Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
DPF ? The reason for poor economy?
ED209
 

Posts: 1,128
Joined: Aug 2011
Location: durham
Post: #1
DPF ? The reason for poor economy?

The below refers to a volvo but as our cars will have DPF could it be the same reason most are struggling to get anywhere near claimed economy figures?

http://www.telegraph.co.uk/motoring/cara...onomy.html

td4 Pure manual in orkney grey, auto wipers/lights, front fogs, spare wheel. carmats4u mats, travall dog guard. Collected 30/03/12.
09-04-2012 08:20pm
Find all posts by this user Quote this message in a reply
ytshome
 

Posts: 550
Joined: Aug 2011
Location: Cheshire
Post: #2
RE: DPF ? The reason for poor economy?

Wouldn't surprise me Ed. mostly short trips I'm still just under 28 mpg.

Arrived. Prestige SD4 Auto 5DR OG September 11
09-04-2012 11:02pm
Find all posts by this user Quote this message in a reply
ED209
 

Posts: 1,128
Joined: Aug 2011
Location: durham
Post: #3
RE: DPF ? The reason for poor economy?

Been reading up a bit and yes it looks like the engine burns more fuel in order to in crease exhaust temp and regenerate the dpf so fuel consumption is increased. First sign of an issue mine is getting replaced with a piece of stainless steel.

td4 Pure manual in orkney grey, auto wipers/lights, front fogs, spare wheel. carmats4u mats, travall dog guard. Collected 30/03/12.
09-04-2012 11:11pm
Find all posts by this user Quote this message in a reply
PhilSkill
 

Posts: 3,880
Joined: Jun 2011
Location: Warwickshire
Post: #4
RE: DPF ? The reason for poor economy?

Certainly not going to help mpg using fuel to regenerate and needing to drive the car with higher revs to do it, also DPF is another thing in the exhaust flow restricting the Engine so less mpg again. Another EU foolish decision in the misconception of what constitutes green values for planet earth, using up rare earth minerals to remove some soot from exhausts and waste further oil doing it.

One would hope the DPF was fitted in the official mpg tests...?

Note the official tests are also done without any ancilliaries like Air con, heaters, audio etc on

MY12 Fuji Dynamic SD4 Manual, Pano Roof, Electric Tailgate with own Close module
[Image: 124529.png][Image: 1004887.png]
09-04-2012 11:21pm
Find all posts by this user Quote this message in a reply
mickydd
 

Posts: 132
Joined: Aug 2011
Location: Halifax
Post: #5
RE: DPF ? The reason for poor economy?

Ed, This looks like it could well be the reason for the poor mpg.
See below copy of actual mpg for Evoque against manufacturers declared mpg.
There is as we all know, a substantial difference.
Enter your own real world mpg here:
http://www.honestjohn.co.uk/RealMpg/Resu...land-rover


Attached File(s) Thumbnail(s)
   

Arrived 24th February. Dynamic 5 dr SD4, manual ,Firenze with Verve interior, 20" Sparkle
(This post was last modified: 09-04-2012 11:30pm by mickydd.)
09-04-2012 11:22pm
Find all posts by this user Quote this message in a reply
J77
 

Posts: 1,272
Joined: Jul 2011
Location: Fife
Post: #6
RE: DPF ? The reason for poor economy?

I don't have a problem with fuel economy regularly hit 42mpg and have had it at 48.9 mpg not what LR claim but I wasn't expecting it to. At the moment just on short journeys it's about 35mpg.

Does it burn extra fuel? That depends whether it is a passive DPF or an active DPF. On active DPFs the
ECU makes changes to the fuel injectors to allow the regeneration process to take place. Passive DPFs are cleaned by long drives allowing the exhaust to reach a high enough temperature to start the regeneration process. According to the owners manual it should take about 10-20mins at speeds between 40-70mph to regenerate, so I would assume it is a passive DPF.

The above is just how I interpret the information I have read I am no mechanic so please don't shoot me down in flames if it is wrong.

18MY Range Rover Velar R-Dynamic SE D240
(This post was last modified: 10-04-2012 01:05am by J77.)
10-04-2012 12:38am
Find all posts by this user Quote this message in a reply
RacingSnake
 

Posts: 1,267
Joined: Sep 2011
Location: Reading
Post: #7
RE: DPF ? The reason for poor economy?

But the DPF also causes a whopping great restriction in the exhaust flow.

It is pretty well known that DPF's severly reduce economy, which is why there are kits to enable you to remove them and bolt them back for the MOT.
I was chatting to a tuning friend of mine and he said that in the 'VW' world someone has developed a switchable DBF (and CAT) bypass system.


It does however make me wonder about the comment up there ^^^ as to whether they were fitted to the economy tests run by LR... after all, would the pre-production cars need to adhere to type approval? I assume not?

Ordered: Fuji Dynamic Lux Coupe / style 7 wheels / Privacy glass / adaptive xenons / something else which I've forgotton.
Should be end of April (was March, then April, then end of May/June).
Collected, Friday 13th Shocked April 2012
10-04-2012 07:23am
Visit this user's website Find all posts by this user Quote this message in a reply
XFullFatTim
Bat wielding forum enforcer

Posts: 9,295
Joined: Oct 2010
Location: Somewhere between here and there.
Post: #8
RE: DPF ? The reason for poor economy?

I think you are all missing a point here guys...................... we are all whinging that the Evoque in diesel engined form is not meeting it's official claimed figures - the fact that there is a DPF there is of no consequence because for the official tests the car must have had a DPF fitted. A DPF will have had to be fitted to the test car to gain homologation/ type approval as construction rules require one.

A Pangea Green New Defender 110 First Edition is now sitting on my drive alongside British Racing Green Electric Mini Cooper SE Level 3. After 21 years in my hands my TDI300 90 was handed on to the next custodian on 15 July 2022.
(This post was last modified: 10-04-2012 09:27am by XFullFatTim.)
10-04-2012 09:24am
Find all posts by this user Quote this message in a reply
ED209
 

Posts: 1,128
Joined: Aug 2011
Location: durham
Post: #9
RE: DPF ? The reason for poor economy?

(10-04-2012 09:24am)XFullFatTim Wrote:  I think you are all missing a point here guys...................... we are all whinging that the Evoque in diesel engined form is not meeting it's official claimed figures - the fact that there is a DPF there is of no consequence because for the official tests the car must have had a DPF fitted. A DPF will have had to be fitted to the test car to gain homologation/ type approval as construction rules require one.

According to the initial post, DPF's are not included in the EU lab tests the figures come from.

td4 Pure manual in orkney grey, auto wipers/lights, front fogs, spare wheel. carmats4u mats, travall dog guard. Collected 30/03/12.
10-04-2012 09:27am
Find all posts by this user Quote this message in a reply
Donny Dog
 

Posts: 773
Joined: Feb 2012
Location: United Kingdom
Post: #10
RE: DPF ? The reason for poor economy?

(09-04-2012 11:11pm)ED209 Wrote:  Been reading up a bit and yes it looks like the engine burns more fuel in order to in crease exhaust temp and regenerate the dpf so fuel consumption is increased. First sign of an issue mine is getting replaced with a piece of stainless steel.

The engine will probably need re-mapping, though, to cater for the changed resistance in the exhaust, etc.


(10-04-2012 07:23am)RacingSnake Wrote:  which is why there are kits to enable you to remove them and bolt them back for the MOT.

It's not actually a requirement of the MOT, only for the type approval. It's a bit like the daylight running lights in that respect - you have to have them fitted, but you don't have to use them. (But the kit will need to alter the engine management to account for their removal).


(10-04-2012 09:27am)ED209 Wrote:  According to the initial post, DPF's are not included in the EU lab tests the figures come from.

If you think about it, if the regeneration process is only occasional, the test wouldn't have lasted long enough for this to happen. (The resistance, of course, would still be there, if it were fitted for the test, but I don't know what the relative effects are between the extra 'burn' and the extra exhaust resistance).
(This post was last modified: 10-04-2012 09:46am by Donny Dog.)
10-04-2012 09:40am
Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)
babyRR is an independent web site and not affiliated with Land Rover