Author Topic: 917 180 degree V 12  (Read 42994 times)

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 4018
  • Switzerland
Re: 917 180 degree V 12
« Reply #210 on: April 09, 2018, 03:04:19 PM »
It would be difficult to get even distribution with one pump and 12 nozzles. This chap managed working fuel injection in 1/4 scale for a turbo version.

https://www.classicdriver.com/en/collectible/porsche-type-917-miniature-engine
Best regards

Roger

Online Vixen

  • Full Member
  • ****
  • Posts: 1324
  • Hampshire UK
Re: 917 180 degree V 12
« Reply #211 on: April 09, 2018, 03:08:25 PM »
Here's to the rest of the world. I've got a Gulf Porsche 917




Yeh, way to go

Mike
It is the journey that matters, not the destination

Online steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10334
  • Central Massachusetts, USA
Re: 917 180 degree V 12
« Reply #212 on: April 09, 2018, 03:18:45 PM »
I didn't know he was an archer!!!!     8)
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline michelko

  • Full Member
  • ****
  • Posts: 195
Re: 917 180 degree V 12
« Reply #213 on: April 09, 2018, 04:26:22 PM »
Hi,
have you heared abaout Hubert W. Schillings ? He wrote a book about modelengines in witch he described a mechanical Injektion System with a gear pump. The book is called Boxer-, Reihen- und V-Motoren als Modell.

Michael

Online steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10334
  • Central Massachusetts, USA
Re: 917 180 degree V 12
« Reply #214 on: April 09, 2018, 04:53:11 PM »
Hi,
have you heared abaout Hubert W. Schillings ? He wrote a book about modelengines in witch he described a mechanical Injektion System with a gear pump. The book is called Boxer-, Reihen- und V-Motoren als Modell.

Michael

Know where I can buy that book?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline gerritv

  • Full Member
  • ****
  • Posts: 551
  • St Catharines, ON
    • Gerrit's Hobbies
Re: 917 180 degree V 12
« Reply #215 on: April 09, 2018, 05:37:37 PM »
Publish date was 2001 and seems out of print. It is 62 pages. Abebooks doesn't have it so no used copies about either.
Don't confuse activity with progress

Offline michelko

  • Full Member
  • ****
  • Posts: 195
Re: 917 180 degree V 12
« Reply #216 on: April 09, 2018, 08:11:25 PM »
I have it.
I can send you the pages with the injection, but it is in german. Not realy much information but an idea how to do.

Michael

Online steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10334
  • Central Massachusetts, USA
Re: 917 180 degree V 12
« Reply #217 on: April 09, 2018, 08:59:38 PM »
I can't do d it in print anywhere.  I'll send a pm.
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline dieselpilot

  • Full Member
  • ****
  • Posts: 280
Re: 917 180 degree V 12
« Reply #218 on: April 10, 2018, 06:12:37 PM »
VTH.de used to sell the book, they still have the plans.  http://shop.vth.de/einspritzanlage.html All of the photos I've ever seen of Schillings engines seem to have carbs.

Flat slide throttles were also used in RC cars. I have a Picco example.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6678
  • Surrey, UK
Re: 917 180 degree V 12
« Reply #219 on: April 10, 2018, 07:12:14 PM »
"this injection test was used to develop the injection system"

You can just see the individual injectors on the engine side of the 4 straight pipes

Second photo is a model of a Daimler Benz 603
« Last Edit: April 10, 2018, 07:19:05 PM by Jasonb »

Online Vixen

  • Full Member
  • ****
  • Posts: 1324
  • Hampshire UK
Re: 917 180 degree V 12
« Reply #220 on: April 10, 2018, 07:39:11 PM »
Jason,

The injection system on that DB603 model is a very crude affair. A single, simple gear pump feeds a constant supply of fuel all the injector nozzles simultaneously via individual check valves. The fuel flow/ pressure is controlled by a by pass valve (needle valve?) which dumps the excess fuel back into the tank. It is all open loop with no throttle control, no speed control, no mass air flow control. It is simply a continuous spray of fuel from all injectors



It is the equivalent to the needle valve mixture control of a model aircraft engine, without the throttle control. So it is limited to mixture control at flat out running, remember the bladder tanks on racing Doolings

Mike
« Last Edit: April 10, 2018, 08:59:28 PM by Vixen »
It is the journey that matters, not the destination

Offline Admiral_dk

  • Full Member
  • ****
  • Posts: 1446
  • S°ften - Denmark
Re: 917 180 degree V 12
« Reply #221 on: April 10, 2018, 09:51:00 PM »
Yes Mike - but he did claim that the leaking of the pump, lowered the pressure enough at lower rpm's that it worked fine over a big range .... or to put it in another way - the pump pressure isn't linear with rpm, but almost linear with demand .... then again it took them some two years to perfect the result .....

Online steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 10334
  • Central Massachusetts, USA
Re: 917 180 degree V 12
« Reply #222 on: April 11, 2018, 12:03:18 AM »
Jason,

The injection system on that DB603 model is a very crude affair. A single, simple gear pump feeds a constant supply of fuel all the injector nozzles simultaneously via individual check valves. The fuel flow/ pressure is controlled by a by pass valve (needle valve?) which dumps the excess fuel back into the tank. It is all open loop with no throttle control, no speed control, no mass air flow control. It is simply a continuous spray of fuel from all injectors

It is the equivalent to the needle valve mixture control of a model aircraft engine, without the throttle control. So it is limited to mixture control at flat out running, remember the bladder tanks on racing Doolings

Mike

Yes but the pump was engine driven, so as Admiral states....it worked...though I share your concern about the crudeness...if I dare call it that ..that must of been a right (@#*  to make and make work.
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline gerritv

  • Full Member
  • ****
  • Posts: 551
  • St Catharines, ON
    • Gerrit's Hobbies
Re: 917 180 degree V 12
« Reply #223 on: April 11, 2018, 03:09:15 AM »
That diagram brings up memories of the Tecalumit Jackson injection system for Mini Cooper engines amongst others.
Don't confuse activity with progress

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 4018
  • Switzerland
Re: 917 180 degree V 12
« Reply #224 on: April 11, 2018, 08:38:48 AM »
I have had a closer look at the pictures of the injection system used on the 1/4 scale model. It looks to be quite a reasonable solution. For manifold injection the pressures are quite low and the timing is not critical so a simple variable stroke pump can be used rather than the controlled spill system that is required for a diesel.
The pump has two gear driven cam shafts operating rockers that are mounted on a central (probably eccentric) pivot shaft to adjust the stroke. This shaft is coupled to the throttle slides by a bell crank. There are two fuel feed galleries on the outside of the pump with individual inlet valves for each plunger delivery valves are fitted on top of the pump.
At 4.5cc per cylinder a 2mm plunger may be too big. The stroke at full output would be 0.3-0.4mm (plus a bit for leakage past the plunger) so something smaller may have been used.
The design of the injectors is not obvious from the picture. A mushroom valve like Find Hansen uses (and was also used on the Lucas PI system) should work well for manifold injection.
The full size 917 fuel pump used a single camshaft although the plungers were offset. The metering system is not obvious but as the pump was developed from a diesel pump it is probably a helix controlled spill system.
Your 1/3 scale version will have larger cylinders so 2mm plungers should be ok and are not too bad to work with. It may be a challenge to fit all the parts into a prototype size fuel pump  :headscratch: but I think it can be done.
Best regards

Roger