CNG vs. Gasoline SMOG comparo

[CNG MOTORS]

This is the tail pipe emmissions report from my daughter CNG bi-fuel H2 Hummer. I probably should not have driven all the way there on CNG, I think thats why the gasoline #'s look so good.

[larrycng]

Re: CNG vs. Gasoline SMOG comparo

It looks good as far as it goes. Where are the NOx, O2, CO2 readings? The missing reading will really tell the tail on how clean the exhaust is. The vehicle has a good ignition system and is running close to stoichiometric. The NOx and CO2 will if the emission s are really low. If it is running too lean CO2 will rise there will be an increase in NOx (oxides of nitrogen) and that ain't good. You need a little CO to help the reduction part of the CAT to help clean up the NOx (the CO will go to CO2 with O2 that comes from the NOx)

That's why I love 5 gas analysis as opposed to the 2 gas reading in the emission report.

Keep going with the CNG

Larrycng

[BobBaldwin]

Re: CNG vs. Gasoline SMOG comparo

Did you get a before test?

[CNG MOTORS]

Re: CNG vs. Gasoline SMOG comparo

No but another 03 Hummer non converted should blow simular.

[larrycng]

Re: CNG vs. Gasoline SMOG comparo

I'll see if I can find some of the "loaded mode" SMOG tests (ASM) I did when we converted to bi-fuel propane. After we got the vehicle running, we took it to the SMOG Dyne and ran it. It was done on gasoline first, the engine switched to LP (the vehicle remained running), the vehicle data entered into the SMOG machine and the test run on LP (this took about 5 minutes). The original reading on gasoline was about the same as the Hummer for HC and CO. The test on LP showed slightly lower readings on LP (1 or 2 ppm HC and .01% CO). The NOx dropped by about 30% , there was about a 1% drop on CO2 and a slight increase in O2%.

That is about all I can remember but that was about 10 years ago. The vehicle was a '97 F-250 with a 460 cid with about 40K miles on it.

Most vehicle that are properly maintained and functioning properly will pass with low numbers. Even my '92 Bird with over 400K miles is still passing (barely) but it still has original CATs

I think the bottom line is that vehicles need to be maintained no matter which they use. But with CNG you can expect about a 20% reduction in CO2 which is one of the goals. The other big goal is to reduce foreign oil dependency.

For what its worth

Larrycng

[CNG MOTORS]

Re: CNG vs. Gasoline SMOG comparo

The problem with the H2's is they are AWD and you can't put it on a loaded dyno.

[larrycng]

Re: CNG vs. Gasoline SMOG comparo

Oops forgot that. I guess that is one way to get out of loaded mode SMOG.

Sorry

Larrycng

[Green GX]

Re: CNG vs. Gasoline SMOG comparo

$19 dollars for a smog test? They jack us up for $75 in California.

How come other states can do stuff for less and not be teetering on the edge of bankruptcy?

Bill

[larrycng]

Re: CNG vs. Gasoline SMOG comparo

There are several problems with California SMOG that affect the price. Much of Calif has been declaired a non-attainment area by the Feds. This requires more sever testing which translated into loaded mode testing and the use of a dynometer and 5 gas analysis to test of oxides of Nitrogen (NOx). When the Calif. program started in '97 the cost of the equipment was around $30,000, plus in the cost of installation, plus supplies (calibration gas) and other required equipment.

If you didn't have a SMOG station on every corner with people trying to cash in on the required every 2 yr inspection the price should be a bit lower. I think the average Calif. test is about $50 last time I checked. (Some new car dealers do get $75). You have to do several test a day to pay off the equipment over a 5 year period, and pay the technician (who is licensed)

I believe Utah is a non-loaded test stated which requires less of an investment in equipment. Some states like where I live in Washington (part of the time) is non SMOG for vehicle registeration. These areas have a less sever SMOG problem that some areas hence the increased of test equipment and the cost of the test to recoup the investment

I hope this helps

Larrycng