Frodus's Brammo Empulse R #24

[EmpulseRider]

Thats the beautiful thing about EVs, they get cleaner every year as the grid cleans up... and they run on anything that can be harnessed to create electricity. Cant really get much better than that.

I dont think we will ever see fuel cell or hydrogen powered motorcycles. Electric is clearly the way to go.

I like the idea of smart charging, though some may worry that it would adversely affect the life of the battery. I also remember hearing of something where the utility company pays customers for the privilege.

[flar]

My 36kwh figure was a theoretical figure - I saw it in a couple of places, including a couple of sources that demonstrated where the EPA derived their figures from and you can find it here: https://en.wikipedia.org/wiki/Gasoline (more precisely 36.6 kwh).

The other figures are conversion based and assume various efficiencies:

The 33.7 figure assumes a 92% conversion rate.
The 34.7 figure assumes a 95% conversion rate.

Neither of those is achievable in a power plant, though - not even close.  This is why I was focused on what is installed in the vehicle vs. what it does with it.

The one overwhelming reason I do that is that it is possible for me to have 0 "loss" power in my EV.  All it takes is installing a solar panel (possibly some wind turbines or some other renewable generation equipment depending on location).  Sure, the solar panel is not 100% efficient in turning sunlight into electrons, but it doesn't kill dinosaurs if it loses some free electrons between my roof and my battery pack.

Tank to road compares to battery pack to road and all other comparisons make assumptions about the power infrastructure that are constantly changing.  If you want to use MPGe then you have to consider what process they are assuming with such a high conversion rate (I believe it is burning it and heating water, but that doesn't propel a car).  If I get my energy from the sun, or hydroelectric, or wind then why should my energy, when compared to a gallon of gas, be modified by some real or theoretical fossil fuel conversion rate?  If I produce my electrons myself, then what does any real world generator scheme have to do with what happens when I twist my wrist?

The ICE driver is "given" 36.6 kwh worth of energy.  There was a lot of power used to get that chunk of energy to them and then on top of that they fumble it badly inside their engine compartment.  The Empulse is bestowed with 9.3 kwh of nominal energy.  It probably drew more than that out of the wall, and that is fair game for some other analysis, but when it's "tank" was "full", it had 9.3 kwh of energy in it (or would a better comparison be the 10.2 kwh figure?).

Tesla has a nice web page that shows where various regions of the country get their electric power from.  If you are in the Northwest your ICE competition should not get a break by underestimating their fossil fuel waste because it has nothing to do with where your electrons came from (http://www.teslamotors.com/goelectric#electricity).

And, installing your own renewable power generation trumps any lines you may want to draw as to how to calculate efficiency of charging.

[protomech]

9.3 kWh is a fair representation for how much energy the Empulse pack holds. The available energy will vary based upon temperature and rate of withdrawal, but it's a good stand-in.

36.6 kWh is the higher heating value of gasoline.
33.7 kWh is the lower heating value of gasoline.

"LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, as opposed to the higher heating value (HHV) (a.k.a. gross calorific value or gross CV) which assumes that all of the water in a combustion process is in a liquid state after a combustion process."

In gasoline combustion all the water products will be in a vapor sent out the exhaust. So LHV is the appropriate value. At least that's my understanding.

https://en.wikipedia.org/wiki/Lower_heating_value#Lower_heating_value

[frodus]

This is all great stuff guys!

It makes me want to get a few solar panels to help offset my carbon emissions via Grid Power..... just need to look into it a little more. We're renting from my GF's parents right now, and they said they don't care. I might just try to put a few 240Watters on the upper level patio with a grid tie inverter.

[flar]

9.3 kWh is a fair representation for how much energy the Empulse pack holds. The available energy will vary based upon temperature and rate of withdrawal, but it's a good stand-in.

36.6 kWh is the higher heating value of gasoline.
33.7 kWh is the lower heating value of gasoline.

"LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, as opposed to the higher heating value (HHV) (a.k.a. gross calorific value or gross CV) which assumes that all of the water in a combustion process is in a liquid state after a combustion process."

In gasoline combustion all the water products will be in a vapor sent out the exhaust. So LHV is the appropriate value. At least that's my understanding.

https://en.wikipedia.org/wiki/Lower_heating_value#Lower_heating_value

In some sense, that is conversion efficiency, no?  If you leave the water as vapor then you haven't fully converted the heat energy in the final byproducts.  If you reclaim the heat that is causing the water to exist in non-liquid form then you have full conversion.  If you don't, then you have a less efficient conversion.

One could just as easily say "a car only gets about 9kwh of energy out of a gallon of gas" and then claim that the gas only contained 9kwh of energy, but the 36.6-9 is its inefficiency.  A "conversion of gas to heated byproducts" is an inefficient conversion of the energy in that gas, just like the combustion of gas in an ever increasingly hot metallic piston chamber is experiencing lots of losses including that heat.

When I ride my Empulse hard it vents heat.  It is being dinged for that inefficiency of converting the energy stored in the LiIon batteries into propulsion.  So should any conversion of the gas in the tank that produces heat, whether the heat settles in the conversion apparatus or the end products.

[frodus]

I got to hang out a bit with Skuzzle this weekend at the OEVA EV awareness day in downtown PDX. He brought his and we fielded questions from people. We got a ton of interest!!!

[frodus]

[frodus]

[Jeff]

That VW bus may be the most awesome electric vehicle I have ever seen.  However, it really needs to replace the snowboarder motif with a gigantic airbrushed wizard shooting lightning bolts everywhere.

[frodus]

It was badass. Gbs cells and an ac50 motor. Had a tv on the rear door that flips down... solar panels on top... a tv and leather seats inside... truly awesome. One of the best conversions I've seen.... ever.

[protomech]

Love the solar VW microbus!

flar, I see I never answered your previous question. (I think it was a question? Maybe it was just a statement : )

Yes. The LHV of gasoline represents a less efficient combustion cycle, versus a the HHV combustion cycle where the heated water vapor is captured.

I think it's important to distinguish between combustion cycle efficiency and engine efficiency.

Cycle efficiency characterizes how much heat energy is extracted from fuel.

Engine efficiency characterizes how much kinetic energy is extracted from heat energy.

Vehicle/driver efficiency characterizes how many miles can be traveled with that kinetic energy.

All three of these metrics are combined into a MPG (or better stated, a quantity of fuel used per distance) metric.

The ICE driver isn't given energy. He's given fuel. There's no "intrinsic" energy associated with the fuel - perhaps you could make an argument for the rest mass / energy equivalency to come up with 9E16 J/kg = 2.5E13 Wh/kg. Next to that, though, any efficiency metric is going to need a whole bunch of zeros.

You can combine cycle efficiency and engine efficiency into a single metric: brake-specific fuel consumption (BSFC) curves do just this. However, if you're talking unitary % efficiency - converting one type of energy into another - then you're talking heat energy into kinetic energy, which is independent of the combustion cycle efficiency (and thus wrangling over HHV vs LHV). Engines use a LHV combustion cycle, so if you're talking % efficiency then you have to discuss it in terms of the LHV heat energy.

At least, that's my thoughts.

[flar]

Yes. The LHV of gasoline represents a less efficient combustion cycle, versus a the HHV combustion cycle where the heated water vapor is captured.

To summarize, let me see if I got this right.

HHV cycle implies recapturing the heat in the water vapor (end products).
LHV cycle implies not recapturing that heat, resulting in a less comprehensive conversion of fuel into usable energy.

?

You can combine cycle efficiency and engine efficiency into a single metric: brake-specific fuel consumption (BSFC) curves do just this. However, if you're talking unitary % efficiency - converting one type of energy into another - then you're talking heat energy into kinetic energy, which is independent of the combustion cycle efficiency (and thus wrangling over HHV vs LHV). Engines use a LHV combustion cycle, so if you're talking % efficiency then you have to discuss it in terms of the LHV heat energy.

Are you saying "[all] engines [must] use a LHV combustion cycle"?  Or are you saying "[current] engines use a LHV combustion cycle"?  If it's the former, I don't see why an engine could not incorporate a system to create kinetic boost from the heat in the exhaust.  Isn't a turbocharger a form of using the heat in your exhaust to boost power?  If it's the latter, then we are simply assuming a present-day inefficiency of our current engine designs and I don't see why we should forgive any inefficiency and simply "live with it" when talking about the energy efficiency of various alternate designs.  Otherwise, why don't we subtract the heat that soaked into the engine block?  Or the energy that moved the pistons instead of being transferred down the crankshaft?

At least, that's my thoughts.

Mine too...

[flar]

That VW bus may be the most awesome electric vehicle I have ever seen.  However, it really needs to replace the snowboarder motif with a gigantic airbrushed wizard shooting lightning bolts everywhere.

Is it just me, or is the bus sitting back on its haunches?  Perhaps some beefier springs in the rear would help?

[frodus]

Maybe its time to start another thread for that topic guys.....

[frodus]

Got to show off my bike to people at the Celebrate Hillsboro street fair on Saturday. People loved it!