eCar kW usage at cruising speed! ... ???

DrkAngel

DrkAngel

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In anticipation of Hybridization of an eCar I'm attempting to determine generator capacity requirements.

I'm trying to find the cruising speed - kW usage. Found 2, so far.
Please post links, or PM me the, link to, info.
I would like to consolidate and re-post.

Toyota Rav4EV 60MPH is ~10kW
http://www.evdrive.com/Rav4ev.html
Not bad for a roomy SUV

Honda Civic 70mph is ~9kW

Permanent Magnet motors should have much better efficiency than series wound motors!
 
DrkAngel said:
I anticipation of Hybridization of an eCar I'm attempting to determine generator capacity requirements.

I'm trying to find the cruising speed - kW usage. Found 2, so far.
Please post links, or PM me the, link to, info.
I would like to consolidate and re-post.

Toyota Rav4EV 60MPH is ~10kW
http://www.evdrive.com/Rav4ev.html
Not bad for a roomy SUV

Honda Civic 70mph is ~9kW

Permanent Magnet motors should have much better efficiency than Induction motors!
Click to expand...

Kind of makes me wonder why there aren't more series hybrids on the market.
 
You might surf through EValbum.com to get range/speed/consumption figures for many different setups.
 
Sounds about right. You can pretty much work this out for any car, if you know the fuel consumption (usually published somewhere at a range of speeds).

It's not exact, but close enough to size average power consumption. Just use the BSFC for the type of ICE (typically around 180 to 210g/kW/hr for a good diesel, and around 250 to 270 g/kW/hr for a petrol (gasoline) engine), the fuel used per unit time (derived from the fuel consumption and speed data) and you'll end up with the average power used.

Here's a worked example for a petrol driven car that does 50mpg at a steady 56mph, with a mid-efficiency engine that runs at around 260g/kW/hr:

If the car travels 56 miles in an hour, it will burn 56/50 = 1.12 imp gals of fuel, which is about 5.1 litres. Petrol has a typical density of around 0.72kg/litre, so in one hour it will have burned about 0.72 x 5.1 = 3.7kg of fuel. As the BSFC is around 260g per kW per hour, we can now work out the average power that the engine used by just dividing the fuel used mass by the BSFC figure, so 3.7kg / 0.26kg = 14.2kW

If the car has been able to do 60mpg at a steady 56 mph then the average power would reduce to about 11.7kW

This relatively low average power is what makes the hybrid solution so attractive for cars, with a big enough electric motor and battery pack to meet the high burst power needs you only need a very modest ICE power.

Jeremy
 
My "ideal", generator capacity, would, at the "continuous" rating, slightly exceed, the kilo watt usage at expressway speed, (65 mph).
For example: A 10kw generator has a continuous rating of 8kw. Which would be perfect for a eCar capable of cruising at 7.5kw.

This would effectively provide "unlimited range", not counting fuel, and bathroom, breaks, every few hours.

Of course, the generator would only be added for trips, and the like.
Small trailer, with extra luggage room,sounds perfect!
 
my experience has been that cruising amps are about 100 to 200 amps. i woulnd mind a small 2000 watt generator for charging when parked. just a couple of hours would extend my range a lot.
 
amps x volts = watts
1000watts = 1kw

Sample vehicle:
100amps x 120volts = 12,000watts or 12kw
Approx. 16 kw generator (continuous mode typically between 75-80% of full), should run vehicle - unlimited range. (Motor 25hp+-)

Generators, over 10kw, tend to be excessively heavy, and pricey.
Could be OK for a pickup conversion, might even be able to take advantage of oem fuel tank!

I'm looking for something a bit more efficient, 8kw continuous, is my target
 
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