Build a Hybrid
#21
07-08-2007, 10:23 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: Build a Hybrid
Xyrus -
"I'm not a moderator, but I play one on T.V."
I hope you will trust me when I say with confidence, Bob knows what he's talking about on this matter. You are over-simplifying things, and your idea does not fit this situation.
Bob is talking about a SMALL gas engine to charge the HV battery. Like a large lawn-mower engine could do the trick. This would never be able to propel the vehicle mechanically, as you were saying. Thus, even with all the conversions, the conversions ( Mech - Elec - Mech ) are required, and the net, due to an appropriate match of battery vs. engine size will be very, very efficient indeed.
"I'm not a moderator, but I play one on T.V."
I hope you will trust me when I say with confidence, Bob knows what he's talking about on this matter. You are over-simplifying things, and your idea does not fit this situation.
Bob is talking about a SMALL gas engine to charge the HV battery. Like a large lawn-mower engine could do the trick. This would never be able to propel the vehicle mechanically, as you were saying. Thus, even with all the conversions, the conversions ( Mech - Elec - Mech ) are required, and the net, due to an appropriate match of battery vs. engine size will be very, very efficient indeed.
#22
07-09-2007, 05:47 AM
Re: Build a Hybrid
Hi,
You're are pretty close in that we are using a 'part' of the ICE power to charge the battery. I'm typically seeing the traction battery charging at 15-17 A., 4.5-5 kW, 6-7 hp. A Prius typically needs about 5 hp to maintain 30 mph. By adding the charging load, this brings the ICE power up to about 11-12 hp until the battery is charged. The gasoline is converted to energy very efficiently at 11-12 hp but the gasoline conversion efficiency drops off at 5 hp. This extra energy is not lost but stored to be used later to sustain the speed with the ICE off and using electric power only. Let me try an analogy.
Without a small refrigerator, you might have to buy 6 eggs for $1 but with a large refrigerator, you could buy 18 eggs for $2. The cost per egg goes down with the larger buy and the large refrigerator lets you keep them long enough to use them. Without the cold storage, the refrigerator, you wouldn't be able to use all of the 18 eggs. The incremental cost of the refrigerator is much lower than the cost of the eggs.
Bob Wilson
Bob is talking about a SMALL gas engine to charge the HV battery. Like a large lawn-mower engine could do the trick. This would never be able to propel the vehicle mechanically, as you were saying. Thus, even with all the conversions, the conversions ( Mech - Elec - Mech ) are required, and the net, due to an appropriate match of battery vs. engine size will be very, very efficient indeed.
Quote:
Originally Posted by Xyrus
My argument against using an ICE to solely generate electricity for electric motors is not efficient, and you'd be better off just using the efficient ICE to power the vehicle.
~X~
Quote:
Originally Posted by Xyrus
My argument against using an ICE to solely generate electricity for electric motors is not efficient, and you'd be better off just using the efficient ICE to power the vehicle.
~X~
Without a small refrigerator, you might have to buy 6 eggs for $1 but with a large refrigerator, you could buy 18 eggs for $2. The cost per egg goes down with the larger buy and the large refrigerator lets you keep them long enough to use them. Without the cold storage, the refrigerator, you wouldn't be able to use all of the 18 eggs. The incremental cost of the refrigerator is much lower than the cost of the eggs.
Bob Wilson
Last edited by bwilson4web; 07-09-2007 at 09:17 AM.
#23
07-15-2007, 02:26 PM
Re: Build a Hybrid
Hi,
New here, hope I am not going to make a fool of myself.
Please remember a few advantages of a hybrid with a ICE running constantly in its most efficient power band directly driving a generator with only an electric motor propelling the vehicle are:
1) You do not need a large bank of batteries. Just enough to help the vehicle to accelerate at a good rate. When cruising the batteries are charged. Remember that an electric motor can be run at more than 100% for short periods of time. So, a smaller motor can be used. Saving weight.
2) A 30 to 45 HP engine is all that is needed at most to drive the generator and accessories, power steering, lights, A/C, etc.
Means that the engine is lighter, thus improving fuel economy.
Remember the VW Beetle of the 1960s had a very small power plant. The problem was that it took about 16 or more seconds to do 0-60mph.
3) No transmission is needed or differential (if two electric motors are used).
Again, a weight savings that is significant.
4) A constant running engine will warm up quickly and makes sure that any water will be driven out of the oil. In the hybrids of today, if you go on short trips the engine does not warm up enough to drive the water out. This can cause problems in the long run.
In conclusion a car built on the principal of an engine driving a generator that supplies an electric motor(s) with a bank of batteries for assist is a good idea.
The weight savings over todays hybrids is significant alone.
Hope this is been made clear enough.
mechengr
New here, hope I am not going to make a fool of myself.
Please remember a few advantages of a hybrid with a ICE running constantly in its most efficient power band directly driving a generator with only an electric motor propelling the vehicle are:
1) You do not need a large bank of batteries. Just enough to help the vehicle to accelerate at a good rate. When cruising the batteries are charged. Remember that an electric motor can be run at more than 100% for short periods of time. So, a smaller motor can be used. Saving weight.
2) A 30 to 45 HP engine is all that is needed at most to drive the generator and accessories, power steering, lights, A/C, etc.
Means that the engine is lighter, thus improving fuel economy.
Remember the VW Beetle of the 1960s had a very small power plant. The problem was that it took about 16 or more seconds to do 0-60mph.
3) No transmission is needed or differential (if two electric motors are used).
Again, a weight savings that is significant.
4) A constant running engine will warm up quickly and makes sure that any water will be driven out of the oil. In the hybrids of today, if you go on short trips the engine does not warm up enough to drive the water out. This can cause problems in the long run.
In conclusion a car built on the principal of an engine driving a generator that supplies an electric motor(s) with a bank of batteries for assist is a good idea.
The weight savings over todays hybrids is significant alone.
Hope this is been made clear enough.
mechengr
#24
07-15-2007, 03:30 PM
Re: Build a Hybrid
Not to worry. Our moderators (in whom we live in fear) do a pretty good job of sorting us out. <grins>
http://www.treehugger.com/files/2006...ybrid_mini.php
A British engineering firm has put together a high-performance hybrid version of BMW's Mini Cooper. The PML Mini QED has a top speed of 150 mph, a 0-60 mph time of 4.5 seconds. The car uses a small gasoline engine with four 160 horsepower electric motors — one on each wheel. The car has been designed to run for four hours of combined urban/extra urban driving, powered only by a battery and bank of ultra capacitors. The QED supports an all-electric range of 200-250 miles and has a total range of about 932 miles (1,500 km). For longer journeys at higher speeds, a small conventional internal combustion engine (ICE) is used to re-charge the battery. In this hybrid mode, fuel economies of up to 80mpg can be achieved.
. . .
The experiment is already in progress. You've also described GM's Volt, more or less.
Bob Wilson
A British engineering firm has put together a high-performance hybrid version of BMW's Mini Cooper. The PML Mini QED has a top speed of 150 mph, a 0-60 mph time of 4.5 seconds. The car uses a small gasoline engine with four 160 horsepower electric motors — one on each wheel. The car has been designed to run for four hours of combined urban/extra urban driving, powered only by a battery and bank of ultra capacitors. The QED supports an all-electric range of 200-250 miles and has a total range of about 932 miles (1,500 km). For longer journeys at higher speeds, a small conventional internal combustion engine (ICE) is used to re-charge the battery. In this hybrid mode, fuel economies of up to 80mpg can be achieved.
. . .
Bob Wilson
#25
07-16-2007, 03:46 AM
Re: Build a Hybrid
Bob,
Thanks for the welcome.
We seem to agree. I was just making the point that weight savings must be included. They would cancel out some of the losses of the ICE running a generator and not directly driving the wheels.
Do not understand why the auto manufacturers did not do this sooner.
Thanks for the welcome.
We seem to agree. I was just making the point that weight savings must be included. They would cancel out some of the losses of the ICE running a generator and not directly driving the wheels.
Do not understand why the auto manufacturers did not do this sooner.
#27
07-16-2007, 01:19 PM
Re: Build a Hybrid
This one?
http://motoringfile.com/2007/05/25/m...ore-efficient/
I guess it's not going to make it to this side of the pond.
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