Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: How does a CNG/Diesel engine work???

  1. #1
    Join Date
    Sep 2008
    Location
    Kansas City
    Posts
    73

    Default How does a CNG/Diesel engine work???

    Just curious. Can anyone explain to me how a CNG/Diesel engine works. Since there is no spark plug, I am assuming it uses both fuels at the same time????? If so, what is the ratio? I am thinking about putting a proposal together for the pencil pushers at my job since we use hundreds of gallons of diesel fuel daily and was wanting to figure how much money could be saved. I assume this is possible, since my city has a new garbage truck coming that runs on cng and have seen other vehicles that are Diesel engines running on CNG.

  2. #2
    Join Date
    May 2008
    Location
    Spanish Fork, Utah
    Posts
    98

    Default Re: How does a CNG/Diesel engine work???

    Bi-fuel diesels DO run like that w/o spark plug, as the diesel injector still acts like the spark plug to get the explosion going, and the CNG is there to make the burn hotter, but you CAN also run dedicated CNG in a diesel platform, but the modifications required are much more extensive, including, but not limited to, installing a spark plug system to make it work. Industrial diesels are good candidates for this since they come with higher compression and heavy duty components for durability. And there ARE big conversion companies who take common industrial buses diesels and such and they convert them to dedicated CNG for city buses and stuff. It is not cost effective for the small end-user guy to do a full dedicated CNG conversion though. Only large fleets ever get considered for that.

  3. #3
    Join Date
    May 2008
    Location
    Spanish Fork, Utah
    Posts
    98

    Default Re: How does a CNG/Diesel engine work???

    Check out this picture: http://www.dieseltruckresource.com/d...70&postcount=9

    This is what the guy quotes off that page: "On a side note , cummins DOES build engines with spark plugs.
    CNG powered engines:"



  4. #4
    Join Date
    Sep 2007
    Location
    Lancaster, Ca (in the High Desert)
    Posts
    4,062
    Blog Entries
    1

    Default Re: How does a CNG/Diesel engine work???

    boomr, I would contact Cummings-Westport to see if they can provide you a White Paper that has all the pertinent data you'll need for your proposal. You may also contact your Clean Cities Coordinator and your local AQMD to assist you. This is what they do.

    You'll find a link to the coordinators list in the Clean Cities forum.

    Curtis Martin
    Program Coordinator
    Antelope Valley Clean Cities Coalition
    Cell # 661-492-5916

  5. #5
    Join Date
    Dec 2007
    Location
    Cadillac, Mi. / Deland, Fl.
    Posts
    1,055

    Default Re: How does a CNG/Diesel engine work???

    There are many ways to run a diesel cycle engine on CNG. If you run with spark plugs, you lose the higher compression effeciency of the diesel. Because NG will not ignite by compression alone, something is needed get the fire burning. I used to own a couple of large 50 year old generator sets that were bi-fuel capable. The engines were rated at 2880 hp and were started as a pure diesel. When inlet air temperture reached 165 degrees and the engine was at 50% load, NG was injected into the cylinder from an additional intake valve. At the same time, diesel fuel injection was reduced to 10% "pilot fuel"--the remaining 90% of the fuel was NG. These engines ran very clean compared to diesel but still had (they were 2 cycle) high NOX emissions. Cummins is working very hard with Westport technologies to build a totally NG engine that doesn't use pilot fuel. In the Westport design the gasous fuel injector has a glow plug type tip that will ignite the fuel when it is injected into the cylinder. It works .

  6. #6
    Join Date
    Jul 2008
    Location
    corpus christi ,Texas
    Posts
    71

    Smile Re: How does a CNG/Diesel engine work???

    Quote Originally Posted by boomr View Post
    Just curious. Can anyone explain to me how a CNG/Diesel engine works. Since there is no spark plug, I am assuming it uses both fuels at the same time????? If so, what is the ratio? I am thinking about putting a proposal together for the pencil pushers at my job since we use hundreds of gallons of diesel fuel daily and was wanting to figure how much money could be saved. I assume this is possible, since my city has a new garbage truck coming that runs on cng and have seen other vehicles that are Diesel engines running on CNG.
    Talk to Tom at Tulsa Gas Tech ther in tulsa. He worked on a project called Co-fueler that does the mix

  7. #7
    Join Date
    Dec 2009
    Location
    Los Angeles, CA
    Posts
    4
    Blog Entries
    1

    Default Re: How does a CNG/Diesel engine work???

    People are beginning to formulate a natural gas and diesel blend called GDIESEL. There is also aftermarket kits which supplement the diesel fuel with natural gas in the intake when the intake suction increases beyond a certain point. I am looking for the latter myself for a Cat 3208 powered school bus.

  8. #8

    Default Re: How does a CNG/Diesel engine work???

    I been running a dual fuel International truck diesel/CNG now for well over 200K miles. Things to note/ consider

    1. The higher the CNG blend ratio i.e. 70% CNG 30% natural gas the more tendency to detinate. especially under loads
    2. High blends ratios also cause extremely high EGT's again especially under loads.
    3. The obvious the more CNG blended in the more you offset you diesel consumption and hence the more savings
    4. Range always remains an issue with the size of CNG tanks

    With all of the above in mind I like to run my truck at a 25% blend, I also have a system shutoff at a predetermine EGT temp. Long term savings for this vehicle has been 33% because there is a cost to CNG after all. My truck holds 42 GGE's of CNG and at 25% it allows me 850-1000 miles range plenty for long trips and to make the next CNG station. However I find myself turning up the blend whenever I'm in Utah as stations are plentyful
    http://WWW.CNGMOTORS.COM
    SAVE TIME. SAVE MONEY. SAVE THE ENVIRONMENT.

    2003 Hummer H2 bi-fuel
    2000 GMC Yukon XL bi-fuel
    1999 International 4700 dual-fuel
    2007 Chevy Avalanche bi-fuel

    FMQ2-36 Fuelmaker w/ 24 GGE cascade

  9. Default Re: How does a CNG/Diesel engine work???

    Hello, I am new here and looking to learn more about the diesel conversion process in view to an investment in a new company working on this. Who are the most experienced and biggest converters of diesel engines now? Aremost of them using a blend like you are talking about? Who are the leaders in the pure cng or dutiful conversions?
    Many thanks for your time in answering my questions,Michael

  10. Default Re: How does a CNG/Diesel engine work???

    I meant to say "who are the leaders in the pure cng or DUAL FUEL conversions". thanks

Page 1 of 2 12 LastLast

Similar Threads

  1. diesel - CNG
    By altfuel in forum Other Natural Gas Vehicles
    Replies: 140
    Last Post: 10-18-2011, 11:16 AM
  2. NG as diesel filler
    By Gerben in forum In The News
    Replies: 1
    Last Post: 04-21-2010, 10:22 PM
  3. Volvo Trucks to market methane-diesel engine
    By Tax Counsel in forum In The News
    Replies: 1
    Last Post: 01-08-2010, 03:37 PM
  4. diesel cng units
    By smartineau in forum CNG Service & Conversion Manufacturers
    Replies: 13
    Last Post: 06-17-2008, 09:15 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •