Diesel MU conversion to partial natural gas use

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  • Member since
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Diesel MU conversion to partial natural gas use
Posted by daveklepper on Thursday, May 30, 2019 4:55 AM

*BRITISH open-access passenger operator Grand Central has unveiled plans to
modify one of its Alstom class 180 Adelante DMUs to ‘dual-fuel’
configuration to operate on a combination of diesel and liquefied natural
gas (LNG). *

[image: {"rendered":"Grand-Central180"}]

*The project is being supported by the Rail Safety and Standards Board
(RSSB) and Grand Central is working with in partnership with G-Volution, a
British firm which has developed a patented dual-fuel technology for
transport applications.  *

*The trial builds on a 2016 RSSB-funded feasibility study, which concluded
30% savings in fuel costs could be achieved through the use of dual-fuel
technologies in rail. This study is being expanded through additional
modelling and analysis to include all types of diesel train on different
lines in Britain. The development of Dual Fuel Multiple Unit (DFMU) is
being used to validate the model outputs. *

*The DFMU project involves modifying one vehicle in a five-car class 180
set to operate in dual-fuel mode. The DFMU is due to begin operating by the
end of the year. *

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Posted by CSSHEGEWISCH on Thursday, May 30, 2019 7:17 AM

Dual-fuel mode has been attempted several times in the United States, with less than stellar results.  The chief issues seem to be the added complexities of the engine and fuel system plus fluctuations in fuel prices.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by Overmod on Thursday, May 30, 2019 12:07 PM

On these smaller engines the dual-fuel operation should be easy to implement and control.  Presumably they have assessed where the increased tankage volume will be needed and know where and how to provide it.

What is interesting to me is that natural gas in Britain is now perceived as so much cheaper as delivered, with its lower heat content as a traction fuel, that it would provide a "30% net savings" in typical railcar duty-cycle operation.

I actually suspect that at least some of this is based on the idea that the engine operating 'on natural gas' could be operated in confined spaces in the way that pure natural-gas engined vehicles like forklifts are.  I haven't seen formal emission analyses of the effect of the ~5% promoter diesel fuel that has to be injected to fire methane effectively in a compression-ignition engine without external initiation, but I would have to assume uncatalyzed exhaust might be comparatively rich in degradation products like formaldehyde that might have "legal" or political implications even at the relatively slight-seeming mass flow of diesel that would be required.

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Posted by tdmidget on Wednesday, July 17, 2019 2:24 PM

daveklepper

*BRITISH open-access passenger operator Grand Central has unveiled plans to
modify one of its Alstom class 180 Adelante DMUs to ‘dual-fuel’
configuration to operate on a combination of diesel and liquefied natural
gas (LNG). *

[image: {"rendered":"Grand-Central180"}]

*The project is being supported by the Rail Safety and Standards Board
(RSSB) and Grand Central is working with in partnership with G-Volution, a
British firm which has developed a patented dual-fuel technology for
transport applications.  *

*The trial builds on a 2016 RSSB-funded feasibility study, which concluded
30% savings in fuel costs could be achieved through the use of dual-fuel
technologies in rail. This study is being expanded through additional
modelling and analysis to include all types of diesel train on different
lines in Britain. The development of Dual Fuel Multiple Unit (DFMU) is
being used to validate the model outputs. *

*The DFMU project involves modifying one vehicle in a five-car class 180
set to operate in dual-fuel mode. The DFMU is due to begin operating by the
end of the year. *

2 attachments — Scan and download all attachments View all images
   image001.jpg
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Can't see your attachments because not all of us bow at the google alter. Lose the Google BS.

The usual apply here. It cannot run on LNG. The gas may be stored as a liquid but enters the cylinder as a vapor. The power loss is 25-30%.

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Posted by Overmod on Thursday, July 18, 2019 4:02 PM

tdmidget
The usual apply here. It cannot run on LNG. The gas may be stored as a liquid but enters the cylinder as a vapor. The power loss is 25-30%.

G-volution apparently has something like 8 years of experience implementing 'dual-fuel' on truck engines, which I think these railcar engines are comparable to.  This is not as sophisticated as some of the HCCI designs in the United States, apparently involving somewhere from 20 to 30% diesel, which really puts it in the assisted-ignition rather than promoted mode. 

The LNG is explicitly described as being vaporized in the intake tract; I'd be very surprised if this didn't involve very high turbocharge pressure using the LNG for 'intercooling' the charge air -- this probably implicitly involves NOx reduction with substantial SCR instead of any measures like EGR that decrease engine thermodynamic efficiency.  It is possible that the special conditions of railcar operation permit relatively lean-burn operation at constant rpm and 'predictable' throttle changes (e.g. predictable with proper GIS/GPS) and it would be interesting to see a technical paper on the specific installation and its control systems.

There is a sort of discussion of the alternatives in a paper (by Doug Greenhalgh) cited in this PDF file on the project (you may need to allow permissions to download a file from within a PDF).  There are some interesting discussions of carrier fuel and BEV economics there that I hadn't seen explicitly discussed before.

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Posted by aegrotatio on Saturday, July 27, 2019 9:51 PM

The very low temperature of the gas when it enters the cylinder reduces power so much.

For reasons I don't fully understand, the weight of passenger trains does not affect energy consumption by too much.  Because of this I envision this problem will eventually be solved with trains using a half-dozen or more heavy battery tenders in the consist along with regenerative braking energy stored in the batteries instead of wasted to atmosphere through the resistors.

 

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