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-juice
MODERATOR /ADMINISTRATOR
Find me at kirstie_h@edmunds.com - or send a private message by clicking on my name.
2015 Kia Soul, 2021 Subaru Forester (kirstie_h), 2024 GMC Sierra 1500 (mr. kirstie_h)
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VW, Honda or Toyota are you listening!! I will put my name on the waiting list for the first automaker that introduces a turbodiesel hybrid! My dream car would either be a hybrid TDI Passat Wagon or a Hybrid diesel Accord wagon.(unlikely but this is only a dream)
And speaking of idle stop, would it be an issue with diesel-hybrid? BTW, the idle-stop feature in HAH has been extended to deceleration (under 10 mph to complete stop).
I realize diesel Semis idle at truck stops as they rarely turn off the engines, but a modern diesel can probably handle the on/off nature of a hybrid just fine once it warms up.
-juice
My name will be right behind yours. Add a medium sized PU to that mix. I'm with you on needing at least a station wagon. None of the sedans can handle all my luggage when my wife takes me to the airport.
To trigger auto-stop, you must come to a complete stop. In some traffic, that simply won't happen that often... or at all.
To make matters worse, some type of timing mechanism must be implemented to prevent the engine from shutting off when you actually still need it. That shortcoming reveals itself rather obviously with the Honda IMA. After coming out of auto-stop, it will not go back in unless your speed gets up to 10 MPH in the meantime. So the engine will continue to run even though you come to a complete stop afterward, which means there is very little benefit in some routine commute delays (like on-ramps & bridges) and drive-thrus.
And then you've got the problem of having to power belt-driven devices, like the A/C. Using it requires the engine to run, which prevents auto-stop from being available.
Factors like that are what make a "full" hybrid far more appealing. They offer the ability to send power to the wheels without needing the engine. The engine can shut off and remain off during slower driving (42 MPH for Prius, 25 MPH for Escape-Hybrid). So the potential for much greater savings is possible. Some (HSD Prius) don't rely on the engine at all to power the A/C, they use the battery-pack instead.
JOHN
How far will the Prius go at say 41 mph without the engine starting, when the battery is fully charged?
And regarding A/C, once again you’re incorrect. Accord Hybrid is utilizing a “hybrid powered” climate control system, which is supposed to allow idle stop and ac to run simultaneously.
Getting the detail about auto-stop on the circumstances of when and how often would be great!
Find out about the A/C would be nice too, but we'll have to patiently wait until about June 2005 before that will be realistic.
By the way, the "10 MPH" question was about the *SECOND* time auto-stop enages, not the first. Why must you acclerate to that speed before the engine shuts off again? Why isn't there a timer instead?
JOHN
Having driven the current generation ICE Civic for several years, I can tell you that the car doesn't need stability control. The Prius does, because it is built high, whereas the civic is built lower to the ground.
Take a look at the two side by side to see what I mean...
As far as the Hybrid Climate Control is concerned, during idle stop, it will be powered via the electrical system. Depending on the situation, it could also derive all or part of the power from gasoline and electrical system (or both at the same time).
Fukui is CEO for Honda and Takimoto is chief of Toyota's power train development in Japan .
The above quotes I got from yesterday's Wall Street Journal. Most major automakers are pursuing more efficient gasoline engines without resorting to expensive batteries or hybrid technology. In order to accomplish this efficiency they are focusing their endeavors on HCCI (homogenous-charge compression-ignition). I will not even attempt to explain HCCI because I am not a combustion engineer nor am I even going to pretend to be one. The following quote from WSJ.com describes HCCI:
"Mechanically, an HCCI engine, like a conventional gasoline engine, sends a finely balanced mixture of air and fuel to the cylinders. In a conventional gas engine, a spark plug ignites the air-fuel mixture to create power. But in an HCCI engine, the air-fuel mixture is compressed by the piston until rising heat inside the chamber ignites the mixture -- a process similar to that used in a diesel engine."
HCCI gasoline vehicles are suppose to accomplish the great mileage of diesels without high emission or nitrogen oxides
Hooray for the Audi A6 because it will be the first gasoline HCCI vehicle in N. America in 05.
In the long-run I believe Honda and Toyota may beat VW to the Holy Grail of selling vehicles with hybrid HCCI gasoline engines. I dont even think VW is seriously pursuing the hybid route.
And “most major automakers” would exclude…?
Speaking of HCCI engines, Honda has come up with its own version of DI engine that can go as lean as 65:1. This engine is being dubbed “i-VTEC I” and has been on sale in Japan for about a year in 2.0-liter form (“K20B”). I suspect, this (or a variation) could become the ICE in next Civic Hybrid. If there is anything that works against HCH at this time, it is the performance aspect. A more powerful engine that can promise at least as good fuel economy with IMA could address that.
And if Honda chooses to implement the autostop at less than 10 mph then who says the electric motor can't be used until it is restarted or more power is needed.
In the mild hybrid, power is not wasted from the ICE powering a generator whne it is not needed, like when the battery is fully charged.
The Full hybrid Prius is always turning a motor generator whether it is need or not. This takes away from the power of the ICE.
I think you should stick with providing information about the Prius instead of the HAH ,because you do not seem to fully understand the IMA and/or the HAH.
YMMV,
MidCow
___Not only do you not own an IMA based Hybrid, you know very little about the way Autostop works.
___Guys, the HCH and AH will autostop at 10 mph and below after an initial autostop but the Insight can autostop below 20. All 3 will have fuel cut at any speed once deceleration w/ regen begins until the ICE reaches 1,100 RPM at which time autostop is entered or fuel is allowed back to the cylinders for idle operation depending on your condition. Idle operation in an Insight 5-speed burns ~ .2 oz of fuel/minute
___The way to autostop without being forced via key in a 5-speed at any speed below 20 is to shift to 2nd and back to neutral. The only way to achieve mid 90 - low 100 mpg in an all-city stop and go environment is to use either this method or use the key. IMA starts the automobile the same whether it is from the key or from the ECU after an autostop if that helps.
___The way A/C Econ works in an IMA equipped hybrid (the AH is different given its electric and mechanical run compressor), the Insight and HCH will drop out the Compressor yet allow autostop and keep the fan running. You stay cool unless you are stuck at the light for more then 2 or 3 minutes at which time there is very little cooling left from the evap. coils. Full A/C mode will prevent Autostop which allows the HCH or Insight to idle with A/C continuing. After an autostop and the ICE is restarted, the compressor kicks back in and you again have full cooling. This mode of operation is not as comfortable as the Prius’ all-electric in a condition of > 2 or 3 minutes and high external ambient temps but it is much more efficient as it doesn’t matter where the power to run the compressor comes from, the power to run the compressor or charge the battery is a large drag on the ICE depending on HSD or IMA equipped hybrid.
___Wayne R. Gerdes
Why is it wasted? Electricity generated goes back out to the 50kW motor. It is functioning as eCVT. Sure there are some loss during conversion. But a full hybrid bypasses 15% energy loss at the torque converter of automatic transmission found in HAH.
"The Full hybrid Prius is always turning a motor generator whether it is need or not. This takes away from the power of the ICE."
It is always needed. Otherwise, there wouldn't be eCVT.
Dennis
HAH A/C can be powered by either gas engine or the HV battery for full blast, otherwise, you only get half load A/C. When is Honda going to stop adding more components and increase the complexity of the car? IMA is probably the most mechanically complex vehicle design there is.
Dennis
Sure it can stop. When will it need to restart again? A full hybrid can accelerate itself back up without the need to restart the ICE. A mildbrid can't do that. Prius has more than 6 times more powerful electric motors than electro-anemic HAH.
Dennis
Q1: Do “full hybrids” have 0% drive train loss? If no, what was your point?
Q2: What has torque converter got to do with mild hybrid?
When is Honda going to stop adding more components and increase the complexity of the car? IMA is probably the most mechanically complex vehicle design there is.
Yeah right! Explain.
Sure it can stop. When will it need to restart again?
Release the brakes and there you go!
A full hybrid can accelerate itself back up without the need to restart the ICE.
And the point is? That is the basic difference between a full hybrid and a mild hybrid! It is not a matter of establishing this is better than that.
Vehicles that sit higher off the ground need it more than others, but that’s not the end of it. Luxury badges offer it, perhaps because it becomes a part of the package. In case of Acura, all (but RSX) have VSA standard. In case of Honda, it is also standard in CR-V and Odyssey (optional in Pilot’s lower trim at this time). And speaking of RL, I was reading a road test (rather, a track test), in rain and being pushed to the limits. The interesting thing about it was that the VSA never triggered. The AWD system did the job.
Sometimes the “benefit” or “need” is defined by the vehicle itself. In case of Prius, Toyota chooses to load it up with gizmos to ensure more people opt for packages (hence extra cost to make $$$) but they get to advertise the vehicle with a much lower base price. This strategy is commonly seen in Toyota/Lexus lineup. Just go ahead and see what you get in a Lexus GS300 for $41K. I couldn’t see it as a luxury touring sedan without an extra expense of about $6K.
Sorry if you misinterpretted the response as personal.
I must've dropped 5 thread subscriptions for the same reason.
Please, I'm asking nicely, be the bigger person and quit arguing all the time.
People come to these threads to learn about the hybrids, not who knows the most about them. I really don't think anyone cares about that.
Thanks.
-juice
You should of read the message that I was referring to. Full hybrids have some loss due to electricity conversion when eCVT is in action, which is all the time. How much electricity is being generated varies from conditions.
"Q2: What has torque converter got to do with mild hybrid?"
Mildbrids do use automatic transmission with torque converter. HAH is an example.
"Yeah right! Explain."
Well let's see. IMA cars have about the same component as traditional cars. It doesn't have starter and alternator but instead ~10kW electric motor/generator. IMA requires complex(auto) traditional transmission to operate like regular cars. On top of that, IMA has battery, hybrid A/C component, VCM components, etc...
"And the point is? That is the basic difference between a full hybrid and a mild hybrid! It is not a matter of establishing this is better than that."
The point is the difference and that is why a full hybrid is better. The more frequent the gas engine is required to use, the more fuel it is going to use. Not to mention the noise and vibrations. A full hybrid can also capture more energy from regenerative braking due to the powerful electric generator.
Dennis
Dennis
I'm glad to see Honda some out with something with more of a performance bent.
-juice
Oh, I agree with that. My statement was about the need for VSC.
Dennis
The mild hybrids also seem to get much closer to the EPA estimates than the "full" hybrids.
Again I will state the current "full hybrid" has a gnerator that continually runs always drawing power from the ICE, even when the hybrid battery is fully charged. This is a waste of energy, because there is aways a loss during conversion from one energy form to another. Mild hybrids sucah as the Honda Accord Hybrid do not have this problem nd are more efficinet on the highway. You will not that the EPA estimates are 30 for City and 37 for Highway. 37 is seven higher than 30.
On the other hand the current Prius has estimates of 60 city and 51 highway. When you subtract 51 from 60 you get a minus 9. The new Lexus RX400H is rate at 36/30 for a minus 6.
Maybe the full hybrid is for city only commuters, soccer moms or for retired folks to get back and forth to their motor homes. But it sounds like the HAH is ideal for a larger population of commuters that travel 15-20+ miles on the highway.
Your hypothesis is that the full hybrid is so much better than the mild hybrid because it has a planetary gear instead of a transmission and is less complicated.
My hypothesis is that the mild hybrid is better than the full hybrid, because it gets better highwya mileage than city mileage and better utilizes the Hybrid generator.
YMMV,
MidCow
YMMV,
MidCow
Mildbrids do use automatic transmission with torque converter. HAH is an example.
My question wasn’t about what HAH uses. It could as well be a fullbrid. HAH could have as well used Antonov 6-speed automatic (doesn’t have a torque converter), and if it did, what would be your argument then? Honda has been fiddling with the 6-speed transmission for couple of years now, but perhaps “the time” isn’t here yet.
IMA requires complex(auto) traditional transmission to operate like regular cars.
I didn’t know regular cars had that much complexity! Haven’t we learned from the “simple” technologies that have been around for decades? ;-)
BTW, you can keep your eCVT around. I’m glad Honda isn’t offering something similar with the Accord, or even a regular CVT. I would had preferred to see 6-speed manual transmission though.
There is nothing that stops IMA implementation with a choice of transmission! That’s not its weakness, the flexibility is its strength! Honda could throw in a planetary gearset based 6-8 speed Antonov automatic, a 6-7 speed ZF Clutchless Manual, a “run of the mill” automatic transmission, a slick shifting 5 or 6 speed manual. No limits that the key! IMA isn’t designed around a transmission, you should realize that.
On top of that, IMA has battery, hybrid A/C component, VCM components, etc...
You forgot seats, wheels, radio, power locks, power windows :-)
Which of the things, that you mention are part of the basic design of an IMA? If we were to go by your rules, center pod would become a must have with a fullbrid design!
The point is the difference and that is why a full hybrid is better.
Difference in the way things are supposed to work don’t make them better or worse. Get over this notion. I’ve mentioned this umpteen times realistic designs are full of compromises. You pick the lesser of the evils, and as long as the package delivers, what would be the problem?
A full hybrid can also capture more energy from regenerative braking due to the powerful electric generator.
It needs more energy to start with! But, that said, where do you get your numbers?
Better than what? ICE only car? Maybe with VCM. HCH CVT EPA Highway is 47 mpg. Larger mid-size Prius EPA Highway is 51 mpg. It was also proven the other way around. Full hybrids can get better mpg in the city over HCH with IMA for obvious reasons.
"Again I will state the current "full hybrid" has a gnerator that continually runs always drawing power from the ICE, even when the hybrid battery is fully charged."
It is called eCVT in action. Also note that, only partial power got split to generate electricity. Majority of ICE power go to the wheels.
"EPA estimates are 30 for City and 37 for Highway."
From analysis above of HCH vs. Prius, V6 270hp Camry full hybrid should get more than 40mpg on highway then. You just can't accept the fact that mildbrids "suck" at city driving. Think back where your thinking went wrong.
"My hypothesis is that the mild hybrid is better than the full hybrid, because it gets better highway mileage than city mileage and better utilizes the Hybrid generator."
Only that full hybrid highway mileage is higher than comparable mildbrid highway mileage.
Dennis
Actually there is evidence on each side of this point, e.g.
http://motortrend.com/roadtests/alternative/112_0405_hybrid/index- 9.html
Note that in MT's "Real-World Hybrid Fuel Economy Test", they saw the following for highway fuel economy:
HCH: EPA 47, MT test 49.8 (ratio 1.06)
Prius: EPA 51, MT test 53.8 (ratio 1.05)
So in this test that simulates real-world driving conditions, not only does the heavier HSD vehicle with the larger ICE engine get higher highway fuel economy than the IMA vehicle, but the closeness to EPA estimates is about the same.
I find it ironic because I feel the same way. Isn't it funny? ;-D
"HAH could have as well used Antonov 6-speed automatic (doesn’t have a torque converter), and if it did, what would be your argument then?"
It wasn't even an argument at all. Midcow had a misconception of how HSD loose efficiency due to converting energy, blah blah. I pointed out efficiency loss of HAH's torque converter(which Prius does not have) to make him see the overall picture. That's when you jump in and tried to "balance" things out.
"There is nothing that stops IMA implementation with a choice of transmission! That’s not its weakness, the flexibility is its strength!"
I see it differently. Transmission was invented to overcome inability of the ICE to deliver power effectively. Since today powertrain(HSD) can substain power output for every driving situations, there isn't a need for shifting/slipping gear transmission. You can say, getting rid of the middle man. When all things being equal, the simplier design wins.
BTW, there is nothing stopping HSD from putting the middle man(transmission) in between. It just wouldn't make sense. If you can walk with your two legs, would you need another two? They would create more problems.
Dennis
I acknowledge that. It's easy to "mild" things out by saying generally agreeable statements. The original discussion was about auto-stop feature and how it affect fuel economy. By looking at the results(ignoring the differences in design), you tell, which get better mileage in the city? Full or mild hybrid?
"It needs more energy to start with! But, that said, where do you get your numbers?"
Arrr... Well.... Let's see.... hmmm..... Prius has 50kW + ~29kW electric motors...... Accord has 12kW electric motor...... Which can capture more energy during braking?
Dennis
It is not ironic, because I did mention it, that I end up putting arguments to balance it out.
I pointed out efficiency loss of HAH's torque converter (which Prius does not have) to make him see the overall picture.
I would disagree with you right there that you somehow manage to provide the “overall picture”. That being said, you continued to mention “IMA” not HAH in specific, or somehow that IMA “requires” everything that HAH has. Regardless, the point should be about losses in general and that they are a part of the real world. Midcow was pointing at your arguments that somehow HSD is out of the world. Remember, I too construed your point as somehow suggesting that HSD resulted in 0% loss.
Either you’re not doing a good job in providing a good perspective, or we’re not getting “the whole picture”.
I see it differently. Transmission was invented to overcome inability of the ICE to deliver power effectively.
No. Transmission (as the name suggests) was invented to “transmit” the output from an engine (doesn’t have to be ICE) to the wheels. So, your assumption that forms the basis for your argument is wrong to start with.
BTW, there is nothing stopping HSD from putting the middle man(transmission) in between. It just wouldn't make sense.
“eCVT” is the middle man. Are you aware of what a “Control System” means?
By looking at the results (ignoring the differences in design), you tell, which get better mileage in the city? Full or mild hybrid?
If you ignored the differences in design, Insight is the best hybrid money can buy today.
But if you don’t ignore the design, and as far as mileage/cost/weight/flexibility is concerned, we shall see when a full hybrid comparable to mild hybrid like HAH comes around. HCH is due for revision anyway!
Arrr... Well.... Let's see.... hmmm..... Prius has 50kW + ~29kW electric motors...... Accord has 12kW electric motor...... Which can capture more energy during braking?
I have not measured it, or read about it. Have you? That said, which of the two would need more energy? A 12kW electric motor in a mild hybrid, or a 79 kW electric motor in a full hybrid?
I mentioned the battery which IMA requires. I mentioned hybrid A/C which is a requirement for auto-stop feature without compromise. I mentioned VCM because HAH implement it to gain more efficiency on highway to stay competitive. I know VCM is not IMA exclusive feature.
Seats, power windows, and other stuffs are things that you added and ended up putting your words in my mouth.
"Midcow was pointing at your arguments that somehow HSD is out of the world. Remember, I too construed your point as somehow suggesting that HSD resulted in 0% loss."
I never stated that HSD has 0% loss in efficiency. In fact, the most energy Prius can extract from the gasoline to the wheel is 37%. What I was pointing out was the misconception that HSD Prius gets lower highway mileage than comparable IMA mildbrid.
"Either you’re not doing a good job in providing a good perspective, or we’re not getting “the whole picture”."
So, are you now claiming to have "the whole picture" or provide a good perspective or both then?
"Transmission (as the name suggests) was invented to “transmit” the output from an engine (doesn’t have to be ICE) to the wheels."
I would add, it was invented to transmit in a way that would best suited for the driving condition. It is like a black box. You provide input to transmission and it spits the result you want back out. HSD can spit out the right results from the powertrain. So, why do you need a black box?
"Are you aware of what a “Control System” means?"
Please provide detail. I don't understand the term that you are using.
"If you ignored the differences in design, Insight is the best hybrid money can buy today."
Good lord. Comparable car size with different design. If you don't want to say it, don't. I don't want to beat a dead horse.
"....which of the two would need more energy?"
What does it got to do with capturing energy from braking? Which has larger battery to store the captured energy? is a better question.
Dennis
What are we trying to determine here?
The other is the difference in hybrid design where one design resulted in simplicity. HSD does not need a complex mechanical exterior transmission while IMA depends on traditional approach. The way I see is that simplicity win. The other see the complicated traditional approach is better because it is the traditional way.
Another issue is "which grass is greener" argument. I feel I am being fair and correcting other's bias arguments. Others feel they have the wider vision and they are the balance one. After all, it is the fuel that keep the discussion going.
Dennis
Whether it can be decided that it is "less fuel efficient" on the hwy is a good argument though.
Is there any other vehicle on the road besides the Prius II that claims higher city EPA than hwy EPA? Does anyone know?
Not really. It could be ultra capacitor pack could replace battery pack (like I mentioned a while ago, UC characteristics bode well with a mild hybrid set up), or simply use any method that allows storage of energy that electric motor could use. But, I have to understand why you brought this up in the first place. HSD doesn’t need batteries? I thought it needed more of them.
I mentioned hybrid A/C which is a requirement for auto-stop feature without compromise.
Not really. For an additional few pounds or so, it should be possible to carry an onboard generator for the purpose eliminating the need for gasoline engine to act as a generator.
I mentioned VCM because HAH implement it to gain more efficiency on highway to stay competitive. I know VCM is not IMA exclusive feature.
So, now you realize it is not an IMA exclusive feature. But speaking of VCM, IMA set up actually goes a little further in taking advantage of VCM’s promises. Under light throttle acceleration, HAH continues to run in 3-cylinder mode with assist coming from electric motor. Without IMA, the all six cylinders will execute.
Seats, power windows, and other stuffs are things that you added and ended up putting your words in my mouth.
Yep. Just to demonstrate the way you were heading.
I never stated that HSD has 0% loss in efficiency.
I know you didn’t. But when was the last time you actually talked about “any” loss in efficiency from HSD?
I would add, it was invented to transmit in a way that would best suited for the driving condition. It is like a black box.
Not really. It is an open book. Quite simple actually, and used for decades, and will continue to be.
Please provide detail. I don't understand the term that you are using.
I don’t have time for providing detail on “control systems”. But briefly., it is a simple term used to imply how you control the logic, to get the job done. And believe me, there isn’t just one way, or one perfect way of doing it.
What does it got to do with capturing energy from braking? Which has larger battery to store the captured energy? is a better question.
To answer your “better question”, why does one use a larger battery? This is like asking why does Suburban use a larger gas tank, isn’t it?
"Is there any other vehicle on the road besides the Prius II that claims higher city EPA than hwy EPA?"
Ford Escape Hybird.
Dennis
OK, but if the design is not important at all, WHY do the full hybrids get lower MPG on the highway?
Is the answer not this>>>>???:
Because the electric assist motor is used FAR LESS on the hwy than in the City.
Is that not the reason?
I brought it up to compare complexity of IMA mildbrid vs. ICE only car. HSD need electric storage device too but lacks transmission so, they cancel out. NiMH battery(current implementation) is maintenance free which transmission isn't. So, it is not really an equal cancellation.
"So, now you realize it is not an IMA exclusive feature."
Yup. HAH will have about extra 15hp before all six cylinders need to fire up. I wonder how much it helps for the 3500+lbs car. Wouldn't you say a more powerful electric assist would further complement the VCM?
"when was the last time you actually talked about “any” loss in efficiency from HSD?"
Check msg#800 on this board.
"it is a simple term used to imply how you control the logic, to get the job done."
And how is that, a full hybrid have the "Control System" and a mildbrid doesn't?
Dennis
In addition to utilizing the best qualities of the gasoline engine and the electric motor, hybrid vehicles also use a feature called regenerative braking to further improve fuel economy. In regenerative braking, when the vehicle's brakes are applied or when it is coasting, the electric motor becomes a generator and captures the energy that would be lost as heat through the brakes. Once the energy is captured, it is transformed into usable electricity, which recharges the batteries and in turn increases the number of miles that can be traveled per gallon of gasoline. This is the reason that the city fuel economy sees an even greater improvement than highway fuel economy in hybrid vehicles.
Yes. Also, you forgot the wind and tire resistence which increases greatly as speed increases.
"WHY do the full hybrids get lower MPG on the highway?"
Because of higher drag and resistences on highway! Highway = High speed. In another word, environment factors pull the MPG down. Prius loose about 15% MPG due to higher speed. Wouldn't you say it is impressive?
Dennis