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New boris bus breaks down
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New boris bus breaks down
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New boris bus breaks down
On Mon, 19 Dec 2011 10:28:03 +0000
Roland Perry wrote: In message , at 09:50:09 on Mon, 19 Dec 2011, d remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. Who knows. Probably the hybrid drive system still has some issues to sort out. On the radio they said it was going northbound so perhaps they already knew about the problem and were trying to get it somewhere to sort it out but didn't make it. B2003 |
New boris bus breaks down
wrote in message
On Mon, 19 Dec 2011 10:28:03 +0000 Roland Perry wrote: In message , at 09:50:09 on Mon, 19 Dec 2011, d remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. Who knows. Probably the hybrid drive system still has some issues to sort out. On the radio they said it was going northbound so perhaps they already knew about the problem and were trying to get it somewhere to sort it out but didn't make it. I speculate that the range-extender hybrid drive is designed for stop-start operation, with the engine having lots of opportunities to charge the battery when the bus is picking up pax or stoppd in traffic. Regenerative brakes will also help keep the battery charged in stop-start traffic. The engine may not have enough continuous output for the bus to go long distances at relatively higher speeds on a motorway. It's also possible that the battery wasn't fully charged at the start of the journey. I wonder if, in normal operation, it's planned that the batteries will be fully topped up overnight in the depot? According to the Autocar review of the bus, the 4-cylinder diesel generator has a max power of only 182bhp (which is less than my car), which is used not only to charge the battery, but also to power the air compressor for the brakes and steering. The battery is rated at 75kWh. |
New boris bus breaks down
On Mon, 19 Dec 2011 11:26:32 +0000
Roland Perry wrote: The circumstances (and some of the comments) are consistent with the drive system becoming overloaded or overheated as a result of sustained high speed. I guess you mean the bit where it says "They claim the bus is not designed to drive as far as Luton and therefore it needed a break". To me that sounds like a bit of spin to disguise a problem. I can't believe the hybrid system can't cope with doing 20 miles on a motorway without overheating. That would just be **** poor engineering. Also it would've taken a week to drive it from the factory in nothern ireland. B2003 |
New boris bus breaks down
On Mon, 19 Dec 2011 11:37:34 -0000
"Recliner" wrote: According to the Autocar review of the bus, the 4-cylinder diesel generator has a max power of only 182bhp (which is less than my car), which is used not only to charge the battery, but also to power the air compressor for the brakes and steering. The battery is rated at 75kWh. Its quite enough to move a double decker on the relatively shallow inclines of a motorway even accounting for losses in converting to electical power. Most buses arn't rated at much more than that anyway. If it can't cope with steady running on a motorway with loads of nice cold air to keep it cool god knows how it'll manage in 30C in summer slowly cooking in a london traffic jam. B2003 |
New boris bus breaks down
wrote in message
On Mon, 19 Dec 2011 11:37:34 -0000 "Recliner" wrote: According to the Autocar review of the bus, the 4-cylinder diesel generator has a max power of only 182bhp (which is less than my car), which is used not only to charge the battery, but also to power the air compressor for the brakes and steering. The battery is rated at 75kWh. Its quite enough to move a double decker on the relatively shallow inclines of a motorway even accounting for losses in converting to electical power. Most buses arn't rated at much more than that anyway. If it can't cope with steady running on a motorway with loads of nice cold air to keep it cool god knows how it'll manage in 30C in summer slowly cooking in a london traffic jam. You're assuming that it overheated, rather than my guess that the battery was running low. I presume that they run the engine for optimum economy, rather than for max power. |
New boris bus breaks down
On Mon, 19 Dec 2011 11:55:54 -0000
"Recliner" wrote: You're assuming that it overheated, rather than my guess that the battery was running low. I presume that they run the engine for optimum economy, rather than for max power. I shouldn't make any difference. Once the battery is flat it runs off the engine just like every hybrid car ever built. B2003 |
New boris bus breaks down
wrote in message
On Mon, 19 Dec 2011 11:55:54 -0000 "Recliner" wrote: You're assuming that it overheated, rather than my guess that the battery was running low. I presume that they run the engine for optimum economy, rather than for max power. I shouldn't make any difference. Once the battery is flat it runs off the engine just like every hybrid car ever built. This is a range-extender hybrid, unlike most existing hybrid cars. In other words, it's more like the Volt, not the Prius (ie, not all hybrid cars are the same). So the only drive to the axle is from the 174bhp motor, powered by the battery, with the generator just acting as a part-time charger, which runs at optimum revs when it runs at all. If the engine isn't charging the battery as fast as it's discharging, the bus will have to stop or slow down for long enough for the charge to accumulate again. Autocar comments that the engine needed to run most of the time during its short road test, probably because it wasn't getting much benefit from regenerative braking, unlike on a normal bus route. This does suggest that the engine isn't really up to powering the bus for a sustained run at motorway speeds (unless the engine is pushed hard, which would destroy the excellent economy and green claims). Wright claims 11.2mpg for the Boris Bus, compared to 8.6mpg for Wright's Gemini 2 Hybrid (and 4.3mpg for a Citaro G bendy bus). The CO2 figures are also much better (640g/km, compared to 864 and 1300, respectively). |
New boris bus breaks down
On Mon, 19 Dec 2011 12:57:20 -0000
"Recliner" wrote: This is a range-extender hybrid, unlike most existing hybrid cars. In other words, it's more like the Volt, not the Prius (ie, not all hybrid cars are the same). So the only drive to the axle is from the 174bhp motor, powered by the battery, with the generator just acting as a part-time charger, which runs at optimum revs when it runs at all. If the engine isn't charging the battery as fast as it's discharging, the bus will have to stop or slow down for long enough for the charge to accumulate again. No reason it should have to stop - the power could be directed straight from generator to motor bypassing the battery. In fact thats what any sane drive system should do since there's no point directing power into the battery if its just going to be used up again immediately. Also unless a radical new battery technology has been invented the motor would almost certainly be able to drain the battery faster than the generator can charge it so I suspect the generator will be running most of the time anyway regardless of traffic conditions. The plus side as you said is it can run at an optimal rpm and regenerative braking can regain some of the energy lost. If they haven't designed the system so it can run on generator alone with a flat battery then shame on them. B2003 |
New boris bus breaks down
On Dec 19, 1:29*pm, wrote:
I shouldn't make any difference. Once the battery is flat it runs off the engine just like every hybrid car ever built. Though with only 182bhp for a vehicle that size, probably quite slowly. Most hybrid cars, by contrast, have an engine that is more than adequate to power the car on its own. Neil |
New boris bus breaks down
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New boris bus breaks down
In message , at 14:04:52 on Mon, 19 Dec
2011, d remarked: If they haven't designed the system so it can run on generator alone with a flat battery then shame on them. If the brief was "in stop-start traffic in London", then engineering it for an extended flat-out run on a motorway might not be appropriate. -- Roland Perry |
New boris bus breaks down
on Mon, 19 Dec 2011, Neil Williams remarked:
I shouldn't make any difference. Once the battery is flat it runs off the engine just like every hybrid car ever built. Though with only 182bhp for a vehicle that size, probably quite slowly. Most hybrid cars, by contrast, have an engine that is more than adequate to power the car on its own. I recall the Parry People Mover coming up as possibly another vehicle whose "top-up" internal combustion engine might not be enough to propel it on its own. -- Roland Perry |
New boris bus breaks down
On Mon, 19 Dec 2011 06:38:28 -0800 (PST)
Neil Williams wrote: On Dec 19, 1:29=A0pm, wrote: I shouldn't make any difference. Once the battery is flat it runs off the engine just like every hybrid car ever built. Though with only 182bhp for a vehicle that size, probably quite slowly. All double deckers in london are underpowered anyway. Anyone who has been stuck in a car behind one crawling its way up highgate hill or around southgate will testify to that. B2003 |
New boris bus breaks down
On Mon, 19 Dec 2011 10:28:03 +0000, Roland Perry wrote:
In message , at 09:50:09 on Mon, 19 Dec 2011, d remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. According to TfL it also ran out of fuel: https://twitter.com/#!/TfLofficial/s...78421156200448 |
New boris bus breaks down
In message , at 15:50:32 on
Mon, 19 Dec 2011, David Walters remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. According to TfL it also ran out of fuel: https://twitter.com/#!/TfLofficial/s...78421156200448 A double whammy. -- Roland Perry |
New boris bus breaks down
On Mon, 19 Dec 2011 16:24:10 +0000
Roland Perry wrote: In message , at 15:50:32 on Mon, 19 Dec 2011, David Walters remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. According to TfL it also ran out of fuel: https://twitter.com/#!/TfLofficial/s...78421156200448 A double whammy. Its probably why the battery went flat. I bet the driver was thinking "ooh this is nice and quiet on the motorway" shortly before he coasted to a stop. B2003 |
New boris bus breaks down
In message , at 16:27:49 on Mon, 19 Dec
2011, d remarked: Oh dear. Not off to a good start then. http://www.lbc.co.uk/new-routemaster...dy-photo-48777 Sounds like the battery went flat. According to TfL it also ran out of fuel: https://twitter.com/#!/TfLofficial/s...78421156200448 A double whammy. Its probably why the battery went flat. I bet the driver was thinking "ooh this is nice and quiet on the motorway" shortly before he coasted to a stop. Very possible. So it's an instrumentation failing (both for the underlying fuel shortage, and the fact that the battery was not being charged at all). The more complicated you make vehicles, the more failure modes they have. -- Roland Perry |
New boris bus breaks down
And in other news, it seems it's a perpetual motion machine in London:
"Transport for London (TfL) said the bus recharged its battery using energy from its brakes, but on long journeys had to run on diesel." http://www.bbc.co.uk/news/uk-england-london-16244634 But I'm glad I diagnosed the problem correctly (there's some value in an engineering degree after all!): "However when the bus undertakes long, non-stopping motorway journeys, such as its journey to Bedfordshire this morning, it can lose charge and the driver is briefed to pull to the side of the road to allow the battery to recharge." -- Roland Perry |
New boris bus breaks down
Roland Perry wrote on 19 December 2011 17:29:16 ...
And in other news, it seems it's a perpetual motion machine in London: "Transport for London (TfL) said the bus recharged its battery using energy from its brakes, but on long journeys had to run on diesel." http://www.bbc.co.uk/news/uk-england-london-16244634 But I'm glad I diagnosed the problem correctly (there's some value in an engineering degree after all!): "However when the bus undertakes long, non-stopping motorway journeys, such as its journey to Bedfordshire this morning, it can lose charge and the driver is briefed to pull to the side of the road to allow the battery to recharge." London to Bedfordshire is not a "long" journey. And briefing the driver to stop on a motorway is tantamount to inciting a criminal offence. A vehicle that is not able to drive from London to Luton on a motorway should not be allowed on a motorway at all. One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. -- Richard J. (to email me, swap 'uk' and 'yon' in address) |
New boris bus breaks down
"Roland Perry" wrote in message ... In message , at 14:04:52 on Mon, 19 Dec 2011, d remarked: If they haven't designed the system so it can run on generator alone with a flat battery then shame on them. If the brief was "in stop-start traffic in London", then engineering it for an extended flat-out run on a motorway might not be appropriate. Wouldn't it have been easier to string a couple of wires up above the bus routes and dispense with carrying a generator and batteries around on the bus? :o) Ian1 |
New boris bus breaks down
On Dec 19, 5:54*pm, "Richard J." wrote: Roland Perry wrote: [...] * * * * *"However when the bus undertakes long, non-stopping motorway * * * * *journeys, such as its journey to Bedfordshire this morning, it * * * * *can lose charge and the driver is briefed to pull to the side of * * * * *the road to allow the battery to recharge." London to Bedfordshire is not a "long" journey. *And briefing the driver to stop on a motorway is tantamount to inciting a criminal offence. *A vehicle that is not able to drive from London to Luton on a motorway should not be allowed on a motorway at all. One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. Er, what air conditioning? |
New boris bus breaks down
In message , at 17:54:57 on Mon, 19
Dec 2011, Richard J. remarked: And in other news, it seems it's a perpetual motion machine in London: "Transport for London (TfL) said the bus recharged its battery using energy from its brakes, but on long journeys had to run on diesel." http://www.bbc.co.uk/news/uk-england-london-16244634 But I'm glad I diagnosed the problem correctly (there's some value in an engineering degree after all!): "However when the bus undertakes long, non-stopping motorway journeys, such as its journey to Bedfordshire this morning, it can lose charge and the driver is briefed to pull to the side of the road to allow the battery to recharge." London to Bedfordshire is not a "long" journey. And briefing the driver to stop on a motorway is tantamount to inciting a criminal offence. A vehicle that is not able to drive from London to Luton on a motorway should not be allowed on a motorway at all. I tend to agree that if as a well rounded engineer, familiar with the foibles on novel solutions, I was asked to deliver that vehicle, I would probably avoid motorways. One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. It doesn't matter if much of the time it's stuck at traffic lights, during which time it can recharge. But the same issues of "duty cycle" apply to all electric and most hybrid vehicles. And let's not forget what happens in a couple of years when the batteries are beginning to retain less of their charge. I was quite disappointed to discover that the prototype hybrid double deckers in Nottingham seemed configured to glide silently to a halt at bus stops, then immediately start their engine at the exact point you'd have preferred less fumes and noise for the passengers while boarding. There's a bit more work required before this technology is optimised. -- Roland Perry |
New boris bus breaks down
Sounds like it could be as unreliable as it bendy predecessor. I
wonder when one will catch fire? Neill |
New boris bus breaks down
Mizter T wrote on 19 December 2011 18:48:13 ...
On Dec 19, 5:54 pm, "Richard wrote: Roland wrote: [...] "However when the bus undertakes long, non-stopping motorway journeys, such as its journey to Bedfordshire this morning, it can lose charge and the driver is briefed to pull to the side of the road to allow the battery to recharge." London to Bedfordshire is not a "long" journey. And briefing the driver to stop on a motorway is tantamount to inciting a criminal offence. A vehicle that is not able to drive from London to Luton on a motorway should not be allowed on a motorway at all. One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. Er, what air conditioning? I was sure I'd seen a reference to air conditioning in this thread, but the only one I can find is on londonist. It's not mentioned in the TfL press release. But the windows don't open! Are they really intending to run a new bus in summer without air conditioning AND with no means of opening any window? Perhaps this is another reason for having an open rear platform, except it won't always be open. -- Richard J. (to email me, swap 'uk' and 'yon' in address) |
New boris bus breaks down
In message , at 20:20:28 on Mon,
19 Dec 2011, Richard J. remarked: Er, what air conditioning? I was sure I'd seen a reference to air conditioning in this thread, but the only one I can find is on londonist. It's not mentioned in the TfL press release. But the windows don't open! Are they really intending to run a new bus in summer without air conditioning AND with no means of opening any window? Perhaps this is another reason for having an open rear platform, except it won't always be open. I've seen reference to "air chillers", which is a kind of aircon-lite. -- Roland Perry |
New boris bus breaks down
On Mon, 19 Dec 2011 19:24:45 +0000
Roland Perry wrote: One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. It doesn't matter if much of the time it's stuck at traffic lights, during which time it can recharge. I suspect like most hybrids the battery on its own can't power the vehicle for more than a few miles so I can't believe that the system can't power the vehicle on the generator alone. I suspect a fault. There's a bit more work required before this technology is optimised. There's probably a trade off between fuel economy and not wrecking the engine and DPF. Even a specially optimised diesel engine won't appreciate being started up and stopped dozens of times a day especially if it never really gets up to working temperature. B2003 |
New boris bus breaks down
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New boris bus breaks down
On Tue, 20 Dec 2011 11:03:50 +0000
Roland Perry wrote: In message , at 09:40:48 on Tue, 20 Dec 2011, d remarked: I suspect like most hybrids the battery on its own can't power the vehicle for more than a few miles so I can't believe that the system can't power the vehicle on the generator alone. I suspect a fault. It seems it's the other way round. The generator isn't capable of powering the bus if the bus is motoring 100% of the time. It's in effect a generator topping up the battery, which is also receives regen braking charge. So the battery [alone] is powering the bus, but the whole system will gradually run out of 'steam' if used too intensively. These are the compromises required to get the outstanding mpg. 180hp is enough to power a double decker albeit slowly. And since its unlikely that the battery could be charged faster than any charge would be taken from it then any power the generator is creating will be going to the motors - with losses via the battery - anyway. So even if after all that only say 100hp makes it to the motors it still shouldn't grind to a halt at the side of the road. B2003 |
New boris bus breaks down
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New boris bus breaks down
On Tue, 20 Dec 2011 13:01:49 +0000
Roland Perry wrote: net drain on the battery. Isn't it limited to 50mph anyway? I'd be surprised if 180hp couldn't manage that. But it's run out of diesel, dear Liza, dear Liza. I thought we were talking in the general sense now, not that specific bus. B2003 |
New boris bus breaks down
In message , at 13:51:06 on Tue, 20 Dec
2011, d remarked: net drain on the battery. Isn't it limited to 50mph anyway? I'd be surprised if 180hp couldn't manage that. You seem easily surprised. But it's run out of diesel, dear Liza, dear Liza. I thought we were talking in the general sense now, not that specific bus. No. -- Roland Perry |
New boris bus breaks down
"Roland Perry" wrote in message
In message , at 20:20:28 on Mon, 19 Dec 2011, Richard J. remarked: Er, what air conditioning? I was sure I'd seen a reference to air conditioning in this thread, but the only one I can find is on londonist. It's not mentioned in the TfL press release. But the windows don't open! Are they really intending to run a new bus in summer without air conditioning AND with no means of opening any window? Perhaps this is another reason for having an open rear platform, except it won't always be open. I've seen reference to "air chillers", which is a kind of aircon-lite. I think the driver's cab has full a/c. |
New boris bus breaks down
On Dec 19, 5:54*pm, "Richard J." wrote:
Roland Perry wrote on 19 December 2011 17:29:16 ... And in other news, it seems it's a perpetual motion machine in London: * * * * *"Transport for London (TfL) said the bus recharged its battery * * * * *using energy from its brakes, but on long journeys had to run on * * * * *diesel." http://www.bbc.co.uk/news/uk-england-london-16244634 But I'm glad I diagnosed the problem correctly (there's some value in an engineering degree after all!): * * * * *"However when the bus undertakes long, non-stopping motorway * * * * *journeys, such as its journey to Bedfordshire this morning, it * * * * *can lose charge and the driver is briefed to pull to the side of * * * * *the road to allow the battery to recharge." London to Bedfordshire is not a "long" journey. *And briefing the driver to stop on a motorway is tantamount to inciting a criminal offence. *A vehicle that is not able to drive from London to Luton on a motorway should not be allowed on a motorway at all. One wonders what the non-stop range is on a hot day with a full load and the air conditioning at full stretch. -- Richard J. (to email me, swap 'uk' and 'yon' in address) But you won't know that a vehicle is unable to drive from London to Luton on a motorway until................................oh yes you attempt to drive it from London to Luton on a motorway. Let's face it vehicles break down everyday on motorways for one reason or another, hardly a big deal is it? |
New boris bus breaks down
In message
, at 08:52:43 on Tue, 20 Dec 2011, George remarked: "Transport for London (TfL) said .... when the bus undertakes long, non-stopping motorway * * * * *journeys, such as its journey to Bedfordshire this morning, it * * * * *can lose charge and the driver is briefed to pull to the side of * * * * *the road to allow the battery to recharge." But you won't know that a vehicle is unable to drive from London to Luton on a motorway until................................oh yes you attempt to drive it from London to Luton on a motorway. It sounds like TfL had an idea it would run out of battery; I wonder if it has a "miles to empty" display [for the battery] like my ten year old petrol car does [for the petrol]? Let's face it vehicles break down everyday on motorways for one reason or another, hardly a big deal is it? Indeed, especially as this would seem to be an empty fuel tank rather than anything more sinister. -- Roland Perry |
New boris bus breaks down
"Roland Perry" wrote in message
In message , at 08:52:43 on Tue, 20 Dec 2011, George remarked: "Transport for London (TfL) said ... when the bus undertakes long, non-stopping motorway journeys, such as its journey to Bedfordshire this morning, it can lose charge and the driver is briefed to pull to the side of the road to allow the battery to recharge." But you won't know that a vehicle is unable to drive from London to Luton on a motorway until................................oh yes you attempt to drive it from London to Luton on a motorway. It sounds like TfL had an idea it would run out of battery; I wonder if it has a "miles to empty" display [for the battery] like my ten year old petrol car does [for the petrol]? Even if it does, I suspect it's not well callibrated on this early build/prototype model. Let's face it vehicles break down everyday on motorways for one reason or another, hardly a big deal is it? Indeed, especially as this would seem to be an empty fuel tank rather than anything more sinister. Which might mean that the (diesel) fuel gauge is also innacurate in this early model. |
New boris bus breaks down
In message , at 17:54:20 on
Tue, 20 Dec 2011, Recliner remarked: Indeed, especially as this would seem to be an empty fuel tank rather than anything more sinister. Which might mean that the (diesel) fuel gauge is also innacurate in this early model. It could easily be broken. -- Roland Perry |
New boris bus breaks down
Recliner wrote:
Which might mean that the (diesel) fuel gauge is also innacurate in this early model. Of course, if it's like the original Routemasters, the fuel gauge is a piece of calibrated plywood which goes through the fuel filler. -- Tciao for Now! John. |
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