Engineering data for ICE vs BEV calculations

[aerohead]

Here are some quanta which I hope will come in handy for members and guests as you navigate between internal combustion, and electrified propulsion:
* REGULAR Unleaded E10 gasoline = 111,836 Btu/ gallon
* 32.7772 kWh/ gallon-e
* 6.138-pounds/ gallon
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* DIESEL fuel = 136,775 Btu / gallon
* 40.086 kWh/ gallon-e
* 7.1089-pounds / gallon
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* 35% thermal efficiency for ICE gasoline engine, 65% waste heat
* 43% thermal efficiency for ICE diesel engine, 57% waste heat
* 90% thermal efficiency for electric motor, 10% waste heat

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* 746-Watts / horsepower
* 3412- Btu / kWh
* 2456- Btu / hour / horsepower
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* 1- meter-squared = 10.76391 square-feet area
* 25.4mm = 1-inch
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* engine-driven accessories = 2% power loss
* Planetary gearset = 99.5% mechanical efficiency
* spur gear set = 99.0- 99.8% mechanical efficiency
* hypoid gearset = 90.0- 93.0% mechanical efficiency
* automotive manual transmission = 92.0-97% mechanical efficiency
* automotive automatic transmission = 90.0-95% mechanical efficiency
* CVT mechanical transmission = 87.0-86% mechanical efficiency
* CVT hydrostatic transmission = 80-86% mechanical efficiency
* Driveshaft ( double- universal joints )= 98% mechanical efficiency
* Rear differential & wheel bearings = 97% mechanical efficiency
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as above, here at the aero forum,
* aerodynamic forces vary as the square of the velocity
* aerodynamic power requirements vary as the cube of the velocity
* aerodynamic data are normalized to reflect SAE 'standard' air density ( rho )
* Use published Cd and Projected Frontal Area if available, otherwise, you're forced to estimate frontal area as a percentage of Width X Height, compared to a vehicle of known frontal area, similar in architecture. Drag coefficients are easier to come by, although some have never, ever, been provided.
* rolling-resistance varies arithmetically with velocity, up to standing-wave ( which occurs above the rated speed rating of any given tire )
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* Presently, in the United States, the highest legal driving speed is 85-mph, on the toll road between Austin ,Texas, and San Antonio, Texas.
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Unit conversion tools are easily available online

[Autobahnschleicher]

I'd say that's a little optimistic for ICE efficiency.
Unless you pulse and glide or go rather fast all the time, you won't average that kind of efficiency.

[aerohead]

Originally Posted by Autobahnschleicher

I'd say that's a little optimistic for ICE efficiency.
Unless you pulse and glide or go rather fast all the time, you won't average that kind of efficiency.

Yes, the overall, well-to-wheels efficiency for a gasoline-powered automobile has been calculated at 15% overall thermal efficiency.
For the sake of simplicity, I'm using a constant-velocity, cruise-speed scenario for highway-only driving.
Short of having specific manufacturer-supplied data, estimating/ guestimating , is all we can do.
And that's the premise of this thread.

[Autobahnschleicher]

I'm purely looking at tank to crankshaft here.
Depending on the speed you're calculating it at, it's still rather optimistic.
If it's a small engine and you're going fast, you might get that efficiency.
However this is not the forum for people going 150 km/h on the highway, rather 80-100 km/h.

Gasoiline has a HHV of 43 MJ/kg or 43000J/g, wich is 11,94 Wh/g or 83,75 g/kWh.
If I'm lucky I can average (!) some 300 g/kWh, wich is 3,58x as much or just under 28% efficiency.

[Stubby79]

Originally Posted by aerohead

* CVT mechanical transmission = 87.0-86% mechanical efficiency

I assume that's a boo-boo. 77-86% or 87-96%? Or you just got your highs and lows backwards...1% difference comes across as much too small.

Give me truth! Or give me better lies!!!

PS: Thanks for putting this all in one place, will come in useful.

[aerohead]

[QUOTE=Stubby79;646378]I assume that's a boo-boo. 77-86% or 87-96%? Or you just got your highs and lows backwards...1% difference comes across as much too small.

Give me truth! Or give me better lies!!!

PS: Thanks for putting this all in one place, will come in useful.[/QUOTE
I'll check for typo.

[aerohead]

I looked, and they're typed as presented by Argonne National Laboratory.

[aerohead]

Originally Posted by Autobahnschleicher

I'm purely looking at tank to crankshaft here.
Depending on the speed you're calculating it at, it's still rather optimistic.
If it's a small engine and you're going fast, you might get that efficiency.
However this is not the forum for people going 150 km/h on the highway, rather 80-100 km/h.

Gasoiline has a HHV of 43 MJ/kg or 43000J/g, wich is 11,94 Wh/g or 83,75 g/kWh.
If I'm lucky I can average (!) some 300 g/kWh, wich is 3,58x as much or just under 28% efficiency.

Toyota has it's most advanced Atkinson-cycle engine rated at 43% thermal efficiency. I don't know if it's in production vehicles yet.
And that would be at the flywheel, before any CVT and constant-velocity joint/ wheel bearing losses.
Mazda's Skyactive series reports some high efficiencies, however, that's without any engine accessory or powertrain losses.
Hopefully, members and new members will chime in with specifics, which will allow us to focus our microscope.

[Autobahnschleicher]

Originally Posted by aerohead

Toyota has it's most advanced Atkinson-cycle engine rated at 43% thermal efficiency.

That is correct, however that's peak efficiency, not something you will average at.
If you look at a BSFC-chart, you'll see that peak efficiency is only reached at a certain point.
Usualy some 80% load in the rpm range where your engine is capable of producing the most torque.
And at that point it's allready producing so much power that you'll break the speed limit in many cases.

To take your own pic as an example, it takes only 14 kW to drive a vehicle at 100 km/h.
(likely less if we consider better aerodynamics as well as better tires)
At that point in the engine produces a lot more than that, even if it's a rather small economy engine.

[aerohead]

Absolutely! The transmission advancements have helped to keep engines closer to their BSFC 'sweet spot', but I'm seeing BEVs routinely, with BSFC-e of 1/3rd that of their ICE counterpart within the same model ( KONA, SOUL, etc. ).
You might look on BEVs as having the Holy Grail, 'adiabatic' engine.
You'll never see a piston engine with this little entropy.