My dad (a former supertanker captain and current marine insurance surveyor) recently got back from investigating a claim where the one of the turbocharger oil seals in one of the engines broke, leading to a runaway. Luckily, the governor was still working, so the air intakes closed before the engine seized or exploded, but IIRC, the engine was severely damaged.
So this got me reading about two-stroke diesel engines. They have an awesome power:weight ratio and diesels are more fuel-efficient, and mechanically simpler than gasoline engines. Why they aren’t used in cars, I have no idea. Most automotive four-stroke diesels have turbochargers, so the added weight of a turbo shouldn’t be an issue.
I was also reading about Bruce Crower’s invention of a six-stroke gasoline cycle, where after the 4th stroke, water is injected into the cylinder, which instantly turns to steam, both providing an extra power stroke, and cooling the engine. I’ve read that he gained a 30% increase in HP, and a 30% decrease in fuel consumption.
So I’m wondering why nobody has thought to apply this to maritime two-stroke diesels. The water needed can be taken from the desalinization system. You’ll get less fuel consumption, more power, and the engine cooling system can be eliminated. So weight and space can be saved, which can be used for more cargo, increasing a ship’s NT.
I’m not an engineer by trade so this is somewhat speculation on my part. But it would seem to me that injecting water into cylinders that are running at least 700 degrees would be a recipe for bad things happening. I think automotive Diesel’s run quite a bit lower so it could be less of a problem there. But on a marine Diesel engine, not so much.
Wonder what the real engineers around here think about this?
[QUOTE=awulfclark;121076]I’m not an engineer by trade so this is somewhat speculation on my part. But it would seem to me that injecting water into cylinders that are running at least 700 degrees would be a recipe for bad things happening. I think automotive Diesel’s run quite a bit lower so it could be less of a problem there. But on a marine Diesel engine, not so much.
Wonder what the real engineers around here think about this?[/QUOTE]
I think the biggest issue is that diesel engines don’t have spark plugs, they use the heat of compression (plus the heat of the cylinder) to ignite the fuel. Cooling the cylinder could be harmful to that process.
I was on an APL Ship which had a bunch of Cal. Polytech scientists aboard experimenting with water emulsion mix for NO2 reduction. We got up to a 50% mix of water/bunker fuel mix but it didn’t reduce the NO2 levels. When I pulled the fuel strainer to swap it the fuel looked like fizzing mayonaise.
Also the 2 stroke marine engines use cylinder oil (oil injected around the liner through small holes) which is burned during the combustion process. You would have oil mixing with the steam which would gum up the rings and deposit gunk on the turbo blades. Water isn’t free on ships as it cost money to make it.
Maybe I’m old school - (just thinking back to my Dad’s 6-71 Detroits on our sportfish) but injecting water sounds bad on several levels. First, there is the matter of uniform heat distribution within the block, then the possibility of plugged water injectors over time, finally the lack of lubrication inherent in water leading rapid corrosion and wear to the rings and liner.
May work in the lab but I wouldn’t want to rely on it to cross an ocean.
I’d prefer a turbo encabulator to optimize diesel performance.
[QUOTE=TSLexi;121169]Couldn’t you use steam cylinder oil, so the steam won’t cause the oil to gunk up everything?[/QUOTE]
Yeah, right. Every 3rd revolution you squirt steam cylinder oil in the thing … think about it.
And for the rest of the believers, consider that the exhaust from the dino power stroke carries out most of the heat of combustion so that the squirt of water just cools the cylinder and wastes time before another power stroke can occur. When the water turns to steam it just removes heat from the structure and the newly compressed charge air, it how can it produce more power than it takes to move that water to the cylinder and to compress the charge air enough to vaporize the water … thermodynamic magic? perpetual motion?
the OEM’s tried water injection in their turbo car engines in the 80’s and as you know if you ever pulled an engine down that had water injection, its spotless as the water has steam cleaned all the parts that also means it steam cleans the oil off the bores and you have massive ring/piston/bore wear.
Water inject will never be used
Updated - - -
what is being tested on light trucks is a mini steam turbine using waste exhaust heat to drive a generator then plug it back in via electric motor