Start /stop does it save fuel ?

[NISFAN]

I do the same and wish you could change the default setting to 'off' rather than 'on'.

Technically they can do this, but I suspect as the CO2 emission test was conducted with SS active, they would need to make that the default mode to comply with homologation rules.

 

[Bellow]

I'm sure you will find that the alternator and battery have been upgraded on ECO SS cars. They do also seem to fire up quicker, so would imagine they have as Bellow has said, and alternator/starter, or a beefed up starter. The car has been designed for it.

Increasingly it's a move toward mild hybridisation. Beefed of 'starternator' fit for warm restart and hefty enough to generate a big current during over-run/decceleration. Which tops up the battery for restarts.
Next step up is a more comprehensive 'starternator' sandwiched between engine and transmission with much larger battery capacity and the capability to add electrical assistance to the drive wheels. Stop/start is a useful mid point technology but not everyone has got it right - smart MHD. By my reckoning the 'spark the ready cylinder' will be the making of the simpler system. But I drive in the sticks, so of little use to me. The same would apply to those predominately plying motorways.

 

[NISFAN]

Increasingly it's a move toward mild hybridisation. Beefed of 'starternator' fit for warm restart and hefty enough to generate a big current during over-run/decceleration. Which tops up the battery for restarts.
Next step up is a more comprehensive 'starternator' sandwiched between engine and transmission with much larger battery capacity and the capability to add electrical assistance to the drive wheels. Stop/start is a useful mid point technology but not everyone has got it right - smart MHD. By my reckoning the 'spark the ready cylinder' will be the making of the simpler system. But I drive in the sticks, so of little use to me. The same would apply to those predominately plying motorways.

Yep, I agree completely.

Most OEM's now have hybrid versions, the only problem with Hybrids is the poor battery technology. Carrying 144kg of battery in the car (New BMW active hybrid battery weight) is counter productive.

I would think someone will invent a giant clockspring or capacitor system to capture the kinetic energy of the engine whilst stopping it, to put back in to start. Hopefully we can leave hybrid to daft cars like Prius

...but sadly, the future medium term will be all electric power, with an IC engine as a range extender.

 

[Borys]

Put yourself in a car with start/stop in summer in heat,hot as in hell
A/C on, nice inside the cabin,M25 traffic bang car stops-engine stops....a/c too
Been there, start/stop is the worsest thing they ever could put in a car
Thanx god you can switch the damn thing off

 

[Bellow]

Mazda (I think) are using or are going to be using capacitors. Light duty only though.
Definitely the ability to capture some energy otherwise lost to braking would be of use. At a certain level of battery size - sufficient to assist re-accelerate to cruise speed after a bout of braking - the battery could be viable, particularly if it allowed for a slightly lighter engine. But that's all the charge capacity I'd be wanting. To hell with setting off in the morning with the entire days charge, which in reality will be spent by lunch-time!

Incidentally, was reading earlier how interested in hydrogen fuel cells the aviation industry has become. I expect accelerated HFC development. Perhaps that's where surplus electrical energy could go - on board hydrolysis.

 

[survey]

I'm sure you will find that the alternator and battery have been upgraded on ECO SS cars. They do also seem to fire up quicker, so would imagine they have as Bellow has said, and alternator/starter, or a beefed up starter. The car has been designed for it.

Can you refer me to the section of the owners manual that even mentions Turbo cool down? ........Nope........because there isn't one.

Now if Mercedes didn't specifically mention it, surely that means that it is NOT necessary? after all they do have a section talking about cooling down the brakes if driven hard.

In any case, if you would prefer to cool the engine and turbo down by idling like they used to in 1985, by all means go ahead and turn off ECO mode. Everbody happy

Lol, at getting a statement that something won't ever get damaged. The manual talks about starting and driving the car....I'm pretty sure MB won't give me a written statement to say that running the engine and driving the car WON'T damage it.

Well, that's encouraging then!

 

[survey]

I switch off start/stop - eco button when I start the engine. If I forget, engine dies when I stop to leave the car park which surprises me every time.

I use eco button when I'm stuck in traffic for a long time or waiting at red light and I know waiting time is long at this one.

I was not sure that I would like the stop/start feature but now after 5 months and 7K miles, I have got used to it and it doesn't irritate me.

 

[Ted]

Guys! Why don't you start smashing up the weaving looms!!
I have this in the Kia. It is fantastic.
All of the concerns expressed have been addressed. If cabin temp falls below the set level, it starts. Heavy duty battery and starter fitted. Additional load from the alternator negated as the charging is turned off when accelerating and back on on the overrun. No chance of flattening the battery. On demist? It is deactivated. You need to reach a certain speed before it reactivates so it doesn't keep activating if you're in very slow traffic.
I honestly have NEVER been caught out or wanted to turn it off.
In the last 5000 miles it has been active for about three hours so I honestly don't know how much fuel it has saved, but I do know that it means that I pay zero road tax.
So stop worrying. You can always turn it off


Oh, and for the record the Kia has no rattles. Nothing. Zilch. Big fat zero. Bugger all.

 

[Peter T]

Had an automatic C Class courtesy car from my local Merc dealer which had this stop/start thingy. This meant that all the stop/starts happened with the transmission in Drive.

Every time the engine started there was a jolt from the transmission which was uncomfortable for the occupants and, more woryingly, must have an adverse effect on transmission life??

 

[Aoraki]

Had an automatic C Class courtesy car from my local Merc dealer which had this stop/start thingy. This meant that all the stop/starts happened with the transmission in Drive.

Every time the engine started there was a jolt from the transmission which was uncomfortable for the occupants and, more woryingly, must have an adverse effect on transmission life??

Never had that happen in my C Class.

 

[kianok]

I do the same and wish you could change the default setting to 'off' rather than 'on'.

Same here, although i have found that you can hold the car at a stand still without the engine cutting out by not pressing the brake pedal quite as much (Auto diesel C class)

 

[Mactech]

Guys! Why don't you start smashing up the weaving looms!!
I have this in the Kia. It is fantastic.
All of the concerns expressed have been addressed. If cabin temp falls below the set level, it starts. Heavy duty battery and starter fitted. Additional load from the alternator negated as the charging is turned off when accelerating and back on on the overrun. No chance of flattening the battery. On demist? It is deactivated. You need to reach a certain speed before it reactivates so it doesn't keep activating if you're in very slow traffic.
I honestly have NEVER been caught out or wanted to turn it off.
In the last 5000 miles it has been active for about three hours so I honestly don't know how much fuel it has saved, but I do know that it means that I pay zero road tax.
So stop worrying. You can always turn it off

Prexactly
I've driven quite a number of cars with this technolgy and they are all good at saving fuel whilst you are stopped in traffic.
The best is a big V8 twin turbo direct injection petol which starts almost imperceptibly as you ease your foof off the brake pedal, and saves buckets of fuel.
The 4 cyl diesel BMW is less smooth (diesel and less cylinders) but is still good and saves a smidge of the black stuff. All have been thought about, endlessly tested in all conditions and are intelligent enough to know if you are getting too warm without the air con working etc.
Takes a little getting used to, but then so does the price of fuel today

 

[Valkirk]

I think there is some confusion in this thread. We aren't talking about taking a non stop/start car and just literally shutting it down and starting it up again as though you turned the key. These changes have been specfically altered, tested and run over thousands and thousands of test miles and simulations by Mercedes.

They will have identified and upgraded all the required components, they will have developed logical code systems that will overide settings under certain conditions like engine temp, AC load etc.

I would expect the system to operate for as long and robustly as any other Mercedes have designed. You put your faith in them by buying their car, why not in the fact thy can design a fuel saving component that will work reliably for many years?