Author Topic: Need help with Injector Pump (Minimum Engine Speed)  (Read 1487 times)

veggie

  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #15 on: May 06, 2021, 06:09:53 PM »

Update:

The timing on my engine was approx. 18 Deg. BTDC
Today I advanced the timing to by 4 Degrees to 22 Deg BTDC.
This had no effect on the engine's ability to run slower, however there was a considerable increase in ignition knock.
A very undesirable result for me since I don't like the knock.  :(

The next adjustment will be to back off the timing to 15 Deg BTDC and run it again.
From the studies I have read, experiments can be performed anywhere between 10 deg and 27 deg with varying outcomes based on the service of the engine, rpm of the engine, and the type of fuel being used.

all in good fun  :)

veggie

- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

veggie

  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #16 on: May 06, 2021, 08:48:18 PM »
Further update ...

Ok, I retarded the injector timing to 15 BTDC.

Starts and runs great.
Even behaves a bit better at low speed.
Ignition knock greatly reduced.

While the engine can run slower, it still has the "8 stoke" phenomenon that cujet noted.

Only when the engine runs at 325 rpm or greater does the 8-stroking go away.

Here is a video of the test run.... at 200 rpm  !
https://www.youtube.com/watch?v=XPzjLtL-RW4
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

veggie

  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #17 on: May 06, 2021, 08:51:55 PM »

IDEA !

Something I can't test at the moment (Alternator not mounted yet), but perhaps the 8 stroking would disappear if there was a slight load ?
Causing the rack to supply enough fuel on every power stroke.  ???

Hmmmm !
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

starfire

  • Sr. Member
  • ****
  • Posts: 282
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #18 on: May 06, 2021, 11:17:11 PM »
I am gunna say its low fuel pressure. Because it starts and runs well, its not compression or injector. When trying low  speed, the fuel pressure drops causing fuel to just dribble into the cylinder without igniting. After several non firing strokes, the raw fuel vaporises from cylinder heat, causing ignition on subsequent compression, then the cycle continues.
 Years ago, a dude fitted a new fuel pump to his toyota Hilux. It needed a tow start, and then would run hot with no power. Turns out it was injecting on the intake stroke, burning vaporised fuel rather than atomised fuel., so this is certainly possible.
 Injector pumps should have constant pressure, and variable quantity. Veggie, I would loosen the injector pop pressure to see any change.... if its a fuel pressure problem then it will have little effect. Mind you, it has little effect anyway that I have seen. Setting the rack at a low speed and testing removed injector spray by cranking may point to the problem.

starfire

  • Sr. Member
  • ****
  • Posts: 282
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #19 on: May 06, 2021, 11:32:45 PM »

starfire,

I looked at your other lister videos. Very nice setup in that shed. (looks like a lister/petter unit off to the side also).
Would it be possible to post a picture of how you mounted the alternators to your engine?
I have a similar plan in mind.

cheers,
veggie
I drilled a 1/4" plate to attach to the two unused threaded holes in the cylinder head, welded some 3/4"  box at right angles to mount standard car alternators. The  two x 80 amp alternators have 4 inch pulleys to slow them down and save precious horsepower, 3.5 hp isnt much to play with. I removed the regulators so they charge at maximum. A seperate control box monitors the lithium packs and cuts the field current at 14 volts. Car alternators arent  made for continuous duty so I have a 3 ohm resistor in series with each field to cut the total output back so they dont work as hard.
Ill get a  pic later today.

MachineNLectricMan

  • Newbie
  • *
  • Posts: 24
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #20 on: June 17, 2021, 02:20:38 AM »
Do you have another pump to try? Possibly the pump position that would result in 200 RPM, produces no fuel?

I'm going to go out and run my engine and see how slow I can run it. I'm pretty sure it will go down to a very low RPM. Checking now.



Update: Tried low RPM by pulling up on the shut off lever. The not warmed up engine was 100% unwilling to run at low RPM. I could hear the injector's clank, so I'm pretty sure it was working. After warming it up, I tried again. The engine would maintain low RPM, but only fired every other time. Even though the injector clanked every time. The engine was difficult to control at this speed, and would occasionally need an open rack to get enough fuel to initiate combustion. Eventually, it slowed down to the point where the injection event brought the engine to a fast stop-n-reverse. At which point I engaged the compression release and the thing rolled backwards for a bit.

That 200 RPM video you posted did not seem to have much of an audible combustion event, and the RPM seemed very even. Mine would speed up and slow down around each combustion event.

Thinking aloud here, it's entirely possible that the compression is insufficient to ignite a tiny fuel quantity, and/or the indirect chamber has insufficient oxygen in it. Hence the 8 cycle running. I really do think the injector is working, as I can hear it.

If the Indian video is real, maybe they have higher compression or adjusted the timing to be closer to TDC, so the engine won't reverse like mine did.

Remember that injectors "pop" open when a certain pressure is reached, then they "pop" shut when the pressure drops below a certain level which is a lot lower than the "trip" pressure (I.E. Hysteresis). This prevents dribble and gives a good well defined injection cycle. You must also note that steel is "elastic" with a modulus of elasticity of about 30 million PSI, this includes your fuel injector delivery tubing! The longer the delivery tubing, the more elastic "storage" it has.  At such low fuel deliveries, the tiny amount of fuel on the first injection may be just enough to expand the elasticity in the tubing, but not accomplishing enough pressure build to trip the injector. On the second injection, the fuel already "stored" in the tubing plus the new injection fuel is enough to trip the injector, so the engine fires.

Have you invented a "Hit and Miss" diesel? ;D

veggie

  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #21 on: June 17, 2021, 03:24:04 PM »

Makes sense.

The minimum stable speed I can achieve with constant ignition is 375 rpm.
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

38ac

  • Hero Member
  • *****
  • Posts: 1988
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #22 on: June 18, 2021, 02:51:14 AM »
Veggie, I wish you would get this figured out as it has ne curious. While the fuel tubing having some flex deal is valid mine has that flex also. Just finished up another Lister 6/1 this week and after a 5 minute run in I grabbed the fuel lever and slowed it down and it hit every other revelution until it was too slow to carry over compression. Has India HP line, Mico injector and Mico innards in the CAV pump.
Collector and horder of about anything diesel

veggie

  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 710
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #23 on: June 18, 2021, 10:40:38 PM »
Veggie, I wish you would get this figured out as it has ne curious. While the fuel tubing having some flex deal is valid mine has that flex also. Just finished up another Lister 6/1 this week and after a 5 minute run in I grabbed the fuel lever and slowed it down and it hit every other revelution until it was too slow to carry over compression. Has India HP line, Mico injector and Mico innards in the CAV pump.

Mine is Direct Injection. Could that have anything to do with it ?
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

38ac

  • Hero Member
  • *****
  • Posts: 1988
    • View Profile
Re: Need help with Injector Pump (Minimum Engine Speed)
« Reply #24 on: June 19, 2021, 11:47:38 AM »
Possible, I have a direct injection 18/1 here but it's still a parts kit. I have a Z4 Bamford that is direct injected but don't think that would provided any pertanent information
Collector and horder of about anything diesel