MB ECO start/stop is kind of freaky

[imcarthur]

Our trusty 02 A4 had used up its affordable life with us. It now seemed to need something every 2 weeks & always when I was out of town. It has been a great car & it only had 160kms but for the last year payback had arrived. It is my wife's DD & our family car & it was letting us down too often. I wanted AWD, 4 dr sedan, auto tranny mandatory, Euro or upmarket Asian. The luxury of a new car 4 year warranty won out over the used options - which were all surprisingly costly. BMW was summarily eliminated due to a painful past experience with a 3 Series sinkhole. Volvo, Infinity, Lexus were all removed because I also wanted ease of service - which means a dealer nearby or 'on the way' so my wife could handle it while I am out. She is fearless in the city but she doesn’t drive on multi-lane highways . . .

So the short list was Audi A4 or M-B C300. Both great. Same price more or less. Btw in Canada, the C300 is a new detuned 3.5l V6 & Benz has just topped the segment in sales here recently with a major push. The Audi salesman blew his app’t with us on my one night available so my wife leased the M-B the next day - which is the one she really wanted anyway. I admit that I liked the idea of the V6 rather than a blown 4 anyway.

So our new appliance:



White is such a hard color to photograph.

I haven’t driven it much but in ECO mode, the engine will shut off at traffic lights. Completely. No noise whatsoever. It is really bizarre. Lifting your foot off the brake restarts the engine in a fraction of a second so there is no lag & very minimal noise. But it sure is strange. It can be defeated with a setting in the wheel-controlled speedo display but it resets to ECO every time the car is shut off. It is claimed to really help with gas mileage of course.

Ian

[EarlyPorsche]

Great cars. Maybe some one sells a chip or tuner to get rid of Eco mode?

[billybek]

Looks like a cool car, Ian.

I had a Peugeot turbo diesel wagon as a rental in England last year and it was equipped with the Eco mode thing too.
I thought the damn thing was stalling on me for the first 10 or 15 minutes that I was driving it!

It did get amazing gas mileage though and moved along quite well.

[petrolhead611]

My daughter's Mini has stop start too. I worry that the starter motor and maybe ringgear and cylinder bores or valvegear(via oil starvation)may wear out prematurely quickly negating any savings on gas costs

[EarlyPorsche]

The whole ECO stop/start thing is mostly just a crowd pleaser for those who don't understand cars. Lots of people out there who think "this option saves the world and my pocket book." When in reality the resources required to fix the issues the vehicle could have prematurely (starter, ring gear, oil cooked top end and rings) outweigh the small fuel savings. Its sort of how people think battery powered cars "save."

[imcarthur]

I found this explanation:

"How the ECO start/stop system works in detail: as a general principle, the engine is switched off every time the vehicle comes to a standstill (auto-stop function. Restarting the engine (auto-starting function) takes place almost imperceptibly; and moving off without any noticeable time lag compared to a stationary vehicle with its engine running. This rapid action is attributable to two special features: a crankshaft Hall sensor which is able to identify the rotational direction of the crankshaft enables the engine control unit to identify the cylinder in which the piston is ideally positioned for starting. The fuel is injected into this cylinder first, thereby speeding up the starting process. An additional electric transmission oil pump supplies the clutches of the automatic transmission with oil pressure prior to starting, so as to enable a swift resumption of the journey after direct starting of the combustion engine via the ECO start/stop function. The starter motor (starter) has also undergone thorough modification: it is now designed to cope with eight times as many starting procedures, ensuring that it will last a car's lifetime in continuous urban driving involving frequent auto-starting. In addition, the on-board electrical system is supported by a second battery."

Source: Under the microscope: ECO start/stop: Sophisticated technology gives the highest levels of efficiency

I am glad that I have a 4 year warranty.

Ian

[Don Plumley]

Originally Posted by EarlyPorsche

The whole ECO stop/start thing is mostly just a crowd pleaser for those who don't understand cars. Lots of people out there who think "this option saves the world and my pocket book." When in reality the resources required to fix the issues the vehicle could have prematurely (starter, ring gear, oil cooked top end and rings) outweigh the small fuel savings. Its sort of how people think battery powered cars "save."

Full disclosure - I have a car with this and I think it is great. I'm not an environmental activist, but I think that hours of idling pumping crud into the air at stop lights is bad, so stopping the engine is good.

However, the primary driver is the increase in fuel economy - I believe the EPA standard includes about 18% of idle time, so if you shut the engine off, it increases mileage and reduces emissions ratings which is important for fleet rating and consumer appeal.

That being said, I don't intend to own the car without a warranty. So I don't care if it causes premature wear on said drivetrain components - certainly within the factory warranty lifetime there should not be excessive wear or the numbers would not pencil out. YMMV.

[jyl]

Hybrids have had start-stop for many years. Prius taxicabs routinely go 350K miles with no problems related to stop-start. Presumably MB can do engineering as well as Toyota.

[oldE]

Drove a Kia Ceed in the UK three years ago and discovered it had this feature.

I say "discovered", because it wasn't mentioned to me and the first time the engine stopped was in stop-and-go traffic on the M25. I clued-in the second time the engine stopped and re-started when I touched the gear shift. I gave it a lot of thought for a while then forgot about it for the next two weeks as it did its job.

You'll get used to it.

If you do a lot of urban driving with frequent stops, I think it would be worthwhile. We spent most of our time in the rural areas and it was never obtrusive, nor did it get caught 'flat-footed. The car always went when it was supposed to.

Having said that, I only had the car for two weeks.

Best
Les

[Christien]

Originally Posted by imcarthur

due to a painful past experience with a 3 Series sinkhole.

Hah! I just bought a 3-series convertible for exactly the same reason! Too many MB money pits. Hopefully we're both wrong!

[EarlyPorsche]

Originally Posted by Don Plumley

Full disclosure - I have a car with this and I think it is great. I'm not an environmental activist, but I think that hours of idling pumping crud into the air at stop lights is bad, so stopping the engine is good.

However, the primary driver is the increase in fuel economy - I believe the EPA standard includes about 18% of idle time, so if you shut the engine off, it increases mileage and reduces emissions ratings which is important for fleet rating and consumer appeal.

That being said, I don't intend to own the car without a warranty. So I don't care if it causes premature wear on said drivetrain components - certainly within the factory warranty lifetime there should not be excessive wear or the numbers would not pencil out. YMMV.

I guess I'm just used to driving where 30seconds-1min is all I would idle at worst. Maybe it's a good system but I'm not into it.

[Scott R]

My Panamera has this "feature." It's been turned off since the day after I purchased the car.

[Don Plumley]

Also, it's smart enough not to turn off when the engine is cold - it needs to be at full operating temperature before it becomes active. If it is very hot out and there is lots of A/C load, it does not turn off. If you start creeping (you can feather the brake to keep it from engaging), it does not stop. If you sit for too long with the A/C running or if the batter falls to a certain level, it will restart the engine. The logic sitting behind it seems really robust and generally well thought through. It was unnerving at first, but now I like it. BTW, when you put the car into sport mode (which is really cool how it remaps shift points and throttle response), auto stop is disabled; plus you can disable it in a situation where it would be annoying, such as in stop and go traffic.

[petrolhead611]

So the starter motor will last 8 times as many starts. My 6 mile journey to work involves more than that number of coming to rest; 8 times is not nearly enough.

[oldE]

Originally Posted by petrolhead611

So the starter motor will last 8 times as many starts. My 6 mile journey to work involves more than that number of coming to rest; 8 times is not nearly enough.

Do you have enough information to make that call?
Since the system isn't enabled until the engine reaches operating temp and the system selects the optimal cylinder to fire first, reducing the use of the starter, the extra starts may not put that much strain in the starter.

Your experience may differ, but I have replaced exactly one starter in the past three decades and that was on a 16 year old pick up truck. We tend to keep our vehicles well into 200,000 km plus.

I have to say, when we were stuck on the M25 I wished every vehicle around me had an auto-stop feature.

Best
Les