Help me drive my diesel car more efficiently

[cRiPpLe_rOoStEr]

Originally Posted by sotiris.bos

My only concern is that this kind of driving may harm the DPF.

Have you ever considered getting a custom ECM tuning with a low-saturation mode to protect the DPF, or even a DPF delete?

[sotiris.bos]

Originally Posted by cRiPpLe_rOoStEr

Have you ever considered getting a custom ECM tuning with a low-saturation mode to protect the DPF, or even a DPF delete?

Not really because the car has a five year warranty and I wouldn't like to void it.

[houseofdiesel]

If you want to beat the rated fuel economy you need to slow down, max 90km/h. Shift as early as possible, say 1600-1800 pms and stay out of boost. Modern diesels add fuel under boost these days to keep emissions down, unlike the old days where boost was free to some extent.
My DSG equipped VW 2L TDI is quite happy running around under 1600rpms, it does all the shifting and never has to see 2000rpm ever, and I can easily beat the posted FE on longer trips.
Let it die on hills, do not increase the throttle but keep a constant load and then lift up a bit on the down hills. Running a scangauge or read out on the dash is essential for this. Diesels of all types prefer a constant load, turbo or not. They hate hard use in terms of fuel economy, better then a gas engine but will never deliver good results when driven hard (the 80% rule doesn't work on turbo diesels, too much fueling).
Yes, this sort of driving is less then ideal on the VNT system (turbo vanes) over the long run, they need some exercise to stay free however the DPF will thank you, running light loads and not punching the throttle will keep it very clean, it is sharp throttle responses that load it up with soot. It will cycle itself as needed, no worry about it getting hot!

[sotiris.bos]

Originally Posted by houseofdiesel

If you want to beat the rated fuel economy you need to slow down, max 90km/h. Shift as early as possible, say 1600-1800 pms and stay out of boost. Modern diesels add fuel under boost these days to keep emissions down, unlike the old days where boost was free to some extent.
My DSG equipped VW 2L TDI is quite happy running around under 1600rpms, it does all the shifting and never has to see 2000rpm ever, and I can easily beat the posted FE on longer trips.
Let it die on hills, do not increase the throttle but keep a constant load and then lift up a bit on the down hills. Running a scangauge or read out on the dash is essential for this. Diesels of all types prefer a constant load, turbo or not. They hate hard use in terms of fuel economy, better then a gas engine but will never deliver good results when driven hard (the 80% rule doesn't work on turbo diesels, too much fueling).
Yes, this sort of driving is less then ideal on the VNT system (turbo vanes) over the long run, they need some exercise to stay free however the DPF will thank you, running light loads and not punching the throttle will keep it very clean, it is sharp throttle responses that load it up with soot. It will cycle itself as needed, no worry about it getting hot!

I know I should drive slower on the highway but I just don't have the patience. I went on a 400km trip and decided to drive at 110km/h and I was really pleased that I got 4L/100km so that is the speed I have decided to be travelling at from now on. I do keep a constant load going uphill (when not using cruise control) but even the cruise control is mapped to decelerate a bit when going up steep hills when in eco mode.

Luckily, I don't have a VNT turbo so no worries there.

The problem is that I drive quite a lot uphill going to work and have to stop at many uphill red lights. And all that happens while the powertrain is cold. So that does hurt my FE a lot, but returning home is just a blast because I mostly coast downhill with the engine on (and even passing people ).

I am currently waiting for my OBD bluetooth adapter to compare data between changing gears lower or higher in the power band. I just use a mix of both depending on the gear and the situation for now. The excess fueling for emissions while on boost does make a lot of sense because lots of NOx's are produced at very lean mixtures but luckily the eco map does use quite a lot less boost.

[houseofdiesel]

Cold and up hills is a drag...have a strong coolant heater so it starts at operating temperature (I have 1500 watt, tank type heater meant for tractors and heavy equipment, at start up I watch the temp drop when its really cold). Let the clutch out in first, then second (no throttle), slowly add power, shift to third asap, anticipate the traffic lights and volume so you never need to slow down or brake, momentum is key especially with hills involved, single lane roads make it very hard/challenging but all in the name of FE. I could always get under 4L/100kms on my Passat tdi (B4), sometimes 3L staying under 80km/h on real back roads/gravel. Just be happy you have a diesel, gas engines really hurt when cold and working hard!

[Piwoslaw]

Originally Posted by sotiris.bos

The problem is that I drive quite a lot uphill going to work and have to stop at many uphill red lights. And all that happens while the powertrain is cold.

The only good side of going uphill in the morning is that it speeds up engine warming time. When we go hiking in the mountains, then on our way back we start with a loooong downhill with a cold engine (no access to electricity for the engine prewarmer) - it can take 20-25km before it gets to operating temp, when it is -20C outside - even longer. And during this time my passengers are demanding I turn on the cabin heat

[cRiPpLe_rOoStEr]

Originally Posted by sotiris.bos

Luckily, I don't have a VNT turbo so no worries there.

It sounds good. At least it probably wouldn't throw error codes if you replace the turbo for an efficiency-oriented one after the warranty ends