DPF passive regeneration

[ferktm Lurker Find all posts View Profile Close ferktm]

Hello,

it has been a very hot day today here in Spain. Above 37ºC. It is the first time I use my 2018 Prado 2.8 in these conditions. I've been using Torque Pro to look at DPF % and S1, S2, S3 temperatures.

It's the first time I see passive regeneration of the DPF in my car. Flat out in the highway, climbing, temperatures 1, 2 and 3 raised over 580ºC and DPF% lower about 4% first time, another 4% the second time, but the third time (over 3 minutes flat out) it dropped almost 30% this longest time. At the beginning DPF% was 94% and at the end was 70%.

It's good to know but I don't love to drive "pedal to the metal" so much time: Moreover fue consumption raised a lot.

I've been thinking about it. How can we raise DPF temperature? If we stop the fresh air with a skid plate, could we achieve passive regenerations?

Just to notice my car has an SCR system using AdBlue as it complies Euro 6.

Greetings!

Fernando

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

It is good to have some feedback from Europe so thank you for posting. My Prado is in Australia but I am in the UK at present and have not been able to find any similar DPF issues here.
I expect you have read the many DPF related threads on here to know that it does seem to be a problem in Australia. Many people have reported that the soot % falls for no apparent reason without the exhaust temperatures rising, we assume this is some kind of recalculation but in your case the exhaust temperatures were high. This is not something I have noticed without a proper regen taking place with the associated extra fuel addition, retarded timing and 5th injector firing.
I have read other posts wondering if the local temperature has any affect on how hot the regeneration becomes. I do not know the answer but common sense suggests that it may make some difference but I doubt that an ambient temperature difference of say 30 degrees would make much difference when we are expecting the exhaust temperatures to rise by 300 degrees.

[RPP Senior Member Find all posts View Profile Close RPP]

If S3 is the DPF Temp, then 580ºC will do it. The 5th injector must have been active for the DPF to get that hot. I regularly see the DPF temperature in the high 500s during the first half of a burn, and then increase over 600ºC in the second half of the burn. This may just be a temperature lag though - does anyone know where the sensor sits relative to the 5th injector?

I was on the highway yesterday doing 100-110Km/hr when the DPF% hit 100% and started a burn - DPF Temp grew to well over 500ºC. I pulled over to see how it went whilst parked with the engine on. The DPF% dropped to 92% quickly. Idle RPMs stayed at 900, but over the next 15minutes the EGT dropped to about 280ºC and the DPF Temp dropped to the EGT level and the burn ceased. After I got on the highway again the DPF burn resumed and went to completion. I wonder how a forced burn in a workshop works.

[ferktm Lurker Find all posts View Profile Close ferktm]

It is good to have some feedback from Europe so thank you for posting. My Prado is in Australia but I am in the UK at present and have not been able to find any similar DPF issues here.
I expect you have read the many DPF related threads on here to know that it does seem to be a problem in Australia. Many people have reported that the soot % falls for no apparent reason without the exhaust temperatures rising, we assume this is some kind of recalculation but in your case the exhaust temperatures were high. This is not something I have noticed without a proper regen taking place with the associated extra fuel addition, retarded timing and 5th injector firing.
I have read other posts wondering if the local temperature has any affect on how hot the regeneration becomes. I do not know the answer but common sense suggests that it may make some difference but I doubt that an ambient temperature difference of say 30 degrees would make much difference when we are expecting the exhaust temperatures to rise by 300 degrees.

I don't know why but DPF issues here in Europe are not so frequent. Asking my Toyota dealer, they say there have been no issues at all with the 2.8. Is the DPF itself different (as it goes with the SCR system)?? Is diesel fuel used better??

If S3 is the DPF Temp, then 580ºC will do it. The 5th injector must have been active for the DPF to get that hot. I regularly see the DPF temperature in the high 500s during the first half of a burn, and then increase over 600ºC in the second half of the burn. This may just be a temperature lag though - does anyone know where the sensor sits relative to the 5th injector?

I was on the highway yesterday doing 100-110Km/hr when the DPF% hit 100% and started a burn - DPF Temp grew to well over 500ºC. I pulled over to see how it went whilst parked with the engine on. The DPF% dropped to 92% quickly. Idle RPMs stayed at 900, but over the next 15minutes the EGT dropped to about 280ºC and the DPF Temp dropped to the EGT level and the burn ceased. After I got on the highway again the DPF burn resumed and went to completion. I wonder how a forced burn in a workshop works.

I am pretty sure it is not the fifth injector working. The major difference is that S1 temp when the fifth injector activates is lower than S2 and S3. In these cases S1 temp is over 550º C too.

Nevertheless I will check it with Techstream.

[RPP Senior Member Find all posts View Profile Close RPP]

Where is the S1 sensor located?

I have never seen the Exhaust Gas Temp get much higher that mid 400ºC, and that is at highway speeds. But I have seen the DPF Temp get over 690ºC during a regen cycle.

It looks like it takes 6-8Km for a vehicle to warm up from a cold start. An interrupted DPF burn cycle wont resume until the engine has warmed up. So I surmise that if a vehicle is only ever driven a few kilometers at a time (ie. 6km say at industrial or mine sites) it might be that the DPF can never do a regeneration cycle.

I have a 2018 Prado and am interested in this topic as next year a group of us will drive a very remote 700Km track. Rocks, rivers, 100Km/day, most days will be in 4L. No towns and no vehicle recovery service.

[ferktm Lurker Find all posts View Profile Close ferktm]

Where is the S1 sensor located?

I have never seen the Exhaust Gas Temp get much higher that mid 400ºC, and that is at highway speeds. But I have seen the DPF Temp get over 690ºC during a regen cycle.

It looks like it takes 6-8Km for a vehicle to warm up from a cold start. An interrupted DPF burn cycle wont resume until the engine has warmed up. So I surmise that if a vehicle is only ever driven a few kilometers at a time (ie. 6km say at industrial or mine sites) it might be that the DPF can never do a regeneration cycle.

I have a 2018 Prado and am interested in this topic as next year a group of us will drive a very remote 700Km track. Rocks, rivers, 100Km/day, most days will be in 4L. No towns and no vehicle recovery service.

S1 sensor is ahead of the 5th injector in the exhaust. In my car it usually goes around 450º at highway speeds. Only at full throttle you can see temperatures as seen in the screen capture.

[RPP Senior Member Find all posts View Profile Close RPP]

Thanks ferktm.

So that is what the readings are when you have your foot to the floor. Coolant temp looks normal though.
I'm using a ScanGauge II, your S1 may be reading the same as my EGT. Mine will get up around 450ºC at highway speeds (110Km/hr). I have been up over 130Km/hr overtaking, but I have never seen it get over 500ºC.

What are your S2 & S3?

If your Prado has AdBlue, is there no longer an EGR system?
The Euro 6 standard is also required here now. I believe the new Prados in Australia will have it.
Not having the EGR system may be an improvement for us!

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

If your DPF pressure is 112,52 bar your exhaust must be constructed with some strong material !! try 2138 (D*256+E)*0.01-327.68
also 5th injector on/off may be useful 213A BIT(E:7)

[ferktm Lurker Find all posts View Profile Close ferktm]

If your DPF pressure is 112,52 bar your exhaust must be constructed with some strong material !! try 2138 (D*256+E)*0.01-327.68
also 5th injector on/off may be useful 213A BIT(E:7)

DPF pressure sometimes gives weird values. Is it possible to know in the fifth injector is working using torque app??

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

Yes it has taken me a lot of effort to find out, I have shared the pid and equation above and attached a screenshot of what my Chinese android head unit looks like.
I am sorry to say that I think your "weird value" is because you have used the standard pid in torque pro, Toyota use "21xx"