Variants of Hybrid Synergy Drive

[bredekamp]

Are the only differences between the HSD in the Highlander, Prius and Camry the ICE? I was just wondering if the larger engines in the other two also uses the Atkinson Cycle like in the Prius.

With the Highlander, Camry and Lexus Hybrids being newer than the Prius, did Toyota make any improvements to the HSD like weight reduction or performance enhancement? I know the Lexus and highlander have an extra motor in the rear. Are the HV battery capacities the same amongst these vehicles? Do they essentially use the same NiMH pack as the Prius?

So many questions....I can't even test drive one of Toyotas other hybrids cause they don't sell them here.

[efusco]

The PSD has gotten smaller, the MGs on the Highlander are larger than on the Prius. The battery on the Highlander is larger...I think the one on the Camry is as well.

The firmware is a bit different as well, but not much.
So yes, they've incorporated some advancements into the newer HSD vehicles.

[bredekamp]

Originally Posted by efusco

The PSD has gotten smaller, the MGs on the Highlander are larger than on the Prius. The battery on the Highlander is larger...I think the one on the Camry is as well.

The firmware is a bit different as well, but not much.
So yes, they've incorporated some advancements into the newer HSD vehicles.

Are the batteries physically larger or did they just manage to up the kWh ratings somehow? Is there a website you can recommend with more technical details of how HSD evolved from the 1997 Prius through to now?

If the battery in a Prius dies, can one use the pack from a highlander?

[efusco]

Physically bigger...but I don't have a good source for you on hand.

[dogfriend]

Originally Posted by bredekamp

Is there a website you can recommend with more technical details of how HSD evolved from the 1997 Prius through to now?

TOYOTA: Company > Technology

Only covers the Prius though. I have seen some comparisons of Camry and Highlander HSD, but I can't remember the source right now. I do know that the Camry battery is higher voltage (245V) compared to the Prius (201V)

[Patrick Wong]

Originally Posted by bredekamp

Are the only differences between the HSD in the Highlander, Prius and Camry the ICE? I was just wondering if the larger engines in the other two also uses the Atkinson Cycle like in the Prius.

With the Highlander, Camry and Lexus Hybrids being newer than the Prius, did Toyota make any improvements to the HSD like weight reduction or performance enhancement? I know the Lexus and highlander have an extra motor in the rear. Are the HV battery capacities the same amongst these vehicles? Do they essentially use the same NiMH pack as the Prius?

So many questions....I can't even test drive one of Toyotas other hybrids cause they don't sell them here.

The Highlander Hybrid ICE uses Otto cycle. Not sure about CamHy.

The Highlander Hybrid battery is rated at 288V nominal compared to the 2G Prius battery at 201.6V and the Classic Prius battery at 273.6V. The HiHy battery is arranged in three separate physical sections to fit under the second row seat.

The batteries cannot be interchanged between the different vehicles. The modules have a different physical appearance, I recall that the HiHy has eight 1.2V cells in a module vs. Prius with six 1.2V cells in a module.

All Toyota hybrid batteries are rated at 6.5AH, they are all the same for legal/licensing reasons. Since the HiHy battery produces more voltage (due to more modules in series) the available battery power is correspondingly greater.

I had taken photos of the HiHy battery but can't find them right now... However, here's a link to my Yahoo Prius group photo album containing five battery photos (you probably need to join the group to gain access): http://autos.ph.groups.yahoo.com/gro...os/browse/2a94

Regarding a website for more info, I suggest the Toyota subscription website: techinfo.toyota.com and look for the New Car Features Manual for the 2001 Prius, the 2004 Prius, the 2006 HiHy, and the 2007 CamHy. It will cost US$50 for one-month access or US$10 for one-day access.

Download and study the various files. (Being a US site, there's no info on the original Prius sold only in Japan.)

[usbseawolf2000]

You can find a lot of info at HYBRID SYNERGY DRIVE

[n8kwx]

Buyhevs, on the GreenHybrid Camry forum posted the following:

The Oak Ridge Lab, as part of the Freedomcar project, performed a very thorough evaluation and teardown of a Camry Hybrid transaxle. The 102 page report is here:

Information Bridge: DOE Scientific and Technical Information - Sponsored by OSTI

My one paragraph summary:

Toyota made significant improvements to the power density of the both the motors and the inverter. The Camry has more power than the Prius in a smaller space. The energy efficiency of both was also improved.

Although not mentioned in the report, I'm sure cost was reduced as well.

I can't wait to see what improvements are made for the upcoming "new" Prius!

[ken1784]

Originally Posted by bredekamp

Are the batteries physically larger or did they just manage to up the kWh ratings somehow?

Product Catalogues | Panasonic EV Energy Co., Ltd.

The NiMH battery performance is increasing model by model.
NHW-10 Prius(1997-2000): cylindrical, 240cells 6Ah poor performance
NHW-11 Prius(2001-2003): plastic case prismatic, 228cells 6.5Ah medium performance
NHW-20 Prius(2004-2008): plastic case prismatic, 168cells 6.5Ah better performance than before
Highlander/RX400h:metal case prismatic, 240cells 6.5Ah better performance than before
Camry:metal case prismatic, 204cells 6.5Ah
GS450h/LS600h:metal case prismatic, 240cells 6.5Ah

The power and capacity become better to increase number of cells.

Ken@Japan

[Tideland Prius]

Originally Posted by bredekamp

Are the only differences between the HSD in the Highlander, Prius and Camry the ICE? I was just wondering if the larger engines in the other two also uses the Atkinson Cycle like in the Prius.

With the Highlander, Camry and Lexus Hybrids being newer than the Prius, did Toyota make any improvements to the HSD like weight reduction or performance enhancement? I know the Lexus and highlander have an extra motor in the rear. Are the HV battery capacities the same amongst these vehicles? Do they essentially use the same NiMH pack as the Prius?

So many questions....I can't even test drive one of Toyotas other hybrids cause they don't sell them here.

L4 = inline 4...easier to read than I4

Prius:
- 201.6V battery
- Max 500V
- 1NZ 1.5 litre DOHC VVT-i L4 on Atkinson cycle
- PSD

Camry Hybrid:
- battery is 288V (~ the same size as the Prius battery, maybe wider)
- Inverter ups it to 650V
- 2AZ 2.4 litre DOHC VVT-i L4 on Atkinson cycle
- PSD w/ reduction gear

HiHy:
- battery is 288V (flattest battery. It lies under the rear 2nd row seat and has 3 separate cooling fans/loops)
- Inverter steps it up to a max of 650V
- 3MZ 3.3 litre DOHC V6 VVT-i on Otto cycle
- CVT w/ reduction gear
- 4WD models have a rear elec. motor


As USBSeawolf said, check out HYBRID SYNERGY DRIVE for more details.