My new CHP project …. Learning as I go. Feel free to comment.

[Dyslexicbloke]

Couldnt add all three pics to the same post!

[jotec]

Looking excellent. and so clean, my bunker is like the black hole. I wear gloves when I am handling anything in it to avoid the grubbiness!
Like the control logic it is a model for me to work to. My problem is that  when I have something that works I tend to move on to something else and it never gets fully finished. Work also gets in the way!
Now off to clean the injector pump on the Lister, I find it gets sticky with veg after about 1000 hours running. It is fine when hot but starting from cold it can hold the revs alarmingly high for a few seconds.
Dick

[Dyslexicbloke]

It may well look OK but its far from satisfactory right now ..... Defiantly a work in progress with a long way to go. ‘O’and remember, I am not running dirty sticky veg yet and the system has done less than 100 Hrs

I know what you mean when it comes to fiddling with things that are ‘working’. I have a few demons in that department, I constantly struggle to find a balance between satisfactory and perfect.
The problem is that I ‘feel’ I should be striving for perfect, although logically I know I will never achieve it, and when I do manage to persuade myself that something is good enough and move on I am seldom satisfied with the result. It all makes gating motivated to do anything a bit of a struggle, but that would be one for the therapist not this forum …. Ah well

Case in point ….
The strategy is working but, as I just discovered, a tach fail results in an immediate over-speed.
I was planning on building some more electronic bits today to control battery charging but now I am going to have to re-visit the strategy and add all those safety trips I had decided were not absolutely necessary at this point in the project. It sounds simple but if they are going to be effective I will have to physically test all the scenarios.

On top of that until I read your comment about gummed up injectors causing overspend I hadn’t considered mechanical issues, silly me . Now I am thinking about it there is plenty that could go wrong with the engine or my controls.

Has anyone got any ideas about what I could use to pull the decompression leaver to use as an emergency stop? (Without spending a fortune I mean)

I’ve attached a pic of the fuel pre-heater, fuel circulation pump and water pump. The pumps are a bit of a shot in the dark but the were cheep as chips, 12v DC, rated at 110C and oil safe.
They may not be big enough but then I won’t know until I try them.

The plate they are all standing on is the 3mm ally which I am going to use to cap the block when I remove the tank/rad thingy ……

‘Busy, busy’. (There should be a smiey for that.)
Al

[biff]

hi al,
    we are not supposed to use the decompression lever to stop the engine, you can fit a little fuel switch on the pump which works ,either to pull back the throttle or to trigger a a switch on the fuel line to the pump,
        for some reason,killing the engine with the decompression lever is frowned upon,perhaps it wears out the cam,i never really found out properly i just got a boxxocking  every time i got caught at it.
                                      biff

[Alan]

Quote from Al “Has anyone got any ideas about what I could use to pull the decompression leaver to use as an emergency stop? “



Engine would stop, fail safe if the voltage was removed from the solenoid coil.

I have various servo motors here. But they are all. Power to open and Power to close if required.
The system would not fail safe.

Some where I have some power to open. Spring to close that would fail safe.

The weight dropping and small latch solenoid would use the least amount of
power and still fail safe.

A solenoid fuel valve. Lift to open and power to latch in the fuel line would also work.


Just read Biffs post.

If the rings are letting by and the engine runs on sump oil / fumes, it wont shut down on a valve
in the fuel line.


Regards

Alan

[jotec]

I am thinking of using the motor of a motorised valve for stopping and decompressing.
I have been offered some that, apparently, have limit switches and return through 90 deg when power is removed.
I have thought of something like Alans but using a spring.
I hear what you say about running on sump oil but it I don't think that it is something that is worth worrying about. It can happen but I think it would be very un usual in a small engine. If the rings are that bad would it start in the first place?
BTW it is the pump ram that gets sticky and causes overspeed not the injector. That may well not be a problem ona more modern engine.
dick

[Dyslexicbloke]

Good stuff guys thanks ……
I like the spring / weight solenoid idea since it would require a mechanical reset. (Thanks Alan)

I will not be routinely stopping the engine with the decomposer it would only be employed as an emergency system from a big red button or under PLC control if I see an over-speed or loose the tach input.

I had wondered about routinely decompressing at start-up. The starter motor struggles to wind the engine over the first compression stroke, its fine once there is some energy in the flywheel but since she always stops against compression it always struggles.

I considdered spring return valve actuators but I was a little concerned about having the decompressor mid way at any point, I cant see that doing anything any good.

More fiddling I guess.

Al

[Alan]

Quote “If the rings are that bad would it start in the first place? “

Compressed air was used to start the bigger engines before fuel was injected.

Doxfords built vertical, opposed-piston two-stroke diesel engines for ships
The ships I was on had two five cylinder engines and all the crankcase explosion doors pointed to the middle section at floor level where the engine controls were.
It used to take about 20 days from New Zealand to Panama.
After about fifteen days continuous running with various carbon hot spots, rings letting by.
You used to be pretty careful about where you did not stand.
and run past the various spring loaded crankcase explosion doors. To avoid the 
Not much H.S.E. In them days.

Quote “I considered spring return valve actuators but I was a little concerned about having the decompresser mid way at any point “

The spring return actuators I have ( some where ) made by Belimo would still take about ten seconds to close.

Regards

Alan