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  • CNG 'assist' for diesels legality??

    I was wondering if different rules apply for CNG blends below a certain amount, comparable to those that add propane to their diesels to give a bit of power boost for instance. Whether its 30% or whatever. Some fuel saved is still saved, even if it's not operating primarily on CNG. I'd considered playing around with CNG on an Oldsmobile 350 Diesel for instance or perhaps a GM 6.2 diesel in an older pickup, the impression I get is that it should be as simple as just adding some CNG to the input stream with the simplest of mixers or rejetted propane carburetors.

    Do different rules apply than for other conversions?

  • #2
    Re: CNG 'assist' for diesels legality??

    The official answer straight from EPA I got was yes it requires a cert at any blend as the vehicle is altered from it's OEM design and/or intent. Now ask Bully Dog if they have a cert. I'm not thinking so. If you are going to try this watch those EGT's you'll burn it up.

    not sure if the 10 year 100k mile rule applies here or perhaps the rule changed 3-5 year or something like that now.
    Last edited by CNG MOTORS; 12-16-2011, 09:26 AM.
    sigpichttp://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

    Comment


    • #3
      Re: CNG 'assist' for diesels legality??

      Actually, if the vehicle is older than 2 model years ago (for example, on Jan 1st 2012 this includes model year 2010 vehicles), there is no certification required unless you are in California. One laboratory FTP test is required (if between 2 and 10 model years old) + an OBD scan tool report. If over 10 years then no lab work is required, just a technical description, 5 gas analyzer tailpipe run at any IM station, and an OBD scan tool report. Details are here:
      http://www.epa.gov/otaq/consumer/fue.../420f11006.htm

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      • #4
        Re: CNG 'assist' for diesels legality??

        John,
        Where would one go to to get a FTP labratory test and how much would that cost? I am
        assuming FTP is Fedral Test Procedure and that it is a exhaust test?

        Brian

        Comment


        • #5
          Re: CNG 'assist' for diesels legality??

          Correct, the FTP is the standard federal test procedure for emissions. It is also called the Urban Driving Cycle. It runs about $1500 and takes two days. So the streamlined EPA rules mean you are probably out only $2000 or so for an Intermediate Age vehicle approval (covers all vehicles of the same model and year) so long as the OBD scan tool report at the lab looks good.

          § 85.515 Exemption provisions for intermediate age vehicles/engines (b)(9) OBD requirements. (i) The OBD system must properly detect and identify malfunctions in all monitored emission related powertrain systems or components including any new monitoring capability necessary to identify potential emission problems associated with the new fuel. These include but are not limited to: Fuel trim lean and rich monitors, catalyst deterioration monitors, engine misfire monitors, oxygen sensor deterioration monitors, EGR system monitors, if applicable, and vapor leak monitors, if applicable. No original OBD system monitor that is still applicable to the vehicle/engine may be aliased, removed, bypassed, or turned-off. No MILs shall be illuminated after the conversion. Readiness flags must be properly set for all monitors that identify any malfunction for all monitored components. (ii) Subsequent to the vehicle/engine fuel conversion, you must clear all OBD codes and reset all OBD monitors to not ready status using an OBD scan tool appropriate for the OBD system in the vehicle/engine in question. You must operate the vehicle/engine with the new fuel on representative road operation or chassis dynamometer/engine dynamometer testing cycles to satisfy the monitors’ enabling criteria. When all monitors have reset to a ready status, you must submit an OBD scan tool report showing that with the vehicle/ engine operating in the key-on/engine onmode, all supported monitors have reset to a ready status and no emission related ‘‘pending’’ (or potential) or ‘‘confirmed’’ (or MIL-on) diagnostic trouble codes (DTCs) have been set. The MIL must not be commanded ‘‘On’’ or be illuminated. A MIL check must also be conducted in a key-on/engine-off modeto verify that the MIL is functioning properly. You must include the VIN/EIN number of the test vehicle/engine. If necessary, the OEM evaporative emission readiness monitor may remain unset for dedicated gaseous fuel conversion systems. (iii) In addition to conducting OBD testing described in this paragraph (b)(9), you must submit to EPA the following statement of compliance, if the OEM vehicles/engines were required to be OBD equipped. The test group/engine family converted to an alternative fuel has fully functional OBD systems and therefore meets the OBD requirements such as those specified in 40 CFR 86, subparts A and S when operating on the alternative fuel."

          Note that if your vehicle is over 14000 GVW then you need to test the engine, not the vehicle.

          EPA used to publish a list of labs here:
          http://www.epa.gov/otaq/consumer/lablist.pdf

          So I attached to this post the EPA and California lab lists from a couple of years ago.
          Attached Files

          Comment


          • #6
            Re: CNG 'assist' for diesels legality??

            This is something that really gets me, i have a 1970 Subaru 360 I would like to convert to CNG because it is a 2 cycle oil injected vehicle, I can adjust the oil rate but apparently its illegal even though it would make less harmfull pollution. It gets mid 60's for MPG now but the fuel system and tank are starting to become junk and leaking so either a new gas tank adn carb or a new CNG tank.

            The other vehicle like the OP stated in a 1982 diesel suburban, it too would have much better pollution output with CNG but apparently i am not allowed to do that either legally.

            has anyone ever bought a kit from here?

            [illegal kit web site link removed by moderators]

            HMMM, that must be a bad site, what type of damage do his kits do to cars?

            Does your motor blow up? I am rather curious about all the kits and used tanks floating around, his kit for a diesel looks too simple to work very well. From what I've read a diesel can support up to 80% (sometimes 90%) at low throttle positions and about 50% at higher loads without detonation, all the mixers I see go the wrong way from a very low percentage to a high percentage where you can grenade the motor.

            Thank You for any info.
            I would think historic vehicles would be excempt, especially those pre-pollutions controls.
            Last edited by John Mitton; 01-25-2012, 11:20 AM. Reason: Removed link to illegal kit supplier

            Comment


            • #7
              Re: CNG 'assist' for diesels legality??

              Kits only blow up motors if fuel isn't metered properly and/or EGT's are not controlled. Minimum requirement for any kit you consider must control the EGT's. We have 600,000 miles now on our test vehicle and original motor. Got two other vehicles total up over 400,000 between also no issues.
              sigpichttp://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

              Comment


              • #8
                Re: CNG 'assist' for diesels legality??

                I removed a link above to a non-certified kit supplier in a previous post. I have, however attached a photo from the misguided site which shows what appears to be a non-DOT certified Chinese tank "mounted" with flimsy straps. In addition, the supplier encourages over-pressurization of these cylinders:

                You can fill with 3,000 or 3,600 psi filling stations with our custom filling nozzle, but you should only fill to 3,000 psi, however, many of our customers fill to 3,600 psi.

                Buyer beware...
                Attached Files

                Comment


                • #9
                  Re: CNG 'assist' for diesels legality??

                  Oh wow. Def not grade 8 eyelet bolts, not that you should be using eyelets for a tank install, but you got to love the 300lbs test straps.
                  sigpichttp://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

                  Comment


                  • #10
                    Re: CNG 'assist' for diesels legality??

                    nice mounting not to code but I have some shoe laces that might bring it up to code if you use the right knots LOL

                    Comment


                    • #11
                      Re: CNG 'assist' for diesels legality??

                      Originally posted by stillsearching View Post
                      I was wondering if different rules apply for CNG blends below a certain amount, comparable to those that add propane to their diesels to give a bit of power boost for instance. Whether its 30% or whatever. Some fuel saved is still saved, even if it's not operating primarily on CNG. I'd considered playing around with CNG on an Oldsmobile 350 Diesel for instance or perhaps a GM 6.2 diesel in an older pickup, the impression I get is that it should be as simple as just adding some CNG to the input stream with the simplest of mixers or rejetted propane carburetors.

                      Do different rules apply than for other conversions?
                      if you are going to fool with a old 350 you will have to go to the bolt house and get grade 8 studs and nuts and hard washers as the main problem with that motor is that it breaks head bolts than blows the head gasket they had a bad name but I ran many miles with this motor you should also use a good diesel oil such delo 15-40 for big trucks

                      Comment


                      • #12
                        Re: CNG 'assist' for diesels legality??

                        Two questions here:

                        1) Adding CNG to diesel changes its exhaust composition, no matter what anyone says about the amount, its adding hydrocarbons to hydrocarbons. Adding CNG at the right time and under the proper load conditions can reduce emissions and maintain power, but not a total substitution as we now have a CNG engine burning a little diesel.

                        2) Adding components to the vehicle to store the fuel that are not to code is dangerous (see the photo from John Mitten for example, and this is not the one one I have seen like this). I have seen tanks held in by plumbers strap, a wooden cradle with conveyor belt strapping, a vehicle frame rail cut out in half-moon shapes to store 6 type 1 cylinders crossways while the dump body bed held them down (!), and one installation that removed the rear seat and held the cylinder down with the seat belts, and new seat padding installed on top of the cylinder (it was even upholstered!)

                        Rules are for a reason.

                        Franz

                        Comment


                        • #13
                          Re: CNG 'assist' for diesels legality??

                          Originally posted by Franz View Post
                          Two questions here:

                          2) Adding components to the vehicle to store the fuel that are not to code is dangerous

                          Rules are for a reason.

                          Franz
                          Where are the mounting rules? As far as I knew they were more or less similar requirements (mounting wise) to what the Propane powered forklifts and utility company trucks follow, which means you can buy per code mounting hardware, having a proper place to mount it is another matter though.

                          As far as pollution my 82 diesel has no pollution controls (never did), a little CNG + a little diesel should mean less heavy carbon emissions, Nox would not be affected either way, CO would also be a wash. Timing would be tough to figure out though, probably have to retard it a bit depending on my goal RPMs...

                          Like all things, if DIY is impossible because of monetary or other reasons, the technology simply won't expand. Propane is widespread and understood, it is unfortunate CNG is not.

                          Comment


                          • #14
                            Re: CNG 'assist' for diesels legality??

                            The rules are adopted by state (in the US, rules are different in other countries or provinces), but most states follow the NFPA 52. The cylinder or fuel system install is NOT per propane powered forklift (retention capability), fuel lines and fittings are very different as well. See: http://goo.gl/xGxda for the NFPA website to the code reference. The NFPA 52 is available for online viewing but to print it out, you must purchase the PDF copy.

                            Your 82 Diesel more than likely has some pollution controls (probably an EGR valve) but it is way past the US EPA defined useful service life and CNG might be of some benefit. Whenever you add fuel to fuel, the total hydrocarbon level increases but since NG displaces some heavy hydrocarbons, the carbon load might decrease some. NOx may increase if you reach the level of detonation at low speeds and heavy load, something that has been a problem when dual fuels are used. CO shouldnt change much unless you start seeing black or white smoke.

                            Franz

                            Comment


                            • #15
                              Re: CNG 'assist' for diesels legality??

                              So I have been doing diesel dual fuel for a while now but I just recently read something on the forum making rethink my logic. We have a 03 duramax that gets 20 MPG on straight diesel unloaded. When a blend of 50/50 CNG/diesel, we get 40 mpg on diesel. My theory and understanding has always been that the truck still gets 20 mpg and that some diesel is substituted/displaced for CNG. Is this correct? Any engineering experts out there. OR does CNG make diesel more efficient and combustable which is where the gains come from.
                              sigpichttp://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

                              Comment

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