Engine Auto Stop/Start

[Keyav8r]

A thread in MJ Tech on fuel economy/mileage started me thinking about the methods auto manufacturers are using to try to meet government fuel mileage mandates. One of the methods I've read about is automatically stopping and re-starting the engine at traffic lights (and under some other conditions). I haven't seen any information on how the engine computer decides under what circumstances to stop the engine. I'm assuming the trigger mechanism may be that the vehicle has come to a complete halt and the brake is still applied. Maybe there's some time delay built in to prevent unnecessary engine stops? The trigger for re-start could be release of the brake followed by pressure on the accelerator. I understand that things like lights, radio and blower keep operating during the stop. Have to wonder what that would do to battery life if all you did was city driving.

Has anyone driven a car with this feature? What was your impression of how useful/practical it might be?

I think it would just be an annoyance to me. But then, I am an Olde Phart and I'm still not convinced that those cell phones aren't just another fad.

[91Pioneer]

No need to have any concerns, the tech works and is designed for situations (climate, voltage, etc.)

[Automan2164]

We have a hybrid Chevy Silverado at my work, as well as a hybrid Civic.

 

One important thing to consider with the Start/Stop system is they use a large stator where the torque converter would be. No traditional starter, alternator, or anything of the sort. The stator charges the battery while cruising, as well as draws current on braking demands, putting drag on the drivetrain. The regenerative braking has to be one of my favorite features. Grabs a charge and helps slow the vehicle and save brakes.

 

The Civic is a normal Hybrid. It uses the hybrid battery as a source of alternate propulsion, and will move on battery power alone, gas engine alone, or in high demand, both. If you floor it, the hybrid system fires up and supplements the small gas engine. As for the start/stop, usually as you are slowing starting at about 15 MPH, it may cut the engine if it desires. It's barely noticeable, and most of the time you have to be actively watching the tachometer to pinpoint when it happens. Upon acceleration, depending on the demand, it may coast off on electric, or refire the gas motor. All of this you can watch on a charge/use indicator that shows draw or recharge depending on application. You can recharge the battery manually by holding the accelerator in park and holding it above 2500 RPM. This has a hybrid battery, and a standard 12V.

 

The Silverado isn't a hybrid at all. It doesn't use the 42 volt battery under the seat for anything but refiring the gas motor and running accessories during the stop feature. Because it doesn't propel itself with the electric motor, it can't be hybrid powered by definition. This one will kill off at about 10 MPH, and coast. It uses a hydroboost power braking system with electric backup to maintain power brakes. This truck is very basic in it's functions. There is nothing to let you know what it is up to other than the tach and a single little start/stop indicator. This also has both a hybrid and standard battery.

 

Rob

[Automan2164]

Ford Owner video:

 

https://www.youtube.com/watch?v=CnrhTDjHLdY

[Keyav8r]

OK, that's pretty cool. Still not sure about those new-fangled cell phones. Probably like pet rocks, just another passing fad.

[dankicksass]

Most vehicles with start/stop tech are not hybrids and do not have any fancy tranny gizmos as described above. Some have a belt driven starter/alternator assembly (Chevy does this) and some just have the regular old parts you're used to (pretty much everybody else does this.)