Would this qualify as an 'electric' vehicle?
Discussion
Purely hypothetical, but as EV's have many government related benefits for parking, emissions zones, ved, tax and so on.
If such a vehicle as this existed, would it be deemed an EV?
Electric motor to provide 100% propulsion.
No batteries connected to the electric motor.
An IC generator (with electric starter).
All electricity is produced by the generator (probably a compact 3 cylinder diesel type thing or smaller).
However all propulsion would come from the electric motor (bit like a diesel electric train).
And having no battery capacity would mean no charging, good range but with the IC running all the time.
Would lack of any storage medium to power the electric motor mean this wouldn't count as an EV?
If such a vehicle as this existed, would it be deemed an EV?
Electric motor to provide 100% propulsion.
No batteries connected to the electric motor.
An IC generator (with electric starter).
All electricity is produced by the generator (probably a compact 3 cylinder diesel type thing or smaller).
However all propulsion would come from the electric motor (bit like a diesel electric train).
And having no battery capacity would mean no charging, good range but with the IC running all the time.
Would lack of any storage medium to power the electric motor mean this wouldn't count as an EV?
No, because it is incapable of moving without running the IC engine.
Whether the primary propulsion is IC, electric, or a tightly wound rubber band, what the emissions rating measures is the amount of CO2 emitted by the vehicle (not just one of its engines - otherwise hybrids would be zero emissions) over a standard driving cycle, so they'd end up measuring the IC emissions anyway.
It would also be horrendously inefficient, so even if you could somehow blag your way out of road tax and congestion charge, you'd probably pay for it thrice over with fuel consumption.
ETA: I ran into this problem (sort of) quite recently with some work I did on the design of a low volume, specialist sports car. The proposal was to use the new Ford EcoBoost engine to take advantage of its low emissions (road tax) bracket. Trouble is, you can't get the road tax rating without putting the vehicle though the type approval emissions cycle testing.
Congestion charge may be a bit different, as it's a comedy system run by muppets who might just be stupid enough to fall for it.
Whether the primary propulsion is IC, electric, or a tightly wound rubber band, what the emissions rating measures is the amount of CO2 emitted by the vehicle (not just one of its engines - otherwise hybrids would be zero emissions) over a standard driving cycle, so they'd end up measuring the IC emissions anyway.
It would also be horrendously inefficient, so even if you could somehow blag your way out of road tax and congestion charge, you'd probably pay for it thrice over with fuel consumption.
ETA: I ran into this problem (sort of) quite recently with some work I did on the design of a low volume, specialist sports car. The proposal was to use the new Ford EcoBoost engine to take advantage of its low emissions (road tax) bracket. Trouble is, you can't get the road tax rating without putting the vehicle though the type approval emissions cycle testing.
Congestion charge may be a bit different, as it's a comedy system run by muppets who might just be stupid enough to fall for it.
Edited by TheLastPost on Thursday 28th February 12:10
Not to mention that your concept is actually LESS efficient than simply coupling the engine to the wheels with a gearbox!
This is because without any energy storage capability, your engine must at all times generate the same power the car is using, and so it must still be sized to provide the peak power requirement, but, just like a conventional car, it will only be running at light load most of the time. Add in the extra losses from going FUEL -> Rotational Power -> electricity - >inverter -> Motor -> Rotational power at wheels and your "amazing new concept" will be approx 30% LESS efficient than a normal powertrain..........
Back to the drawing board for you sonny! ;-)
This is because without any energy storage capability, your engine must at all times generate the same power the car is using, and so it must still be sized to provide the peak power requirement, but, just like a conventional car, it will only be running at light load most of the time. Add in the extra losses from going FUEL -> Rotational Power -> electricity - >inverter -> Motor -> Rotational power at wheels and your "amazing new concept" will be approx 30% LESS efficient than a normal powertrain..........
Back to the drawing board for you sonny! ;-)
kambites said:
Max_Torque said:
Not to mention that your concept is actually LESS efficient than simply coupling the engine to the wheels with a gearbox!
That's only just true. IIRC, a generator/motor combination is only marginally less efficient than a gearbox and differential. Most geartrains average losses range from ~7% (fwd) to ~12% (rwd) over the power domain under which they operate.
No electric powertain i have yet tested can get above 72% efficiency (not including battery losses) over the EUDC cycle..........
BTW, if you just want to be able to park for free in the city centre, i can recommend simply sticking a "charging socket" onto the side of your car (doesn't need to be connected to anything). For full effect two final mods really help:
1) Add some sort of massively pretentious graphics to the cars side that say something along the line of "PolarBear saving green electric technology demonstrator"
and
2) Make sure you have a small but obvious flashing LED on the dash that has "Charging" written next to it.
If you are ever questioned about the car, tell 'em it is an EU funded technology demonstrator, but that you aren't allowed to talk about it yet......... ;-)
1) Add some sort of massively pretentious graphics to the cars side that say something along the line of "PolarBear saving green electric technology demonstrator"
and
2) Make sure you have a small but obvious flashing LED on the dash that has "Charging" written next to it.
If you are ever questioned about the car, tell 'em it is an EU funded technology demonstrator, but that you aren't allowed to talk about it yet......... ;-)
Interesting, the last study I read had generators running about about 96% and motors at about 90%, for automotive purposes. I also thought the combination of a helical gearbox and a torsion diff (I was looking at a very specific example, can't remember why) typically gave more like 10-11% losses.
Plus the motor/generator combination should give engine efficiency equivalent to a CVT rather than a stepped gearbox, which must help at least a tiny bit?
Plus the motor/generator combination should give engine efficiency equivalent to a CVT rather than a stepped gearbox, which must help at least a tiny bit?
Edited by kambites on Thursday 28th February 15:40
For power electronics at light loads the loses in terms of % can be very poor, even if not in terms of actually Watts.
Power must flow as follows (all efficiencies for EUDC cycle)
IC engine -> Generator (94%) -> Rectifier (90%) -> Inverter (90%) -> Motor (94%) = 71.5% (assuming hub motors (no extra mech losses between motor and wheel) and no transmisson losses between rectifier and inverter.
Add in the fact that without a storage system you cannot capture any of the vehicles KE during a deccel and what you have is a very expensive but competely rubbish electric transmission system only.
Power must flow as follows (all efficiencies for EUDC cycle)
IC engine -> Generator (94%) -> Rectifier (90%) -> Inverter (90%) -> Motor (94%) = 71.5% (assuming hub motors (no extra mech losses between motor and wheel) and no transmisson losses between rectifier and inverter.
Add in the fact that without a storage system you cannot capture any of the vehicles KE during a deccel and what you have is a very expensive but competely rubbish electric transmission system only.
Max_Torque said:
For power electronics at light loads the loses in terms of % can be very poor, even if not in terms of actually Watts.
Power must flow as follows (all efficiencies for EUDC cycle)
IC engine -> Generator (94%) -> Rectifier (90%) -> Inverter (90%) -> Motor (94%) = 71.5% (assuming hub motors (no extra mech losses between motor and wheel) and no transmission losses between rectifier and inverter.
Add in the fact that without a storage system you cannot capture any of the vehicles KE during a deccel and what you have is a very expensive but completely rubbish electric transmission system only.
shhhh stop being teh smarts dis r intarnetz Power must flow as follows (all efficiencies for EUDC cycle)
IC engine -> Generator (94%) -> Rectifier (90%) -> Inverter (90%) -> Motor (94%) = 71.5% (assuming hub motors (no extra mech losses between motor and wheel) and no transmission losses between rectifier and inverter.
Add in the fact that without a storage system you cannot capture any of the vehicles KE during a deccel and what you have is a very expensive but completely rubbish electric transmission system only.
By EUDC you mean the Extra-Urban bit of the NEDC or are you acronym mashing?
I have a car which can travel for short distances on just battery power using an electric motor. When battery power is low, or when more performance is needed the internal coombustion engine can be started and drives the car directly as well as charging the battery.
I have two questions:
1 - Does this count as a hybrid?
2 - Is this any different to a traditional car with a button to turn over the starter motor without firing the engine? Because that's what it is.
I suspect the answers are:
1 - Yes of course.
2 - Wait, what? The answer to 1 should have been no. Dammit.
I have two questions:
1 - Does this count as a hybrid?
2 - Is this any different to a traditional car with a button to turn over the starter motor without firing the engine? Because that's what it is.
I suspect the answers are:
1 - Yes of course.
2 - Wait, what? The answer to 1 should have been no. Dammit.
kambites said:
Ah that's what I'd missed. Why AC motors?
Probably not really what you would call a pure AC motor (i.e. a squirrel cage AC induction motor) more likely a permantent magnet BrushlessDC (BLDC) motor for efficiency reasons.You could use an old fashioned Brushed permanent magnet motor, where the comutation is done mechanically with slip brushes and a segmented commutator, but this would be:
1) very very inefficient
2) Massively limit the power potential (due to brush heating and the near imposibility to do field weakening)
3) require a massive amount of maintainance (replacement brushes and replacement comutators under higher loads)
4) Mean the only way to actually stop the car from moving would be to turn the engine off
5) Result probably in a blown system / major fire because nothing would stop a stalled traction motor going overcurrent if you rev'd the engine!
In reality, using electronically commutated Emachines allows your electric CVT transmission (for that is what it becomes) to at least work with a wide range on input / output speeds. (although depending on the base KE (winding) of your traction machine, your engine speed will at least have to follow road speed to avoid the requirement for excessive and efficiency sapping Field weakening due to a low DC link voltage.
scarble said:
1. It's called a range extender so in pop culture yes but technically there's nothing "hybrid" about the drivetrain, it's a fully electric drivetrain.
2. The difference is your starter motor turns the engine which then turns the wheels so yes, very different.
1 - It's a parallel hybrid. You could use a pancake motor instead of the starter motor and it'd be just like an Insight.2. The difference is your starter motor turns the engine which then turns the wheels so yes, very different.
2 - Just like an Insight. Except I'm paying a lot more tax, obviously.
Max_Torque said:
No it ain't and i have the data to prove it!
Most geartrains average losses range from ~7% (fwd) to ~12% (rwd) over the power domain under which they operate.
No electric powertain i have yet tested can get above 72% efficiency (not including battery losses) over the EUDC cycle..........
Bit disingenuous as you're not including the difference between part load and peak efficiency of a conventional IC setup. Most geartrains average losses range from ~7% (fwd) to ~12% (rwd) over the power domain under which they operate.
No electric powertain i have yet tested can get above 72% efficiency (not including battery losses) over the EUDC cycle..........
Plus if you're charging the battery during part load you don't need to spec the IC engine for peak power, you need to spec it for average power plus a safety margin with all of the implications that has for IC engine design and efficiency.
Horses for courses though obviously, some situations (like high speeds) conventional all the way, but slower speed and stop start traffic a well calibrated SHEV should be better.
Max_Torque said:
IC engine -> Generator (94%) -> Rectifier (90%) -> Inverter (90%) -> Motor (94%) = 71.5% (assuming hub motors (no extra mech losses between motor and wheel) and no transmisson losses between rectifier and inverter.
Is that maximum or average efficiency? Presumably the efficiency of the electric motors varies with speed, while I'm guessing the generating system reuns at pretty constant efficiency?The Wookie said:
Max_Torque said:
No it ain't and i have the data to prove it!
Most geartrains average losses range from ~7% (fwd) to ~12% (rwd) over the power domain under which they operate.
No electric powertain i have yet tested can get above 72% efficiency (not including battery losses) over the EUDC cycle..........
Bit disingenuous as you're not including the difference between part load and peak efficiency of a conventional IC setup. Most geartrains average losses range from ~7% (fwd) to ~12% (rwd) over the power domain under which they operate.
No electric powertain i have yet tested can get above 72% efficiency (not including battery losses) over the EUDC cycle..........
Plus if you're charging the battery during part load you don't need to spec the IC engine for peak power, you need to spec it for average power plus a safety margin with all of the implications that has for IC engine design and efficiency.
Horses for courses though obviously, some situations (like high speeds) conventional all the way, but slower speed and stop start traffic a well calibrated SHEV should be better.
(Obviously, for a practical system that DOES have energy storage, large gains are availible through optimising the IC engines operating point (but you still loose more power in the "transmission" than on a conventional powertrain)
Captain Muppet said:
1 - It's a parallel hybrid. You could use a pancake motor instead of the starter motor and it'd be just like an Insight.
2 - Just like an Insight. Except I'm paying a lot more tax, obviously.
oh yea sorry I completely misread 2 - Just like an Insight. Except I'm paying a lot more tax, obviously.
-1 internetz 4 me
An Insight really can't decouple? I know the Insight (and CRZ) use something called Integrated Motor Assist but uh.. hmm do they do EV only even?
Anyway uh, various degrees of hybridity are possible or infinitely varying degrees I suppose (meaning infinitely small steps rather than infinite bounds) so uh.. hm.. uh..
I guess technically kinda yea if you had separate ignition and starter switches it'd be possible and I guess technically kinda a hybrid, as I guess technically is any car if you start it in gear
But I'm sure the law has already thought of that so no loop holes for you
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