flywheel effect

[automaxx]

I am working on a prototype engine from wisconsin. Yes they are still around. this engine is in a manlift.
the origianal worked ok. When we went to the pre production engine in the unit it was a complete pig and would not work.
I found a few differences in the two engines and started investigating them. The manufacturer is not being very helpful and they try to blame everything on something else.
One of the biggest things I found was the flywheel mass. It was not even close. the first one was about 45-50 pounds. The next one was only about 18-20 pounds.
The engineer will not believe me that a bigger flywheel will make it work better and neither will the manufacturer.
with the prototype it will pull the pump over relief before the engine starts to lug and the governor can keep up.
The other one drags the engine down instantly.
how far off am i? You can run a hay bailer with a 20 hp engine and a 200 pound flywheel.

 

[BillPSU]

I assume you are driving a hydraulic pump with this engine. You need to make sure your volume on your pump and RPM on the engine versus your operating pressures and flows matchup. You may be pushing too big a flow and your engine cannot deliver. Combustion chamber design can also have an impact. Is this a Tier 3 engine or a Tier 2. The EGR on Tier 3 engines cut into the low end performance of all diesels.

 

[HydroMET]

Yes

Sizing hyd pump disp for gasoline internal combustion engine, especially a wisconsin type cane be sensitive.

I have been through all the sticky claculation, but in the end testing is the only way to be sure of the max disp you can turn at the max pressure you need.

I sugggest to find a couple of cheap gear pumps to test starting at a theroetical disp less 50%. yes 1/2 of theroetical disp for 20 HP will get you close.

good luck

hydroMET

 

[kcj]

can you elaborate onthe 50% rule of thumb?
was the engine in good shape, putting out actual hp, etc.
or was it engine mfr hyping up the hp figures beyond what engine actual capable of?

Last small Toro lawnmower I bought advertises '6.5 hp' in big letters on engine, in manual, etc. In the fine print in manual, it clarifies that it is a 6.5 hp engine, as by mfr, at some applications, but not necessarily in this application. Only as an engineer did I figure out the engine may be 6.5 hp when used on a gen set at 3600 rpm, but on the lawnmower it runs at some lower speed, and is really only about 4 hp, the same as mowers have been forever.....
i.e. pure marketing BS,


kcj