V90 D4 MPG Improvement

[MOzS90]

Stop start was fitted to (before they changed it) gain lower road find licence rates for UK cars with the offset of environmental benefits surely??

What’s your background Quacker - give us some meat to your credibility claims. Engine designer or keyboard warrior?

[Fursty Ferret]

Believe what you like, but I've given you facts. I know how this stuff works, and what doesn't.

Why would Volvo spend money developing, testing, and certifying a technology that actually uses more fuel?

[anotherv60]

Originally Posted by Fursty Ferret

Why would Volvo spend money developing, testing, and certifying a technology that actually uses more fuel?

Type Approval testing, they get fines if fleet fuel consumption on NEDC (now alto) is to high. Dieselgate also springs to mind.

[anotherv60]

Here’s another perspective to consider. Reading reviews when the V90 launched there was criticism that the car wasn’t much more efficient that the equivalent 6 cylinder from the Germans, but the comparison is never made ( probably quite rightly as you pay for fuel used) that the V90 is up to 20% heavier than the German competition. So if they had used a 6 cyclinder the fuel consumption would have been much worse than the competitors.

Carrying an extra 200 Kg is going to be noticed in fuel consumption.

[Quacker]

Originally Posted by MOzS90

Stop start was fitted to (before they changed it) gain lower road find licence rates for UK cars with the offset of environmental benefits surely??

What’s your background Quacker - give us some meat to your credibility claims. Engine designer or keyboard warrior?

Engineering with many years in a main dealership for industrial vehicles with service vans. Many years of fault diagnosis and system efficiency diagnosis and improvement. Other businesses still owned outside of that industry as I am now retired from the automotive sector. Retired from that to concentrate on my own business eight years ago.
Yesterday was mostly spent setting up a spreadsheet for VAT recording and transfer using bridging software to HMRC VAT and submitting monthly returns for the first time in accordance with the new MTD regulations. I did this all myself and the diagnostic experience made it all rather enjoyable and plain sailing.
Rather a lot of people seem to be surprised and rather suspicious of my breadth and depth of knowledge in certain rather unusual areas of the motor industry but I have been on the inside and keen at it. That is a fairly narrow window of knowledge though, so if you were to ask me about something outside it, I would be at least as clueless as the next man or more so.
However, I do have a fair spread of knowledge of how powertrains and vehicles work and a damn site more than average. That's not boasting. It's fact. It doesn't mean I know it all though and I don't get everything right all the time, but I have no issue whatsoever admitting when I'm wrong.

[Quacker]

Originally Posted by anotherv60

Type Approval testing, they get fines if fleet fuel consumption on NEDC (now alto) is to high. Dieselgate also springs to mind.

Cars get marked down considerably in reviews and in official tests if they don't fit stop-start. In town it is beneficial more than in rural areas because there are simply more traffic lights and stop-go. It is a system that is never likely to be cost-effective but, like all emission equipment, it does contribute to cleaner air when the greater proportion of all vehicles are thusly fitted. The fuel cost saved is never likely to exceed the initial capital cost and the extra long term repair costs, steeper long term depreciation and probably the early scrapping of such cars due to that cost.

[volvocat]

Originally Posted by James77

Hmmm, I thought I had successfully updated this with car details, apparently not.

There's only one engine that returns that sort of mileage in the range, T5 currently, I suspect T6 will be a tad worse.

I don't care about fuel, you run out you fill up what's the problem. Over the period of ownership the fuel savings on diesel/vs petrol aren’t going to change your life!

I suspected as much - V90/CC...? XC60?
Perhaps surprisingly, my T6 is returning 29.4 ave.
I do care about fuel cost but maybe not that much or I wouldn't have traded a D5 for it...
I justified it by a steadily decreasing annual mileage - except that it’s such a blast to drive, maybe that trend will soon be reversed - the power, the power!

[Whaty]

I’ve just clocked over 3000 miles in the 3 months since I got my car. I drive in Comfort mode all the time and whilst I don’t drive it like a sports car, I get on with it…

I don’t take too much notice of single journey figures, but I do always record the tank to tank MPG, these are mine so far:

366.8 miles – 44.70mpg
383.6 miles – 48.69mpg
418 miles – 48.94mpg
505 miles – 49.95mpg
530.9 miles – 49.08mpg
562 miles – 52.63mpg

90% of this mileage is my daily commute, 25 miles each way, a mix of motorway, 50mph A roads and approx. 5 miles town traffic.

The eagle eyed amongst you will note these mileages do not add up to 3000 however, there was fuel in the car when I received it and this record only started from when I first filled up… and, I’m also 100 and odd miles into my current tank fill.

I’m really pleased with these numbers. I’d put the steady improvement down to the car ‘settling in’ but of course, the warmer weather may be a factor?

Terry

PS Rightly or wrongly I never use stop / start, I turn it off as soon as I set off...

[Quacker]

My XC90 D5 improved fairly consistently over the first 15,000 miles. I get 6 to 8mpg better out of it now than was the case in the first 5000 miles. It has just covered 30,000 and I think it is at its best and don't expect much, if any, further improvement in economy.

[AdamP]

Sorry for dragging up an old thread but I was looking for mpg comparisons and stumbled across it.

Coasting uses less fuel under some circumstances and more for others. Engine frictional losses increase with the (almost) square of engine speed, therefore you lose more kinetic energy to engine 'braking' at 1600rpm than you input in fuel to idle the engine at 800rpm, even at 40% thermal efficiency. Therefore if you are maintaining a speed it is more energy efficient to coast. However if you are trying to slow down it is obviously not efficient to continue to add energy (fuel) so engine braking is more efficient. My experience is that the Volvo system is pretty good at deciding when to coast and when not to, as for whether is makes a significant difference to mpg I couldn't say!