[earthian]

Guys:
I find the auto start/stop feature in most modern cars quite irksome and have been pondering about its positives and negatives. What do you think about this?

https://youtu.be/k159M8QhCIE

Mods: I couldn't find an existing thread to place this and hence starting a new one.

[reignofchaos]

First thing I turn off when I get into the car is the auto start stop. It's totally useless in Indian traffic especially in Bangalore.

In the developed world where you only stop at signals and stop signs, it's not that bad and can actually help you save fuel.

[nitinralli]

Useless feature according to me. Whenever by default it was on, one of the bulb either headlight or fog light one used to conk off.

[deep_bang]

There are a few advantages of Start Stop even in Bangalore. The assumption is that if you don't have start-stop, you would still switch off the engine during long signals.

One big use is that when the engine switches off, the doors don't get unlocked. This is useful both from the safety perspective (no thief can just open the door from outside) as well as from the passenger safety perspective (kids cant open the door by accident).

Another use is that when you switch off the engine at night, the lights switch on. You don't want the lights to switch on in a traffic light. When in StartStop mode, the lights don't come on.

However, the system comes with its cons.
The system just switches off if:
1. Speed is 0.
2. You are in neutral and clutch is fully released.

Many times, these conditions are satisfied when you DONT want to engage the start-stop too. So that part is frustrating!!

[Kestrel5915]

Originally Posted by earthian

Guys:
I find the auto start/stop feature in most modern cars quite irksome and have been pondering about its positives and negatives. What do you think about this?

Mods: I couldn't find an existing thread to place this and hence starting a new one.

Frequent start-stop will definitely have a negative impact on the engine.

During starting the combustion process inside the engine is not in its optimum state hence the amount of soot is higer than normal and if the starting process occurs frequently then there can be higer amounts of deposits in the exhaust passages and turbocharger.

Also the hydrodynamic film for crankshaft bearing lubrication is not formed until the shaft is turning so during the start condition when the engine starts cranking, the oil film is not there.
Usually this is compensated for in the bearing using specific materials and coatings or flash layers to give a certain life period.

Other than that, in diesel turbocharged cars certain idling period is required during starting and before stopping so that is also not taken care of in auto start-stop.

So basically, if the engine and its components are specifically made for utilizing this auto start-stop feature then it's good but I highly doubt that this is the case since from an engineering perspective it's not easy to achieve in a consumer grade vehicle.
Achieving this entails special materials for bearings, liners, high temperature areas like exhaust valves and passages, some kind of lubrication arrangement for the turbo (may be a small gravity based reservoir), etc.

[Nalin1]

Originally Posted by earthian

Guys:
I find the auto start/stop feature in most modern cars quite irksome and have been pondering about its positives and negatives. What do you think about this?



Mods: I couldn't find an existing thread to place this and hence starting a new one.

Are you talking about the micro-hybrid technology (don't know what it is called in other cars) in the Mahindra cars? Drawing from some limited experience of this feature, I can say that it does not make much sense in stop-go traffic. Every few minutes in peak Bangalore traffic everything comes to a standstill with or without signals!. For an engine to switch off and on every half a kilometre once for saving a few millilitres of fuel without taking into account the idling rule can be harmful I think...

[jkdas]

Its not about 'love it ' or 'hate it' ; its a feature which was introduced coz they found it useful and hence ine shouldn't see it as a switch which just kills the engine at red light . Its usefulness for our traffic has to be verified though.

[GTO]

Poll added & voted for hate it. I have the feature in my car and it is always switched off. Have experienced the start/stop system in mass market cars as well as 1+ crore rides and one thing for sure, the stop & start action is simply not seamless. That constant shudder is so annoying.

Not to mention, the air-con's cooling stops (as the compressor switches off) and I'm worried about the effect on the engine, turbo (no cool down period) & battery.

I have no doubt that it'll lead to slightly better fuel economy, but the price you pay & inconvenience are too high.

[ajmat]

Originally Posted by GTO

I have no doubt that it'll lead to slightly better fuel economy, but the price you pay & inconvenience are too high.

It leads to better emissions performance which now rules various performance/ taxation parameters abroad. It, technically, has no value in practical terms and leads to more wear and tear

[i74js]

Loving something like this was difficult, this feature is not present in any of my cars but have seen it happening with a friends Ciaz and it is downright irritating.

No mater how much I would like to save the fuel, the requirement of air conditioning in Indian conditions does not warrant this feature for at least 7 to 8 months in a year (Summers and Monsoons). More so I was particularly irritated that this cannot be programmed for "permanent off condition" as was told by friend.

Even in winters, when the car has just started and I come out of my society, it switches off (within say 100 meters of my apartment) when I want the engine to run, so as to warm up to the operating temperature; the engineers would have programmed it for such conditions that auto-off will not come into play unless the car reaches its operating temperature, but even that has not been thought off.

The SHVS and Microhybrid were just used as tools to get the FAME benefit, which has now been withdrawn for these technologies starting April 1, 2017.

In Ciaz (not aware of M&M), the SHVS does not even have a quality battery, just a different 48 volt lead acid battery from Exide has been placed which the sales advisor says has been specially manufactured for MSIL.

In all its a redundant feature, rather a marketing gimmick for claiming additional mileage and reduced taxation. There are discussions about reduced emissions; can a technical study confirm this in a stop and go traffic of Delhi, Mumbai, Bangalore etc.? This may be possible in ideal / test conditions.

Advantage to the customer? or long term impact on the engine and its components - well not known, personally I would consider it detrimental to the health of car.

[R2D2]

I was driving my cousin's 320D (F30) and honestly speaking I found this feature a real PITA.

Pune has traffic signals as frequently as every few hundred meters with the stop signal staying on for as less as 60-90 seconds. I wouldn't want an expensive AGM battery and even more expensive starter motor being messed up over the long term only to save a few ml of diesel at every signal. I advised him to switch it off.

If any car I buy comes with this "feature" it will remain switched off (if available as an option).

[iabhishekkumar]

Originally Posted by deep_bang

One big use is that when the engine switches off, the doors don't get unlocked. This is useful both from the safety perspective (no thief can just open the door from outside) as well as from the passenger safety perspective (kids cant open the door by accident).

This feature is present in my safari storme even though it does not have auto start/stop feature. When I switch off the engine, the doors does not gets unlocked by default, rather it only gets unlocked when I take the keys out from keyhole.

Voted for "Hate It!".

Cheers!

[Dani7766]

Voted for hate it. Don't have the feature in my cars. But have experienced it in my friend's 3 series. It was quite annoying every time the car used to start. Also worried about the frequent start and stoppage which we face in our traffic conditions. Wouldn't it harm the components?

[abhishek46]

Voted for hate it.
That's because I absolutely hate it. It stops the engine in un predictable situations, like in slow moving stop go traffic.
Secondly, the benefits of stopping the engine and restarting it withing 20-30 secs is highly debatable.

[sgiitk]

The idea looks good. I have some queries -

1. Is the starter system robust enough? Just look at the wear and team.
2. What happens to the Aircon when stop start is functional.
3. Adverse effects on starter and battery life? What happens if I have a battery on its way out.