# Here's what a regen looks like graphically



## pacolino (Aug 1, 2015)

diesel said:


> Lightly rolling hills, relatively constant speed, you can see the impact the regen had on the MPG graph.
> 
> View attachment 205857


Wow....you almost hit the 300,000 km mark, that's remarkable. [emoji6] 

Sent from my LGMS631 using Tapatalk


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## sparkman (Oct 15, 2015)

What the heck is a regen?


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## BrandoFisher117 (Mar 14, 2016)

sparkman said:


> What the heck is a regen?


Its for them diesel drivers. I had to look it up too! :tongue:

https://en.wikipedia.org/wiki/Diesel_particulate_filter


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## chevrasaki (May 1, 2015)

sparkman said:


> What the heck is a regen?


Diesels have a particulate filter in the exhaust system that fills with soot. Every now and then it "regenerates" Which means it dumps diesel fuel into the filter to cause really high temperatures with burns the soot off. It helps with emissions and makes the exhaust clean, hence the "clean diesel" that doesn't pour black smoke out of the exhaust.


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## oldestof11 (Apr 3, 2016)

BrandoFisher117 said:


> Its for them diesel drivers. I had to look it up too! :tongue:
> 
> https://en.wikipedia.org/wiki/Diesel_particulate_filter


Soon to include direct injected gassers too.


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## MP81 (Jul 20, 2015)

oldestof11 said:


> Soon to include direct injected gassers too.


With the amount of particulate matter they produce - absolutely.

It's one of those things, where you end up creating another problem, while solving something else.


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## diesel (Jun 8, 2013)

MP81 said:


> With the amount of particulate matter they produce - absolutely.
> 
> It's one of those things, where you end up creating another problem, while solving something else.


It's going to be fun when the gasser owners can complain as much as the diesel owners do about emissions equipment!


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## MP81 (Jul 20, 2015)

diesel said:


> It's going to be fun when the gasser owners can complain as much as the diesel owners do about emissions equipment!


Yup - we won't be the only ones. 

There has been more talk of engines with higher compression ratios, or a variable compression ratio, since it is more efficient (in theory, if a gasoline engine could run at the same compression ratio a diesel engine could, it would actually be more efficient - but it cannot without detonation) and makes more power. Something they don't mention, however, is that higher compression ratios lead to a hotter charge - which increases NOx levels. 

So you'll literally have gasoline cars with the same emissions garbage we currently have. It's quite funny, actually.


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## obermd (Mar 3, 2012)

MP81 said:


> Yup - we won't be the only ones.
> 
> There has been more talk of engines with higher compression ratios, or a variable compression ratio, since it is more efficient (in theory, if a gasoline engine could run at the same compression ratio a diesel engine could, it would actually be more efficient - but it cannot without detonation) and makes more power. Something they don't mention, however, is that higher compression ratios lead to a hotter charge - which increases NOx levels.
> 
> So you'll literally have gasoline cars with the same emissions garbage we currently have. It's quite funny, actually.


And this is why carbon based fuels are on their way out. It won't happen overnight but it will happen. I really think diesels are already on the way out for personal transportation and I suspect gasoline won't be far behind.


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## Aussie (Sep 16, 2012)

Next big change, maybe?

Hyundai's Experimental Gas Engine Runs Without Spark Plugs – Feature – Car and Driver


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## pandrad61 (Jul 8, 2015)

> With the amount of particulate matter they produce - absolutely.
> 
> It's one of those things, where you end up creating another problem, while solving something else.


that puts a smile on my face. the emissions restrictions should be equal on gas and diesel. why should diesel be penalized yet you can drive with bad 02 sencor and cats and simple CEL nothing else


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## MP81 (Jul 20, 2015)

Aussie said:


> Next big change, maybe?
> 
> Hyundai's Experimental Gas Engine Runs Without Spark Plugs – Feature – Car and Driver


I'm not sure how they can say the combustion temperatures are lower - higher compression is going to yield higher combustion temperatures. I saw nothing in the article to state how it was suddenly cooler, yet making more power. A cooler combustion charge makes less power than a hotter one - this is what EGR does - it cools the combustion charge down (replacing excess O2 with reused exhaust gas) to lower NOx emissions, at the expense of some power.

Unless I'm missing something (It's been a few years since the few different ICE classes I took before I graduated, for my Automotive concentration), they've made contradictory statements.


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## Aussie (Sep 16, 2012)

My diesel runs in the mid 80'sC and my daughter's 1.6T petrol runs at 105C, yet the diesel has much higher torque and runs at 16.5-1 compression.


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## MP81 (Jul 20, 2015)

Aussie said:


> My diesel runs in the mid 80'sC and my daughter's 1.6T petrol runs at 105C, yet the diesel has much higher torque and runs at 16.5-1 compression.


You have sensors inside the combustion chamber? Combustion temps in the cylinder are easily 700+C. Coolant temp doesn't correlate 1:1., it depends on how well the engine dissipates, or doesn't dissipate, heat from combustion into the block/coolant. It is not a direct relation to how hot the combustion is.


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## Aussie (Sep 16, 2012)

MP81 said:


> You have sensors inside the combustion chamber? Combustion temps in the cylinder are easily 700+C. Coolant temp doesn't correlate 1:1., it depends on how well the engine dissipates, or doesn't dissipate, heat from combustion into the block/coolant. It is not a direct relation to how hot the combustion is.


I can only go off the coolant temperature and the digital readout is 20C cooler in the diesel. It takes the diesel about 3 times as long to reach normal operating temperature compared to the petrol engine, so I assumed it was a cooler running engine.

I found this. http://hypertextbook.com/facts/2005/EileenTang.shtml


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## MP81 (Jul 20, 2015)

Aussie said:


> I can only go off the coolant temperature and the digital readout is 20C cooler in the diesel. It takes the diesel about 3 times as long to reach normal operating temperature compared to the petrol engine, so I assumed it was a cooler running engine.


Yeah, diesels always take a lot longer to warm up - especially in the winter (which is why we have the electric aux heater).

Wikipedia actually has a good summary:



> A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air-fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, and therefore the energy wasted to the atmosphere. Diesel engines actually have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust.


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## Kalpazan (Dec 17, 2015)

So much for diesels in EU 

Renault considers killing off diesel engines - BBC News


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## LiveTrash (May 24, 2015)

diesel said:


> Lightly rolling hills, relatively constant speed, you can see the impact the regen had on the MPG graph.
> 
> View attachment 205857


No wonder my MPG has been bad recently. Didn't realize it had this big of an effect. The last 4 regens I've had have been no more than 150km (93 mi) apart. I'd finish the regen and it would go up to 21 grams within the first 40km and stay there until it hit 21/22 later on. Right now it seems to be returning to the normal interval. We'll see...


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## Aussie (Sep 16, 2012)

Just got back from a DPF cleaning drive. Went to drive home from the shops and the DPF warning light was on. It took 15 minutes of continuous driving at 2,000rpm+ for it to go out. This is only the second time in 49,000km that this has come on, but I have been doing a lot of really short trips lately.


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## diesel (Jun 8, 2013)

Aussie said:


> Just got back from a DPF cleaning drive. Went to drive home from the shops and the DPF warning light was on. It took 15 minutes of continuous driving at 2,000rpm+ for it to go out. This is only the second time in 49,000km that this has come on, but I have been doing a lot of really short trips lately.


I wish the warning light in the US worked. Sounds like yours has successfully saved you trips to the dealer.


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## MP81 (Jul 20, 2015)

diesel said:


> I wish the warning light in the US worked. Sounds like yours has successfully saved you trips to the dealer.


And so far, it doesn't seem like any of the aftermarket tunes have been able to suddenly make it work - it's clearly in the cluster, just not used.


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## IndyDiesel (May 24, 2015)

LiveTrash said:


> No wonder my MPG has been bad recently. Didn't realize it had this big of an effect. The last 4 regens I've had have been no more than 150km (93 mi) apart. I'd finish the regen and it would go up to 21 grams within the first 40km and stay there until it hit 21/22 later on. Right now it seems to be returning to the normal interval. We'll see...


My last regen was 89 miles, haven't been on a road trip in a bit, go on a modest 200 mile one next week for work. Of the 89 about 10 of that was while it was in regen. It doesn't make me a very happy camper. Never had a car I hated the emissions like I hate this set up. I will either eventually sell the car or delete the crap. Love the car but I don't like the emissions stuff and so far no out of pocket expense but it is pretty darn obvious it will happen after warranty goes out, not before. Bought a f150 week and half ago and enjoy driving a truck so been driving it.


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