In article . 170,
Adrian wrote:
Though it is an oddity of the regs that, rather than having blanket
regulations for particular classes of vehicle, that it distinguished
between different fuel types.

It's an oddity in that it says "This is what you do to the exhaust"
rather than "This is what you should be shoving out the exhaust" -
legislating the means not the target.

You've not been paying attention. There are no regs requiring a cat. on a
petrol engine - merely that what comes out of the exhaust passes the spec
for emissions. Which in practice means a cat. - although some engines come
very close without one.

A hint of lobbying from the precious metal miners, p'raps?

Oh, and LB can't meet the NOx regulations specified for petrol engines.

It can't... at the state of development it was left in when compulsory
cats killed it.

It was widely publicised that they could never meet the NOX emissions regs.

--
*I don't suffer from insanity, I enjoy every minute of it *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) ) gurgled happily, sounding
much like they were saying :

It's an oddity in that it says "This is what you do to the exhaust"
rather than "This is what you should be shoving out the exhaust" -
legislating the means not the target.

You've not been paying attention. There are no regs requiring a cat.
on a petrol engine - merely that what comes out of the exhaust passes
the spec for emissions.

You sure? MOT certainly doesn't, but C&U does.

Oh, and LB can't meet the NOx regulations specified for petrol
engines.

It can't... at the state of development it was left in when
compulsory cats killed it.

It was widely publicised that they could never meet the NOX emissions
regs.

At the state of development it was at at the time.
Who knows what further active development would have resulted in?

John Wright wrote:
On Fri, 30 Dec 2005 00:38:20 +0000 (GMT), "Dave Plowman (News)"
wrote:
John Wright wrote:

If there was a possibility of them passing after more development,
why would this stop if they had other benefits?

I think Honda, Toyota and others are still doing the research. But
whatever they do it will need a cat as well for type approval.

Or Type Approval will get changed when the reasons are sound enough.

LED lights weren't allowed until fairly recently, IIRC. Now they are even
used for pressure sensitive brake lights. Damn good idea.

Add a double flashing hazard light for when you can only see one on a parked
up truck and we're getting somewhere.

"Adrian" wrote
DavidR ) gurgled happily, sounding much like

Oh, and LB can't meet the NOx regulations specified for petrol engines.

It can't... at the state of development it was left in when compulsory
cats killed it.

NOx is a function of heating the air, not a combustion product. How do you
lower temperature and keep efficient?

Given LB uses excess air (more free oxygen), perhaps it makes NOx even
worse?

"Dave Plowman (News)" wrote
DavidR wrote:


If there was a possibility of them passing after more development, why
would this stop if they had other benefits?

It didn't stop development. Diesels are lean burn.

The power output of a diesel is controlled by the amount of fuel
injected.

Yes, as a petrol engine.

In principle is there any reason, other than the technical difficulty in
implementation, why a petrol engine couldn't have a fuel demand valve
connected to the pedal with the engine management determining the necessary
throttle setting?

Not the same thing.

Diesel requires excess air. LB requires excess air.

In article ,
DavidR wrote:
The power output of a diesel is controlled by the amount of fuel
injected.

Yes, as a petrol engine.

No. A petrol engine is controlled by the amount of air admitted via the
throttle. Petrol is then injected to give the correct mixture. This is one
major reason why petrol engines are less efficient at part throttle -
pumping losses. There are developments to change this like using variable
valve timing rather than a throttle, but IIRC still only in development.

In principle is there any reason, other than the technical difficulty in
implementation, why a petrol engine couldn't have a fuel demand valve
connected to the pedal with the engine management determining the
necessary throttle setting?

Because petrol can only burn satisfactorily within a small range of
fuel/air ratio.

Not the same thing.

Diesel requires excess air. LB requires excess air.

The wherewithal to allow diesel to burn when injected is always present -
the air within the cylinders is compressed to a point where the heat from
this will ignite the injected fuel. Petrol engines don't and can't work
like this.

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
The wherewithal to allow diesel to burn when injected is always present
- the air within the cylinders is compressed to a point where the heat
from this will ignite the injected fuel. Petrol engines don't and can't
work like this.
They can and in some cases do. A few years ago it became a requirement
for a tank to run on any fuel from petrol to diesel, and the experiment
succeeded, the only problem was that as the fuel fractions go lighter so
the fuel economy got worse.
--
Clive

PC Paul wrote:
LED lights weren't allowed until fairly recently, IIRC. Now they are even
used for pressure sensitive brake lights. Damn good idea.

They can be bought for cars, etc. What are the regulations
on these (cluster) lamps (they can be much brighter than
incandescent lamps)?

Add a double flashing hazard light for when you can only see one on a parked
up truck and we're getting somewhere.

Hm.

Dave Plowman (News) ) gurgled happily, sounding
much like they were saying :

The power output of a diesel is controlled by the amount of fuel
injected.

Yes, as a petrol engine.

No. A petrol engine is controlled by the amount of air admitted via
the throttle. Petrol is then injected to give the correct mixture.
This is one major reason why petrol engines are less efficient at part
throttle - pumping losses. There are developments to change this like
using variable valve timing rather than a throttle, but IIRC still
only in development.

Don't forget that BMW have had a throttle-less petrol in production for a
few years.

In principle is there any reason, other than the technical difficulty
in implementation, why a petrol engine couldn't have a fuel demand
valve connected to the pedal with the engine management determining
the necessary throttle setting?

Sounds like fairly conventional fuel injection to me...

Because petrol can only burn satisfactorily within a small range of
fuel/air ratio.

Using conventional stochiometry, yes - around 14:1. Which isn't actually
the best range for either economy or power, but is the limited range around
which a conventional three-way cat works for best emissions - hence
lambdas.

LeanBurn is somewhere around 25:1 - which brings NOx back down again
according to http://www.designnews.com/article/CA159977.html

"PC Paul" wrote in message
...

Add a double flashing hazard light for when you can only
see one on a parked up truck and we're getting somewhere.

This would be the "I matter and other people don't, so I'm going to park
where the hell I like" sort of hazard?

IMO anyone who uses hazard lights when there is another vehicle parked
behind them should be prosecuted. They look just like someone who wants to
pull out, which shows down drivers who always stop to let a car pull out. Of
course, if you're the sort of driver who never lets anyone pull out, it
wouldn't bother you.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

John Rowland wrote:
"PC Paul" wrote in message
...

Add a double flashing hazard light for when you can only
see one on a parked up truck and we're getting somewhere.

This would be the "I matter and other people don't, so I'm going to
park where the hell I like" sort of hazard?

IMO anyone who uses hazard lights when there is another vehicle parked
behind them should be prosecuted.

What about when they've been stopped for a while and someone pulls up behind
them?

"Dave Plowman (News)" wrote
DavidR wrote:

In principle is there any reason, other than the technical difficulty in
implementation, why a petrol engine couldn't have a fuel demand valve
connected to the pedal with the engine management determining the
necessary throttle setting?

Because petrol can only burn satisfactorily within a small range of
fuel/air ratio.

That doesn't answer the question.

Not the same thing.

Diesel requires excess air. LB requires excess air.

The wherewithal to allow diesel to burn when injected is always present -
the air within the cylinders is compressed to a point where the heat from
this will ignite the injected fuel. Petrol engines don't and can't work
like this.

You're only describing the difference in method of ignition.

In article ,
DavidR wrote:
In principle is there any reason, other than the technical difficulty in
implementation, why a petrol engine couldn't have a fuel demand valve
connected to the pedal with the engine management determining the
necessary throttle setting?

Because petrol can only burn satisfactorily within a small range of
fuel/air ratio.

That doesn't answer the question.

Then there's no point continuing.

--
*Never slap a man who's chewing tobacco *

Dave Plowman London SW
To e-mail, change noise into sound.

"Brimstone" wrote in message
...
John Rowland wrote:
"PC Paul" wrote in message
...

Add a double flashing hazard light for when you can only
see one on a parked up truck and we're getting somewhere.

This would be the "I matter and other people don't,
so I'm going to park where the hell I like" sort of hazard?

IMO anyone who uses hazard lights when there is
another vehicle parked behind them should be prosecuted.

What about when they've been stopped
for a while and someone pulls up behind them?

If they are stopped for a while in a place where they are a hazard, they
should have stopped somewhere else.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

John Rowland wrote:
"Brimstone" wrote in message
...
John Rowland wrote:
"PC Paul" wrote in message
...

Add a double flashing hazard light for when you can only
see one on a parked up truck and we're getting somewhere.

This would be the "I matter and other people don't,
so I'm going to park where the hell I like" sort of hazard?

IMO anyone who uses hazard lights when there is
another vehicle parked behind them should be prosecuted.

What about when they've been stopped
for a while and someone pulls up behind them?

If they are stopped for a while in a place where they are a hazard,
they should have stopped somewhere else.

Which fails to answer the question. "A while" could the few minutes it takes
a delivery driver to get the item being delivered out of the loadspace.

Ian_m wrote:

Best cars, maybe 18% efficiency, power stations lucky if 25%, fluidised coal
bed stations can reach 33% efficiency.

diesel engines are better. the most efficient non vehicular diesel
engine can achieve over 50% efficiency.

a demonstration 1 litre car was able to travel over 100km on 0.89
litres of fuel. in practice production cars can do 100km on 3 litres of
fuel.

shokk

"Dave Plowman (News)" wrote
DavidR wrote:

In principle is there any reason, other than the technical difficulty
in
implementation, why a petrol engine couldn't have a fuel demand valve
connected to the pedal with the engine management determining the
necessary throttle setting?

Because petrol can only burn satisfactorily within a small range of
fuel/air ratio.

That doesn't answer the question.

Then there's no point continuing.

Well it does seem odd when your replies essentially say "they're not
the same because they're different" but on consideration, I think I see
what you were trying to say.

In a diesel a droplet of fuel will spontaneously combust because the air
surrounding it is hot.

A petrol engine requires a chain reaction where the flame from one droplet
reaches the next and if the distance from one droplet to the next is too
great, the fire goes out. I guess that in a petrol lean burn engine keeping
fuel saturated air and plain air separate is the main stumbling block.

Apart from the differences in ignition, I would still say that the fact of
having excess air is the qualification for lean burn.

In message , DavidR
writes
In a diesel a droplet of fuel will spontaneously combust because the
air surrounding it is hot.
If it works with diesel, then it'll work with all lighter fractions.
--
Clive

In article ,
Clive wrote:
In a diesel a droplet of fuel will spontaneously combust because the
air surrounding it is hot.

If it works with diesel, then it'll work with all lighter fractions.

Then put petrol in a diesel car and see if it will run.

--
*Where do forest rangers go to "get away from it all?"

Dave Plowman London SW
To e-mail, change noise into sound.

On Mon, 02 Jan 2006 01:17:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Clive wrote:
In a diesel a droplet of fuel will spontaneously combust because the
air surrounding it is hot.

If it works with diesel, then it'll work with all lighter fractions.

Then put petrol in a diesel car and see if it will run.

I did (a full tankfull) and it does.

But I dd get it drained down within 300 metres.

I don't know what would have happened if I hadn't, AIUI there is an
incompatibility risk to seals within the fuel pump/injection system

I was on the point of departing on a 5,000 mile tour round Europe
culminating in Krakow, Poland, and my diesel mechanic's 17 year old
daughter was coming with us in the car.

He became insistant that we drained down and discarded the tankfull of
fuel. :-(

We got there, and back!

DG

In message , AJH
writes
hence it has a cetane rating which is sort of opposite to octane
rating,
What rubbish, one has 10 Carbons in a chain, the other has 8. How
dense do you have to be not to understand either i.c. Engines or
c.i.engines?
--
Clive

"Brimstone" wrote in message
...


John Rowland wrote:
"Brimstone" wrote in message
...
John Rowland wrote:
"PC Paul" wrote in message
...

Add a double flashing hazard light for when you can only
see one on a parked up truck and we're getting somewhere.

This would be the "I matter and other people don't,
so I'm going to park where the hell I like" sort of hazard?

IMO anyone who uses hazard lights when there is
another vehicle parked behind them should be prosecuted.

What about when they've been stopped
for a while and someone pulls up behind them?

If they are stopped for a while in a place where they are a hazard,
they should have stopped somewhere else.

Which fails to answer the question. "A while" could the few minutes it
takes a delivery driver to get the item being delivered out of the
loadspace.

This is all quite academic if this gets to light and it has backing. And
all this will be yesterday's technology when the new batteries get made
en-mass and cheap enough, then we will all be electric. Thank God.

Dave Plowman (News) wrote:
Clive wrote:

In a diesel a droplet of fuel will spontaneously combust because the
air surrounding it is hot.

If it works with diesel, then it'll work with all lighter fractions.

Then put petrol in a diesel car and see if it will run.

Of course it will, but not very well, just as an engine designed
for 5* will run, but not very well, on "premium" unleaded.

In message , AJH
writes
Both types of engine we were discussing are internal combustion engines
only the diesel is a compression ignition engine.
Both can be, as has been pointed out before, a diesel car will not run
very well on petrol, but it will run, I know, I've done it. (Mistakenly)
--
Clive

On Mon, 2 Jan 2006 10:25:56 +0000, Doctor Drivel wrote
(in message ews.net):

And
all this will be yesterday's technology when the new batteries get made
en-mass and cheap enough, then we will all be electric. Thank God.

Oh no, not the inneficient and environmentally unfriendly electric vehicle
argument again ! Hybrid=good (under the right conditions). Electric vehicles
bad - yes they look great when you don't look beyond the filler/charging
point, but that electricity comes from somewhere and there's a LOT of losses
between the original fuel and the road wheels.

On Sat, 24 Dec 2005 23:45:39 +0000, Dave Plowman (News) wrote
(in message ):

In article ,
Simon Hobson wrote:
Not to mention that to make a cat work properly, excess fuel is burned
to create the right conditions in the exhaust.

Excess fuelling will kill a cat. in short order, surely? That's why you
have a lambda sensor to keep the fuelling constant once it's gone closed
loop?

Not THAT much excess fuelling !

But an engine running on the lean side will NOT make a cat work, the fuelling
has to be very slightly rich - richer than best economy anyway. So
effectively, installing a cat means that the engine has to be set up richer
than it would be for best economy.

But, as I mentioned already, manufactuers were already experimenting with
lean burn engines with significantly reduced emissions AIUI - but since these
don't work with cats, and the regs (AIUI) mandated cats, not specific
emmissions, lean burn got shelved.

In article ,
Simon Hobson wrote:
On Sat, 24 Dec 2005 23:45:39 +0000, Dave Plowman (News) wrote
(in message ):

In article ,
Simon Hobson wrote:
Not to mention that to make a cat work properly, excess fuel is burned
to create the right conditions in the exhaust.

Excess fuelling will kill a cat. in short order, surely? That's why
you have a lambda sensor to keep the fuelling constant once it's gone
closed loop?

Not THAT much excess fuelling !

But an engine running on the lean side will NOT make a cat work, the
fuelling has to be very slightly rich - richer than best economy
anyway.

Well, modern engines seem to deliver at least as good fuel economy than
before cats. became the norm. Or actually better.

So effectively, installing a cat means that the engine has to
be set up richer than it would be for best economy.

I'd say it depends on where it's measured. A lean burn engine may give
better economy at cruise - but may be worse under other conditions. I
don't know this for a fact, but the fact is modern engines are more
efficient than when lean burn was being developed.

But, as I mentioned already, manufactuers were already experimenting
with lean burn engines with significantly reduced emissions AIUI

*Some* emissions. Not all.

- but
since these don't work with cats, and the regs (AIUI) mandated cats,
not specific emmissions, lean burn got shelved.

There have been lots of developments since - near universal multi valve
engines often with variable valve timing. These have produced more power
and torque - and rather better efficiency. Whether they would do the same
with lean burn - who can tell?

--
*When the going gets tough, the tough take a coffee break *

Dave Plowman London SW
To e-mail, change noise into sound.

"Simon Hobson" wrote in message
et...
On Mon, 2 Jan 2006 10:25:56 +0000, Doctor Drivel wrote
(in message ews.net):

And all this will be yesterday's technology
when the new batteries get made
en-mass and cheap enough, then we
will all be electric. Thank God.

Oh no, not the inneficient and environmentally
nfriendly electric vehicle argument again !
Hybrid=good (under the right conditions).

They are indeed.

Electric vehicles bad

er, no.

- yes they look great when you don't
look beyond the filler/charging
point, but that electricity comes from
somewhere and there's a LOT of losses
between the original fuel and the road wheels.

The gripe by environmentalists is that electricity is dirty and inefficient
from power station to point use with latent heat and line losses. True when
looking at heating buildings and hot water, where natural gas can be burnt
at point of use at 90% efficiency (heating your domestic hot water by
electricity is about 30% efficient end to end). However power generation is
now more efficient with energy reclaim measures in place in the newer and
more advanced stations - not to mention wind, solar, hydro etc.
However, the vehicle is another matter. It is more efficient to pour fuel
into an engine at a power station with advanced stack scrubbers, that drives
a genny, that sends the electricity down a line, then into a cars battery
and propel the car, than pour the fuel directly into a current car. 75% of
energy stored in your tank is wasted, while only a few percentage points of
energy is wasted from a battery pack - and the electric car is 100% clean at
point of use, cleaning up cities at a stroke. Electric cars are also
briliant and super quiet to to drive. The only thing that will prevent this
charge towards 100% electric is the vested interest of auto and oil giants
(who want to go hydrogen and fuel cell as well) and lack of political will -
and ignorance too. Interesting times ahead and the back of filthy
agricultural diesels we may see for good

Doctor Drivel wrote:

[snip] It is more efficient to pour
fuel into an engine at a power station with advanced stack scrubbers,
that drives a genny, that sends the electricity down a line, then into a
cars battery and propel the car, than pour the fuel directly into a
current car.

Utter ****e, as usual.

75% of energy stored in your tank is wasted,

Incorrect.

while only a
few percentage points of energy is wasted from a battery pack - and the
electric car is 100% clean at point of use, cleaning up cities at a
stroke.

Dumping the **** in someone's back garden.

Electric cars are also briliant and super quiet to to drive.
The only thing that will prevent this charge towards 100% electric is
the vested interest of auto and oil giants (who want to go hydrogen and
fuel cell as well) and lack of political will - and ignorance too.
Interesting times ahead and the back of filthy agricultural diesels we
may see for good

You really are as mad as a box of frogs.

"Steve Firth" wrote in message
...
Doctor Drivel wrote:

[snip] It is more efficient to pour fuel into an engine at a power
station with advanced stack scrubbers, that drives a genny, that sends
the electricity down a line, then into a cars battery and propel the car,
than pour the fuel directly into a current car.

Utter ****e, as usual.

Well you used to kicking that. What else does he say....

75% of energy stored in your tank is wasted,

Incorrect.

Yes he did inaccurately say that. It's all that ****e kicking that does it.

while only a few percentage points of energy is wasted from a battery
pack - and the electric car is 100% clean at point of use, cleaning up
cities at a stroke.

Dumping the **** in someone's back garden.

Hopefully yours.

Electric cars are also briliant and super quiet to to drive. The only
thing that will prevent this charge towards 100% electric is the vested
interest of auto and oil giants (who want to go hydrogen and fuel cell as
well) and lack of political will - and ignorance too. Interesting times
ahead and the back of filthy agricultural diesels we may see for good

You really are as mad as a box of frogs.

Yes, he did say that, yes he said a 'box of frogs'

"John Wright" wrote in message
news
On Mon, 2 Jan 2006 23:34:16 +0000, Simon Hobson
wrote:

On Mon, 2 Jan 2006 10:25:56 +0000, Doctor Drivel wrote
(in message ews.net):

And
all this will be yesterday's technology when the new batteries get made
en-mass and cheap enough, then we will all be electric. Thank God.

Oh no, not the inneficient and environmentally unfriendly electric vehicle
argument again ! Hybrid=good (under the right conditions). Electric
vehicles
bad - yes they look great when you don't look beyond the filler/charging
point, but that electricity comes from somewhere and there's a LOT of
losses
between the original fuel and the road wheels.

Roll on fuel cells.

If battery technology progresses like it is, then even these will be
by-passed to direct electric drives.

Doctor Drivel ) gurgled happily, sounding much like
they were saying :

Roll on fuel cells.

If battery technology progresses like it is, then even these will be
by-passed to direct electric drives.

Battery technology will ALWAYS have the problem of the charging delay.

In article , Steve Firth says...

75% of energy stored in your tank is wasted,

Incorrect.

I think he's going along the lines that the average petrol engine is
only 25% efficient.


--
Conor

I'm so grateful to the USA for their contribution to the war on terror.
After all, if they hadn't funded the IRA for 30 years, we wouldn't know
what terror was.

"Conor" wrote in message
t...
In article , Steve Firth says...

75% of energy stored in your tank is wasted,

Incorrect.

I think he's going along the lines that the average petrol engine is
only 25% efficient.

Yes. He couldn't figure this simple thing out.

"John Wright" wrote in message
...
On Tue, 3 Jan 2006 11:43:18 -0000, "Doctor Drivel"
wrote:
"John Wright" wrote in message
news
On Mon, 2 Jan 2006 23:34:16 +0000, Simon Hobson
wrote:

On Mon, 2 Jan 2006 10:25:56 +0000, Doctor Drivel wrote
(in message ews.net):

And
all this will be yesterday's technology when the new batteries get
made
en-mass and cheap enough, then we will all be electric. Thank God.

Oh no, not the inneficient and environmentally unfriendly electric
vehicle
argument again ! Hybrid=good (under the right conditions). Electric
vehicles
bad - yes they look great when you don't look beyond the filler/charging
point, but that electricity comes from somewhere and there's a LOT of
losses
between the original fuel and the road wheels.

Roll on fuel cells.

If battery technology progresses
like it is, then even these will be
by-passed to direct electric drives.

Batteries have to be supplied with energy
from somewhere (either
chemical or other electricity generation
sources).

Yes you are right. The normal methods via a power station appear very good.
The new Toshiba batteries can be 80% charged in 3 mins a and 100% in 5 or 6.
Just pull up into a charging station, which may have downloaded electricity
overnight, and take a zap as quick as filling petrol. Many will charge
their batteries overnight too, taking strain from the system.

"Adrian" wrote in message
. 244.170...
Doctor Drivel ) gurgled happily, sounding much like
they were saying :

Roll on fuel cells.

If battery technology progresses like it is, then even these will be
by-passed to direct electric drives.

Battery technology will ALWAYS have
the problem of the charging delay.

Not with the new Toshiba batteries it doesn't.

Conor wrote:
In article , Steve Firth says...

75% of energy stored in your tank is wasted,
Incorrect.

I think he's going along the lines that the average petrol engine is
only 25% efficient.

Which would be fine if it were true.

In article , Steve Firth says...
Conor wrote:
In article , Steve Firth says...

75% of energy stored in your tank is wasted,
Incorrect.

I think he's going along the lines that the average petrol engine is
only 25% efficient.

Which would be fine if it were true.

It's the "standard" reference figure for a petrol engine as is 40% for
diesel.

--
Conor

I'm so grateful to the USA for their contribution to the war on terror.
After all, if they hadn't funded the IRA for 30 years, we wouldn't know
what terror was.

"Adrian" wrote in message
. 244.170...
Doctor Drivel ) gurgled happily, sounding much like they
were saying :

Battery technology will ALWAYS have
the problem of the charging delay.

Not with the new Toshiba batteries it doesn't.

They charge *instantly*? Off a domestic power supply?

extremely sceptical

Trickle on domestic and commercial stations a big zap using appropriate
equipment of course

I recall one idea was to have two battery packs and one trickling in the
garage and one in the car. The packs slotted in. Just an idea that sounded
useful.


I can "recharge" 600 miles+ of
70mph range into my current car in less than
five minutes.

Do you tow a tank?

To do that with batteries would require
either an IMMENSELY high charging
current or a MASSIVE decrease in
the current required to run the car.

Nope. The new batteries are very different. Don't judge by what you are
familiar with.

"Conor" wrote in message
t...
In article , Steve Firth says...
Conor wrote:
In article , Steve Firth says...

75% of energy stored in your tank is wasted,
Incorrect.

I think he's going along the lines that the
average petrol engine is
only 25% efficient.

Which would be fine if it were true.

It's the "standard" reference figure for a petrol engine as is 40% for
diesel.

A diesel is more like 30-33%. Even 40% is hopeless.