Progressive Automotive X-Prize Knockout Round

I think that the X-Prize competition is fulfilling the objective of focusing on vehicle efficiency.  Starting with the results so far, I am hoping to contribute to the discussion and to the process.

Here’s the link to the PDF that shows the results of the X-Prize Knockout Round.

The measured MPGe of the teams in this round — remember this is the Combined number from the City, Urban, and Highway tests:

American HyPower    54.5    Hybrid
Spira        84.8    ICE (E10)
FVT eVaro        152.5    Hybrid (serial)
Zap        111.0    EV
Tata        134.3    EV
Electric Raceabout    128.1    EV
AMP         86.7    EV
West Philly (MS)    63.5    Hybrid
West Philly (Alt)    53.7    Hybrid
Global-E        50.4    Hybrid
Li-ion         182.3    EV
Aptera        140.1    EV
TW4XP        107.0    EV
WWU        92.5    Hybrid
Tango        86.8    EV
BITW        51.1    ICE (diesel)
X-Tracer (#72)    180.0    EV
X-Tracer (#79)    188.8    EV
Illuminati        119.8    EV
Enginer        53.0    Hybrid (electric/ICE w/ steam heat recovery)
Edison2 (#95 Alt)    97.0    ICE (E85)
Edison2 (#97 MS)    101.4    ICE (E85)
Edison2 (#98 MS)     80.3    ICE (E85)

I think these results speak for themselves!  The electric cars are in general, giving much better efficiency, and several of those (the X-Tracer, FVT, Tata, and the Aptera) also have excellent acceleration.  The Li-ion,  Illuminati, TW4XP, and Edison2 (among others) were not as quick — the Li-ion and Edison2 cars are through to the finals, though.  I am sad that neither the FVT eVaro nor the Illuminati Seven made it through, due to (relatively) minor technical reasons.  They failed at the moment (which is how racing/competitions work, to be sure), but I think their problems are solvable, and the strong merits of their vehicles are obvious.

The Aptera is through, but still a bit disappointing — it’s aero is equal or better to anybody (save the X-Tracer), but their efficiency seems to have suffered.  It barely betters the Tata, which is “just” a well executed EV conversion of a decent but ordinary hatchback.  The Global-E had an ignition mapping error that made their number lower.

So the lowest MPGe of an electric drive; the AMP’d Sky was 86.7MPGe (Tango was 86.8), while the best of a car with an internal combustion is the Edison2 #97 at 101.4.  (Actually, the FVT has a ICE powered generator onboard, but did not need it *at all* in the X-Prize. It would be great to see how the eVaro does for MPGe in charging mode!)  The hybrids all were all below the 67MPGe — except the WWU at 92.5 (and the FVT).

The average of the 12 vehicles using electric drive MPGe (I’m including the FVT in this) was 134.7MPGe
The average of the 6 hybrids (not including the FVT) was 61.26MPGe (please note, these are all parallel hybrids?)
The average of the 5 internal combustion drive cars was 82.92MPGe

The X-Prize results table does not include weights, but I daresay that the average weight of the internal combustion cars was lowest (the Edison2 and Spira are all much lighter!).

The best aero drag is on the X-Tracer, followed by a very close group including the Aptera, Edison2, Li-ion.

As many have said, the X-Prize is setting a very high standard (which is both good and bad).  They are essentially looking for the complete package, and virtually no glitches.  Even the well financed/professional teams had several glitches.  I would have set up the X-Prize a bit differently; to measure (and therefore emphasize and encourage) the four main things that need to be improved to get the maximum efficiency.

Those four critical things are; from most important to least important (as I am interpreting the Knockout results):

* Drivetrain Efficiency
* Aerodynamic Drag
* Weight
* Rolling Efficiency

I would have scored these in relative terms, which pits each vehicle against the others (rather than setting standards that are somewhat arbitrary).  On drivetrain efficiency, I would either use a dynamometer or the best result of the three economy tests: the City, Urban, or Highway.  (This will indicate what vehicle is good for a particular role, and measures the drivetrain at it’s best.)

For Drivetrain Efficiency, the points awarded would be the best MPGe x Number of Seats.  So, using the Overall MPGe for 23 vehicles that competed in the Knockout Round listed above (we do not have the separate measured results from the City, Urban, and Highway test): the X-Tracer #79 would be 188.8 x 2 = 377.6 points, and so on.  The best mainstream MPGe was the Illuminati Seven: 119.8 x 4 = 479.2 points.

Aerodynamic Drag would use the Weight and the Rolling Efficiency, and the results of a Coastdown test to determine the Cd of each car.  I would take the inverse of the number of entrants divided by the Cd, then multiplied by the Number of Seats: So the Aptera and the Li-ion and the Edison2 alternate cars may be at the top: 23 (22, 21) / 0.15 x 2 = ~306.6 and ~293.3 and ~280 points respectively.  The Edison2 mainstream cars would get 20 and 19 (or higher depending on their Cd) resulting in 20 (19) / 0.15 x 4 = 533.3 and 506.6 points respectively.

For Weight, I would take the lightest one and score it by inverting the number of Entrants x the Number of Seats – the Spira would get 23 x 2 (seats) giving it 46 points.  The Edison2 alternate car would be next with 22 x 2 = 44 points.  The two Edison2 mainstream cars would be 21 x 4 = 84 points and 20 x 4 = 80 points respectively; and so on.  This give priority to the cars that seat more people, and it is realistic in terms of what is achievable in the real world.

Rolling Efficiency includes tires and alignment and would be prorated for weight – a slower coastdown test using a ramp would be needed.  I think an inverted number of the entrants would be a fair way to award points.

Obviously, all four of the critical factors are interrelated, and they all would be reflected in the Overall MPGe number – but testing for them and awarding points (in some manner) for them separately, helps focus the designs on the most important aspects – and more importantly helps demonstrate their performance; whether or not the designs get ALL of them right and in the right balance, and if there is something that lags (or breaks) and the vehicle is DQ’d, people will still be able to judge the merits of the design.

We could quibble about how each of these was scored – I am just throwing this out there.  At this moment in time, I feel that the emphasis on the safety, and meeting the letter of the rules, etc. are  distracting the designers from the main point; of maximizing the efficiency.  Obviously, for a finished, production, reasonably priced, appealing vehicle – ALL of these things are also critically important.  These would be determined by finished vehicle, and the buying public.  But, I feel that an emphasis on the overall efficiency, and the four most important factors that directly contribute to maximum efficiency, would have better served the purposes of the X-Prize.

One of the most important things I learned while I was at the X-Prize Knockout competition was: do not dismiss or ignore anybody!  There is a LOT more than meets the eye with all of the entrants, and no matter the results, all the designs have strengths – and weaknesses that are all very informative.

I also was floored by the height of passion by so many people.  The sight of Oliver Kuttner with tears streaming down his face; returning from the starting line of the City Test with the first of his cars about to actually get to the heart of the matter; moves me to tears, as well.  And I’m quite sure that every person involved in the X-Prize, who has put in a similar Herculean effort, feels the same.

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