Are All Hybrids Created Equally

i thought the prius had the ability to make the car move using either the gas
or electric, or both at the same time. the honda could not do this.

 

You asked a big question. I am sure someone will give you very lengthy answers.
In short, Toyota's HSD is a parallel hybrid (or full hybrid). Both electric and ICE can drive the vehicle separately or together. It is more complex, therefore high cost in producing.
Honda's hybrid system is the so called mild hybrid, which is less complex and less cost in producing. To me it is engineering trade-off really. You may think of Honda's hybrid system as a supercharger (thru electric motor) attached to the drive shaft. It can start engine or assist acceleration. Honda claims that the new IMA (as they call it) can run on pure electric mode also.
However, most owners rarely see it happens. In really world, Honda's IMA is not as efficient as Toyota HSD. However, don't forget to factor in the fact that Honda's IMA is cheaper to produce.
In short, with IMA, you get 80% of HSD at 60% of the cost (roughly speak).
Honda claim to be able to reduce IMA cost to $1800 very soon, in comparison, HSD carries a premium of about $3000-4500. I am sure Toyota is working on cost cutting as well.
Competition is good for all.

 

I think not (they aren't the same)
Prius is design groud-up as Hybrid.... everything works in great harmony....it can P&G by Electric for great distance during city drive (while putting engine to rest)

While most other Hybrid (Camery/ Civic /Accord) I belive adopt/add-on Hybrid technolgy on top on oridnary design... which doesn't work as efficent / as intergrated nicely as Prius... which result less MPG.

In Civic case....it was a very fuel-efficient car as is ...adding Hybrid system to a civic helps adding few more miles to the gallon.. but still not as efficient as Prius.

 

Why yes, all hybrids are equally created: none of them evolved :_>

But were they are all created equal? No: Toyota's system has no clutch or fluid drive components, and has proven to be highly reliable and allow excellent fuel economy. Honda's hybrids use a conventional transmission and do not offer as-good economy. Ford's hybrids were developed independently but are very similar to Toyota's. Nissan's hybrids are identical to Toyota's because they licensed the design and (I think) buy the same parts.

 

If you want the best fuel economy find a Honda Insight. Last year in the rally one got 80mpg. I don't have this year's results but the Insight's display was reading 100mpg. The Prius' MFDs were showing in the 60's.

 

If you want the best fuel economy find a Honda Insight.

as always there is so many options to consider why buying a car. i thought the honda
insight was too small for my needs, the hybrid camry to large, and the prius just right.
i was willing to sacrifice some things for others...

i really like the insight... but boy is that a small car in my opinion. i see two in nashua
on a regular basis but never had the pleasure to drive one. just judging from the outside
looking in.

 

The Honda Civic hybrid is priced about the same as the Prius--$24K MSRP.
Maybe Honda has some other smaller models that might be cheaper in the future, but the Civic is priced about the same as the Prius right now. You can bet that Toyota is aggressively pursuing a hybrid model line that will be competitive with anybody.

 

They are definitely not ALL created equally. Off the top of my head, we've got:
- series/parallel full hybrids such as those in HSD (in the current Prius) and THS - TOYOTA: Company > Technology
- parallel full hybrids such as Honda's IMA - Honda Worldwide | Technology Picture Book | IMA
- parallel BAS (belted-alternator-starter) mild hybrids Belt Alternator Starter (BAS - Wikicars)
- two mode hybrids - GM is shipping this right now in the form of the ~20 mpg Yukon and Tahoe hybrids

Nissan's Altima Hybrid uses technology and components from Toyota and apparently is very similar to what's in the HyCam (except that the rest of the car other than the hybrid components is from Nissan).

I wouldn't call IMA a mild hybrid. Mild hybrid would be the BAS systems used in the cheaper GM vehicles.

You can see a review of the Aura "Green Line" mild hybrid vs. the NAH vs. the HyCam at 2007 Hybrid Sedan Comparison Test. I esp. like their quotes:

"The Aura's electric motor is used to start the gasoline engine and can add small amounts of power under high-load conditions. Both the electric motor and gasoline engine, which are coupled in a fixed ratio, drive a conventional four-speed automatic transmission. Like the Camry and Altima, the gasoline engine shuts off under certain conditions and the electric motor restarts it. But with far less electric power than the Toyota and Nissan, the Saturn offers full electric propulsion only up to about 3 mph. Consequently, the gasoline engine is forced to do most of the work."
"the Saturn Aura Hybrid feels like a weak four-cylinder car that gets crappy mileage. (Over the 50-mile city route I averaged 19 mpg.)"

 

The following "for dummy" documents were created to provide overviews...

.

.

Links to each for downloading are available on my homepage.

 

Hi Ct..,

The Prius HSD transmission concept is kinda like an electric torque converter. At low speeds the MG1 (MG stands for Motor Generator) overspeeds, generates electricity, which is then fed to MG2. This possible due to the planetary gearset (or PSD - power sharing device) that couples the engine and two motors all the time.

MG2 is geared to the wheels and spins in a direct ratio of the wheel rpm. Consequently MG2 is a large motor, with lots of torque capacity. Which is what the extra electricity from MG1 is used for. This is a series/parallel hybrid mode.

There are no clutches (bands in automatic transmission parlance) in the Prius/HSD transmission. These are the main things that wear out in conventional automatic transmissions. So the Prius transmission can last a long time. Non-HSD hybrids such as the Hybrid Civic, and the GM hybrids - both BAS and 2-mode use conventional automatic and manual transmission clutches, which will wear out in the usual manner.

With that basic setup, there are all sorts of other modes the transmission can run in. Below 41 mph, MG1 can be stationary, the engine off, and MG2 turn by itself. If battery power is fed to MG2, the car is effectively an EV. If not, the car can effectively coast, and since there are no clutches, the car can coast - in gear.

During braking MG2 is used as a generator, and recharges the battery. And in reverse, the drive signals to MG2 are just run backwards - no gear changing needed. The car is always in the same gear, all the time.

At highway speeds the car runs in a parallel hybrid mode. Most of the engine torque goes right to the wheels, but the either MG1, or MG2 may be used to peak the torqure, depending on the the actual speed and torque requirement. This is why the Prius does better on the highway than other cars with similar sized engines (yaris, fit, versa), and similar to the Honda Civic Hybrid - which is a parallel hybrid car).

Additionally, the car can run down the road, with the engine torque split to the wheels and MG1, and MG2 doing very little. The electricity generated by MG1 is then used to recharge the battery, if the battery is lower than the nominal state of charge. In suburban secondary street driving, the car varies back and forth between this mode, EV mode and coasting. The engine is off in the EV mode and when coasting. Consequently the engine is used mostly at output levels where its efficient and otherwise its turned off.

The HSD transmission runs the engine up to 1000 RPM before its started, so there is no need for another starter. And the MG1 charges the hybrid battery. And the hybrid battery drives a personal computer style switching power supply for 12 V power - so no alternator is needed either.

 

Don't know why I'm feeling so pedantic today, but with the engine off if MG2 is turning, MG1 is turning in opposition - it's just not contributing any torque. Look at a PSD simulator to see this. This is why you can't dinghy-tow a prius - you'll overspeed MG1 above 42 MPH.

 

Hi Again Ct...,

The Honda IMA hybrid system is a pure parallel hybrid system. It has a motor that is mounted between the clutch and transmission. When the clutch is closed, engine is spinning, it can add torque to drive the wheels. When the clutch is open, or closed, it can take torque and charge the battery (regenerative braking), or provide slow speed EV action. The motor is similar in power to the MG1 in the Prius, or about 1/3 the size of MG2 in the Prius. The Honda achieves good mileage performance with a 1.3 liter engine, and the hybrid system, but the car is not as quick as the Prius (14-15 seconds, versus 10.5 for the Prius to 60). To match the Prius they would need a bigger battery and motor. The Honda Civic has very good highway cruising mileage.

The first generation Honda Civic could not drive the car by electric alone. The second generation can run the car around in parking lots on electric only, but not up to roadway speeds. The IMA motor is used to start the engine.

 

Oops. You are right. I was thinking, but not typing, "with the engine stationary, and MG1 deenergized".

The PSD simulator only shows the first generation Prius setup. The second generation Prius has a MG1 max RPM of 10000 rpm, not 6000. This alows coasting up over 42 mph (but less than 60 mph!) with the engine off, if one shifts into neutral at the top of a hill in a glide.

 

You only get Toyota reliability from 1 manufacturer, can you guess which one?
This also applies to hybrids.
No other manufacturer has built a car which is designed from a blank sheet as a hybrid.
I believe Nissan use Toyota's hybrid technology, unfortunately it is wrapped in a Nissan.

 

I'll take Nissan's stylists every day of the week.

 

My sympathy to you and your family.

 

I have nothing new to add to descriptions already given, but I do have a RANT:
It bugs me when people describe the Toyota HSD as "complex". Sure, the software is complex, but software doesn't rust. There is complex electronics, but car-oriented people don't appreciate that electronic complexity is DIFFERENT. The HSD is nowhere near as complex as the GPS positioning system sitting on their dash, but people don't thing about that because the complexity is contained on two or three chips. I view the HSD complexity as being about the same as ABS braking systems, and people have gotten used to those systems. Mechanically, the planetary gearset is so much simpler than a conventional automatic transmission that it should be viewed as a potential cost-saver. As someone has already said: no belts, no clutches, no bands, no vacuum lines, etc. As soon as battery prices go down hybrids will be cheaper than regular cars...

 

That used to bug me too. But then it became clear that they either had no idea what they were talking about or they were intentionally attempting to mislead.

It doesn't take much study of the design to see that it isn't actually that "complex". In fact, it is simplier than the typical automatic transmission.

.

 

Doesn't civic hybrid use a CVT tranny also?