What is a reboot and what is the purpose of doing this?

 

The IMA computer on Honda hybrids estimate when the battery needs a charge. When it thinks it's time for a charge, the charge level will go to zero in a matter of seconds and nothing will stop this. That usually known as a recalibration or recal. Takes about twenty minutes of highway driving to restore the charge.

The IMA computer attempts to keep the charge above 15% and below 85% for maximum battery life.

Hope that was fairly accurate....

 

I could swear others were using the term to describe turning the key to the "off" position to kill the engine and essentially force autostop even if the car was in motion. Then again, since it's sort of an invented word, perhaps we've got a few different uses going on around here...

 

I've allways heard of what Delta Flyer is talking about as a recal. To me a reboot is what AZdude is talking about, a forced autostop. The name comes because the dash goes completely dead for a second then lights up everything in a POST and then starts working normally again.

If in fact I understand the term correctly, I use the reboot all the time to coast in "pinewood derby car" mode using zero gas for as long as the car is off. Hybrids are very cool because they still have power steering (because it is electric) and still have a few stops left in the power brakes (because of the vacuum canister).

There is a safety factor involved. You do loose PS for a second and the power brakes will not last for repeated applications. If you don't know exactly what to expect and/or if there is a lot of traffic you should not do a reboot.

 

BTW, there is a glossary on greenhybrid with definitions. I believe this word is defined but if it isn't maybe someone could add it.

 

I never quite understood how you could save much gas with rebooting. Under the conditions it's normally performed (coasting for short distances), the Fuel Consumption Display (FCD) would be pegged at 120+ mpg anyway, even with the engine running.

Hyper-milers, edify me.

Mike

 

when the car drops below 20mpg the fcd does not stay at 120.

 

It is true that it does not save a lot when used for short distances. The technique might not be of much use for flat landers. However it saves quite a bit when combined with long downhills. There is one spot on my way home where if I make the light at the bottom of a hill the car can go over 2 miles with engine completely off. Even if the display is maxed out you are still burning some gas idling the engine. Think about it. Hybrids have auto-stop just to save what little gas you burn idling the engine while stopped for a light (or whatever). Forced auto-stop (reboot) is just a logical extension of the same idea.

 

Borrowing from a more general automotive philosophy, there is one more safety pitfall in driving with the key off. You lose a rarely-used, but important ability to surge forward out of a potential hazard. Click and Clack would tell you not to even knock a car into neutral to coast down a steep hill. Drivers beware. This is not a habit you'd want to bring to the attention of your insurance agent after an incident.

I'm a bit of a buzzkill today.

 

I don't think anyone here would use it on a steep hill. After all, on a steep hill, you could leave it in gear and still use zero fuel because the engine will cut the fuel injectors anyway. It seems to mainly be a tool for flat ground when coasting to a known stop point such as a neighborhood stop sign, or on extremely gentle downhills where it would lose speed if you were in gear, but can coast at a steady speed without gaining or losing any velocity if you're in neutral.

I've been doing a little experimentation of my own with high speed coasting and the pulse & glide technique using my ScanGauge to try to get a feel for how it helps. I still need to do a controlled test, but definitely there's a few specific conditions where at the very least coasting in neutral would be beneficial. Shutting the engine off is just the next step beyond simply coasting. I'm not sure I'll be able to make extensive use of it though since it requires a lot more thought and planning and usually when I'm driving to or from work I just want to keep an eye out for crazy drivers rather than spending too much concentration on getting another couple miles per gallon.