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

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)

"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?

)

Ian1

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?

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

Sounds like it could be as unreliable as it bendy predecessor. I
wonder when one will catch fire?

Neill

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)

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

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

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.
--
Roland Perry