Research Question

[RFH]

Hello there, haven’t been on here much as I’m taking a break from cars for a bit, but I’m still working on engines. Anyways, my university research involves looking at Low Temperature Combustion strategies in engines. Right now we are interested in a dual fuel combustion strategy that uses commercially available gasoline and diesel fuels. We have been told a few times by OEMs that they aren’t interested in the technology because consumers wouldn’t like having 2 fuel tanks on their vehicles. I don’t really believe them, so I am putting the question to the test and asking consumers (you guys). Though our technology is far from being commercially viable, what is your interest (on a scale of 1-5, in the poll) and/or opinion of having a dual fuel vehicle? Here’s some links to our work;

Green Car Congress: University of Wisconsin Researchers Investigating Dual-Fuel (Gasoline and Diesel) Partially Premixed Combustion for High-Efficiency, Ultra-Low Emission Combustion; 53% Thermal Efficiency

Gasoline-diesel ‘cocktail’ — a potent recipe for cleaner, more efficient engines, Perspective newspaper for alumni, Fall 2009, UW-Madison Engineering

Reinventing the Gasoline Engine | MIT Technology Review

Green Car Congress: Reactivity Controlled Compression Ignition (RCCI) for Simultaneous Reduction of Fuel Consumption, NOx and PM

Dual-fuel lab engines achieve high efficiencies, low emissions

Diesel's Dual-Fuel Future - Diesel Power Magazine

Green Car Congress: U. of Wisconsin RCCI combustion work progressing; modeled 53% gross indicated efficiency in a light-duty engine could result in 2x fuel savings compared to SI gasoline

Green Car Congress: Direct injection of both fuels in RCCI may offer a way to decrease HC and CO emissions without sacrificing efficiency and NOx/PM benefits

Green Car Congress: U. Wisconsin team reports gross indicated thermal efficiency of RCCI operation near 60%

Green Car Congress: Study finds moderate biofuel blends increase benefits of RCCI in light-duty engines

The gist of all that is we are using diesel to auto-ignite gasoline and control combustion phasing by ratio of 2 fuels. It is very similar to HCCI for those of you who have heard of that. RCCI/HCCI/LTC, etc. all result in lower combustion temps and lower heat transfer losses, thereby increasing engine thermal efficiency and lowering PM and NOx. I can go in depth if interested…

Overall here’s a break down of the cost increase, thermal efficiency and fuel economy benefits for the most common types of vehicles;


PFI/Spark Ignition (Ford Fusion)

~ 50% improvement, so 30 to 45 mpg, cost increase ~ $2000

Diesel (VW Jetta)

7-15% improvement, so 45 to 50 mpg, $<1000 cost increase, maybe cheaper

Parallel Hybrid (Toyota Prius)

10% improvement, so 50 to 60 mpg, cost increase similar to an SI engine

Series hybrid vehicle (Chevy Volt)

Not sure on this one but with testing we maybe able to go from 26 to 40ish mpg in Saturn Vue series hybrid. cost increase similar to an SI engine

H-D vehicles (Class 8 trucks)

7-15% improvement, plus can use cheaper fuel (either gasoline or natural gas) so 6 to 7 mpg. $<1000 cost increase, maybe cheaper

Thanks for reading all this, and like I said earlier, I’m interested to hear your opinions, thoughts, etc. whether you would be interested in purchasing such a vehicle if it operated the same as current vehicles but had 2 fuel tanks that would run out of fuel at roughly the same time with the above cost and fuel economy improvements.

 

[JBird_Cobra]

So all of the above options require two different fuels?

 

[James Snover]

No way, not a chance in hell. I am not going to watch two fuel gauges.

When you say "low temperature combustion," what range are we talking about?

 

[DefCon3]

If there was an option to run on one fuel OR the other in addition to BOTH fuels combined, I would consider.

 

[RFH]

Thanks for the comments.

right now yes, they all require 2 fuels. You might be able to run on just diesel in a pinch though. Its not really practical to run on just gasoline with a compression ignition engine.

There would be a lot of work needed to make sure it was painless to keep track of both tanks, but new diesels have to keep track of the Urea tank too..

Finally, LTC has peak combustion temperatures less than 1900K (the temperature where NOx forms), where as with diesel and SI they are around 2500K.




An alternate question, how expensive would gas have to be to consider this?

 

[MachJoe]

It really all depends how everything turned out. I voted 'would consider' I'd much rather run 2 different fuels than have a battery powered car.

 

[95gts5oh]

I voted, would consider. Edit: Nevermind I realize now the reason for two tanks haha. I was thinking about mixing the fuels....

 

[Gray_Ghost]

Yeah, it sounds freaking cool from an engineering perspective, but watching 2 fuel gauges? Plus, I could see some idiot putting gas in the diesel tank and "oh ****...." Now if gas really gets that bad price wise, I'll do like my uncle does and convert an antique diesel Mercedes to run on used cooking oil. He's got 4 at last count that are converted and it costs him very little to drive these cars.

 

[Coiled03]

I wouldn't have an issue with two gauges at all, depending on how they're presented.

I think people have the perception that the two gauges will be like old-school analog gauges on totally opposite sides of the dashboard.

If you were to convert the fuel gauges to something similar to a clustered column chart, and present both next to each other, it wouldn't be that big of a deal. And with digital dashboards nowdays, that'd be a piece of cake to implement.

 

[Torch10th]

The technology sounds cool, but it would honestly be a pain in the ass to fill. The way that pumps are utilized right now not only would I have to wait for a pump to open up that has diesel and gasoline (usually only 1 pump in my area), but I would also have to make two transactions to purchase the fuels.

What money it might save me on better fuel mileage, is wasted on the time spent going through the steps to achieve it.

 

[DaleM]

You prove that I can get 100mpg and I'll use 4 fuels!

 

[cariacou]

what's the hp / torque / responsiveness change ?

 

[RFH]

I wouldn't have an issue with two gauges at all, depending on how they're presented.

I think people have the perception that the two gauges will be like old-school analog gauges on totally opposite sides of the dashboard.

If you were to convert the fuel gauges to something similar to a clustered column chart, and present both next to each other, it wouldn't be that big of a deal. And with digital dashboards nowdays, that'd be a piece of cake to implement.

this is kind of how I thought to do it. it would be nice if gas stations could have some sort of 2 fuel filler nozzle but that might be a tough sell.

Right now the hp/trq curve follows current diesel engines. We havent been able to test at high (for a diesel) engine speeds, like 4000+ rpm, but if it works there it could have an interesting power curve.

it might get 100 mpg if you put it in a older Honda Insight

 

[VictorySong]

Thanks for the comments.

right now yes, they all require 2 fuels. You might be able to run on just diesel in a pinch though. Its not really practical to run on just gasoline with a compression ignition engine.

There would be a lot of work needed to make sure it was painless to keep track of both tanks, but new diesels have to keep track of the Urea tank too..
Finally, LTC has peak combustion temperatures less than 1900K (the temperature where NOx forms), where as with diesel and SI they are around 2500K.




An alternate question, how expensive would gas have to be to consider this?

LOL no. Replacing urea is nothing like filling up a vehicle with gas & diesel. Urea tanks are closer to oil changes than filling up at the pump. Not that it matters. I haven't seen a used diesel truck that still had urea tanks on it.

Would I do it? No. The MPG improvements you've listed aren't even in the ballpark of being worth the hassle it would create.

 

[leo2hot4tv]

So the cost increase mentioned in the OP, is it a one time deal or a retrofit cost?

 

[RFH]

it would be the cost increase for a new vehcile, and thats just a random ass guess by me

 

[DefCon3]

I wouldn't have an issue with two gauges at all, depending on how they're presented.

I think people have the perception that the two gauges will be like old-school analog gauges on totally opposite sides of the dashboard.

If you were to convert the fuel gauges to something similar to a clustered column chart, and present both next to each other, it wouldn't be that big of a deal. And with digital dashboards nowdays, that'd be a piece of cake to implement.

Exactly. A modern-looking version could be made showing side-by-side vertical bars representing the 2 fuel levels (as in this VU meter):

And for that "old school" look, equip ONE gauge with two needles, like this:

 

[LogiWorld123]

americans still manage to put diesel in their gas cars so this wont fly at all with the major motoring public. which is exactly why the car companies don't want it.

try it with CNG and you might have a few more interested motorheads, but nothing that Soccer Mom Sally is going to want to worry about.

 

[RFH]

CNG and LNG (and possible LPG) are our new focus. I think H-D vehciles would do better with this approach and is likely the only practical path to mass production for RCCI.

I am just curious about thoughts on light-duty stuff too.

 

[PaladinMan187]

You prove that I can get 100mpg and I'll use 4 fuels!

You and me both.

On a serious note, I'd rather get a military 6x6 m35 with the Hercules Multifuel engine and drop on an aux WVO/WMO/WTF tank/valve system. I'd probably hack the frame and turn it into a 4x4 but so much easier than taking care of a new car with 2 fuel tanks.

Instead of these new exotic power plants for vehicles, why aren't we building DIESEL POWERPLANTS for these cars? They do it all over the rest of the world. Why not here? Europe? Yep. Australia? Hell yes! South America? Of course. Africa? Surely. Hell, GM builds a GMC Canyon *DIESEL* variation for use overseas but we can't see it in the USA. I'm tired of people hyping up these new motors when we could do so much more with the technology we currently have.