danwat12345

Hey guys,

So the CVTs on Subarus have a torque converter on the front end I guess so it doesn't need a computer controlled clutch when starting out. It may unlock the torque converter also when you romp on it, not sure. So it's not a true, pure CVT. Does anybody know the layout of the 2014 Civic CVT? Also the 2014 Carolla CVT? Any 0-60 videos for the new CVT? Curious how quickly the engine can get up to peak HP range. With the Subaru CVTs (in auto mode anyway), it doesn't reach peak HP RPM range until over 30MPH, like a long first gear (ugh). Maybe in manual mode it would be different though.

I'll do some Googling and see if I can find a datasheet.

ezone

Go drive one. Let your butt-dyno tell you the story.


Look for how the new CVT works in the 13 Accord 4 cyl, the one in the new Civic is a similar style.

Dual torque converter: One conventional fluid coupler (replaces the start clutch used in previous design CVT) with TCC , the second is the basic CVT belt drive.


I like it a lot better than the previous type with start clutch. Drives much more like a normal trans when driven sedately.

danwat12345

Thanks.
You mean single torque converter that replaces the start clutch, and then the pure steel belt CVT after that? Then it looks to be of similar design to the Subaru. Maybe Toyota also designed similarly. Hopefully the converter stays locked when you floor it at speed and the belt ratios can bring the engine right up to 6K RPM and hold it. But from the CVTs I've seen in videos they really aren't infinitely variable even though they are continuously variable. If it was it could bring the engine to 6K RPM at 10MPH and hold it but I have yet to see a CVT come close and with torque converter locked so no energy loss.
Maybe MPGomatic will make a video before long.

I think the '14 Accord hybrid is awesome with not having a transmission at all, not even an e-CVT (planetary gearset)..

ezone

I've never studied other manufacturers CVT designs at length, so I have no input there.
Maybe it's just me, but it feels like the Civics seem to move through the ranges in stages when driving normally (calm and sedate), as if they wanted to simulate shift points of a conventional automatic....just not as pronounced.

Yes, you tromp the go pedal and the RPM goes high and stays there until you let off. It doesn't go high immediately from a dead stop though. It's like it has to go through first gear first, then it stays high.



As I said before, the 14 Accord Hybrid is equipped with what Honda calls an e-CVT.

danwat12345

Good info. BTW it's funny you mention it, I just wrote an Email to Honda about how their '14 Accord hybrid and plugin hybrid pages on their site is way out of date. And it's direct drive all the time, no e-CVT so I suggested under 'specifications' that they rename it to a direct drive transmission. Their grade logic control section is unapplicable in the 'performance' section.

ezone

Really?
Do enlighten me.

danwat12345

2 minutes into it he describes the drivetrain.

ezone

Ok I see where you are getting your info now.
That video sure looks like it's directed by the marketing department, aimed at the consumer.


Nonetheless, the trans in the 14 Accord Hybrid is still called e-CVT.
It can run in electric only mode, gas only mode, or both.
It can run in parallel or series hybrid modes.

I'm not sure what you (or they) are calling "direct drive", this really only has one electric motor directly coupled to the countershaft of the trans at all times, regardless of whether that electric motor is actively powered or not.

So if the car is underway, but that particular electric motor is not powered, wouldn't it no longer considered "direct drive"?

danwat12345

It can be in series mode at any speed but can only be in parallel hybrid mode at speeds faster than 44MPH or so.

With EV and series hybrid mode the engine isn't connected to the wheels of course and it's just a direct drive from the main motor/generator.

in Parallel mode the main motor/generator may be propelling the car but the engine is assisting directly and the generator may be sucking some power from the engine like in series hybrid mode.
There is no transmission, no planetary gearset like other hybrids.

If the main motor/generator isn't on then the motor rotor is still turning. The clutch connects the engine / 2nd motor/generator shaft to the main motor/generator shaft. I wouldn't call that a transmission, maybe a gearless transmission if you want to. But it's all direct 1:1

ezone

One electric motor is always coupled to the final drive gear, via motor shaft and counter shaft.
It's not a 1:1 ratio with the axles.

Here's the major parts inside that mysterious chunk of cast aluminum hanging between the gasoline engine and the axles, as per training information:


Input shaft
Motor shaft (with integral drive gear)
Generator shaft (with integral driven gear)
Motor
Generator/motor
Counter shaft (between Motor shaft and final driven gear, includes pinion gear)
Overdrive gear
Overdrive clutch
Final driven gear (ring gear)
Differential gear set (side gears and spider gears)
Parking gear
Dual oil pumps
Shift solenoids
Pressure switches

Sure sounds like a lot of stuff that goes in a transmission to me.

danwat12345

I should have said "real" hybrids like Ford's Chevy, Toyota, they use the planetary gearset type CVT, what they call e-CVT.

Honda's '14 Accord is Honda/Acura's first "real" 2 motor hybrid.

I know there is some reduction gear around the differential but I mean 1:1 from the engine to that point.

Are you saying the video is false and the car has multiple gears? Shift solenoids indicate maybe a traditional fluidic transmission.


Where did you get that list from and please confirm it is for this car?

This article (http://www.motortrend.com/roadtests/...d_first_drive/) seems to agree with you, however the comments correct the article, search for "misty" in the comments.

http://www.caranddriver.com/features...stem-tech-dept shows it as direct drive to the differential, no transmission.

Same here http://www.gizmag.com/2014-honda-acc...mpg-epa/29350/

Same here http://autos.yahoo.com/blogs/motoram...142237390.html

ezone

Hondas technical training, MAC16: Accord Hybrid E-Drive System Operation.


I'm not concerned with sales hype, I can't fix cars with that.