CNG, is it the Fuel Answer for the Fuel Crisis? (Part 1 of 3)

September 30, 2008 07:00 PM

Forget veggie oil, bio-diesel, power programmers and hydrogen water separators. And hear the gospel of CNG/diesel. The beauty of this system is if I can't find a Compressed Natural Gas fill up station, I just run on diesel.

From the math I've been doing, at 4 to 1, buying CNG in Colorado at $2.89, I can save 25%. Which is like buying diesel at $3 instead of $4 or increasing MPG by 25%. But if I buy at $.90 like in Oklahoma, I can lower my cost per mile from $.40 to .15 or 63%, yes 63% savings! And did I mention more power?

It's not about waiting for a hybrid truck or hydrogen fuel cell to save us, but something we have in abundance in the USA that we can use now. You see the T. Boone Pickens ads on TV every day. There's something to his plan with CNG. Propane and CNG have been used to boost diesel engine power, but I'm talking about replacing most of the diesel with CNG. Approximately 4 to 1 and 2 to 1 towing a trailer.

Strange to be writing an article about increasing fuel mileage without my final mileage numbers, but that's part of the story, how hard it is to get CNG fuel. Not hard to find but complicated to buy. Many fueling stations use a special card only, that you have to apply for. Mark Deluca installed my unit in Ohio, he had to fill me up, as a special card was required, the same for a station in Indiana.

As a kid on the farm, we had a propane Minneapolis Moline farm tractor, filling propane was a pain. But CNG is a snap with just a coupler, similar to a air compressor coupling with a locking lever. Gasoline Gallon Equivalent is how CNG is sold at the pump, so you don't have to bring your calculator to convert BTU's into cubic feet and then into gallons.

I had to go to Ann Arbor near Detroit to get my next fill. And since CNG stations are farther apart than my two 10 gallon tanks will run, I can't get a tank to tank read on what my cost per mile is. Which is the only accurate way to judge what I'm saving by using CNG. A week ago I faxed in my application to Clean Energy, which controls all the CNG filling stations in Colorado. I downloaded the app from and faxed in my 4 page application plus copy of credit card and drivers license.

They require a $100 deposit and bill your credit card a day after you use their special cards to buy CNG. Clean Energy HQ is in California where they operate dozens of stations that use credit cards like a gas station. This should spread to other stations around the country as CNG becomes more popular. Clean Energy bought Phill Home Fueling Stations for CNG and are in a joint venture with GM for opening Hydrogen cell fueling stations.

So far using CNG in my 2006 Ford F250 diesel test truck added 180 miles to my overall range. 280 miles on CNG/diesel with a trailer using two 10 pounder tanks. Paid $2.19  for CNG in Ohio, $1.94 in Michigan, in part 2 we'll have real world numbers on what the actual fuel savings is and what it takes to pay off a CNG conversion and tank with fuel savings. Twenty CNG stations in my state, Colorado, 62 in Utah, 51 in Oklahoma, 92 in New York, 40 in Arizona and 183 stations in California. 778 stations in the country. Utah ($.88 this week) and Oklahoma ($1.14) have the cheapest fuel. For current prices and locations,

With diesel and gas prices doubling in one year, no one was prepared for this. We knew higher prices were coming and oil is running out, but not all at once. We all feel the pain, from fuel prices. But the good side and there always is a good side if you look hard, the dramatic fuel price increase has put the whole country on alert speeding up development and brain storming for a solution.

For the businesses that survived the fuel crisis, bank crisis and bail out crisis, it's time to sort through the new ideas for the real improvements in mpg for commercial trucks and pickup trucks. I've tried engine programmers, bigger exhaust, bigger air intake, roof wings, lower air dams, tonneau covers etc. and never got a large improvement for more than 10%.

Reading Diesel Power Magazine with a diesel truck mod shootout, one of the trucks had a CNG added to a Duramax getting 38 mpg. Sounded interesting but didn't sink in until my nephew Greg, called wondering if I had more info on CNG. Researched the source and found Marc Deluca in Ohio up to his elbow's in installing CNG on diesels. Called some engineers at Ford to see what would happen if I added CNG to our test truck, a 2006 F250 with the 6.0L Power Stroke diesel with new head gaskets, new EG cooler and 65,000 miles.

The main concern was boost and internal cylinder pressures. The boost was actually reduced with CNG. We may try a boost regulator before we go to larger loads than the 10,000 lb trailer we're using now. My concern was lubricity since I would be using less diesel, I was told by an engineer that lubricity wasn't a problem as only diesel was going through the injectors where lubrication was a concern.

Mark Deluca explained that CNG makes the engine more efficient, diesel explodes in the center bowl of the piston and leaves some oxygen and diesel unburned in the outside ring of the piston. CNG helps use the fuel and oxygen in the outside ring, giving you more power. Diesel engines compress hot air and CNG for a more complete burn of fuel and air in the compression stroke.

Since the CNG venturi tube is in the air snorkel after the air filter, the low pressure fumigation CNG fuel, is sucked into the turbo and mixes air with CNG as it travels through the turbo and intercooler on it's way to the engine. No CNG is used at idle and it takes about 1500 rpm to open the spring valve on the regulator for the gas to flow. Drawing CNG into intake manifold has advantages over bio-diesel or waste oil which goes thru pumps and injectors causing some problems on seals, o-rings or gelling from cooking oil waste/fuel.

Talked to farmers in Ohio who built a portable unit with regulators, argon tanks for CNG that lifts out of their Dodge 2500 with Cummins diesel and onto a combine for harvest. They have natural gas wells and get some free CNG. Even with an expensive step-up pump, they said they saved a couple hundred dollars a day using CNG in farm equipment.

Major companies are working on CNG projects, John Deere has CNG gas engines in trucks and buses, Cummins has a CNG engine and in 2001 Cummins had a 15 L Cummins/Westport CNG/diesel that they tested which burned mostly CNG with a dual injector with diesel. Mahindra Tractors is launching new models, using CNG and LPG.  it is estimated that the new models will be at least 30 per cent more fuel-efficient than diesel-run tractors.

Author H. Kent Sundling writes for via a special agreement with  

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