“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Saturday, June 06, 2009

The amazing 110 m.p.g. Mustang

Doug Pelmear of HP2g and something called HorsepowerSales.net has made a lot of claims for his engine development. He claims to have developed a "rod and piston" engine capable of developing 400 horsepower and 500 foot pounds of torque. It's also, per Pelmear, capable of 110 m.p.g. equivalent. It's "equivalent" because the engine uses E85 fuel, 85% ethanol and 15% gasoline.

Pelmear had touted his entry into the Progressive Automotive X Prize competition, whose organizers will distribute a $10M prize pool for teams that produce commercially viable vehicles capable of achieving a sustained fuel economy of 100 MPGe (m.p.g. equivalent). Pelmear's HP2g entry was to have been a 1987 Mustang with his proprietary engine installed. However, a press release dated June 4, 2009 states that the HP2g Mustang has been withdrawn from the competition despite several videos (see here and here for example) showing Pelmear expressing his confidence that he'd win the prize. Various reasons are given for the withdrawal, I have no data regarding the legitimacy of the rationale, so I'll just take it at face value.

There are several articles on the HP2g web site announcing the opening, on June 1, 2009 of an engine R & D and manufacturing plant. There's also news of an agreement between HP2g and "Revenge Designs" to install the engines in the "Revenge Verde," a super car of some sort. I can't find a lot of detail about the Revenge Verde, but a rendering is at left.

Little information about the actual technology being employed is available on HP2g's web site or in any of the recorded interviews at the various media events Pelmear has attended. He's referred to technology originated during World War 2 by his grandfather and to extensive electronics. There are a couple of vague references to "more precise manufacturing techniques" and "tighter tolerances." In all the videos, the hood of the car is closed and in most the Mustang is sitting still. In the ones where it's moving, it's driving in a very normal fashion, no 400 h.p. tire smoking burnouts. Though his site has a "table of fill ups and miles driven", no independent authentication is given or even implied.

Skepticism is rampant on the Ecomodder Blog about the Mustang, as might be inferred from the title of the article ("runs on hot air and cattle manure" for those not wanting to click on or mouse over the link). I actually commented there and didn't find it to be utterly, completely, totally impossible for Pelmear's claims to be true. But his site includes a section entitled "Test Data" that should enable me to get a more precise estimate as to the plausibility of his claims.

The relevant data is as follows (and compliments to Pelmear and HP2g for publishing them, though the pertinent ones are really just stock Mustang numbers):
  • Cd (Coefficient of Drag): 0.42
  • Frontal Area: 22 ft^2 (2.044 m^2)
  • Curb weight: 3250 pounds (curb mass of 1474 kg)
We'll add the following: two 75 kilogram passengers; tires with coefficient of rolling resistance of 0.010 (this is relatively low, but what the heck).

So what does that mean at 55 m.p.h., or 24.59 m/s? Ignoring the energy in the rotating masses and using the methodology I've illustrated many times in the course of this blog, I'd estimate that about 470 newtons would propel this Mustang down the highway at a steady speed on level ground with no wind. As I've frequently mentioned, force times speed is power (assuming that the force is directed parallel to the velocity so that vector calculations aren't required) so 470 newtons at 24.59 m/s requires 11.56 kilowatts or 15.51 horsepower.

Moving on, E85 fuel should have a heat of combustion (that is, energy converted through burning) of 8.653*10^7 j/gal (joules/gallon). I will assume "110 MPGe" means that if E85 had the same specific energy (energy per unit volume) as gasoline, the vehicle would travel 110 miles on a gallon of it. So I'll multiply 110 miles by the ratio of the energy content of E85 to that of gasoline, or 8.653*10^7/1.225*10^8 and speculate that Pelmear is claiming about 77.7 miles out of a gallon of E85. Equivalently, Pelmear would be burning 1/77.7 or 0.01287 gallons of E85 per mile. In that fraction of a gallon, there are 1.1136*10^6 joules of thermal energy available through combustion.

We'll ignore the fuel needed to add the kinetic energy required to get the vehicle to 55 m.p.h. and the various rotating masses in motion and just look at the energy required to maintain 55 m.p.h. with conditions as detailed above. A mile is 1609 meters, so exerting a force of 470 newtons over that distance requires doing work of 756,700 joules. These joules come from burning the E85 so Pelmear is claiming an efficiency of at least (remember we ignored adding kinetic energy, hills, wind, etc.) of 7.567*10^5/1.1136*10^6 or 68%.

This would be above the maximum theoretical thermodynamic efficiency possible with an Otto cycle engine. Even granting that E85 has a significantly higher octane rating than any straight gasoline and thus allows much higher compression ratios to be used and assuming Pelmear has increased his compression ratio to 15:1 (which would require much more massive components than those in a stock gasoline engine), the maximum theoretical efficiency would be about 66%. This assumes no friction in the engine, no throttling or pumping losses, no energy to accessories, etc.

Note that I've given Pelmear the benefit of the doubt at every turn. The most generous assumption I've made is to run the calculations at 55 m.p.h. His site references speeds of 70 m.p.h. where much more energy would be required. And any variance from the idealized conditions hypothesized would reduce the fuel efficiency. I'm sorry, but unless someone points out an error in my calculations or data, I'm calling shenanigans.

Update: I've looked at more of the figures from HP2g's site for fill ups and mileage. They are showing numbers as high as 136.85 m.p.g. (actual miles divided by actual U.S. gallons, MPGe would be much higher). This would mean that the HP2g Mustang was getting significantly more than 100% of the energy available in the E85.

Update 2: A series of email correspondences with HP2g is shown below. Make of them what you will (start at the bottom and work up). Note that the engine "does not necessarily defy the laws of physics" (italics mine).

Update 3: Progressive Insurance Automotive X PRIZE Responds to HP2g Claims

Update 4: In this video the interviewer (from CNN) states that developers think that with a little more tweaking they'll get 500 miles per gallon.

Edison had naysayers too, I'm glad he continued on... Please refrain from contacting us again. First/Last warning.

-----Original Message----- From: Rob

Sent: Monday, June 8, 2009 02:34 PM


Subject: RE: Your claims

Good morning,

No technologies enable more energy to be derived from fuel than is available in the fuel to begin with. Certainly there are thermodynamic cycles other than the Otto cycle, but none of them allow the conversion of more chemical energy to kinetic energy and work than are available in the chemical energy to begin with. Mileage figures such as 136.85 m.p.g. with the drag area of a Mustang and the rolling resistance of any tires currently available would exceed that amount by a considerable margin. There are a variety of reasons why such a claim would be made, but getting more energy out than is in the fuel is not one of them. Pending further information, it's very difficult for me to find such claims plausible. If you can supply such information, fine. If not, I guess time will tell.




Sent: Monday, June 08, 2009 11:00 AM

To: Rob

Subject: Re: Your claims

Hello, Rob: The HP2g not only has been EPA tested, but its fuel economy has been ested in over 8,000 miles of driving in cities, towns, interstates, desserts, mountains and speed tests. The HP2g’s technologies are not those that you know and are familiar with. The engine does not necessarily defy the laws of physics just our prior understanding of how engines are supposed to work. When we are authorized to release the EPA info we will. It is in our possession. Thank you,

Team HP2g

-----Original Message----- From: Rob

Sent: Monday, June 8, 2009 12:17 AM


Subject: RE: Your claims

Can you provide documentation? It’s very difficult to defy the laws of physics.



Sent: Sunday, June 07, 2009 9:11 PM

To: Rob

Subject: Re: Your claims

EPA tested.

-----Original Message----- From: Rob

Sent: Sunday, June 7, 2009 10:36 PM


Subject: Your claims

I’m afraid that very straightforward calculations show that your claims, as stated, cannot be correct. I wish that they were.

The calculations are at http://hamiltonianfunction.blogspot.com/2009/06/amazing-110-mpg-mustang_06.html.

If there are errors there, I’m sure you’ll point them out.



Anonymous said...

Just curious - why do you even care what these people are claiming? I do not see them seeking to take money from anyone off this (unless I am mistaken?). So your motivation cannot be to "protect" anyone from getting ripped off from a "scam".

So again, why do you even care what these people are doing or claiming when it does not effect you one iota?

King of the Road said...

There are a variety of reasons. It's true that I am not foolish enough to lose money to such a "venture." But it's sad to see such a large number of people getting their hopes up, thinking of buying such an engine, hoping for a job producing it, etc.

Further, I think it demeans us as a society to be so scientifically illiterate as to credulously buy into something that cannot be possible.

I am sure that at some point, money will change hands either to purchase something that cannot meet its claimed properties, to invest in something that cannot, or a combination.

But fundamentally, I wanted to illustrate how basic physical principles can be easily used to evaluate whether something claimed is actually plausible or even possible.

Thank you for asking.

Anonymous said...

If I remember my engineering class correctly, the maximum theoretical limit for efficiency of ANY Carnot cycle engine is 47%. The Otto cycle is the 4 stroke type, and includes all types of known automobile engines even the Wankel.

The Carnot cycle, however, is the basis for converting chemical energy into kinetic using a heat engine (heat, volume, and pressure).

That is 48% efficient when the the temperature difference is a follows:
After combustion, the expanding gases are at 500 degrees F. And after compression, when the fuel/air mix is injected, the cylinder is only 50 degrees F. That's super cold (AKA no entropy).

No engine can achieve this ideal. And even if it could. 110 mpg would still not be possible using E85.

Anonymous said...

Furthermore, to answer the question of "why do I care".

Yes, someone is being ripped off. The methodology is simple.

1) Make an outrageous claim at a time when the world needs so very much for it to be true.

2) Be ambiguous about the claim, so no one can directly dispute you and that unfounded, scientific techno babblers can have imaginations running wild to fill in the gaps of reality.

3) Claim the technology has been around for 60 years so that the conspiracy theory nuts can shout "suppression".

4) Talk more about the environmental and social implications than about the technology. So that every reporter salivates and publishes the story.

5) Never ask for money publicly. If you make your claims well, the investors come to you. A few, large investments are all you need. Patents cost tens of thousands of dollars.

6) Always claim that the full release of the technology is "just over the horizon" to spur investors into "hopping on a leaving train".

7) Quietly, fade off into obscurity. Claim some Big Oil company threatened you, or Auto X-Prize committee wanted to steal your technology.

Why have a real job when you can just work on and drive your Mustang all day and have people pay you for it.

Schtoogie said...

Information about the technology that is part of the HP2G engine has somewhat recently surfaced: apparently, somewhere on the engine is an integrated electric motor, and there are ceramic magnets on the tops of the pistons themselves as well as "Electromagnetic HP Effectors" the end of which I have no idea that they serve due to my engineering ignorance. I don't know if there is anything else providing power to the electric motor, though that wouldn't make very much sense to me as it would likely be counterproductive towards achieving extra efficiency.

The main things on my mind are that if the pistons have magnets in them, they are going to be quite a bit heavier than normal pistons. This will undoubtedly translate to more fuel consumption per RPM, strictly gas-burner speaking, than if there were no magnets at all. However, as long as the crankshaft is spinning, that electric motor is being subject to magnetic fields in a very predictable and consistent manner. I'm also not sure how strong the magnets must be to motivate a conventional motor that would fit the bill of this engine, whether they would have to go through the head itself or if there is some other sneaky way of getting power to the rotor.

Perhaps you could revisit the HP2G mystery with this newfound information?

- Schtoogie