Author Topic: Common rail injection (Read 4758 times)

firestorm13666 · « **on:** November 17, 2006, 06:58:49 pm »

Would it be possable to install a common rail injection system on a 1.6 or 1.9 IDI engine?Form what i can understand the biggest problme to over come in the search for power is the timing,because it is limited by the mech injection pump.

RabbitJockey · « **Reply #1 on:** November 17, 2006, 08:27:42 pm »

it's possible, how easy it is who knows. i am curious if you could stick a tdi pump and computer onto an idi, wonder how it would run

jtanguay · « **Reply #2 on:** November 17, 2006, 10:29:06 pm »

practically anything is possible if you've got money to burn

you'd need to add sensors from the TDI to your IDI engine so that the computer knows when the engine is at TDC, etc. the injection pressures are much higher so I don't think it would work so well...

burn_your_money · « **Reply #3 on:** November 17, 2006, 11:00:55 pm »

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money to burn

jtanguay · « **Reply #4 on:** November 17, 2006, 11:47:41 pm »

hehe reminds me of that episode of fresh prince of belair when they had to burn the money to keep warm... man what a crappy episode! it could be -15C and i'd still be able to keep warm without burning that precious money lol... what a lame life lesson! could have bought many giles pumps, and and passenger performance manifolds & dp's... :lol:

Slave2School · « **Reply #5 on:** November 18, 2006, 12:02:30 am »

timing isn't controlled by the pump on a CR system though so the pump would be the least of the worries.

firestorm13666 · « **Reply #6 on:** November 18, 2006, 01:46:39 am »

I was thinking that the best way to go about this is to used parts form other engines.I was think of parts form the Duramax.I think the injection pump is a Bosch CP3 which is belt driven.As for the injector's i think Piezo type would be grate but the price would be high form what i understand.The fuel rail would most likely have to be a one off piece,as would the adaptors for the injectors.Now as for engine control i think you could use a aftermarket fully programmable ECM would work.My reason for this is that it would have everything there you need to start with but would need some R&D time to run a diesel right.It would have a crank sensor for the injection timing as well as a MAP or MAF sensor and O2 to get a diesel to run better i think.I think with the help of a air senor the engine will have a better AF ratio thus better MPG and power and so on would improve.The one down side i see to this for most it would complicate the simple mech injection pump,but in the end it might give those that are looking for more power what they need to do so.Thanks and do keep on helping with this idea!

burn_your_money · « **Reply #7 on:** November 18, 2006, 07:37:08 am »

Isn't red rotors building a electronically controlled IDI? It was in the "there's hope for the IDI" thread or whatever it was called....

firestorm13666 · « **Reply #8 on:** December 02, 2006, 04:31:13 pm »

Anyone have any ideas where i should start?I was thinking maybe some Bosch tech manuals?Thanks

QuickTD · « **Reply #9 on:** December 02, 2006, 05:05:26 pm »

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Anyone have any ideas where i should start?I was thinking maybe some Bosch tech manuals?Thanks

A degree in electronics engineering would be an excellent start. The ECM for such a system would have to be built from the ground up, there are no commercial standalone fuel management computers for use with diesel common rail fuel systems. Diesel engine control requires that the injection event be both very accurately timed and very accurately proportioned, gasoline engines require only the proportional part. Commercial systems cannot accurately time an injection event nor meter fuel accurately on a cylinder-by-cylinder basis in real time as required by a diesel. Gasoline standalone systems also lack the high injector drive current (20+amps) required for a common rail injector. You'll also need to have pintle type common rail injectors custom made, there are no common rail IDI engines that I know of, hole type injectors will not work with prechambers.

All for not anyway, the greatest limitation on IDI engine power appears to be the strength of the bottom end, most notably the connecting rods. In the quest for more power the mechanical hurdles need to be overcome first. Fueling is not really a problem, a 12mm plunger in a mechanical pump will provide enough for 200+hp, all you need to do is supply the air via compound turbocharging and then try to keep it together mechanically...

jtanguay · « **Reply #10 on:** December 02, 2006, 05:09:51 pm »

thing is with common rail, is that the actual injection pump is inside the injector...

maybe not injection pump as on our idi's but its kinda the same idea...

what would be the main purpose for wanting common rail? if you were in fact able to get the common rail injectors to fit in an idi block, that would be pretty cool. if it was all electronic, you would need a lot of programming unless there was a setup you could swap over. main thing you need is firing sequence, fuel limiter, boost compensation... etc...

again, money to burn

burn your money!

oh about the tdi pump on an idi... if you could get the cr down to around 17:1, and got the tdi injectors to fit... (not to mention the tdi ip to fit...) then yea it would probably work great. there might be some issues on valve timin though... probably need to be tweaked. isn't tdi timing a bit more advanced ? hehe that would be one weird setup... 1.6TDI yessss!

you know what... 1.6 block... tdi head... hmmm isn't there an extra oil port on the tdi head?

the tdi head and thickest head gasket possible might just be able to lower cr to 18:1 or so. imo that would be one sweet car.

QuickTD · « **Reply #11 on:** December 02, 2006, 07:23:32 pm »

Quote from: "jtanguay"

thing is with common rail, is that the actual injection pump is inside the injector...

Nope, you're thinking of PD or unit injector systems, the pump plunger is in the injector and is driven by the camshaft. In a common rail system a simple piston pump and an electronically controlled pressure regulator maintain full injection pressure at the injectors at all times. A balanced spool hydraulic solenoid valve is used to open the injector and inject fuel.

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what would be the main purpose for wanting common rail?

The holy grail of common rail is the ability to inject fuel at any time, including during the exhaust stroke. This allows the automakers to use new aftertreatment technologies to reduce emissions. Injecting raw fuel into the exhaust stream permits the "burnoff" of particulate traps and speeds the lightoff of catalysts. A small amount of fuel can also be injected during the compression stroke to start the burn and reduce the sudden pressure rise that causes the familiar diesel clatter.