CNG outboards?

Hello all, I haven't posted in a while but my recent search for an outboard got my gears turning, and somewhat grinding. I stumbled upon the company Lehr that makes the propane outboards. My local dealer actually stocks them. I wouldn't go this route and this isn't a question about their products but simply a thought that crossed my mind. (Possibly this should be moved to a different thread but I'm not sure how to do that now, since it's not a specific topic on outboards, maybe an admin can help me with that.) I live in Northeast Pennsylvania and as many of you around me know we have seen a huge boom in the natural gas industry in the last few years. If this technology took off could you see outboard manufacturers producing CNG (compressed natural gas) engines? I have first hand experience with this brand new technology because I drive a truck from a major paper plant with product to its nearby warehouse. As far as I know we were the first to run CNG trucks and have a CNG filling station on the property, at least here in PA. A few years later there are a handful of public gas stations that sell CNG in the area. Every once in a while you will see a pickup truck going down the road powered by it. I can honestly say that in my opinion this technology is in its infancy and the bugs have definitely not been worked out yet. As we bring product from the plant to the warehouse we climb a very long steep hill which with our old diesel truck we could hit 35-40mph under a load. With the CNG trucks your lucky to hit half that. If anyone lives around northeast PA and knows where the Proctor and Gamble plant is, the one that makes Bounty, Charmin, and Pampers diapers, I'm sure you've seen a few of these trucks on the road. We have also experienced exorbitant maintenance costs on things like "spark plugs" or "glow plugs" I'm not even sure what they are classified as. Also just overall poor engine performance. One plug is just over $700 and I believe we have 16 per engine. We actually have 14 trucks, class A vehicles, by that I mean full blown tractor trailers with 18 wheels pulling 53 foot trailers and in the first year of service every one of them blew an engine. But this isn't really about trucks, again I just had a thought that maybe someday we would be running our outboards on compressed natural gas. Just something to think about, anyone with any thoughts or experiences like I had chime in. As a side note when I fueled the truck today CNG was going for $1.99 GGE which mean Gas Gallon Equivelent. Not a bad price but when you consider you get half the fuel mileage it's a null factor. Also please excuse the grammar and flow of this because I'm writing it on my iPhone.

Jacob,
You make some interesting points. I have worked around gas compressors that burn the product[gas] and most of these engines run turbochargers in order to produce more power. I don't think that we will be seeing turbos on outboards any time soon do you.

Regards, Keith

Yea your absolutely right about the turbo point, and I had not taken that into consideration. It was just a kind of food for thought post. However I have seen a few trucks come in run by "Raven" transportation who are running not CNG (compressed natural gas) but LNG (liquid natural gas). Granted these are big trucks so they also require a turbo but I've been told that if the gas could be made into liquid form it would be much more efficient and easier for the general consumer market to use. These are the first vehicles I've seen use LNG and I have to say I believe the gas to liquid process must take place on the vehicle itself because I noticed frosted over fuel lines from the tanks, to me that says there must be a huge pressure change going on somewhere. This was in the summer time by the way. And warnings all over the tanks not to touch them or touch the lines themselves; severe burn warnings. But it's interesting to me that possibly if this was able to be transported as a liquid, without having to pressurize or de-pressurize whichever process is going on, I don't see why it wouldn't be a viable source of fuel. Obviously the automotive market would adapt to it first and outboards would probably be the last but it's still fun to think about. I know allot of the country doesn't see the push for this fuel we have had here in the last 2 years or so. By the way, if I see a concept liquid natural gas outboard on the market a few months from now from some genius engineer who read this, I want %50 haha.

On the LNG the only thing that keeps it a liquid is super cold not pressure.
Regards, Keith

Keith1 said:

I don't think that we will be seeing turbos on outboards any time soon do you.

Click to expand...

Check out the Mercury Verados.....

So Keith, your saying that the LNG trucks have some kind of refrigeration system on them that keeps the tanks super cold? Thats incredible. I have seen trucks deliver liquid hydrogen to the plant and they get frosted over as well when they transfer their load to bulk tanks. Actually I don't even like driving past them because there's so much "steam" or "evaporating frost" around them lingering on the ground that to me it seems like the smallest mishap would result in a very large expensive fireworks show. To the other poster, I'm assuming the Merc Verado has a small turbo?

actually Verados are supercharged.

and they have power steering too

You'll have a heavy vessel to contain the CNG...or LNG (both under pressure)...adds weight. You'll also have the junk to run the motor on CNG, expensive. Good idea though, if we can get it figured out how to safely store CNG, keep the weight down to a minimum, and then still manage to make the same horsepower and torque. Adding the turbo or blower would be neat, and would help the HP immensely, however, that too adds weight-and complexity. I've never seen a turbocharged outboard motor....the turbine housing would have to be water cooled and it's already heavy by design, so the best option would be supercharged, which would need a drive mechanism of some sorts (whether it be centrifugal or screw/roots), which also adds weight.

Big trucks work pretty good once the cylinder head is replaced, and a system of fuel and spark control are added. They use more fuel and they have less power. I used to work along with a couple other guys at a landfill, converting the garbage trucks (Cummins ISX) over to CNG. The drivers hated them. Gutless they said, and adds more weight because they had to carry more fuel. Also, the same city had us convert their dodge Hemi 3/4 ton trucks over. The guys who drive them love them except that they have NO power (even less than when they ran on gasoline), don't go as far on a "fill up",...but at one time, fuel was cheaper. BUT....the cost to convert them (the Dodges), was in the $10,000 range once it was all done. We did the first two, though I stuck mostly with the Cummins stuff and away from the Dodges, then the dealer the the other 8. By time they converted them all over, gasoline price dropped out to under $1.80/gallon and diesel $1.85. Once the cost to convert the ISX was figured in, even WITH the tax incentives that the city was able to score in converting all of the city-owned vehicles over to CNG, they still lost money-taxpayer money mind you. They are now replacing the vehicles with gasoline and diesel powered vehicles....and I am hearing that some of the big garbage trucks will now have gasoline engines in them (since the emissions requirements of the diesels is so stringent and therefore expensive to maintain/fix/buy). I am not surprised. They lost their butt on converting to CNG, or the taxpayers did.

A lot of the same principles will carry over to the outboard motors...costs, weight (weight is not an issue with what I dealt with when I was at the city), safety are the biggest 3 concerns. And then secondary concerns are of convenience since there aren't a lot of places to fill up a CNG or LNG tank.

Then to the engine itself, the valves and seats usually need to be different material than a gas or diesel engine because there is ZERO lubrication in CNG/LNG. It was common to drive the CNG trucks over to the dealer, with a miss, and they'd have to pull the head(s) to replace a valve or seat. Said NG is hard on them. Now those were engines that ran 1/4 load, under 1/4 throttle most of the time, where an outboard motor will have to deal with extended idling at times, and then extended full throttle full load operation. I can't say how the full throttle/load would affect an NG engine, no experience there.

But those are some things to ponder on, and I have thought about it some, even with lawn & garden equipment since that's what I'm messing with nowadays. Storing the fuel is the biggest hurdle with this kind of stuff, then the cost to convert or in some cases the initial higher cost to buy a new unit already converted at the factory (see a few with LPG). Lack of power/torque, so the operator has to run slower (more time=more money). Then the extra cost of repairs down the road, and then possibly more downtime trying to find a tech who knows how to work on 'em. Just a lot of negatives in all honesty. Only positive is that fuel usage is a little better (not much, at least not with LP), and it burns cleaner. It's not cheaper by any means.

Turbo,
One thing that you did not mention is when burning gas it's much cleaner and you can extend the oil changes way out. Also if you keep the engine pretty well loaded up not much carbon forms on the heads or piston tops. Other than that for me I don't see any advantage over burning gasoline.

Regards, Keith