Buck Marine Diesel

could it be sold as a 3 or 4 and then later made a 6?

another advantage might be for long range cruising to use no more of an engine than you need for economy and full engine for weather and docking etc.

 

No. The long parts do not interchange. (carrier, crank, cam, etc.) Unless you mean buying a 6 and only having 3 active cylinders. I'm not sure on that one. I don't think it would work. There would be a lot of stuff that you would have to change to make it possible.

 

I'm not sure on that one. I don't think it would work. There would be a lot of stuff that you would have to change to make it possible.


Lots of cars run on reduced cylinder count as an "economy" measure.

They simply cut off the fuel to the cylinder , and its not bad as most of the energy compressing air is returned on the down stroke.

To keep the cylinders warm and not loaded with oil they change the dead cylinders around every few cycles.


This might be a big advance for a marine engine , perhaps for the economy ,but mostly to reduce damage from severe under loading.

FF

 

Yeah, sorry. For some reason I wasn't even thinking about selective cylinder control. That is something we've talked about. I'm not sure how well it will actually work in a boat, but we will try it.

 

Why should´nt that work? It did from the 30ies til now.
BTW what is the displacement of your engines?

 

" For some reason I wasn't even thinking about selective cylinder control. That is something we've talked about. I'm not sure how well it will actually work in a boat, but we will try it."


PLEASE post the fuel map of the finished engine , and the fuel maps if you do give it a try.

Somehow fuel maps are harder to obtain than plans for a T88 nuke device.

Sure is hard to design an efficient vessel with some dumb prop curve.

FF

 

I am under the impression that the real advantage of selective cylinder control is really advantageous in that it allows the enging to effectively decrease the amount of horsepower being output during those times when the demand on the engine is slight. Now this is great for a truck designed for heavy towing that is being driven to soccer practice but I just don't see the application in a boat. Where the power demanded is going to be a significant fraction of the possible maximum output of the engine anyway (say 80-85%) assuming the engines are properly sized to begin with.

I guess I could see some advantage in a large planing hull that is operating at displacement speeds for long periods of time, or commercial vessels that operate with significantly different loads depending on what they are doing (fishing boats going in and coming out for instance), but otherwise I doubt you would see nearly the fuel savings that a car would. Combine this with the added expense of the computer system to monitor this and it seems that there just isn't that much justification in boats as opposed to cars.

I may be wrong on this but I just don't see how it would radically change fuel efficiency numbers for most applications, but it would have to add to the expense and complexity.

 

Now this is great for a truck designed for heavy towing that is being driven to soccer practice but I just don't see the application in a boat. Where the power demanded is going to be a significant fraction of the possible maximum output of the engine anyway (say 80-85%) assuming the engines are properly sized to begin with.

Besides the fishing , both commercial and sport with long term low power needs many pleasure boats have severe restrictions , inshore on wake production.

Even a displacement boat when stuck in canals with 10Klick speed restrictions will be underloaded , big time.

"assuming the engines are properly sized to begin with. "

Here is the biggest problem , many cruisers have the engine the advertising dept wants , not the boats designer.

Since they don't have to pay for the operation,maint ,or repair expenses , "bigger sells better".(faster , less time with borrowed credit from the banksters)

As Captain of a container ship or oil tanker , you don't see oversized engines .

FF

 

You´re right! You see much more of a fuel saving in a boat than in a Truck, where you have a gear to shift!

On passages most boats run at about 30 to 50% rpm settings for fuel saving reasons. As long as they do´nt have a CPP installed (the best solution), a selective cyl. management would be quite helpful to keep the "iron sail" happy.
A smaller engine never is a solution (apart from US market where almost every second boat is overpowered), there are situations when you need the power installed. Thats valid for the recreational craft as for the fishing fleet. (though to a smaller bandwidth sometimes)

Regards
Richard