Author Topic: Governing a Diesel (Read 1781 times)

Fla._Deadheader · « **on:** September 10, 2006, 07:49:48 am »

Putting together another Bandmill. Found a Diesel engine from a small pickup. Price is VERY good.

How would one go about governing this engine

Anyone here that can 'splain how to hook up a cruise control to govern this thing

footer · « **Reply #1 on:** September 10, 2006, 08:50:19 am »

A cruise control is not goimg to work. Its reaction time is too slow. Your engine speed would be constantly wandering. I don't know right off hand how you would do it. If it is new enough, it is possible to control it through the computer if you installed an aftermarket computer.

jpgreen · « **Reply #2 on:** September 10, 2006, 11:00:34 am »

A simple govenor that would be great for your app would be like the one on my old Onan diesel generator engine. It's just a tentioned spring and some linkage.

I ordered a manual for it, and when it gets here maybe there's a good diagram for it. I could send you a copy if that would help.

DanG · « **Reply #3 on:** September 10, 2006, 11:14:59 am »

I gotta go up ta Hootie's this week to look for Tnlogger's axle shaft. Mr. H must have a thousand old froze up diesels laying around and some are bound to have guvn'rs on'em.

beenthere · « **Reply #4 on:** September 10, 2006, 12:32:20 pm »

15 years ago, a cruise control for a car that I installed was just a magnet glued to the drive shaft, with a pickup sensor, feeding the control box that did nothing but pull on the throttle control. When set speed was reached, it didn't pull anymore. That may not be fast enough feedback for you, as mentioned. Seems however it would work fairly well.

D._Frederick · « **Reply #5 on:** September 10, 2006, 03:06:43 pm »

Get a "fly ball" governor from the Surplus Center and run it with a Vee belt. Connect it to your injection pump.

Fla._Deadheader · « **Reply #6 on:** September 10, 2006, 03:34:15 pm »

Somewhere in Florida, We have one off the Porsche engine we first put on Homey.
Might hafta wait a couple more weeks, and put it in my luggage when I return from the states.

Timburr · « **Reply #7 on:** September 10, 2006, 05:27:24 pm »

Folks, I might be missing something here, why would a diesel need an external governer

The whole ethos of a diesel's being is that it requires a governer to function.

An inline injection pump has a centrifugal governer. A DPA (rotary) pump is usually governed hydraulically. The throttle sets the governer on both.

Percy · « **Reply #8 on:** September 10, 2006, 05:55:04 pm »

Quote from: Timburr on September 10, 2006, 05:27:24 pm

Folks, I might be missing something here, why would a diesel need an external governer The whole ethos of a diesel's being is that it requires a governer to function.

An inline injection pump has a centrifugal governer. A DPA (rotary) pump is usually governed hydraulically. The throttle sets the governer on both.

I could be out to lunch on this but my experience with diesel truck engines tells me there are several different ways of governing a diesel. There are full range governors where the position of the foot pedel/lever/whatever determins the governed rpm in which case the engine will apply more "throttle" to maintain the selected rpm. A throttle controlled diesel engine operates similar to a gas engine as far as the pedal/whatever is concerned. These engines have a maximum RPM governor that is probably adjustable by a knowledgable mechanic. I owned a old Cummins N series 350 hp in a log truck that had a throttle as oppposed to a full range governor. I added an air governor( was fairly cheap) for going slowly up steep hills. It worked very well holding its rpm steady. Mebey there is somthing like that available

D._Frederick · « **Reply #9 on:** September 10, 2006, 05:56:46 pm »

After thinking, Timbur is correct about having a governor in the injector pump, the Mercedes diesel car I had way back when had an over speed governor. When you were shifting gears the engine would only rev to a certian speed. I don't know if all small diesels have this feature. Way back when, the Cummin and the Detroit engines came with this style of govenor and were used in the small sawmills.

Fla._Deadheader · « **Reply #10 on:** September 10, 2006, 07:01:28 pm »

I've never tried a truck engine on a sawmill. Stationary power plants have governors. I am not sure about small trucks. Guess I'll find out when I crank up the mill

Timburr · « **Reply #11 on:** September 10, 2006, 08:00:54 pm »

Percy, now you mention it, I remember reading about Cummins having only a maximum rpm governer in certain applications. Not over here though. I only ever worked on the full range governed NTAs. Cummins and Jimmies were unique, 'cos they had cam driven injection pump combined injector units.

To my knowledge, all common smaller diesels have variable rpm governers. Even the ones that are electrically governed, but you don't want to go there. Not for powering sawmills any way

ladylake · « **Reply #12 on:** September 10, 2006, 08:24:56 pm »

Have to agree with Timburr every diesel i've owned has a governer in the the pump. On my M5 Moline the governer didn't work. No power whatsoever untill I got it fixed. Steve

Percy · « **Reply #13 on:** September 10, 2006, 10:02:19 pm »

Quote from: Timburr on September 10, 2006, 08:00:54 pm

Percy, now you mention it, I remember reading about Cummins having only a maximum rpm governer in certain applications. Not over here though. I only ever worked on the full range governed NTAs. Cummins and Jimmies were unique, 'cos they had cam driven injection pump combined injector units.

To my knowledge, all common smaller diesels have variable rpm governers. Even the ones that are electrically governed, but you don't want to go there. Not for powering sawmills any way

Heya Timbur.
Thanks for the info. So all FLDH has to do is set the rpm and cut away, ya??? The diesel Jetta I drove seemed to be more "throttle like" as opposed to "full range governor like". Are they full range governed as well?? Theyd be a great choice for sawmill engine...

Timburr · « **Reply #14 on:** September 11, 2006, 04:48:47 am »

Percy, ya and yes!

scsmith42 · « **Reply #15 on:** September 11, 2006, 05:54:07 am »

DH - I'm going to think out loud for a moment...

The small engine that you found - do you know what it's max RPM (governed RPM) is? Do you want to operate it at this speed, or a lower one? The reason that I ask is that as I understand it the engine governor will maintain it at the max RPM, but this may not be the same RPM that you want to operate it at. As I recall, most torque/HP curves for diesel engines show that the peak HP is usually somewhat below max rpm.

Let's say that the max engine RPM is currently 2500, and your targeted RPM is 2100. (this just happens to be what a Perkins turbo-diesel in one of my farm tractors uses. The PTO speed is 2100, and the engine should last much longer at that speed than at 2500).

If you can identify the current governor on the injector pump, and adjust it to a slightly lower speed (to improve durability), you should be set to go without the need for an additional governor.

I do know that injector pumps for motors designed for stationary duty are usually different than those for vehicles - the former is optimized for the operating RPM.

Good luck. Scott

Fla._Deadheader · « **Reply #16 on:** September 11, 2006, 07:33:27 am »

Thanks guys. Don't know what brand the engine is, yet. Once I find that out, I will look for the power curve-torque specs, and see what I have. I can use pulley sizing to get the blade speed where I want it.

slowzuki · « **Reply #17 on:** September 11, 2006, 08:41:00 am »

Most diesels have a governor because in a gas engine if the rpm drops with the same throttle setting the vaccum drops, more air and fuel comes in and the engine produces more power (its stable)

In a diesel the fuel rail sets the volume per rotation so if rpm drops from load the power drops off as well since no more fuel per cycle is injected. Very unstable if no governor is fitted.

rpg52 · « **Reply #18 on:** September 11, 2006, 03:29:33 pm »

I'm no expert, but from a Detroit Diesel owners manual, there are 3 types of diesel govenors: 1) variable speed mechanical, used in trucks, 2) constant speed mechanical, used in tractors, etc. and 3) hydraulic. The best one for a sawmill is hydraulic, which uses flyweights, a pump and oil pressure from the engine to maintain constant rpm. It has the least speed "droop", i.e. is best at maintaining a set rpm as load is added or taken away.

It may be more critical for a circular saw than a bandsaw, I really don't know. Good luck.
Ray

Tim · « **Reply #19 on:** September 16, 2006, 07:38:40 am »

I've been down this governor / cruise control road... I tried to mount a cruise control on the shingle mill... it was sort of like hitting yourself in the head with a hammer... it felt good when you stopped.

I found an enclosed Pierce governor on an old Case combine that a neighbour had. I bought it off him and added it to the shingle mill. Sweet little unit, roughly the size of a large travel mug. To the best of my knowledge, they are still manufacturing them some place in Illinois. Do a search on them to see. If you don't find anything, Deadheader, let me know and I'll take the info off the governor I have.

If your diesel has a throttle body, and I assume it does as it came out of a truck, the simplest means to hook it up, is to link it to the throttle.

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Author Topic: Governing a Diesel (Read 1781 times)