Wandering round the estate (west of Hull (city of culture)), I
notice more of these electric-petrol hybrids appearing.
Do any members of the group run these and, if so, have they any
idea on real world efficiency/economy figures?
Is an electric drive inherently more efficient than an i c engine?
Does regenerative braking make a serious
contribution to energy
I suppose it is unlikely that anyone will run a specific make and
model of petrol car then swap this for an identical spec hybrid
version. But I guess this would be the closest comparison
possible - given that it would probably be driven by the same
person in the same way on the same roads.
We got an Auris Hybrid about 6 months ago. I'm keeping a spreadsheet of
fuel purchased vs. miles driven and charting (a) mileage between
fillups, (b) average mileage over last five fillups, and (c) average
mileage since purchase.
Latest values (after about 4200 miles): (a) 59mpg (b) 58mpg (c) 55mpg.
It does seem to mean that if you happen to do a period of start/stop,
consumption does not shoot up as it would without a battery.
Consumption so far is somewhat better than the diesel C4 we had before,
and emissions should be better as there is less carbon in a litre of
petrol than a litre of diesel.
One for car experts.
This car has a screen where a bar chart shows consumption over the last
15 minutes in 1 minute intervals. It also shows, in symbols, how much
energy has been saved by regeneration during each one minute. For us,
from home into Canterbury, it seems to gather about 200Wh - we are up
highish and its downhill all the way.
Now: a litre of fuel contains about 10kWh. If a petrol engine runs at
an efficient point, I'm guessing that's about 40% efficiency. Thus, the
litre contains about 4kWh of useful energy. So I have to make 20 such
journeys to save a litre of fuel. Unfortunately it doesn't seem
possible to get the car aggregate those numbers over some period (such
as between fillups), but I may over a fillup period save mebbe a couple
of litres that would otherwise be wasted. That's about a 5% saving in
my case. That just shows up as improved fuel consumption.
"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted" -- Bill of Rights 1689
Back in the 70's, Autocar used to cover car rallies where the main
aim was use the least amount of fuel.
Even driving cars of that era, astonishing MPG was being
attained which must be down to very careful driving.
I suspect todays hybrids just superimpose the action of
a careful driver onto a normal driver to achieve the same
sort of economy.
In stop/start slow traffic a hybrid must have a massive
advantage while there is stored energy available, whereas
a gentle cross country run would show less advantage.
Yes, there's a certain amount of driver training - the displays make it like
a video game, where you're aiming to get the high score (mpg).
However that's not bad as such: if you drive it like an F1 car you'll
likely get terrible mpg - just like an F1 car. So a bit of training isn't a
bad thing. Some hybrids (eg Prius) are very conservatively built, so won't
enter the WRC anytime soon, while others are sportier - but if you drive one
sportily then expect to pay for it.
But there's still enough advantages to make it worthwhile: you probably
won't be driving around town sportily anyway, and it can still make
efficiency savings if you do.
Indeed. Though driving at 55 rather than 70 shows a marked advantage.
(I was on the motorway the other day stuck behind a crane doing 40 and it
kicked into battery-only mode - so even then it can help)
To answe the OP's questions:
I haev a 10 year old Gen2 Prius, which are getting cheap on the secondhamd
market now. I'm getting about 58mpg on the display, town or motorway.
I think the display over-reads by about 3mpg, but haven't done enough to
properly calibrate it.
Maybe I should try a tank's-worth of thrashing it, just to see how bad I can
get the average ;-)
The battery is used at times when the IC would be inefficient
The battery can provide bursts of pwoer, so the IC engine can be sized
smaller and operate in a more efficient region - eg the Prius is 1.5l for a
large-ish car that might typically be a 2l petrol.
The gearbox is simplified, reducing losses over a typical automatic
It's possible to drive entirely on electric, if you aren't going far enough
to be worth warming up the engine.
Additionally there are some IC engine energy saving tricks, eg putting the
engine oil in a Thermos flask to keep it warm when stopped. I think they
gave up on that in future models because it wasn't worth it.
I typically get 50-100Wh in 5 minutes of town driving, or decelerating from
70 to a stop at the lights at the top of a motorway ramp. That's enough to
go 1/8 - 1/4 mile. So not massive, but it helps. It also means almost
never having to change brake pads or discs.
Mine has an eco mode and a power mode as well as just so-called
"normal". It's all drive-by-wire anyway, the gas pedal is connected to
the computer, nothing else. I'm usually in power mode, but that does
not mean F1 driving, just I'd like be able to crank the speed up if
Mine won't do battery mode above about 25. But going Canterbury to
Chorley the other week, I got about 65mpg on that tankful.
Oddly enough the engine in mine is 1.8l for some reason.
There's no obfuscated Perl contest because it's pointless.
firstname.lastname@example.org laid this down on his screen :
My 2L straight diesel in a big heavy car regularly manages 50mpg solo.
I once managed over 60mpg on a single run to and from the coast. I
don't use it for town work, only open road and for towing. In towns I
use an hybrid, called a modern bus :D
If all you're going to do is 70mph cruising, they're equal in mpg to a
diesel (though the other advantages like lower maintenance still stand).
The difference is that the diesel is much worse when driven slower, while
the hybrid has a pretty much constant mpg across the range. So if you drive
on the motorway when it's congested, it does a lot better. Or you do much
town driving - there's a good reason a lot of taxis have switched to
On 11/06/2017 10:38, email@example.com wrote:
Look it up on here <https://www.honestjohn.co.uk/realmpg/ , and compare
typical driver's results with other cars. You may be an unusually
economical driver. The Prius, BTW, doesn't do as well as the book figures.
My son had an Astra diesel until recently, when he switched to a Mazda 3
Which is using less fuel.
It's a lot nicer to drive too!
Yes, low / zero road tax and exempt the congestion charge. ;-)
I guess if you are driving for your living, all that is very
But re road tax ... whist I can see it an incentive to some (those who
can't afford to pay whatever the cost ... or need otherwise (like
tradesmen etc)), if the point of road tax is to pay for using (and
maintaining) the roads, does that mean like FIT, the rest of us are
paying more just because our income / lifestyles mean we can't use or
Like, I often tow stuff and am not sure how many EV's or Hybrids can
have a tow bar?
And what when we are all driving them?
Cheers, T i m
On Sun, 11 Jun 2017 13:55:33 +0100, "Dave Plowman (News)"
About the only std car I'm aware of that isn't approved for a towbar
is a (1.3) Ka (so potentially also the Fiat 500)?
Daughter has a towbar on her 1.2 16V Corsa and it tows a small camping
/ goods trailer with no issue. ;-)
Cheers, T i m
You do have to pick through the dross. However there isn't a whole lot to
go wrong. I've seen listings for secondhand ones with 300-400K miles on
them and they still go. Bear in mind that the engine only runs when it
feels the need, so it's very easy on it.
In the >150K range, basically you should expect to budget for a new high
voltage battery (GBP950) - a bit like doing the DPF on a diesel. Around
then you tend to hit maintenance things you'd have earlier on another car:
pads/discs, spark plugs, transmission oil, coolant (radiator and inverter),
12V battery, tyres, AC regas. Almost all of those are things Toyota offers
for fixed prices (<GBP200 mostly). The drive itself is basically
Like any used car, finding one that's been treated well helps - not the one
I viewed that had no oil in it and emitted black smoke. I don't think
there's an issue with a well-kept high-miler, it's the one that's been
flogged is the problem.
I managed to avoid a couple of turkeys by reading the codes when I went to
view - when the car says 'replace HV battery now' that's probably not one
you want to be buying unless that's already priced in. Also a lot of
dealers keep them on the forecourt with a flat 12V battery - while you can
jump start them, running on a low aux supply tends to confuse the
electronics which isn't a good idea when you want to see if everything
Basically they take high miles well, they just don't like being
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