Does anyone know of some resources that explain and compare the two hybrid systems and the advantages of each over the other?

Boy howdy are you askin' for it. That seems to be one of those topics that quickly devolves into an Apple vs. Windows style "holy war."

The Honda system is optimized for highway performance and the Toyota system optimized for City. This is reflected in the EPA numbers and if you'll look at the GreenHybrid database, you'll the relative performance of the Prius II and Honda Civic and see how each performs.

Mechanically, the Honda system has fewer parts. However, the Prius system has an electric-only capability for low speeds and very short distances. Otherwise, either is an excellent choice and should be chosen based upon your requirements.

My best recommendation is test drive and better yet, rent one for a couple of days. Then you'll know which one best meets your needs.

Bob Wilson

Operation Iraqi Oil Freedom:

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My other 1500 cc car:

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The take home differences are straight forward Civic vs Prius
The Prius is about 2-3 mpg better- 4%-6% or so-with similarily motivated drivers.This is a tiny difference-14 gallons more per 10,000 miles.
The Prius is about 1.5 seconds quicker 0-60. This is a big difference.The Civic is a 12 second car-slowish.
Price difference is at least $2500-when you figure in the tax credit it is about $2000.THIS IS BIG!
All the Civics come with side side curtain airbags.This is a big difference.With a Prius the bags are usually bundled with some other c _ _ p you won't want.
With the current Prius or the Civic you will reach breakeven miles against all the vehicles you could reasonable compare it to .The last 3 take about 150,000 miles to break even at $3/gal.
4 Cyl LE Camry cost ~$23000-drive off lot
4Cyl LX Accord $21500- 16,000 miles (18-40)
4Cyl LX Civic-$19000 -90,000(25 vs 40)
4 Cyl LE Corolla $19000 90,000 miles (25 vs 40)
4 Cyl Matrix- $21000- about 35000 miles (22 vs 40)
Fit-$18000- at roughly 155,000 miles-at 28 vs 40 mpg overall.
Scion-$17000
Yaris-$17000
Prius $22,850 for PK 4 with $3150 credit($26000 before credit)
H Civic $20500-with $2500 credit.
The Civic reaches breakeven much sooner.It would take the Prius 500,000 miles to break even against the Civic Hybrid.
The Scion,Yaris, and Fit are the small cars that you might favor ,since you figure they are smarter choices.I'm using OTD prices on side side curtain equipped cars, so they aren't the cheapest of their breed.I'm also using New Orleans 9% sales tax.I also use low mpg figures that reflect what I think(guess)I would get using these cars in mainly city driving.
The Matrix is the car closest to the Prius in size,performance, interior volume, but the Prius has more interior length(5"+) behind the front seats.
We-wife,greyhound,me-take long trips (1500 miles one way).We sleep enroute-one drives, one sleeps on an air mattress in the back.The Prius has 70" of length behind the front seats.I fill in the space between the seat back and rear seat top with plywood and foam.This is why interior length is critical for me.The Civic Hybrid,Yaris,and Scion were just too short.The Fit might have worked-60"-but it wouldn't have been as comfortable.
Oh, Phoebe-dog-refuses to take her turn behind the wheel.
If you don't mind the slow accelleration,and don't need the extra room,the Civic wins.These prices all assume you get the $3150 credit on the Prius.
With the credit, the hybrids are great deals.You can buy a Prius for Corolla $$.Luck,Charlie

bwilson gave an ideal answer. If you want details as to the technical guts of one system vs the other (HSD vs IMA), do a search on "howstuffworks.com" or wikipedia

So is the situation that in bad stop and go traffic, the Civic won't be able to use enough assist to burn off the energy as fast as it can take it on from the regenerative braking?

www.fueleconomy.gov has a hybrid flash tutorial.

Personally, I think of IMA as a gas engine with an electric motor to assist it, and HSD as an electric motor with a gas engine to assist it.

First 4WD Hypermiler

Have you read the FEH FAQ?

Live in Michigan? Let it be known in Michigan Roll Call

Just the reverse. It will expend more that it can recover, because the contribution from regen braking in stop-and-go driving is very minimal. The Civic recharges best when you coast a long time before stopping.

*** Retired after 65,000 outstanding miles ***

This is a confusing question and doesn't address all of the factors involved. But as a general rule, the effectiveness of regenerative braking will be proportional to the generator power divided by the vehicle mass. In the case of the Civic, use the power rating of the electrical motor and in the case of the Prius, use the MG2 power rating. Lookup the values and do the math for the best case regenerative braking performance. But there is a short cut, the EPA city ratings:

48 mpg - Civic I CVT
49 mpg - Civic II CVT

52 mpg - Prius I CVT
60 mpg - Prius II CVT

On the other side of the coin, highway performance, you need the drag at highway speed and the engine specific output (hp/gal/hour). In this, the Civic has 'lean burn' technology and the Prius uses the Atkinson cycle. The aerodynamic drag is a product of the coefficient of drag, area and velocity squared. The rolling drag is fairly constant at all speeds. Again, the EPA highway ratings provides a quick answer:

47 mpg - Civic I CVT
51 mpg - Civic II CVT

45 mpg - Prius I CVT
51 mpg - Prius II CVT

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

So how would the Prius have an advantage? Better or higher capacity regen braking?