when on the move - i do lots of motorway miles and havent really noticed any change in behaviour from time to time - would be interested to know waht is up to!

 

cheers

 

John

It's very difficult to tell when on the move.

At junctions you'll notice the idle RPM is higher (around 1,000 RPM). If the engine is turned off mid way through a regen the cooling fans may stay on after the ignition is turned off combined with a slight burning smell.

Some do notice a reduction in fuel economy during the regent but I haven't.

Edited 5 January, 201511 yr by silver1011

The only way I notice when I'm moving is by the fuel economy in the maxi dot. Today, my journey was returning 52 mpg. Five miles and 15 minutes later it had dropped to 44.  It guzzles fuel like nobody's business.

 

It'd be good to have an indication that it's in progress and also an ability to postpone it. I've lost count of the number of times a regen has started at the end of my road when I've a big journey to make the day after.

If the system is calibrated correctly, you should not notice that a regeneration is happening while driving.

 

As mentioned above, when regen is active you may notice:

    - 1000rpm idle speed when stationary (Idle is always increased when the car is moving)

    - Stop Start is not available because "Engine must be running"

    - Fans running fast and/or a rubber smell when you stop the car (completely normal, just cooling the exhaust down)

    - Drop in instantaeous fuel economy

 

It would be nice if the StopStart information system would display something like "Regeneration In Progress" rather than "Engine must be running" which can be misread.

Edited 6 January, 201511 yr by Gabbo

As above. Tell tale is the higher idle and fans remaining on when the engine is shut off...also stop start wont work.

I've yet to have an active regen (where the light illuminates on the dash and you basically should drive the car at medium revs until it goes out) on any car ive owned with DPFs and im on my 4th VAG DPF equipped car.

If the system is calibrated correctly, you should not notice that a regeneration is happening while driving.

 

Surely if additional fuel is going through system you will notice a difference during driving.....i.e. it feels more responsive/lively due to additional fueling?.

A couple of times I've noticed mine has an extra "kick"......then at idle you notice the extra revs.

The DPF is a real downer i think. Appears to consume more fuel, worry me the engine is about to overheat, a smell produced as if something it melting/has melted, nullifies the start/stop.

Would have been nice for the dealer to discuss the idiosyncrasies of the DPF prior to delivery and during collection. I almost took the car back as i thought it was about to suffer a failed head gasket.

Mistake buying a DPF diesel. This has converted me to the future of petrol hybrids. I feel it's becoming the end of the general consumer diesel car. (I'm not a fleet car owner).

Surely if additional fuel is going through system you will notice a difference during driving.....i.e. it feels more responsive/lively due to additional fueling?.

A couple of times I've noticed mine has an extra "kick"......then at idle you notice the extra revs.

 

When the DPF is regenerating the extra fuel is being added very late so that it passes largely unburnt into the exhaust manifold where it then generates the increased temperatures.

As this injection is during the exhaust stroke it should not generate any additional torque.

 

However, during regeneration you would usually keep the EGR valve closed so the engine may feel slightly more response when you tip-in.

The DPF is a real downer i think. Appears to consume more fuel, worry me the engine is about to overheat, a smell produced as if something it melting/has melted, nullifies the start/stop.

Would have been nice for the dealer to discuss the idiosyncrasies of the DPF prior to delivery and during collection. I almost took the car back as i thought it was about to suffer a failed head gasket.

Mistake buying a DPF diesel. This has converted me to the future of petrol hybrids. I feel it's becoming the end of the general consumer diesel car. (I'm not a fleet car owner).

 

I think all manufacturers are lacking with the information they provide about DPF even now many years after they were first introduced.

It wouldn't be too hard to produce a small brochure explain what a DPF is how it works & the problems you may encounter if your driving profile is not suited.

 

 

However, I wouldn't agree that diesels are dead.

Modern DPF technology is very good compared to when it was first released & providing you driving for long enough periods to get the engine warm, regeneration can take place during town-driving or stop-start traffic which was not possible previously.

For many drivers they wont even know that a regeneration is happening.

 

CO2 tax, Fuel economy & the price of fuel are still a big advantage for diesel.

In many parts of Europe diesel is cheaper than petrol unlike the UK.