Team-BHP - Switching off the engine at traffic lights

I think 60+ seconds would be ideal. Driving a turbo charged engine, i will have to take care of idling before switching off (This is necessary to make sure the the turbo is lubricated until it stops) and idling before moving (waiting for the lubricant to reach turbo before i start loading it) giving 20 secs for each, another 20 secs for break even between fuel cost and my laziness (trust me, it has to be accounted, everything counts).

but more often than not, you might have to move a little bit in between gaps.. so i wouldn't be in a situation to switch off the engine most of the times. But i do switch off head lamps..

OK, new question on the same old topic.

On my route to work, 2km from my house, there is a major junction. Which has metro construction above it. This means that signal wait times are frequently above 2 minutes. Going by all that has been discussed on this thread, I switch off the engine.

BUT, I have also heard (unsure about the reliability of the source) that a modern car takes about 3-4km of driving to warm up properly. So if I am switching off at this signal, I have switched off my car when it hasn't warmed up properly. Isn't this detrimental to the engine? Will it reduce the life of the engine?

Quote:

Originally Posted by KiloAlpha (Post 3060451)

Assuming you have a petrol car, there is nothing wrong in switching off the engine if it hasnt warmed up. What is not recommended however is not to rev the engine hard before it warms up completely. And 2 kms is a pretty decent distance. My car usually reaches to almost 70% of its operating temperature in this distance. So it will be sufficiently warmed up, if not fully. Even with a diesel heart, I presume it must be ok provided you follow the idling before start and stop rule.

I don't know how much time you can stay off without opening your car windows after switching off the engine. Once you open those windows, lot of smoke, dust and highly polluted gases can pour inside. Is it really worth switching off engine at a red signal in a highly polluted area if we need to wait for a long time ?

Switching off the engine at traffic lights-save-fuel.png

Source : HT Delhi

These studies are conducted without proper research. They are simply spreading awareness to switch off the engine at each and every red-light. But any switch-off and restart within 30 to 60 seconds may consume more fuel than it is actually intended for and that too differ from manufacture to manufacture:Frustrati. I suggest all manufactures should mandatory provide a time frame between stop - start of their engines which should be in the correct threshold for fuel savings.

OT: How do Auto Stop-Start function like in Audi actually save fuel when stopping are less than a minute?

Vinu

One as you mentioned there could be confusion for some people - it is not supposed to be very light , secondly i am not entirely sure how effective the campaign is either - its half way into September and i am yet to see anything about the campaign other than what you just put up! :)

Quote:

Originally Posted by myavu (Post 3238683)

Attachment 1139209

These studies are conducted without proper research. They are simply spreading awareness to switch off the engine at each and every red-light. But any switch-off and restart within 30 to 60 seconds may consume more fuel than it is actually intended for and that too differ from manufacture to manufacture:Frustrati. I suggest all manufactures should mandatory provide a time frame between stop - start of their engines which should be in the correct threshold for fuel savings.

Quote:

Originally Posted by hillram (Post 945882)

I had a strange experiance once when i turned off my Engine in Corsa..the central locking opened and and young lad tried opening my rear door and run away with my laptop bag(with my laptop in it)..I was saved,but too a decision never to switch off engine at red lights.

Locking the car doors would be a good approach.

Quote:

Originally Posted by HappyWheels (Post 946083)

During night times, I also switch off the headlight, when in the signal. This is not for saving the bulb(!), but to avoid the glaring effect it might have on others due to vehicle parked in front.

I do the same in roadworks, out of consideration to oncoming traffic in areas which aren't lit by street lighting. Negotiating roadworks in the dark can be difficult enough without having a series of headlamps blinding you.

Quote:

Originally Posted by myavu (Post 3238683)

Attachment 1139209

But any switch-off and restart within 30 to 60 seconds may consume more fuel than it is actually intended for and that too differ from manufacture to manufacture:Frustrati.

Vinu

If your car restarts reliably and quickly then switching off for just 40 seconds will most likely save more fuel than is required to recharge the battery on restarting.

Quote:

Originally Posted by prabhu (Post 3067527)

If the problem is of choking due to lack of air or stale air, then switch off the engine but keep the ignition ON with blower speed at 2. Since the signal will not be more than 60 seconds on average it is OK keeping the blower ON. Once the signal is green switch on the A/C.

Anurag.

Dear All,

As the traffic in our cities increases the stop tie at the red lights has been going up. In Delhi NCR the traffic police department has equipped the traffic lights with count down timers.

One question that comes to my mind is : what is the minimum duration before which one should wait before turning off the engine at red lights ? This will be different for Normally Aspirated petrol engines and the turbo charged diesels that are becoming increasing popular on Indian roads.

we have also read about the turbo charger idling pracice efore engine shut off being a good practce to prolong the life of the turbocharger. At the same time car manufacturers like Mahianda & Mahindra have introduced micro hybrids which turn off the engine when the car is stationary for some time.

I would request the gurus to shed some light on this subject, as one would like to conserve fuel and protect the environment and at the same time not do anything to drastically effect the life of turbochargers and starter motors.

This topic which you have raised is definitely a very important topic. I doubt anybody would have answers because it would really require a good amount of testing before one can derive the optimum answer for the minimum time the engine should be off at traffic lights to give us the advantage of increased fuel efficiency.

The fuel saved in this period should he high enough to justify the early replacement of batteries which have a limited number of engine start cycles.

Also the engine idle time before switch off should also be optimized to avoid damage to the turbocharger. I wonder how Mahindra designed Micro Hybrid for a turbo charger engine. I mean how much time it takes in idle, neutral gear before the engine switches off using the Micro Hybrid technology. I think they should have done enough testing before they came out with this technology to avoid turbo charger damage and also at the same time give substantial fuel efficiency savings.

I remember watching top gear where they experimented and found that this start stop technology at traffic signals does really save fuel and in return bad emissions.

I personally follow a minimum 30 to 45 second rule before switching off the diesel engine even though my vehicle has been driving slow in heavy traffic.

Quote:

Originally Posted by rajneeesh (Post 3596664)

what is the minimum duration before which one should wait before turning off the engine at red lights ? This will be different for Normally Aspirated petrol engines and the turbo charged diesels that are becoming increasing popular on Indian roads.

Quote:

Originally Posted by amit_purohit20 (Post 3596742)

Also the engine idle time before switch off should also be optimized to avoid damage to the turbocharger. I think they should have done enough testing before they came out with this technology to avoid turbo charger damage and also at the same time give substantial fuel efficiency savings.

The other aspect around 'different rules for NA and TC' is to also separately make allowances for turbocharged petrols that are gradually gaining popularity (Ford's EcoBoost, VAG's TSI, Tata's Revotron, Fiat's T-JET) - this is because the temperature of exhaust gases in a petrol engine are higher, which will lead to higher heat soak in a petrol engine that is at standstill.

Doesn't starting a car esp. naturally aspirated ones require a lot of fuel? Also I've noticed that if you switch off the A/C, when you restart it takes a while to cool again. Meaning more fuel again. Plus in Bangalore at least signals don't have a stop. It's always Go-Get ready-Creep. Never stop.