Is it safe to stop a diesel by cutting off the fuel supply?

[Crossy]

Not really motoring related, but this is the place where those likely to know hang out.

 

A mate has a small diesel generator which he wants to automate.

 

It's electric-start so that's not a problem, but it has a lever to pull which "does something mechanical" on the engine in order to stop. Note, I've not seen this unit yet, so what the lever does has to remain "something mechanical".

 

Is it safe (for the engine) for him to put a (fuel safe) solenoid valve in the fuel line in order to stop the engine?

 

Any and all input appreciated.

 

[Daffy D]

Yes.

 

The way to stop a diesel is to cut the fuel supply. Unlike a petrol where you cut the electric spark.

 

As long as the "automate" system does not allow any air in it should be good to go.

 

 

Reading through your post again perhaps he could fix up a solinoid to "Pull" the stop lever.

 

Edited February 26, 2018 by Daffy D
Additional information

[Crossy]

I was thinking something like this https://www.aliexpress.com/item/Brass-12V-DC-1-4-Electric-Solenoid-Valve-Water-Air-Fuels-Gas-2Way-Normal-Closed/32785422621.html

 

Pulling the stop lever may be an option, but it's doubtful a sensibly sized solenoid would have the oomph. Solenoids tend to have short travel and are weakest when they first start to pull in. Worth a look mind.

[Daffy D]

Looks Good

 

If I'm reading right it would normally be open and closed on activation, so a simple bell push switch could be used to activate the unit and cut the fuel to stop the engine.

 

You could use an on/of switch but then there's the chance one day you'r mate will spend hours fixing a non starting engine only to find the fuel switch was left off.  

 

That has happend more time than you would immagine.

 

[VocalNeal]

I would be tempted to have a look at "diesel engine shutoff solenoids"  

 

Most are not simple liquid shut offs. Most activate the mechanism on the injector pump in the same way that your mates lever does. 

You may even find the correct one for the job. 

 

As is the case in a lift truck "runaway" the other way to stop an engine is to cut off the air with a butterfly in the inlet but that means mechanically modifying the engine.

 

The next interesting problem is how to tell if the engine has started so you can disengage the starter.

 

 

Edited February 26, 2018 by VocalNeal

[Daffy D]

1 hour ago, Crossy said:

Pulling the stop lever may be an option, but it's doubtful a sensibly sized solenoid would have the oomph. Solenoids tend to have short travel and are weakest when they first start to pull in. Worth a look mind.

In the old days in Africa when there was all the Mau Mau troubles decent folk would barricade themselves in their houses and not venture out after dark, they would run a string from the house out to the generator to pull on the stop lever and stop the engind when they whent to bed. 

 

So i'm told.

[canthai55]

A simple fuel cutoff solenoid will work well.

This is required for all trucks and heavy equipment operating in the oil patch -

https://pacbrake.com/product-types/valves/

[Crossy]

54 minutes ago, VocalNeal said:

The next interesting problem is how to tell if the engine has started so you can disengage the starter.

All the commercial controllers I've seen monitor the generator output, once it achieves 100V or so it assumes the engine has caught. 

 

I'll certainly look at getting the injector pump solenoid if one is available at a sensible price 

 

 

[canthai55]

1 hour ago, Crossy said:

I'll certainly look at getting the injector pump solenoid if one is available at a sensible price

Look at what Toyota or Isuzu uses for their pickups

At least you will be sure of being able to source a replacement if original goes south

Edited February 26, 2018 by canthai55

[Anythingleft?]

Just make sure the solenoid is before the fuel pump and after the fuel filter
The lever fitted could well be a decompression system, they used to be fairly common

Sent from my SM-N950F using Tapatalk

[VocalNeal]

1 hour ago, canthai55 said:

A simple fuel cutoff solenoid will work well.

This is required for all trucks and heavy equipment operating in the oil patch -

https://pacbrake.com/product-types/valves/

Just curious why say a simple cut off solenoid will work and then show pictures of "runaway" shut off valves or did I miss something? 

 

21 minutes ago, canthai55 said:

Look at what Toyota or Isuzu uses for their pickups

At least you will be sure of being able to source a replacement if original goes south

If a modern electronic injection engine they might simply shut off the injectors? I don't know just sayin...

[VocalNeal]

9 minutes ago, Anythingleft? said:

The lever fitted could well be a decompression system, they used to be fairly common

Ah a Lister fire pump engine. Crank, and crank, and crank and then simultaneously using one's third hand keep cranking whilst flipping the decompression lever. That was my fire drill job. I don't ever remember shutting it off. I guess that was someone else's job:-)

 

I think a site inspection with a few beers should tell the OP how the existing stop lever works. 

Edited February 26, 2018 by VocalNeal

[canthai55]

3 hours ago, VocalNeal said:

As is the case in a lift truck "runaway" the other way to stop an engine is to cut off the air with a butterfly in the inlet but that means mechanically modifying the engine.

No need to modify the engine - fits into the air inlet plumbing, after the intercooler

1 hour ago, VocalNeal said:

Just curious why say a simple cut off solenoid will work and then show pictures of "runaway" shut off valves or did I miss something?

Reply to your forklift statement above

[NanLaew]

On 2/26/2018 at 9:18 AM, VocalNeal said:

As is the case in a lift truck "runaway" the other way to stop an engine is to cut off the air with a butterfly in the inlet but that means mechanically modifying the engine.

...or more simply putting your hand over the air intake of the 'small diesel generator' in the OP.

[Daffy D]

4 hours ago, NanLaew said:

...or more simply putting your hand over the air intake of the 'small diesel generator' in the OP.

A bit tricky if it has an air filter.

 

Anyway the origional request was for a system to shut of the motor remotely.

 

[digbeth]

I've had diesel engine in a car that has blown the piston seals and head gasket that won't turn off even when the ignition is off and is drawing in engine oil to combust

[Crossy]

Just an update in case anyone is interested.

 

We have decided to go with the "pull the stop lever" option. Whilst the lever does need a good pull the engine stops promptly and the lever returns to the "run" position under the influence of a spring.

 

No way a solenoid is going to cut the mustard so we've ordered one of these. It's a central locking actuator, 4kg of pull and 20mm of travel. Should do the trick :-

 

 

https://www.aliexpress.com/item/New-Car-Auto-Heavy-Duty-Power-Door-Lock-Actuator-Motor-5-Wire-DC-12V-Black-TD1/32806371709.html

 

 

[lemonjelly]

I've had diesel engine in a car that has blown the piston seals and head gasket that won't turn off even when the ignition is off and is drawing in engine oil to combust

Eeek... nasty..... I once crank started a rotavator, flipped the compression valve and the piston bounced down and started the engine backwards, i, not noticing the exhaust puffing out of the air filter rather than the exhaust pipe, put the thing in gear, let the clutch out and nearly got chewed up by the blasted thing as it lurched backwards



Sent from my shed using Thailand Forum - Thaivisa mobile app

[canthai55]

Used those same style actuators to open car doors. Work well.

[HAKAPALITA]

9 hours ago, lemonjelly said:

Eeek... nasty..... I once crank started a rotavator, flipped the compression valve and the piston bounced down and started the engine backwards, i, not noticing the exhaust puffing out of the air filter rather than the exhaust pipe, put the thing in gear, let the clutch out and nearly got chewed up by the blasted thing as it lurched backwards



Sent from my shed using Thailand Forum - Thaivisa mobile app

Ford make Rotorvators .?.

[Slimdawg]

As previously mentioned i would run a air kill on a solenoid. Actually be quite simple.

 

You can  even spend  a little  more and use a bluetooth actuated  solenoid,  and control it by your phone.

 

 

 

 

Also,its much better to kill the air on a diesel than kill the fuel.

[Daffy D]

On ‎3‎/‎21‎/‎2018 at 8:41 AM, Crossy said:

Just an update in case anyone is interested.

 

We have decided to go with the "pull the stop lever" option. Whilst the lever does need a good pull the engine stops promptly and the lever returns to the "run" position under the influence of a spring.

 

No way a solenoid is going to cut the mustard so we've ordered one of these. It's a central locking actuator, 4kg of pull and 20mm of travel. Should do the trick :-

 

 

https://www.aliexpress.com/item/New-Car-Auto-Heavy-Duty-Power-Door-Lock-Actuator-Motor-5-Wire-DC-12V-Black-TD1/32806371709.html

 

 

 

So guess the string pull option was'nt Hi-Tec enough

[canthai55]

16 hours ago, Slimdawg said:

Also,its much better to kill the air on a diesel than kill the fuel.

Every diesel I know of - tractor trailers,dozers, loaders, excavators, rock trucks ...

Shut down by stopping fuel supply.

[Daffy D]

Crossy - Are you going to use a remote control module with the actuator so it can be operated from the house?