[Eaglesview]

I am interested to know the following.

I understand the DPF is regenerated by elevating the exhaust temperature to burn off the accumulated soot. I've seen reference to injection of diesel injection into the exhaust and delaying valve timing to accomplish this. Which one is used in the 28d?

Does increased engine load, i.e. pulling a trailer or high speed increase DEF consumption? I.e., is DEF flowrate directly related to fuel flow rate?

What is the volume of the DEF tank in the X3? I realize there are two but there is only one fill point inside the fuel cap door.

Thank you for all responses.

[TheCoolX3]

Now I am by no means a diesel expert and I am backing this by pure speculation but, I would imagine this question could be answered with common sense. The DEF is meant to, dummied down a bit, clean the exhaust coming out of the engine. With extra load put on the engine, more fuel would be put into the engine and subsequently more exhaust gasses wold be produced. Now because there is more exhaust gasses more DEF must be used to 'scrub' those gasses. Causing the increased DEF consumption.

Ultimately, "is DEF flow rate directly related to fuel flow rate?" Yes.

Originally Posted by Eaglesview

Does increased engine load, i.e. pulling a trailer or high speed increase DEF consumption? I.e., is DEF flow rate directly related to fuel flow rate?
.

[Eaglesview]

Sir, you are not the first to say I lack common sense....

But I do appreciate your response!

[Eaglesview]

I believe my inquiry was incomplete.

I should have added "Please, no ultracrepadrian replies."

[POBEP]

Originally Posted by Eaglesview

I am interested to know the following.

What is the volume of the DEF tank in the X3? I realize there are two but there is only one fill point inside the fuel cap door.

Eaglesview

The single filling port is designed such active tank is filled first - the remaining DEF is poured into passive one.
It is achieved by active tank placement below the passive one.

I found F-series US/NA SCR volume specs except for F25 in the SCR 2 (US) document

all values in liters
Chassis: Passive/Active (999 Warning Level)
F02: 15.0/0.0 (?)
F10: 15.0/0.0 (?)
F15: 13.7/15.4 (3.5)
F30: 8.7/9.4 (3.0)
F31: 8.7/9.4 (3.0)

My initial calculation based on filling 2.5G of DEF at 0.5G increments produced the following data for F25
Passive: 4.5 (may not be accurate as I did not have enough DEF to fill passive completely)
Active: 13.6
999 Warning: 4.2

I monitored DEF level with ISTA during fill up.
- 999 warning started at 31 points
- each KRUSE bottle (0.5G) resulted in ~14 points increase
- (active tank) "full" level reached at 101 points

HTH