[freddie]

At work we'll be doing some testing on a 6.7L on a dyno. We already have the truck, and now just need to find a way to shut it down quickly if something goes wrong.

What would be the most effective item on the truck to kill power to, to shut it down as quickly as possible?

Another engineer thought we should kill power to the PCM, but I didn't think that sounded like a good idea.

I thought maybe killing power to the low pressure pump, assuming it has one? I just wasn't sure if this would harm the HPP or anything else, and if it would even kill the engine quickly enough.

 

[rolsmojave3]

Phone book/wood over the intake. That would be simple enough. Maybe a simple master switch on the main battery positive.

 

[JimTJr]

Phone book/wood over the intake. That would be simple enough. Maybe a simple master switch on the main battery positive.

Phone book you mean over where the filter would hook? I imagine they'll want a filter on there,,,
Removing the battery out of the picture won't kill the motor,,,, after the trucks started it runs off the alternators!

Some way to stop the fuel of course,, I don't know much about these yet,, but if the HPP is electronic in anyway, (And one of the problems now is it's switching modes, causing a ticking sound) then if you shut it down, I guess that would shut the motor down... don't know how fast.

 

[freddie]

Yeah shutting down the HPP would certainly kill the engine I assume. Afterall, you don't have the xx,xxxPSI supply to the injectors. I just wasn't sure how the HPP was operated. Can anyone relay any info on this?

I thought about the LPP, but wasn't sure how long the engine could continue running with the HPP still pressurizing fuel.

 

[lead foot]

IMHO Cutting the Fuel Is the way to go!

I've had Issues with my machine at work Not cutting off with the Key and had to Cut the Fuel off to Kill it!

The machine is a Log handler,called a Scan-log with 400 hp cummins in it,the cummins has a little dial on the Fuel pump that you can turn and shut off the fuel,the motor dies Pretty Quick...

Cutting off the air would be the second choice but Kinda hard to Do on Most motors due to the Intake designs....

I would fab Up something to kill the fuel Right at the fuel Rail Prolly wouldn't be to hard ....

 

[rolsmojave3]

Kill the main power to the fuse block, then it can't fire the injectors, it's done.

 

[nitrogen]

typically the reason you need an emergency shutdown is because you have a engine runaway situation. this means you have lost control of the fuel delivery, it may even be fueling partially off engine oil. the ONLY sure way to kill the engine is to stop the air. thats why every heavy sled puller uses a air shut off, mandatory on hotter classes

 

[lead foot]

typically the reason you need an emergency shutdown is because you have a engine runaway situation. this means you have lost control of the fuel delivery, it may even be fueling partially off engine oil. the ONLY sure way to kill the engine is to stop the air. thats why every heavy sled puller uses a air shut off, mandatory on hotter classes

Yeap You are the wiener LOL I should have thought about that,if your gonna fab something then it would be easy to put a Cut-off in the Intake tube...

I was thinking Just killing a Motor, not acutally killing one under operation!

I do believe killing the Air would be faster than killing the Fuel,Due to the Fuel being in the Line from the Cut-off to the Cylinder...

What did he win ? LOL

 

[Boats313]

We usually have both air and fuel shutdowns on marine diesels. The air is the faster way to go. Our fuel cut offs are usually between the engine and the tanks and they will run for awhile on whats left in the pipes.
I have been told (have not seen for myself) that a concern with some air shutdowns is the suction caused by shutting off the air to a runaway engine can do some damage. Of course we are dealing with much bigger engines and in some cases much older too.

 

[silverpsd_06]

tryin to kill fuel takes too much time and your gonna need somethin bigger than a phonebook otherwise you will have pretty burnt confetti and your pecker in ur hand wondering whats next 3/4 plywood does the trick quite well

 

[freddie]

I like the idea of killing air, but I'm wondering how much modification would then need to be done to put that idea into application.

Lets think more electrical..

 

[silverpsd_06]

you have to understand under any other circumstances the truck will shut down turnkey you start modifying a fuel system and for some reason get something wrong it'll runaway whichever gives first turbo or internals... otherwise turnkey or just a full kill switch give the pcm no power to run it... there is also the possibility of a motor running on its own oil.. it only takes 3 things to make a motor fire air fuel and spark... plywood takes away 2 at once no air and in our motors no air means no spark cause there is no air to compress

 

[rolsmojave3]

The old supercharged Detroits were known to run on oil during a runaway due to the air shutoff creating such a vaccum that it would pull in the seals on the supercharger and pump oil into itself....not to many turbo seal get sucked in, but it could draw oil from the CCV I suppose.

 

[cowboy_dan]

I would not try to cutoff the fuel supply on a HPCR engine. The fuel is frequently the lubricant for the HPFP. Lose fuel, and you run the risk of cavitation. And without lubrication, you can seize the HPFP pistons in their bores.

Air cutoff is the only way to go.
House had some good pictures and descriptions here: Making an air shut off - Powerstroke Nation

Add a fuel cutoff ONLY if you already have a master power cutoff. You don't want the HPFP still pumping and sucking air.


FWIW, I had a 10.3L Ag engine on a dyno a few weeks ago with only a power cutofff to the ECM. Granted we were not changing any hard parts. Just making a few stock pulls and them adding a power module.

If you're staying close to stock parts & programming, then I wouldn't worry about having a shutoff.

 

[freddie]

Thanks for the tips!

I think a power cutoff is the best bet. We will be on stock parts and programming, but that's not the concern. We'll be doing some testing, and would like some E-stop buttons around the test area in case anything happens, whether its a truck issue, dyno issue, or something else. We just would like to be able to shut the truck off as quickly as possible, from outside the truck.

 

[BFT]

what exactly are you doing on the 6.7 that you are really concerned on shutting the motor down?

 

[freddie]

We will be doing some FTP driving cycles, etc. Not pushing the the truck at all, but the safety committee here at work insisted we have E-stops, especially if we end up automating the driving so that the truck cycles on its own without a driver. Obviously we would still have someone there conducting the testing, but we would eliminate the need to have someone sit in the vehicle driving, on a dyno, for 8 hours/day.

 

[MN_MountainMan]

If flammable gas or vapor is drawn into the intake of a diesel engine it acts as an additional ungoverned fuel supply. This may result in uncontrolled engine overspeed, followed by dangerous mechanical failure or flash back through the air intake, and the ignition of the surrounding gas or vapor cloud.

Once a flammable mixture is being drawn into the engine intake it may not be possible to stop the engine by closing down the fuel supply. An air intake valve guaraantees a rapid and safe engine shut down.

air intake shut off valve by amot control - emergency shut down valve

 

[silverpsd_06]

taking the compressor outside of its designed map will also do it in the event of having weak seals... i believe once taking the compressor outside its map creates more backpressure than boost pushing the cooling and lubricating oil out of the center cartridge into the intake tract thus causing an oil fired runaway

 

[KEM Performance]

We will be doing some FTP driving cycles, etc. Not pushing the the truck at all, but the safety committee here at work insisted we have E-stops, especially if we end up automating the driving so that the truck cycles on its own without a driver. Obviously we would still have someone there conducting the testing, but we would eliminate the need to have someone sit in the vehicle driving, on a dyno, for 8 hours/day.

Are you doing In Use testing? Give me a call, I have some info for you.

Mike