Hypermiling a diesel

[HAHA]

As you can see from my numbers, P&G pays off well in this case. The last trip was on highway at about 90 km/h average speed. I like to find myself a big semi behind which I can pulse & glide into the draft. This gives you some idea about the average speed. The highest gear (5) results in about 2000 rpm at that speed.

Interesting about the intercooler...

The chip trimmer company mentioned above actually achieves the results partly by replacing the intercooler with a larger one.
See: Power Kit L200 Triton 2,5 DI-D
They refer to less pressure drop so maybe the same effect is had by removing it altogether.

The question remains...
What happens with efficiency during the lag phase?

There is no black smoke or anything so perhaps the ECU does the best of it.

[ConnClark]

Originally Posted by Diesel_Dave

How did you manage to get a DPF on a '85 vehicle?

It was the very first vehicle to have them. Its a Kalifornistani model.

[HAHA]

Just adding some information for completion...
I communicated with STT Emtec about the Mitsubishi L200 engine mapping and the perceived turbo lag. I learned the following:

The lag is not really a turbo lag but rather the computer not supplying enough fuel to get things moving. This is done to control the emissions (regulations on diesels are very strict these days). The trim box is able to overcome the lag by injecting more fuel in the beginning of the acceleration phase.

I also got the information that the engine delivered peak efficiency at slightly above 2000 rpm and ~300Nm torque (~85 hp), which equals a fuel consumption of about 200g/kWh.

I also learned that installing the trim box will cause the fuel instrumentation to miscalculate because it is not actually measuring the flow and the box is piggybacked on the ECU (south). The "optimizations" are active only at more than 75% throttle so for normal driving, this won't be an issue. For p&g eco-driving, the instrumentation would become pretty useless since you alsmost only use the engine at 75+%.

Anyway, from this I draw the conclusion that the lag during initial acceleration is pretty harmless from the point of eco-driving.

[ConnClark]

Originally Posted by HAHA

They refer to less pressure drop so maybe the same effect is had by removing it altogether.

Don't remove the intercooler. It aids in fuel economy too. By reducing the combustion gas temperatures it reduces heat lost to the cooling system allowing more energy to be extracted by the piston.

[Vekke]

What comes to intercooler off, temps on my Lupo 3L are now with steady throttle and no grill block at the moment:
80 kmh = 40 celsius
100kmh = 48 celsius
120kmh = 70 celsius
Outside temperature 13 celsius and wet.
On winter if you have a intercooler those intake temperatures will be on minus for the first 10 kilometers and your engine will warm up slower. There is no power gains to be made if you feed minus celsius air to your engine at least with my current knowledge. You should try to get the engine warm up not froze it.

They have propably reached those power figured with bigger intercooler for sure, but if you are hypermiling your acceleration times will be so short that intake temps wont have time to raise so high that you would need it. The intercooler propably also flows better but if you take it all out its har to beat that in flow efficiency. Every bend in your pressure pipes makes little drag and depending on how many bends you have the turbo has to work harder to be able to produce the same boost level. Usually the pressure drop is about 0.1 to 0.15 bar.

On summer in a big truck you propably still need it but that can be tested with fuel consumtion meters like ultragauge etc where you can see the intake temps.

Oh and in Finland and Sweden the winter temperatures can be as low as -35 degrees celsius or -31 degrees fahrenheit. So the biggest problems are to first get the engine running and after that make it warm so that you dont need freeze inside the car.

[SwamiSalami]

I definitely think that hypermiling in a diesel makes a much bigger difference than in a gasoline car. I own both. If you check out my cars on Fuelly, you'll be able to tell.

Good luck and remember, if it sounds too complicated, the person who's saying it probably doesn't know what they're talking about.

[ausias]

The 1.9 TDI 110 cv engine is one of the best efficiency ones, but maybe some ECU ecotuning will reduce your fuel consumption between -10% to -15%, you could try if any change is made also reducing coefficient of drag (covering full or the most of the upper grill, remember Audi A2 grill?) and fine tuning your camshaft timing. Try some "search" in Fred's TDI Page. TDIClub.com. VW TDI Enthusiast Community.
I did -13% at 82km/h to -18% at 122km/h using cruise control, fine tuning camshaft timing and with aerodrag reduction,
http://ecomodder.com/forum/showthrea...3-a-19233.html
http://ecomodder.com/forum/showthrea...ape-19191.html

I had a manual of how to fine tuning camshaft timing in my other 1.9 TDI 110cv AHF, but i did'nt find now.
I will try doing P & G while data logging using VAG COM OBDII.
But, max efficiency of my engine is about 0.4 and using cruise control in fifth gear, .32 is worst efficiency maintainaing cruise control in fifth. teretically 20% less fuel consumption was possible, i think easier with larger gears, bu i Will try.

[Diesel_Dave]

Originally Posted by HAHA

The lag is not really a turbo lag but rather the computer not supplying enough fuel to get things moving. This is done to control the emissions (regulations on diesels are very strict these days). The trim box is able to overcome the lag by injecting more fuel in the beginning of the acceleration phase.

The ECM not supplying "enough" fuel is most probably due to emissions contraints (probably smoke). Typically smoke comes from too rich of a mixture. Keep in mind that smoke levels from the stock engine are probably seceral times less that the visible smoke range. The chip tuner may actually be increasing smoke quite a bit, but you still might not be able to see anything. Another possiblity is that the chip tuner is advancing the timing to get more power. This probably increases the NOx above the stock level. At the same time it probably lowers the smoke too (more advanced timing generally lowers smoke). That's just my guess..

[meelis11]

This TDI powered Audi A4 is really good! Dont know yet how accurate is onboard trip computer but this weekend I made some driving. Trip is about 106km one way, resetted computer, engine was warm. When I arrived to destination, computer trip average was 4.0L/100km (58.8mpg) Made some city driving (many short trips) next day, still was 4.5L/100km, not bad at all!

Driving back 2 days later, resetted computer again, I managed 4.1L/100km (57.37mpg). Route was little bit longer, total trip time was 6 minutes longer.

Driving style: I was driving around 90-100km/h, made some P&G in neutral if it was possible (no cars behind me)

[TX_Dj]

In my case, I just see no point in spooling the turbo (much)... more boost == more fuel... by planting your foot to P&G, are you not spooling the turbo and increasing fueling?

I've always been a skeptic of P&G (even though I've seen evidence to say it works) because well, Newton says you can't get more out of it than what you put into it... and if you put X into it by speeding up fast and coasting down, getting X as the result, that's great... but seems to me that if you use the technique of getting on the torque peak, mashing the pedal and spooling it all up for a hard pull, X > Y output... because well, it takes more power to accelerate quickly and your glide will be relatively constant from any speed all other factors being the same.

What seems to be working best for me in my truck (granted, an 8000 lbs dually is a bit of a different game than a 1.9 TDI) is to keep boost and pyro low, RPM near or just under peak torque and cruise steady rate while allowing the vehicle to slow on inclines in order to stay below target boost/pyro numbers. Then again, I'm definitely getting nowhere near as good as Dave, and he's admitted to P&G techniques. His truck is also lighter, shorter, more aero and less rolling resistance than mine.