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How do Hybrids work? Newbie questions encouraged! - READ ONLY

139 messages,  Last post on Aug 02, 2007 at 5:38 PM

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#117 of 139
Re: MG1 spins needlessly ?? [midnightcowboy] by usbseawolf2000
Mar 28, 2006 (6:54 pm)

Replying to: midnightcowboy (Oct 27, 2005 7:47 am)

"Why in the world would someone design something where the ICE power is converted into electrical power of the MG1 which is immediately converted into supply power for the MG2. Then the MG2 acts as a motor further converting power with additional energy loss. Why not use the power directly from the ICE? Double and triple conversion of energy is just not an efficient design."
 
Why? Because that's the basic principle of E-CVT. Yes, that's how HSD transmission works in a nutshell. The ICE make only 82 lbs-ft torque. It does not produce enough twisting power to properly accelerate the Prius. This situation prevents the ICE from making it's maximum power since it can't rev the RPM fast enough (already too hard to twist).
 
So what does it do? The Power Split Device comes to the rescue. It spins the MG1 so fast that it generates electricity. This allows ICE to make maximum (or necessary) power while MG1 steals away that energy. MG1 generating electricity and supplying it to MG2 creates massive (295 lbs-ft) torque -- equivalent of 1st gear. Now, all the power of ICE is going out to the wheel.
 
E-CVT stands for electrically controlled variable transmission. How does it control electrically? Well, it depends on the speed of MG1 -- how much electricity it generates. If you stop the MG1, you loose the control and it can't be variable anymore. You might as well call it E-NCST (Electrically Not Controlled Static Transmission).
 
----------------------------------------------------
"In my higher math, before calculus of several variables, I thought that 66 was greater than 51."
 
You do not need Calculus for this, just Arithmetic and Common-sense. You are comparing 1.0 liter Insight ICE to 1.5 liter Prius ICE. Why don't you look at the Civic Hybrid 1.3 liter highway 47 mpg? Which is greater? 51 or 47?
 
By looking at the results, Honda's IMA is less efficient because 1.3 liter engine is getting less mpg on the highway than Prius 1.5 liter engine. Prius is even bigger than Civic.
 
-------------------------------------------------------
"Why is the highway mileage of the Prius less than the City mileage while the Insight is higher?"
 
Because Insight simply sux in the City, even though there is less air drag in low speed city driving. Prius is equally good in both City and Highway. The reason Highway mpg is lower is due to air resistance at high speed.
 
PS: I know I am replying to a very old post because no one actually addressed it.
 
Dennis
#118 of 139
Re: MG1 spins needlessly ?? [usbseawolf2000] by midnightcowboy
Mar 29, 2006 (9:31 am)

Replying to: usbseawolf2000 (Mar 28, 2006 6:54 pm)

LOL- how to justify energy conversion losses. You should become a politician
#119 of 139
Re: MG1 spins needlessly ?? [midnightcowboy] by usbseawolf2000
Mar 29, 2006 (6:25 pm)

Replying to: midnightcowboy (Mar 29, 2006 9:31 am)

Less energy loss than traditional and IMA implementation. Just look at the results.
#120 of 139
Any info about the HH by melski
Jul 26, 2006 (7:26 am)
I am looking into buying a HH. I currently have a 4Runner and a preschooler with alot of stuff. Can you tell me anything about the car. How it drives, stops (I read about the breaking problem), anything you feel could be helpful to me. Also if anyone knows of a better car. I want a Hybrid for the green factor and to hopefully save a few pennies. I would like to hear from people who love their car and why. I also want to know what you hate abouy it. Are the cupholders in a good place. I am still a woman and we like to know these trival things. THANK YOU all in advance for any help,ideas.
#121 of 139
Re: Any info about the HH [melski] by kirstie_h HOST
Jul 26, 2006 (7:48 am)

Replying to: melski (Jul 26, 2006 7:26 am)

Hi melski,
You can get tons of feedback on this vehicle in our Toyota Highlander Hybrid discussion. Lots of current owners participate there.
#122 of 139
Newbie ICE starting question. by enrolb
Aug 22, 2006 (12:15 pm)
Having just recently purchased a Toyota Prius. I find it amazing that when the ICE starts it is so seamless, less noticeable than a typical automatic transmission shift! I was wondering if the ICE internals where always moving with the CVT therefore no spinup time is required?
 
 
#123 of 139
Re: Newbie ICE starting question. [enrolb] by toyolla2
Oct 28, 2006 (8:13 pm)

Replying to: enrolb (Aug 22, 2006 12:15 pm)

Hi enrolb,
 
The quick answer is for speeds below 42mph you'll find the engine is fully stopped quite often. It is always fully meshed with the drive train same as an auto transmission. However the similarity ends there because there are no slipping clutches or hydraulic torque converters employed here.
 
 What there is is just this differential gear that the engine feeds to. A small but powerful servo feeds this differential gear system also. Power takeoff to the wheels is through a third gear. It is this gear which drives directly to the wheel axle with a 4:1 stepdown.
 
 If the wheels are turning and the engine is not required then the Prius computers will instruct the small servo to rotate precisely at the right speed so that the crankshaft can remain stationary.
 
But how does it do it is a whole other question !
If you want to know more, first take a look at the line dwg on Post #470 on the Toyota Camry Hybrid board. That top drawing is your car.
 
See the planetary gear in the centre ? Well it's not clear from the drawing, at least not as clear as it could be, but the crankshaft of your engine is connected to the planetary carrier which supports the planet gears which race around the sun.
 
The sun gear itself is driven by a hollow shaft from the smaller servo (if you can call 30kw (42Hp) small ! ) commonly referred to as MG1.
 
Now here's the tricky part. In order for the crankshaft to meet the planet carrier it has to go through the hollow center of MG1 and its shaft and then proceed through to the other side of the side of the planetary assy where it can then join rigidly to the carrier.
 
The third part of a planetary gearbox is the outer ring gear. This is the internal tooth gear the planets run around inside. It also connects directly to MG2, your main 67Hp traction motor. And eventually the wheels as the diagram shows.
 
  
T2
#124 of 139
Running the Airconditioner While the car is parked by ellen4
Feb 19, 2007 (9:32 pm)
I'm thinking about buying a Camry Hybrid. I'm in sales and during the summer, in between sales calls, I will sit in my car for 1/2-1hour, with the airconditioner running. My question is, will I be able to do this in the Camry Hybrid, or will it ruin the battery?
#125 of 139
Re: Running the Airconditioner While the car is parked [ellen4] by stevedebi
Feb 21, 2007 (1:25 pm)

Replying to: ellen4 (Feb 19, 2007 9:32 pm)

"I'm thinking about buying a Camry Hybrid. I'm in sales and during the summer, in between sales calls, I will sit in my car for 1/2-1hour, with the airconditioner running. My question is, will I be able to do this in the Camry Hybrid, or will it ruin the battery?"
 
No, the engine will come on to charge the battery when needed. You will use up gasoline, of course... are you sure you will have enough cargo room for your sales stuff? I actually think the Prius may be a better choice for carrying cargo.
#126 of 139
Re: Running the Airconditioner While the car is parked [stevedebi] by ellen4
Feb 21, 2007 (4:29 pm)

Replying to: stevedebi (Feb 21, 2007 1:25 pm)

Thanks so much for your quick reply

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