GM's hybrids better than Toyota?
Michelle Krebs says two modes are better than one, but where is her proof?Recently, GM sponsored an event for a few journalists to check out their new Tahoe hybrid. More important, it was a chance for journalists to check out the new hybrid powertrain that was co-developed by GM, Chrysler and BMW - a collaboration which Krebs calls "unprecedented" (read more from Krebs).
Additionally, Krebs insists that the two-mode hybrid is superior to, for example, Toyota's single mode hybrid powertrain because it has a bigger "toolbox" to control fuel efficiency optimization. As a result, the two-mode hybrid achieves about a 25 percent overall improvement in fuel economy.
Talk, talk, talk.
I say, settle down Mrs. Krebs. First, a 25 percent improvement in fuel economy is in the same league as other hybrid cars. Second, while the two-mode hybrid ...(Finish GM's hybrids better than Toyota?)
Labels: GM, hybrid cars, tahoe hybrid, yukon hybrid
posted by Dahcredyns at
6:31 AM
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Recently, GM sponsored an event for a few journalists to check out their new Tahoe hybrid. More important, it was a chance for journalists to check out the new hybrid powertrain that was co-developed by GM, Chrysler and BMW - a collaboration which Krebs calls "unprecedented" (read more from Krebs).
Additionally, Krebs insists that the two-mode hybrid is superior to, for example, Toyota's single mode hybrid powertrain because it has a bigger "toolbox" to control fuel efficiency optimization. As a result, the two-mode hybrid achieves about a 25 percent overall improvement in fuel economy.
Talk, talk, talk.
I say, settle down Mrs. Krebs. First, a 25 percent improvement in fuel economy is in the same league as other hybrid cars. Second, while the two-mode hybrid might offer an advantage at highway driving and in towing conditions, Toyota's single-mode hybrids might offer an advantage in congestion or city driving - a bigger toolbox doesn't always mean better. Third, the price difference for GM's dual mode hybrids is expected to be pretty significant, possibly as much as $10,000 according to Krebs. Fourth, let's actually wait until some dual mode hybrids are on the road, driven by consumers, before we hand the king of hybrid technology award to Detroit.
Also, it is very interesting to note that GM's dual mode hybrids are not really a step towards the Chevy Volt and its series hybrid technology. So, if the Chevy Volt succeeds - and the e Flex drive - what happens to the dual mode hybrid drive? This makes one wonder, can the dual mode hybrid powertrain, like the Hybrid Synergy Drive, evolve into a fuel cell powertrain, for example? If so, why is GM also working on the E-Flex drive? Is the dual mode powertrain really just in interim technology to the Volt and the E-Flex drive? Wouldn't consolidation of two hybrid drives into one hybrid drive offer better economies of scale and, thus, cheaper costs?
We're all excited about full hybrid vehicles coming out of Detroit, but let's maintain a little objectivity. GM also claims the Aura 'mild' hybrid is a better deal than the Toyota Prius, so just because GM says they are the best doesn't necessarily make it so - no matter how much their advertising is worth to Edmunds.
Hi:
Have you really done your homework?
Our training group at our local college just completed preparing a course for technicians on hybrid powertrains, and it was a very interesting assignment.
During the process we encountered numerous pro-Toyota folks that made comments that sounded good to the uninformed, but technically were not accurate.
Even your own comment of waiting for Two-mode to hit the road was off, as two mode hit the road a few years ago. GM owns Allison, did you forget about that? GM's position was to start with the worst offenders first- city buses- compare little cars driven for a hour to work vs. huge city buses driven for 16 hours a day in stop and go operations.
I realize it's popular to hit GM and say "Go Toyota"... but we're not talking sports here... it's pure technology... science. And from that perspective TWO-Mode is better, and I will give you very quick illustration as to why.
Hybrid vehicles combine (or 'synergize" 'if you wish) two types of torque. Traditional mechanical transmission of torque via gears where engine torque is multiplied through gearing. It takes energy to turn those gears, so overall the mechanical transfer of torque is about 90% efficient.
The other type of torque is 'electromechanical' torque where the gas engine turns a generator that converts that to electricity then it is sent by wire to an electric motor that ‘reassembles’ the torque into mechanical torque to turn the wheels. Electromechanical torque is about 70% efficient. This begs a couple of questions… Why do it? Or Hybrids, use EM torque and are better on fuel – explain that. You see having an electric form of propulsion increases the powertrain’s ‘versatility’ vs. straight efficiency. Because we constantly accelerate and slow down, and go up and down hills, the hybrid EM torque technology can use regenerative braking to reclaim energy- conventional technology can’t.
Plus, the other consideration, is that electric motors make lots of torque from zero rpm, but then starts to produce less as rpm’s increase, gas engines are the opposite. Let the electric motors help or even do all of the off the line acceleration and bring in the gas once the vehicle is in motion.
Okay let me puts this altogether for you.
Toyota synergy does have an Achilles’ heal in that from a mechanical transmission of torque it only has ‘one speed’ or range. This one ratio is supported by one, sometimes even two more sources of EM torque via the electric motors. Think of it this way, instead of having multiple speeds like a conventional car, the Toyota Hybrid system utilizes multiple paths of torque. BUT here’s the key. 28% of the torque is mechanical and 72% is EM, think about 70/90 rule. The GM TWO-mode system offers all of Toyota’s EM torque advantages, plus three more speeds mechanically, PLUS the EM torque can be blended and multiplied through transmission gearing something Toyota doesn’t really do.
The Toyota Hybrid system is wonderful technology, and it is made Toyota perfect in terms of reliability. I am not bashing them, I am just being objective here the technology itself has ‘no emotions’ if you know what I mean.
Let me give you a challenge… Pretend you’re going up a long mountain hill in your Toyota Hybrid- the HV battery is only good for a few miles before it needs recharging, now to maintain speed the gas engine must now increase rpm to increase the generator’s ability to power the electric motor that is providing MOST of the torque. Fuel economy goes down considerably. In a GM two mode system, there are four mechanical ranges (90% efficient – especially at highway speeds in overdrive) plus two ranges of EM torque. The motor can run at relaxed pace, and utilize the 90% efficiency… yes there really are more ‘tools’ in the tool box.
In a consumer’s report study on real world fuel economy they found that the Toyota hybrids had the biggest discrepancy between posted highway fuel economy vs. actual. The EPA addressed this for 2008 by completely redoing their test procedures – this is no small thing- this is the FIRST adjustment to the actual procedure since the start in 1973. Anyways, I am out of time, for now.
Take care,
Hope that makes things more clear.
HD
Hardy,
There is a huge difference between a dual mode hybrid powertrain in a bus and a car or SUV. Hybrid buses don't give most consumers a chance to act more responsibly.
While it's great that GM has created dual mode hybrid buses - something I've wrote about, it doesn't help consumers, and consumers need to take a role in fighting things like foreign oil dependency and global warming.
I agree that the dual mode hybrid powertrain offers advantages on the highway, however, I do not agree that dual mode hybrids match the hybrid synergy drive in congestion.
More important, however, is the cost-feasibility of the technologies in question.
GM's dual mode hybrids are only being developed for large vehicles and there has been concern as to how cost-effective a dual mode hybrid powertrain is in smaller car, such as the size of a Prius.
Already the Malibu hybrid has been delayed and that is larger than a Prius.
Perhaps you look at the world too mechanically. Great technology is great, such as GM's fuel cell vehicles, but they are far too expensive for today.
Similarly, there are still serious questions about the costs of GM's dual mode hybrids, thus I've said talk, talk, talk.
It just doesn't matter until GM's hybrids hit the road - not just in terms of fuel efficiency, performance, etc, but in terms of consumer demand.
In sales, the costs of technology are also extremely important. Most consumers really aren't too focused on torque when buying a vehicle.
Does that make things more clear?
BTW - The Consumer Reports study you note also found some of the biggest overall differences in stated and real world mileage in large trucks and SUVs during city driving.
As congestion is becoming more and more the norm, I take that more seriously than highway fuel economy - its the future.
Besides how can you blame Toyota for the EPA - it's largely been the Big 3 that have stopped any changes to the EPA's testing.
I am looking forward to GM's hybrid technology specifically because they have elected to go to the big vehicles. We have a horse trailer and need the power! So, we currently own a big SUV for that task. But, we also own hybrids.
I own a Toyota Highlander Hybrid and my wife drives a Prius, both purchased in mid 2006. We live in Upstate NY, in a very hilly area. Lots of stop and go, mixed with about 25% highway miles. Typical results: Highlander: 25-27 mpg back and forth to work (short drive: 5 miles one way, over very big hills), 27-30 mpg when taken on long hauls. Prius: 44-47 mpg on 20-25 mile trips into nearby city each day. On long trips, I have achieved 55+mpg
Give me the Highlanders numbers (or close to it) with a Tahoe and I'm sold! I think its worth the premium because $4 a gallon gas is right around the corner!
BTW, the Highlander has 27,000 miles and has only required oil changes and tire rotations. Same with the Prius, which has 17,000.
I know this was a bit off topic, but I wanted to underscore how the Toyota technology is really making a difference!
Prius is a total waste of money and horrible for the US and bad for the air as well. Hands the technology is a BUZZ and on the highway you will get plenty of BUZZ.
In 10 years it will save you 2000 dollars in fuel over 35-MPG ford focus, or Honda civic or any other good small car. You can get a ford focus used for like 6k too???
AT 30k new price where 90% of the money goes to a country that is not US does not re-invest any money back to the USA. The Adverts are very deceptive that Toyota launches to trick people saying there cars are made in the USA where only 1000 dollars per car goes back into our economy. This causes the US to become DUMB and turn our society to basic assemblers who do not produce or engineer and basically is hurting us, just look at the economy now. So people are selling out on their country to be in style that’s horrible.
To build one new car a huge amount of energy is wasted natural resources are depleted causing major amount of green to be lost.
Keeping your old car is much better for the environment.
Henry fords wife drove an all-electric car the 1918 Detroit electric used no gas at all and went 40 miles on a charge. So much for Prius being advanced.
So there you have it this Wonder Car the Prius is causing a huge amount of damage.
I am waiting for the GM volt.
Personally I think that those of you who are always praising Toyota and always _______ on GM Need to get in a row boat and go to Japan!
Hardy,
Prius actually has ECVT (Electronically controlled continuously variable transmission). Google for CVT to better understand how it works. Despite of the many disadvantages of the early CVTs the two advantages are (as described in wikipedia.org):
- CVTs can compensate for changing vehicle speeds, allowing the engine speed to remain at its level of peak efficiency. This improves fuel economy and by effect, exhaust emissions.
- CVTs operate smoothly since there are no gear changes which cause sudden jerks.
Regards,
Ivm
my name is thomas and i actually work for a mobile marketing company traveling around the country in all three models offered as hybrids from toyota and over the 14 months of driving each i was able to exceed the 06 posted numbers listed from the epa... inflated tires and braking early will increase mpg greatly... a clean air filter helps as well- you might not know this but ford pays toyota royalties to toyota on each hybrid they sell and nissan actually uses toyota components under the hood of their hybrids... if you can't beat them join the... the partnership of bmw, dodge and gm was an effort to band together in a fight all three has been losing for years... but in the same breath the more hybrids on the road= less co2 so the more the better....
Lets just dump this gorebull warming crap right now. GW is nothing more that a scam and mother nature is proving it by lowering the global temperature sense 1998. Evening mentioning it will dilute any credibility to anything else you might say.
But reducing or dependency on foreign oil is a good plan and we should follow all options from drilling here to increasing the MPG of the vehicles we need in our lives. SUV's are the most practical vehicle for the suburban American family. SUV's are not going away and I consider a jump from 15mpg to 20mpg a major improvement. It's looks like GM has been thinking about better milage, they are just a little slow.
Anon-
GW is a fact. Please. If you want to argue that it isn't caused by man, you can make that argument, but, overall, the last several hundred years have demonstrated that the planet has warmed. In fact, even those in your camp typically accept that global warming is real. in fact, they are now claiming it helped prevent a mini ice age.
Hardy-
That dual mode hybrid powertrain is really kicking ass in the real world. I think my comments proved much more accurate than yours.
I guess that finally clears things up.
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