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

[Lewisham2221]

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.

Yes, I know that's how it works in a car. I was questioning how it would work on a bus with an automatic gearbox (the stop-start buses I've driven were all of the "door open" variety).

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

Not if it's a stop-start vehicle where the engine is only going to restart when you release the handbrake though?

I suppose I'm thinking more of junctions on an incline, where you're more likely to want to keep the handbrake on to reduce the risk of rolling back. Maybe I'm just overthinking it

 

[GusB]

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?

My first encounter with stop-start technology was with a batch of Enviro 200s that Stagecoach obtained a few years ago. I can't speak for drivers, but as a passenger I honestly don't care; it hasn't had any impact on my journey time. Shutting down the engine at bus stops makes sense; stopping it at traffic lights isn't so sensible if it's likely to have any impact on traffic flow.

Why does it bother you so much?

 

[TUC]

Plenty of modern cars, including diesel, have stop-start as a default, including at traffic lights. Is that not the case with buses?

 

[Lewisham2221]

Plenty of modern cars, including diesel, have stop-start as a default, including at traffic lights. Is that not the case with buses?

With cars, stop-start generally works when you apply the handbrake, neutral & release the clutch - restarting the engine when you put the clutch back in. (No idea if, or how, it works on automatic transmission cars).

With buses, whilst stop-start has been around for a good few years now, I wouldn't say it's use was particularly widespread. It also works differently, due to the fact that modern buses have automatic transmission - so no clutch, and generally aren't put in neutral all that much.

 

[Andyh82]

I wonder how many customers think it’s a fault, especially buses with stop/start technology are mixed in on a route without it

“I didn’t think I’d ever get here Sandra, the bus kept cutting out every time it stopped”

 

[Lewisham2221]

I wonder how many customers think it’s a fault, especially buses with stop/start technology are mixed in on a route without it

“I didn’t think I’d ever get here Sandra, the bus kept cutting out every time it stopped”

I've certainly had passengers asking "why do you keep turning the engine off at every bus stop?"

 

[Mikey C]

The driver of my bus (a modern E200MMC with stop start) went to the toilet as it was the terminus, and while he was away the engine started up again!

 

[py_megapixel]

The driver of my bus (a modern E200MMC with stop start) went to the toilet as it was the terminus, and while he was away the engine started up again!

If it's like stop/start cars, it'll sometimes restart automatically to avoid draining the battery too far. I imagine the intention is that the driver fully shuts down the bus to stop this from happening if they're leaving it unattended, but it's easy to see how this could slip their mind if the engine has already stopped automatically of course.

 

[Lewisham2221]

If it's like stop/start cars, it'll sometimes restart automatically to avoid draining the battery too far. I imagine the intention is that the driver fully shuts down the bus to stop this from happening if they're leaving it unattended, but it's easy to see how this could slip their mind if the engine has already stopped automatically of course.

Wright Streetdecks disable the automatic restart when you open the cab door, to prevent this sort of thing.

 

[Ghostbus]

The phenomena of an auto stopped engine starting up again despite nothing having happened (that you can perceive?) or an unknown set delay time (oil circulation?), is extremely disconcerting.

 

[73001]

The phenomena of an auto stopped engine starting up again despite nothing having happened (that you can perceive?) or an unknown set delay time (oil circulation?), is extremely disconcerting.

Our e400MMCs do that if you are sat for a while. I've never been out of the cab though so I don't know if it would do it once the cab door is opened?

 

[Mikey C]

From memory, the driver had shut the cab door after he popped off, but the entrance door of the bus was open.

 

[ac6000cw]

With cars, stop-start generally works when you apply the handbrake, neutral & release the clutch - restarting the engine when you put the clutch back in. (No idea if, or how, it works on automatic transmission cars).

I drive an automatic transmission car with stop-start - when it's in 'drive' and the brake pedal is depressed for more than a short time when stationary, it stops the engine. It starts it again as soon as you ease off the brake pedal (which means it's possible restart the engine without fully releasing the brakes, if I want to pre-empt things). This ties in with the usual driving technique for automatics of holding it on the footbrake alone for short pauses at junctions, traffic lights and in traffic queues.

 

[PeterC]

If it's like stop/start cars, it'll sometimes restart automatically to avoid draining the battery too far. I imagine the intention is that the driver fully shuts down the bus to stop this from happening if they're leaving it unattended, but it's easy to see how this could slip their mind if the engine has already stopped automatically of course.

I have made this mistake with my car before now. Luckily the door open warning activates when I try to get out.

 

[Towers]

The phenomena of an auto stopped engine starting up again despite nothing having happened (that you can perceive?) or an unknown set delay time (oil circulation?), is extremely disconcerting.

It’s the same on cars, and is designed to protect the battery - when the engine ‘auto stops’ any auxiliary equipment, for example lights, will continue to operate. There is only a certain amount of time that the vehicle can draw enough power from a battery alone to keep it all running, so after a while the engine will restart. All part of the system!