Bus engine shuts down at stops, but not at lights?

[Howardh]

I find it annoying when a diesel bus is continually shutting down and restarting at stops, even if one pax gets on. Can't be doing the engine any good?

But I get that if it stops for a while then it's not pouring toxins out. So all good then, but if that's the case, why is the engine left to run at traffic lights where it can be stopped for minutes?

Does the driver have any input in that, ie the engine only shuts down when the door is opened?

 

[Spsf3232]

It's just like start stop in a car but only operates with doors open. Driver doesn't have any input in how the system works as it's set up from new as an option

 

[Dai Corner]

I'm not a bus driver, but start-stop in my car only kicks in if it's in neutral with the parking brake on and the air-con isn't running.

At traffic lights or queues, many drivers just use the brake pedal, and even engage first gear and keep the clutch down in a manual transmission vehicle. You can tell by observing the brake lights.

 

[Vespa]

I turn mine off when I get into my car as a matter of routine.

The only get round is to keep the brake pressed or dip clutch in buses, stop start is pointless.

 

[Scotrail88]

You got to remember that it needs to meet strict emission standards to achieve enhanced payments from DfT.

Might not seem much but even 10 seconds of stationary will contribute to pollution - engines are built to accomodate this and been in place for many years now.

 

[Howardh]

Thanks for the input, seems odd that it's when the doors open only when buses can be stuck at lights for a high % of their running time. Surely this could be looked at for the future - although on saying that electric buses ate (thankfully) taking over now it seems.

 

[signed]

The main issue with excessive start and stop will be the battery that will take a hit as starting leads to a huge burst of current on non-Hybrids (Hybrids will use the traction battery and electric motors to start the car)

Else, it has very little impact on the engine, the oil won't have time to flow out of the upper-engine in the few minutes it stopped each time + the system will never engage if the engine is cold (that would mean increased metal-to-metal contact, which is very bad)

 

[Gloster]

On Southern Vectis the newest buses have this: if the door is opened when the handbrake is on the engine will stop. If the passenger is waiting to get off and does so immediately, then the engine will be restarted after only a couple of seconds. A good idea taken to tick-box extremes.

 

[Howardh]

The main issue with excessive start and stop will be the battery that will take a hit as starting leads to a huge burst of current on non-Hybrids

Is there any evidence of buses breaking down because of battery issues caused by insessent off/on?

 

[Andyh82]

Thanks for the input, seems odd that it's when the doors open only when buses can be stuck at lights for a high % of their running time. Surely this could be looked at for the future - although on saying that electric buses ate (thankfully) taking over now it seems.

Like the other replies, it’s probably just because the driver hasn’t used the handbrake whilst waiting at lights, but will always do at bus stops

 

[Spsf3232]

Like the other replies, it’s probably just because the driver hasn’t used the handbrake whilst waiting at lights, but will always do at bus stops

The start stop is linked to the doors, not handbrake so that won't change the situation at traffic lights. To open the doors the handbrake must be on as they are interlinked.

 

[busken]

Is there any evidence of buses breaking down because of battery issues caused by insessent off/on?

The start/stop system only works when there is sufficient power in the battery to restart the vehicle.

 

[Howardh]

I've been educated on this, thanks!

 

[signed]

I've been educated on this, thanks!

And the system will also never engage if it is too hot or cold outside, because of the service battery as well

 

[73001]

I drive some where it's on the handbrake, not the doors but as stated above, a lot of the time drivers will just use the footbrake at lights. It can be quite tiresome with it stopping and starting all the time especially as they get older and fail to start sometimes meaning you need to go through the start up procedure again and again.

 

[Trainman40083]

On Southern Vectis the newest buses have this: if the door is opened when the handbrake is on the engine will stop. If the passenger is waiting to get off and does so immediately, then the engine will be restarted after only a couple of seconds. A good idea taken to tick-box extremes.

So if the doors open and the engine doesn't go off, the handbrake has not been applied?

== Doublepost prevention - post automatically merged: 5 Oct 2024 ==

I drive some where it's on the handbrake, not the doors but as stated above, a lot of the time drivers will just use the footbrake at lights. It can be quite tiresome with it stopping and starting all the time especially as they get older and fail to start sometimes meaning you need to go through the start up procedure again and again.

Must get through starter motors will all that stop/start.

 

[derbybusdepot]

I travelled on one of the Trent Barton new e200 mmcs yesterday on the Ilkeston Flyer route. The engine cut out when the bus stopped at the traffic lights - I have never known this happen on any of their other, older e200 mmc. I assume it is now linked to just handbrake being on rather than handbrake and door?

 

[MCR247]

I travelled on one of the Trent Barton new e200 mmcs yesterday on the Ilkeston Flyer route. The engine cut out when the bus stopped at the traffic lights - I have never known this happen on any of their other, older e200 mmc. I assume it is now linked to just handbrake being on rather than handbrake and door?

I first ever experienced it on a Trent Barton i4 E200 MMC when new so unless they later turned it off it has been around a while.

 

[Goldfish62]

I first ever experienced it on a Trent Barton i4 E200 MMC when new so unless they later turned it off it has been around a while.

ADL E200 and E400MMCs have had stop-start for a long time, but I think it's an optional package.

 

[AB93]

The start stop is linked to the doors, not handbrake so that won't change the situation at traffic lights. To open the doors the handbrake must be on as they are interlinked.

The start/stop system only works when there is sufficient power in the battery to restart the vehicle.

On ADL buses it can be set on either the door being open, or the handbrake being on.

 

[WibbleWobble]

Is there any evidence of buses breaking down because of battery issues caused by insessent off/on?

If anything it would be the starter motor that would suffer, but modern systems would surely be designed to withstand a higher number of start-ups.

 

[stevieinselby]

I turn mine off when I get into my car as a matter of routine.

The only get round is to keep the brake pressed or dip clutch in buses, stop start is pointless.

Why would you choose to burn more fuel and pump out more pollution for no gain?
Allowing the engine to hibernate when you're stationary for more than 10 seconds will save fuel, and will make the street a more pleasant place for people walking and cycling past and generally living in the area.
Doesn't sound "pointless" to me.

== Doublepost prevention - post automatically merged: 5 Oct 2024 ==

The start/stop system only works when there is sufficient power in the battery to restart the vehicle.

If it's anything like the system that's used in cars, it's got intelligent sensors checking the battery condition, and it won't hibernate if the battery is looking low on charge. This means that early in the journey when the engine is cold then it probably won't cut out, or if you've got the aircon on then it is less likely to, or if you've had a lot of stop–start traffic on a journey and it has been repeatedly going into hibernation then it may get to a point where it stops cutting out until the battery is properly recharged. I've had my car for 8 years and I've always allowed the engine to hibernate when I'm stopped for more than about 10 seconds, and I've never once had any problem with it restarting.

 

[Vespa]

Why would you choose to burn more fuel and pump out more pollution for no gain?
Allowing the engine to hibernate when you're stationary for more than 10 seconds will save fuel, and will make the street a more pleasant place for people walking and cycling past and generally living in the area.
Doesn't sound "pointless" to me.

It's called choices I'm not an environment zealot, less wear on my starter motor and engine, the constant stopping and starting annoys me.

FYI China and India are the biggest polluters on the Earth, the UK puts out only a fraction of what they pump out.

 

[ac6000cw]

If it's anything like the system that's used in cars, it's got intelligent sensors checking the battery condition, and it won't hibernate if the battery is looking low on charge. This means that early in the journey when the engine is cold then it probably won't cut out, or if you've got the aircon on then it is less likely to, or if you've had a lot of stop–start traffic on a journey and it has been repeatedly going into hibernation then it may get to a point where it stops cutting out until the battery is properly recharged. I've had my car for 8 years and I've always allowed the engine to hibernate when I'm stopped for more than about 10 seconds, and I've never once had any problem with it restarting.

One of our cars has auto engine stop-start and I really like it, to the point where I get slightly annoyed if it doesn't stop the engine when I think it should. I wish our other car had it, but it's a bit too old. If I'm waiting at a gated or full-barrier rail crossing I've always turned the engine off manually - why waste fuel and create pollution and noise hotspots?

Why would you choose to burn more fuel and pump out more pollution for no gain?
Allowing the engine to hibernate when you're stationary for more than 10 seconds will save fuel, and will make the street a more pleasant place for people walking and cycling past and generally living in the area.
Doesn't sound "pointless" to me.

Quite - I agree.

 

[Lewisham2221]

So if the doors open and the engine doesn't go off, the handbrake has not been applied?

No, the doors won't open unless the handbrake is applied.

== Doublepost prevention - post automatically merged: 5 Oct 2024 ==

I drive some where it's on the handbrake, not the doors but as stated above, a lot of the time drivers will just use the footbrake at lights. It can be quite tiresome with it stopping and starting all the time especially as they get older and fail to start sometimes meaning you need to go through the start up procedure again and again.

That must be an absolute nightmare if you use the handbrake at a junction and you've then got to take into account the engine restart when calculating how much of a gap you need to pull out?

 

[73001]

No, the doors won't open unless the handbrake is applied.

== Doublepost prevention - post automatically merged: 5 Oct 2024 ==


That must be an absolute nightmare if you use the handbrake at a junction and you've then got to take into account the engine restart when calculating how much of a gap you need to pull out?

If it works properly it's a second or two at the most... nowhere as bad as the delay you get with some buses where you put your foot down and then several seconds later the bus decides it's going to go - awful on busy roundabouts.

 

[Dai Corner]

No, the doors won't open unless the handbrake is applied.

== Doublepost prevention - post automatically merged: 5 Oct 2024 ==


That must be an absolute nightmare if you use the handbrake at a junction and you've then got to take into account the engine restart when calculating how much of a gap you need to pull out?

You take the handbrake off, engage first gear and hold on the clutch and footbrake when you see a potential opportunity to pull out approaching.

 

[py_megapixel]

It's called choices I'm not an environment zealot, less wear on my starter motor and engine, the constant stopping and starting annoys me.

FYI China and India are the biggest polluters on the Earth, the UK puts out only a fraction of what they pump out.

This has very little to do with global scale CO2 emissions and much more to do with local air quality and possibly also noise pollution.

 

[Merle Haggard]

When starting a diesel engine (in, for example, a bus) the conventional design of pump automatically moves the fuel rack to full fuel. As diesels rarely fire on the first theoretical firing stroke this means that, when it starts up it initially emits a mist of (obviously unburnt) diesel fuel. This is regarded as very unhealthy, perhaps more so than the products of diesel combustion. I wonder which is more hazardous to health; diesel fumes for 10 seconds or a cloud of atomised fuel? It's not a straightforward comparison.

 

[Spsf3232]

You take the handbrake off, engage first gear and hold on the clutch and footbrake when you see a potential opportunity to pull out approaching.

Slightly impossibly when most buses are now automatic.

Foot on break, engage drive, hand brake off and go. Or rev it with handbrake on to build revs up and release