Bullwinkle reaches into his hat - again. aka Gasoline and Diesel - 'together at last'

[AMERICA 123]

Title of the referenced article says it all.

Another fine example of the area with one of the greatest potentials for massive improvement ie the fuel itself.

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

3 August 2009


Researchers at the University of Wisconsin, led by Dr. Rolf Reitz, are investigating a blended dual-fuel (gasoline and diesel) concept to extend the operating range of partially premixed charge compression ignition combustion by using the varying fuel reactivity of the charge blend, which is determined in real time.

In an invited talk given at the DEER 2009 conference in Dearborn, Michigan, Reitz described experimental results showing the dual-fuel partially premixed combustion (PPC) approach at 9-11 bar IMEP operating point (about 60% load) easily meeting US 2010 emissions standards in-cylinder while achieving thermal efficiency of 53%, compared to 45% for conventional low temperature diesel combustion (LTC).


The University of Wisconsin concept proposes the use of dual fuel tanks, with port fuel injection of gasoline and direct injection of diesel, with the in-cylinder mixing of the fuels. Mixing ratios vary based on real-time operating conditions.

(Another paper presented at DEER 2009 by Christopher Gehrke of Caterpillar described their work with a pre-blended gasoline-diesel fuel with a derived cetane of 25-26 which did not have the same level of positive results as the UW approach.

“There may be some benefit in pursuing this fuel blending-type strategy...but injecting the fuels through the same nozzles may not be the way to go.”)

Low temperature combustion (LTC) strategies (MK, PCCI, HCCI) are one way researchers are looking to reduce engine-out emissions while maintaining high engine efficiency.

LTC has disadvantages, however, including difficulty at high load and no direct control of combustion timing.

This has lead numerous researchers to look for a hybrid between low temperature diesel combustion and homogeneous charge combustion, Reitz said.

A lot of very interesting work has been done by Shell Global Solutions lab, Dr. Kalghatgi, for example, where he argues that as long as the equivalence ratios are low enough, in other words that the combustion process fuel preparation is mixed enough so that one stays in the low emission window, one can see some interesting results.


Partially premixed combustion increases ignition delay to add mixing time.

There are two ways to achieve this partially premixed combustion strategy:

one is with high EGR rates to reduce PM formation with low combustion temperatures, the other is by exploiting the properties of fuels.

Kalghatgi and his group explored both the use of low-cetane fuels and exhaust gas recirculation (SAE 2007-01-0006).

Other researchers have looked at high EGR rates (Akihama et al. SAE 2001-01-0655), and optimizing fuel reactivity (Bessonette et al., SAE 2007-01-0191).

Bessonette et al. found that they were able to extend HCCI load range by varying composition: 16 bar BMEP required 27 cetane fuel, while 3 bar BMEP required 45 cetane fuel. In other words, Reitz said, at high loads, you achieve best operation with gasoline-like fuels, while at low-loads, diesel-like fuel produces the best results.

Using the proposed “fast-response fuel blending”, the fuel mix might be as high as 85% gasoline to 15% diesel under heavy loads; under lighter loads, the percentage of diesel would increase to a roughly 50-50 mix.

For a small engine to even approach these massive engine efficiencies is remarkable.

Even more striking, the blending strategy could also be applied to automotive gasoline engines, which usually average a much lower 25 percent thermal efficiency.

Here, the potential for fuel economy improvement would even be larger than in diesel truck engines.


The US consumes about 13.5 million barrels of oil per day in transportation.

Hypothetically, if the such dual-fuel engines with 53% thermal efficiency could be applied across the entire fleet, the US could reduce its oil consumption by 4 million barrels per day—about one-third of all oil destined for transportation, Reitz said.

The work is funded by DOE and the College of Engineering Diesel Emissions Reduction Consortium, which includes 24 industry partners.

Resources

*

Sage Kokjohn, Reed Hanson, Derek Splitter and Rolf Reitz (2009) High-Efficiency, Ultra-Low Emission Combustion in a Heavy-Duty Engine via Fuel Reactivity Control (DEER 2009)
*

Improving Fuel Efficiency with Fuel-Reactivity-Controlled Combustion (Reitz et al., ERC Symposium 2009) Rolf D. Reitz,
*

Christopher Gehrke (2009) Development of Advanced Combustion Technologies for Increased Thermal Efficiency (DEER 2009)
*

Gautam T. Kalghatgi, Per Risberg, Hans-Erik Angstrom (2007) Partially Pre-Mixed Auto-Ignition of Gasoline to Attain Low Smoke and Low NOx at High Load in a Compression Ignition Engine and Comparison with a Diesel Fuel (SAE 2007-01-0006)
*

Reed Hanson, Rolf Reitz, Derek Splitter (2009) Operating a Heavy-Duty Direct-Injection Compression-Ignition Engine with Gasoline for Low Emissions (SAE 2009-01-1442)
*

Paul W. Bessonette, Charles H. Schleyer, Kevin P. Duffy, William L. Hardy, Michael P. Liechty (2007) Effects of Fuel Property Changes on Heavy-Duty HCCI Combustion (SAE 2007-01-0191)
*

Kazuhiro Akihama, Yoshiki Takatori, Kazuhisa Inagaki, Shizuo Sasaki, Anthony M. Dean (2001) Mechanism of the Smokeless Rich Diesel Combustion By Reducing Temperature (SAE 2001-01-0655)

http://www.greencarcongress.com/2009...0803.html#more

There are many more 'out of the box' type solutions to be considered besides this one in this area ie fuel in general and a bi fuel approach in particular.

There are also other attractive combinations...............

And then.......

There are also some things outside of fuel that then would very likely fit well together with this - in a multiplicative sense.

[SchmSte8]

Reitz estimates that if all cars and trucks were to achieve the efficiency levels demonstrated in the project, it could lead to a reduction in transportation-based U.S. oil consumption by one-third.

"What's more important than fuel efficiency, especially for the trucking industry, is that we are meeting the EPA's 2010 emissions regulations quite easily," Reitz says.

http://www.sciencedaily.com/releases...0803132737.htm

[PistonsFan]

There are actually a lot of people in the industry looking at the effects of using a gasoline-diesel mixture to improve engine-out emissions. It's likely that we'll hear more about this in the coming years.

[johnstarnes]

I just read this yesterday...interesting concept. I can imagine variants like bio-diesel and biobutanol, or bio-diesel and cellulosic ethanol being tested too.

[hrcslam]

Great idea, especially since it works. However, what happens if you don't have desiel available? I know many places where you have to hunt down desiel, especially in area's where trucks rarely go. Can it run on just gasoline if it needs too? I can see this catching on with truckers, but not with Joe Smo nieghbor because it requires more effort to fill two tanks with two different fuels.

I know I sound negative, but I am just trying to be a realist. I would love to have this system put in my Suburban, I just want to know when I can buy one. And does it work with Turbo's or Superchargers?

[44 mpg by 2010]

Originally Posted by hrcslam

Great idea, especially since it works. However, what happens if you don't have desiel available? I know many places where you have to hunt down desiel, especially in area's where trucks rarely go. Can it run on just gasoline if it needs too? I can see this catching on with truckers, but not with Joe Smo nieghbor because it requires more effort to fill two tanks with two different fuels.

I know I sound negative, but I am just trying to be a realist. I would love to have this system put in my Suburban, I just want to know when I can buy one. And does it work with Turbo's or Superchargers?

Assuming your vehicle is gasoline, would roughly doubling your range per fill-up reduce your concern about having to fill 2 tanks?

Ooops, how many failures would result from "miss fueling" the 2 tanks?

[PistonsFan]

Originally Posted by 44 mpg by 2010

Assuming your vehicle is gasoline, would roughly doubling your range per fill-up reduce your concern about having to fill 2 tanks?

Ooops, how many failures would result from "miss fueling" the 2 tanks?

Well, one method is dual-fuel, which isn't very "production-friendly". The other is a pre-mixed gas-diesel blend.

Gas-diesel mixtures for diesel engines is still in a research phase. But the end-implementation would be a gas-diesel mixture directly from the pump. So like E85, it may be something like G20 Diesel (20%gas, 80%diesel). Diesel is bad for NOx. Gasoline is bad for fuel economy and nano-particulates. A gas-diesel mixture would be a comprise of the two.

[hrcslam]

Originally Posted by 44 mpg by 2010

Assuming your vehicle is gasoline, would roughly doubling your range per fill-up reduce your concern about having to fill 2 tanks?

Ooops, how many failures would result from "miss fueling" the 2 tanks?

Actually with twice the amount of fuel getting twice the fuel economy the range of said vehicle should be quadrupled. So on my Suburban, about 1600-2000 mile between fill ups. That is crazy.

[ShefZ28]

Originally Posted by hrcslam

Actually with twice the amount of fuel getting twice the fuel economy the range of said vehicle should be quadrupled. So on my Suburban, about 1600-2000 mile between fill ups. That is crazy.

But now you're looking at twice the size of the gas tanks.

If a normal car had a 12 gallon tank.. and switched to half and half... you would think it would have two 6 gallon tanks.

Overall mileage would increase, just not 4x.

[Dr. Show-Me]

You'd still have the same relative size of tank, only containing the blend. It wouldn't surprise me, though, if the car companies then started putting in smaller tanks to save room and weight.