My HCHII won't autostop 'til it's warmed up, which is well known. On my commute, I run into some traffic lights early on, so I often have to stop and idle waiting for a green light. If I shift into neutral while waiting, I can feel the engine unload, and the rpm's increase.

Is it better for the engine, and FE, to shift into neutral while idling? Any difference if it is cold vs. warmed up (for a non-hybrid)? How about emissions? Interested in comments.

 

In my HCHI have fared better in Neutral than in Drive. Problem is remembering to put it back on Drive when light turns green :-) I usually end up losing the economy by forgetting to shift.

 

http://www.insightcentral.net/encyclopedia/encvt.html -- This link refers to the insight's CVT, but the behavior described there is spot on with what I see in my HCH-I so I believe everything should apply.

Rather than an automatic transmission that uses a torque converter, the CVT has a clutch pack. In an automatic, when stopped, the torque converter simply freewheels as it's a fluid connection. The CVT though has to simulate this effect by varying the clutch plate pressure via computer control. Pressing on the brake causes the creeping clutch to almost release, but it doesn't do so completely. You can feel this by tapping on the brake extremely lightly, then releasing it. When sitting at a light though, it seems like you're wearing out the creep clutch for no good reason. Shifting into neutral seems quite prudent to me.

Another feature of note from the article is that with the clutch on driven end of the tranny, the belt always spins in sync with the engine, this allows faster downshifting, and it also means that coasting in neutral shouldn't cause it to spin excessively (as would happen in an automatic).

 

if i know it's going to be a relatively long light (or if i know the order/timings of the lights), i kill the engine myself and restart before my light turns green. however, if i'm not sure or if a restart isn't feasible, i always shift into neutral.

 

This is my drive thru procedure!

 

You do that when the engine is cold? Well, obviously you do or you would be autostopping. I've always been told that it's bad for an engine to only go a short distance and then shut down before it's warm, because cold starts are the hardest thing there is for an engine. Myth?

 

3d option - park and "off." When the light changes, start and "D".

Bob Wilson

 

Usually I do a FAS. I shut the engine off, put the car in neutral, and then restart the car when the light turns green.

 

Any engine experts out there that would like to comment on how a forced autostop on an engine that is not completely warmed up affects the engine? Is it okay, or does it depend on how warm it is, or should it be avoided?