[sputnik]

My science hubby wants to know how letting the Insight slow down in gear (foot OFF clutch) enhances regenerative braking? He says this is counter-intuitive to the way he usually drives a manual.

"Experimentally" he knows it is true, because when he keeps the car in gear as long as possible the battery charge stays high. When he drives the other way, the battery charge plummets.

I printed out the IC FAQ-efficiency tip "Maximize Regenerative Braking" but if there is a diagram or picture anywhere showing how the brakes, the transmission and battery work together, that would be just the thing.

Thank-you.

 

[HafNHaf]

if you push the clutch pedal all the way in there is a switch that prevents regen and assist. honda made it that way so the engine wouldnt stall if max regen was applied with the tranny out of gear.

 

[Insightful Trekker]

Reads like he's overlooked regen on decel.

"Disconnect" the wheels from the engine and the IMA motor doesn't have any deceleration "energy" available to recover. You've gotta know that the IMA motor is coupled to the engine with the clutch being in between the IMA motor and the transmission. The conventional approach of "power" decoupled by the clutch from the transmission.

Honda could have done it slightly differently and in theory allowing for a 100% electric only mode. But it would require an additional unique electronic control for the IMA motor to prevent any loading of the gear sets if trying to shift and the IMA system being in either assist or regen. Essentially an electronic "clutch" of the electric motor. Gear sets under load don't want to release easily and won't engage at all. Nor is the system designed to "take" the extra load of an electric only mode.

If you ponder the operational differences between what your hubby would like vs. how it is I think you can foresee some other "quirks" that don't have as elegant a solution as the current system does. (I've not attempted to explain the few the above introduces)

It also reads that his right foot is heavy.

HTH!

 

[b1shmu63]

If the IMA motor was attached permanently to the transmision it could not be used to start the gasoline engine, neither could it be used for idle shutoff and restart. A second clutch would be needed. It would have to be electrically or hydraulically actuated. The extra weight, complexity, size, and cost would not be justified by the somewhat increased regeneration efficiency.

 

[Insightful Trekker]

Aww Kip :!:

I was leaving that one for Kathleen's husband.

 

[sputnik]

Thanks all for the info.

Your posts plus a diagram found on the IC Encyclopedia "IMA Motor" kept David busy most of the afternoon. He said he understands the electric motor-clutch connection better now...but it's complicated with still a few mysteries.

David said the guys who figured out this IMA business are just plain brilliant.