Re: OT - Diesel engines
- From: "Scruff" <scruffyted@xxxxxxxxxxx>
- Date: Wed, 05 Sep 2007 20:01:27 GMT
"Recliner" <nigelp@xxxxxxxxxxxxxxx> wrote in message
news:1188984744.22660.0@xxxxxxxxxxxxxxxxxxxxxxxxx
"Terry Harper" <terry.harper@xxxxxxxxxxxxxx> wrote in message
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On Tue, 04 Sep 2007 01:19:30 -0700, guy <guyswettenham@xxxxxxxxxxxxxx>
wrote:
Last year I made about 20 trips from Edinburgh to home by car .19
Octavia PD diesel 136hp = so nothing special. every trip took 3hrs
10mins +-10secs, same driving conditions, traffic etc every trip.
However, when the outside temperature was 24C I got about 63-63 MPG
(trip computer), when it was 15C I got about 56-57MPG. obviously
there is the fuel cost in keeping the engine hot but this seems a big
difference.
Any explanations?
It's not just diesels. Our Suzuki Wagon R shows a definite variation
through the seasons, from about 37mpg in winter to 42 mpg in summer.
Most of the journeys are short, so much of that can be put down to
longer warming-up times.
Don't trust the trip computer, by the way. Tank brim full to brim full
is the only reliable way, and even that will vary. In theory, engines
are more efficient if the intake air is cold, less so if it is hot.
This may be an accurate way of measuring the fuel consumed, but the
mileage shown on the odometer is also not precisely accurate. Quite apart
from any internal inaccuracies, the tyre pressures will also affect it --
if you over-inflate the tyres, you will be recorded as travelling fewer
miles than if you under-inflate them. This will affect any calculations of
mpg, whether by trip computer or brim-to-brim calculations. I assume this
effect will be greater with higher than lower profile tyres.
I've compared the odometer readings with GPS readings and distances
predicted by Autoroute, and the car tends to claim to have travelled a bit
further than I would have expected.
Its also windier in winter, wind direction and strength makes a big
difference.
The skoda will probably have climate control which will heat more at lower
temperatures and cool more in higher temperatures, depending on what
temperature it is set at will affect fuel economy.
leaving the heated rear screen and mirrors on (my favourite trick!) affect
economy too, as will having the lights on.
.
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- OT - Diesel engines
- From: guy
- Re: OT - Diesel engines
- From: Terry Harper
- Re: OT - Diesel engines
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