An inspiration?

[Smelly]

Well as occasionally happens I needed to nip out for an hour while the engine was charging the batteries today. Whenever it happens and there's no-one around to keep a neighbourly ear on the engine I feel a bit guilty as I've had two close escapes myself; one oil leak and one fan belt failure, and know somebody who had to replace his engine after an oil filter failed while he was in the pub.

 

I think I've had a good idea tho.

 

What if, parallel to the engine alarm buzzer, via a latch relay a la the alt paralleling thread, you paralleled the alarm buzzer to a relay, the feed across which, when closed, engaged the engine stop solenoid? That way if the engine buzzer sounds it'll stop the engine. The latch relay means you'd need to press a button to engage the system so your engine would start and wouldn't suddenly cut out if you were in a sticky situation. (Running up the Severn as it flooded a couple of years ago had me worried the engine would overheat...)

 

There's need to be some form of protection for the solenoid, either via a thermal fuse to stop it burning out, or via a switch that only closed for a few seconds (is it isostable or monostable that'll do that, I can't remember).

 

I looked at the prices of the switches a couple of years back and they're not expensive, I reckon the whole kit fitted would cost less than 30 quid and could prevent a rather expensive problem. Also I'll have some nice green lights and buttons to match the red one's for the alt paralleling contactor

 

Excuse the lack of diagram but I've not much bandwith out here in the Boondocks...

 

What do we reckon?

Edited January 29, 2010 by Smelly

[DHutch]

Depends how reliable the buzzer is at detecting a fault.

- However assuming buzzer sounds for low oil pressure its a start...

- I would have an override too however for when boating.

[Rick-n-Jo]

smug mode on[

 

Me generator (which is also the main power source) already does that, via thermo switches on cyl head, exhaust manifold, stator coils, oil pressure switch and water leak detector.

 

]smug mode off

 

unfortunately, so far, the battery monitor which is supposed to switch the gen off when batts are charged, doesn't, so I have to shut it down meself

Ah well, isn't science wonderful?

 

Tis a good idea of yours though. You could also incorporate a remote engine stop via Big Red Button, if it would be any use in emergencies.

[lazyboy]

smug mode on[

 

Me generator (which is also the main power source) already does that, via thermo switches on cyl head, exhaust manifold, stator coils, oil pressure switch and water leak detector.

 

]smug mode off

 

unfortunately, so far, the battery monitor which is supposed to switch the gen off when batts are charged, doesn't, so I have to shut it down meself

Ah well, isn't science wonderful?

 

Tis a good idea of yours though. You could also incorporate a remote engine stop via Big Red Button, if it would be any use in emergencies.

 

During my time employed as an engine tester at Listers, All canal star engines were tested with a fail safe electrical protection system incorporating an oil pressure sensor fitted into the crankcase cam gallery and a water temperature sensor fitted into the water pump housing. These were connected via the wiring loom to an energize to run fuel control solenoid conected to the fuel rack shut off. If the engine suffered a loss of coolant or loss of lubrication oil or drive belt failure to the water pump,the solenoid would shut down the engine safely and before any major damage could occure. The engine could only be restarted with the manual operation of a system overide button.

[barge sara]

Should be able to arrange for ther engine to text you to tell you its feeling poorly.....

[DHutch]

During my time employed as an engine tester at Listers, All canal star engines were tested with a fail safe electrical protection system incorporating an oil pressure sensor fitted into the crankcase cam gallery and a water temperature sensor fitted into the water pump housing. These were connected via the wiring loom to an energize to run fuel control solenoid conected to the fuel rack shut off. If the engine suffered a loss of coolant or loss of lubrication oil or drive belt failure to the water pump,the solenoid would shut down the engine safely and before any major damage could occure. The engine could only be restarted with the manual operation of a system overide button.

Yeah, similar at JCB

- Coolent sensors, oil sensors, smoke/heat detector, and a perimeter fence.

- If any of these where broken then the engine cut of dead. All very simple.

 

Daniel

[EricMark]

It is common on stationary engines to fit oil, water, cylinder temp, and other auto-shut down systems. However with prime mover engines it is considered engine failure during manoeuvres can be dangerous. Consider what will happen if engine fails while in the lock or just when your about to engage reverse to stop. The auto stop would need to be engaged and disengaged so not active while under way. There are oil light switches that work other way around and make with pressure using a insulated return engine run solenoid with these and override button to start it is very easy to wire. Water temperature is not so easy as a burst can mean there is no water to measure temperature of so sensor needs to measure engine temperature. However Deutz, and Lister Petter air cooled engines do have sensors of this type being air cooled so likely they can be adapted. Other option is oil temperature which will of course rise if water cooling fails. Coolant flow switches are best idea.

 

But do have some means to over-ride while manoeuvring. Think safe.

Edited January 30, 2010 by EricMark

[John Orentas]

There is a long standing and very sensible tradition with marine engines that they do not 'fail safe' or shut themselves down for any reason at all.. If you were beam on to an on shore gale with rocks approaching about the last thing you would want is for the engine to decide to switch itself off..

 

True canal boat are rather different but any of us can think of a scenario similar to the above.. Some years ago there was a bit of a to-do when one of the engine manufacturers decided to marinise one of their electronically controlled jobs, then someone realised that if you loose electrical power the engine stops.. Not good.

[Smelly]

engine failure during manoeuvres can be dangerous. Consider what will happen if engine fails while in the lock or just when your about to engage reverse to stop.

 

But do have some means to over-ride while manoeuvring. Think safe.

 

 

There is a long standing and very sensible tradition with marine engines that they do not 'fail safe' or shut themselves down for any reason at all.. If you were beam on to an on shore gale with rocks approaching about the last thing you would want is for the engine to decide to switch itself off..

 

True canal boat are rather different but any of us can think of a scenario similar to the above.. Some years ago there was a bit of a to-do when one of the engine manufacturers decided to marinise one of their electronically controlled jobs, then someone realised that if you loose electrical power the engine stops.. Not good.

 

Hence the latch relay. You would only need to engage the system if you fancied a pint needed to go to the shop while charging batteries.

[EricMark]

Hence the latch relay. You would only need to engage the system if you fancied a pint needed to go to the shop while charging batteries.

 

I would agree with a multi-purpose power unit there may be times when you want to engage a fail safe. If the engaging of fail safe also prevented you selecting gears then ideal.

 

I only use my son and daughter-in-laws boat with them around, and have never read the rules and regulations. With cars, wagons etc you are not allowed to leave the vehicle with engine running. I remember a problem with a gully emptier where the driver got out to help mate and it was touch and go if he went to court. However it had a sandwich box that one engaged would not allow the vehicle to be driven even if you were to engage the gears. And so the case was dropped.

 

With a wagon it would be hard for even a large dog to fall or otherwise engage the gears. However not so sure with a boat! I did note at locks it is common to leave engine running and I should not think there are any rules to stop you leaving it running.

 

You know your boat. I suppose just as easy to engage bow thrusters in error. But when I was a kid I loved railway engines, boats and any other thing with a motor in it. Although I would not have done anything on purpose. I may have done things by error. I think of "Last of Summer Wine" and "Full Steam Behind" there are some (many grown-ups as well as kids) who love to fiddle.

 

Sorry I could not enjoy a drink like that I would be on tender hooks all the times I was away from the boat.

Edited January 31, 2010 by EricMark

[mayalld]

Hence the latch relay. You would only need to engage the system if you fancied a pint needed to go to the shop while charging batteries.

 

In order for it to be safe the other way (no prospect of a shutdown in use), I would want an automatic disable function, such that engaging gear brings a "don't stop" relay into operation.

 

Idealy that would be arranged (big capacitor??) such that it stayed engaged for 5 minutes after the engine was last in gear.

[kbarber]

In order for it to be safe the other way (no prospect of a shutdown in use), I would want an automatic disable function, such that engaging gear brings a "don't stop" relay into operation.

 

Idealy that would be arranged (big capacitor??) such that it stayed engaged for 5 minutes after the engine was last in gear.

Is "fail-safe" the right word here?

 

Dave's original idea requires (a) that the parallel relay pick up to operate the engine stop and (b ) that the engine stop solenoid then pick up to stop the engine. To be truly fail-safe the system would rely on both dropping away (and would thus shut down in the event of power failure, which puts us in the realm of John Orentas' manufacturer - as he says, not good). So true fail-safe operation isn't possible here without importing unacceptable risk, I fear.

 

The problem is that any failure in such a system may be a wrong-side failure, ie it will lead to creation of the danger it is intended to protect against.

 

If the risk of relay & solenoid not picking when energised is acceptable, the issue is to ensure such a system (I'll call it auto-shutdown) can't be operational when the boat is under way. Seems to me there's two approaches, but ideally either should only be resettable with the engine shut down.

 

In the first approach, the auto-shutdown could be engaged at any time when the gears are disengaged; ideally that would not just be in neutral, but - if it's a morse lever setup - with the gears locked out. Once that has been done the gears should be locked in neutral. If precautions were not taken it would still be possible for the auto-shutdown to be engaged while under way, at a time when the gearbox happened to be in neutral.

 

In the second approach the decision needs to be made before starting the engine and one or other system is locked out by selecting the other. Seems to me that would be simpler to engineer (note I said simpler, not simple) but would reduce flexibility - if you needed to do a quick bit of manoeuvering you'd need to stop the engine before charging batteries.

 

If t'were me I'd go for the second option. I'd also like to see the changeover control remote from the steering position, preferably in some kind of locked box (but with a visible indicator) so that accidental operation was impossible.

 

My twopenn'orth, but hope it's useful.

[ditchcrawler]

Is "fail-safe" the right word here?

 

Dave's original idea requires (a) that the parallel relay pick up to operate the engine stop and (b ) that the engine stop solenoid then pick up to stop the engine. To be truly fail-safe the system would rely on both dropping away (and would thus shut down in the event of power failure, which puts us in the realm of John Orentas' manufacturer - as he says, not good). So true fail-safe operation isn't possible here without importing unacceptable risk, I fear.

 

The problem is that any failure in such a system may be a wrong-side failure, ie it will lead to creation of the danger it is intended to protect against.

 

If the risk of relay & solenoid not picking when energised is acceptable, the issue is to ensure such a system (I'll call it auto-shutdown) can't be operational when the boat is under way. Seems to me there's two approaches, but ideally either should only be resettable with the engine shut down.

 

In the first approach, the auto-shutdown could be engaged at any time when the gears are disengaged; ideally that would not just be in neutral, but - if it's a morse lever setup - with the gears locked out. Once that has been done the gears should be locked in neutral. If precautions were not taken it would still be possible for the auto-shutdown to be engaged while under way, at a time when the gearbox happened to be in neutral.

 

In the second approach the decision needs to be made before starting the engine and one or other system is locked out by selecting the other. Seems to me that would be simpler to engineer (note I said simpler, not simple) but would reduce flexibility - if you needed to do a quick bit of manoeuvering you'd need to stop the engine before charging batteries.

 

If t'were me I'd go for the second option. I'd also like to see the changeover control remote from the steering position, preferably in some kind of locked box (but with a visible indicator) so that accidental operation was impossible.

 

My twopenn'orth, but hope it's useful.

Just have your beer on the boat while you charge the batteries, its much easier and you can enjoy the same noise as the other boats moored around you.

Brian