumption of 59mpg is pretty much what we would expect for the gen2 Prius after the battery is depleted. Electric consumption of 3.48 mpkwh, (AC 287wh/m) seems close to DC 200-250wh/m that we expect. Using this approach, when we get an EPA mpkwh, we should be able with the EPA hybrid mpg to rank PHEVs in terms of efficiency.
Good Luck
Andrew