2nd clutch Insight for EV mode

**IamIan** · 08-28-2005, 09:04 PM

Found a paper from university of michagan engineering deartment about a project to add a 2nd cluth to the Honda Insight between the ICE and the IMA motor.... the idea is to give the Insight EV only mode and remove ICE drag when the ICE is not needed ....

the paper is a MS Word file located at :

http://rds.yahoo.com/S=2766679/K=cleane ... Hybrid.doc

They have done some testing and completed some computer modeling... I haven't been able to find out any other information about this project to see if they are moving it forward to make a prototype test vehicle or what....

I like the idea.... would be a beautiful addition to a MIMA Insight....

Any one else heard of this??? or have any conections in the university of michigan ???

Insightful Trekker · 08-28-2005, 10:05 PM

Interesting computer modeling only study. Thanks for the link Ian

Only 2 problems to work out.

1) Higher IMA battery loads/ cycling.
2) ICE clutch transition lag.

A snip from the summary of the article:

"The Insight model was modified to increase fuel economy and decrease emissions by adding a mechanical clutch between the ICE and Electric Motor. This allowed a more aggressive "engine shut-off" strategy. The Insight powertrain designed showed simulation improvement as a result of adding the clutch and modifying the powertrain theory of operation. Emissions were increased an average of 7.2% and fuel economy increased by 14.2 MPG. All this is great in theory, but there is a real reason why this was not implemented in the Insight design. Every time the FC clutch is open, there is a temporary disconnection between the ICE and wheels. This will create a delay when the driver demands acceleration and the clutch is open."

In simple english, It'll be twitchy on acceleration.

Seems like Honda does ascribe to the advantages though. They've included an electric only mode in the new (06) Civic Hybrid by modifing their VTEC system to effectively "turn-off" the ICE and avoid the second clutch lag issues.

Wayne M · 08-29-2005, 07:12 PM

One other thing would be that we would need a seriously larger electric motor / generator as it's a bit of a weenie to push the car with at 'the equivilent of .5 liter gas engine' as it now exists.

What's it rated, 13 HP?

**IamIan** · 08-29-2005, 10:41 PM

yeagh....... the best option would be a new Insight Designed similar to the new Civic design with a new modified Vtech Engine to allow a pure EV mode and Electric AC etc... a little bigger battery would be nice and a plug in option would down right rock....

the insight should stay around as Honda's example MPG King for those of us out there willing to push further.... the technology in the current Insight hasn't really changed in 5+ years .... but the world and what is availible has.... Lithium Batteries should be used and a plug in option in addition to the new civic stuff...

still ... this is a nice idea and some nice work .... baby steps toward the ideal.... but I figured a bit neat and was wondering if anyone else knew any more about it as this one is just test data and computer modeling.

Dougie · 08-30-2005, 01:20 AM

It would be interesting to see what the Advisor numbers come out to if you started with a Civic hybrid. The Insight is so totally different from the Prius that it's hard to compare them. If the improvement by adding a second clutch was comparable to the improvement they got with the Insight model, then the Civic would give a better overall result than the Prius.

Prius: 53.2 mpg. Insight: 65.2; Modified "TNT" Insight: 79.4, a 21.8% improvement.

HCH: 47 mpg. Modified HCH with 21.8% improvement: 57.2 mpg, better than the Prius.

And I think that the clutch engagement difficulty could be managed. After all, some exotic Audis have two separate computer-controlled clutches in their transmissions.

Insightful Trekker · 08-30-2005, 06:59 AM

Take a look at the 06 HCH.

Thats "basically" what they did

flunkysama · 08-30-2005, 12:36 PM

I thought it was a nest idea when I first saw new VTEC method that shut both intake and exhaust valves to minimize drag and allow EV only mode. Then I though why not just put a clutch between the IMA motor and the engine. With the vtec method you still have alot of drag from internal friction, oil and water pumps, etc.etc. There is also alot more moving parts and complexity with the VTEC method verses the clutch. I think the clutch is the better way to go, but honda engineers just love their VTEC.

But the paper hit on the biggest problem with the clutch, the delay to start to the gas engine. Imagine push down on the gas pedal and waiting a full second before you get that acceleration. It would make turbo lag seem trival.

IMHO, the electric motor is plenty powerful. It can probably handle much more current for short brusts. It's that a stronger and larger battery pack is needed.

clett · 08-30-2005, 03:01 PM

The problem, as always, is patents (and, by extension, pride).

Honda would sooner eat dirt than be seen groveling to another manufacturer to use their patents. Much better to just design another way around a problem, no matter how round about that may seem to outsiders.

BTW, GMs new hybrid system will have two clutches, as in their hybrid buses.

Mike Dabrowski 2000 · 08-30-2005, 03:27 PM

This is all we need to do to get an ev only mode on the Insight. Get two of these:
http://www.bodine-electric.com/etorq/
and replace the rear wheel bearing assembly with the motors adapted to the suspension. Get one of their regenerative drives,and the motors set up for 144v, and hook up to a tripple capacity prius pack based super battery, and you have a 4 wheel drive monster car, that would go a little too fast for it's own good. Of course that motor/generator would be tied into MIMA/PIMA or is it PAMA/MIMA,
MAMA MIA this is confusing.
:twisted: