Buck Marine Diesel

Great project, and great post. Its good to see people with innovative ideas come here with facts and figures. I hope this works out, I would certainly put my 3 boats up as candidates for repower with your engines.

K9

 

Agreed... this is looking very promising.

I can see how it would be a bit more expensive up-front; it's a new design, and the efficient mass-production systems used by the 'big guys' do not scale well to smaller companies with new technology. But I think with some careful engineering and optimization of the various fabrication and assembly processes, it could be competitive.

If the torque curve looks as nice as the thing sounds, you may have a winner. The trick, IMHO, will be marketing..... not an easy task in a field dominated by a few longstanding, ruthless rivals.

 

matt, that is one thing we're concerned with too. We're the first new diesel engine company in the US in about 100 yrs. Kind of cool to think about

 

Some thoughts on your engine design

The test trials you've got on your new engine yielded a very high exhaust gas temperature already. Normally, diesel engines in power and marine applications usually operate at 500 deg. C (932 deg F) limit, such that you have already exceeded by around 68 deg. F. It will surely cause you overheat problems and valves will be burned in prolonged operation.

I understand that this will be turbocharged engine considering that you are using two (2) injectors per cylinder. It's the first time that I've encountered an engine having two injectors per cyl. Although you might want to operate it alternately during low load (small injector) and high load (the bigger injector), why not just controlling the amount of fuel injected during those load shifts with only one injector. I think you will be having many controls if you're doubling up the hardware, notwithstanding twice the amount of maintenance to be done later on.

Is this might be the reason of high EGT? You're loading more fuel without charging more air to the cylinder, therefore decreasing the air-fuel ratio. And I don't believe that you're getting cleaner emissions with more fuel burned without increasing your charged air.

The coolant temperatures are too early to tell because its a new engine, however, considering the very high exhaust gas temperature early in the game and at moderate load, it surely will increase dramatically during actual use. And you said that you're using saltwater for lube oil cooler? I think its already a bad concept since any leaks inside will surely wreak your crankcase lube system. Better to use fresh water cause its one less of a headache if contamination occurs (saltwater is more corrosive than fresh).

But I appreciate though your good concept in cooling each and every cylinder separately. Its a good idea and just hope the design would not complicate maintenance activities especially for guys doing the major overhauls.

More power to you!

 

The exhaust gas temperatures are not that high. Yanmar's standard for their engines are around 1350 deg F. When we had a problem, we have had our heads and carrier over 350 deg F (someone forgot to put a key in the coolant pump shaft, so we had no coolant circulation once it got hot enough for the impeller to expand and slip) without having any problems. We ran it until it locked up, which it did from a connecting rod issue that we have since solved. When we disassembled the engine, we did not burn a valve, butt a ring, or cook a piston. All of the upper end components were perfectly fine and reusable.

The injectors will be alternated as you said, using the small for low load/idling and the larger for high power. We may also use the smaller injector for a pre-ignition injection at high power. The reasoning behind using 2 injectors is simple. To get the maximum amount of power out of an engine, you have to have an injector large enough to inject the required amount of fuel for that kind of power. Unfortunately, that means at low power, no matter how much it is dialed back, you are still putting more fuel into the cylinder than you can burn. We are trying to reduce emissions and increase fuel economy. While there is a slight increase in the amount of hardware and software needed, it is not an extreme amount more.

The test data posted and videos shown are using a single injector setup because we have had some issues finding companies to reliably supply us with good injectors. This will be solved by making our own in the future. As of right now, we are using a single, standard Bosch injector.

You said:

"The coolant temperatures are too early to tell because its a new engine, however, considering the very high exhaust gas temperature early in the game and at moderate load, it surely will increase dramatically during actual use. "

I don't understand how being a new engine will effect the coolant temperatures... We did have more than a moderate load on the engine at the time. As I said, our dyno wasn't working so we don't know exact numbers, but our water brake valve was open nearly all the way and the engine was running at about 2400 rpm. There was a fairly heavy load being placed on it.

There is NO saltwater getting into any part of the engine other than through a tube-pack style heat exchanger located inside of the exhaust manifold. The raw water (it would only be salt if you were in the ocean) is drawn from whatever body of water the boat is sitting in and passed the heat exchanger and oil cooler. A separate, oil-based coolant is pumped around the cylinders, through the heads,and around the heat exchanger before being sent back through the system.

You don't seem to full realize the amount of time, labor, and machining the engine will REMOVE from the overhaul process. We are estimating that a complete 6-cylinder engine overhaul that includes rod bearings, rods, pistons, cylinders, heads, injectors, rockers, rocker shafts, and push rods should only take about TWO (2) HOURS! And it can be done without removing the engine from the boat or removing the oil pan. All of this work can be done from the top using only a few simple hand tools.

If you have any more questions or need more clarification, please feel free to ask.

 

When can I expect the arrival of my 3 cyl 50 hp model?

Honestly I'd love to have one of your engines in our trawler project. Right now we're considering diesel/electric. Being a bit of a technophile I'd be more than happy to offer my boat as a test bed for your engine! If all goes well we'll begin construction int he spring of a 31' L x 10' W stitch & glue trawler.

Keeping an eye on your progress and good luck.

 

Thanks for the reply...

But I still have some clarifications....

You said that:

"We may also use the smaller injector for a pre-ignition injection at high power."

At what degrees before TDC (top-dead-center) do you intend to inject the fuel? Although injecting fuel a few degrees before TDC might increase the Pmax (max. firing pressure), incorrect injection timing will also tend to induce negative force or work as shown in the PV or Pressure vs. crank angle diagram. Sudden increase of pressure will only be effective if done right before the TDC, if not, it will only create counterproductive force of the compressing piston, thus, lowering the Pmax. Increasing PMax has its downward effect such as increasing the EGT.

Also, if you use the small injector during idling (low power), is it automatically adjusting its fuel injection timing? Is it different than when both (larger and smaller injector) are operating? Or shall it take the setting of the larger one which is more appropriate? You already said that its use for pre-ignition when both are operating. Is there flexibility when it is at idling?

You said that:

"The raw water (it would only be salt if you were in the ocean) is drawn from whatever body of water the boat is sitting in and passed the heat exchanger and oil cooler."

If you are manufacturing that heavy engines surely it will be most applicable for propulsion for seawater boats. As you said, you are circulating it on the heat exchanger (for fresh jacket cooling water) and OIL COOLER. I suggest that you should not include the oil cooler here. Leaks which is a very common problem in the marine engine installations, if that happens will surely wreak not just the system but the whole engine as well.

Thanks again if you care to reply.

 

We are still working on the complete fuel map. Once the engine is mapped, I will be able to tell you more about the injection timings of each injector. We are using electronic injectors, so a small board gives us full control over the injector pulse width, timing before TDC, and fuel pump duty cycle.

As for the oil cooler, the cooler is a copper-nickle tubed cooler. This type of cooler is used extensively throughout the marine market. We have yet to have a problem with it. The same type of cooler is also used for transmission coolers. This type is used to take some of the load off of the engine coolant.

Knotty, we are hoping for more like 400 HP out of our 3 cylinder
I would like to hear more about your project though. My e-mail is tim@buckdiesel.com

 

Oh ok, well cound me in for a 1 cyl version then!

So far it's a Jacques Mertens designed TW28 stretched almost 40" which will bring it to almost 31'-6"x 10' beam.

http://www.bateau.com/studyplans/TW28_study.htm?prod=TW28

Designer calls for 30 to 50 hp for the original and has stated that up to 80 hp would be ok as long as the weight doesn't exceed specs. (still waiting for that figure but I'm guessing it's around 500 lbs. Being a gadget-a-holic I've been considering a diesel/electric setup. The concept I like the most is the Fisher Panda Aziprop but the bottom line price would likey be the determining factor (we're building out of pocket) and pretty much any diesel/electric setup is at least double the cost of a conventional direct drive diesel.

 

"Designer calls for 30 to 50 hp for the original and has stated that up to 80 hp would be ok as long as the weight doesn't exceed specs.'

Bigger isn't better , FULLY LOADED is far better.

Well OK, a 70% load at the rpm required to cruise will usually still give efficency , although 80% loading will give better fuel use and longer life.

80 Hp is fine if tou wiah to attempt to run at semi disp speeds SL x 1.6 or so at 4 or 5 GPH..

I would guess a SL 1.1 would cost 1/2 to 3/4 gph.with a -35 rated hp engine.

You choose ,it is your Ca$h.

FF

 

What is the material, cast steel or aluminum?
Where is the camshaft located?
2 or 4 valves?

 

The engine carrier is gray cast iron. The heads and cylinder jugs are aluminum and there is a ductile iron sleeve pressed into the jugs for the piston to ride in.

The camshaft is located inside of the carrier.

The current configuration is a 2-valve.

 

Metric or imperial system?

 

Imperial

 

When are you going to learn?
I will find something else to put in my hull.