Firmware predates the virtual flex fuel sensor and he has no hard wire sensor.
Port Injection causing engine failure
- Thread starter dyezak
- Start date
Firmware predates the virtual flex fuel sensor and he has no hard wire sensor.
Any experience with injector dynamics? I'm running their ID1300 injectors and flow matched. Hope they run well
Injector dynamics are probably the best injectors you can buy. They start out as bosch units and are all flow matched. Id1300 seems big for pi though
What is the deal with all this leaky injector business? Everyone sells shitty injectors or what?
Yea I think most of them are remanned units but I can't confirm nor deny. I'm sure some vendors will chime in and clarify.
Being batch fired flow matching isn't crucial from my understanding but being a better injector gets you better quality.. just look at the better tolerance as better reliability
Being batch fired flow matching isn't crucial from my understanding but being a better injector gets you better quality.. just look at the better tolerance as better reliability
If intake cam duration is say 240 degrees, you might get an extra 600HP power capacity on E50 from 2000cc port injectors by pulsing sequentially, mirroring the direct injectors with inherent safety to cover DI cuts? A single digital output from the DME would turn on the port injector mirroring and when it was enabled the injector scaling in the ECU would be switched to suit the new total flow. You would have to think about when to switch, glitches during the switch, how to decode the DI waveform which has various phases. The equivalent to add 6 port injectors to 6 existing port injectors is done on other OEM ECUs.
Intake cam duration doesn't really matter for PFI because you still have the ability to inject onto the back of a closed valve and the fuel will just sit and wait for the valve to open. Of course you will change impingement, atomization, and crevice volume HC's but those don't really matter from our perspective.
I think using some sort of transistor on each DI injector signal to trigger the start of injection for the paried PFI injector would be by far the best solution. I'm sure electrically that is a lot easier said than done, along with changing pulsewidth to tune in fuel required
If we inject onto the back of a closed valve, we have a lean event when the DI is turned off. That was the reason behind the idea to use larger injectors and only inject through an open intake valve.
I think if we config to cut spark on each cyl DI is shut off, it should be fine no? It would be too lean to auto-ignite I would think. However, then you are sending a good amount of fuel into the turbo / exhaust.
I think to do it properly we want to aim to escalate two levels beyond where the non-Syvecs methods are at. Level 1 would be to achieve matching port injection per cylinder to direct injection within one cylinder event. Level 2 would be to do it on the same cylinder event.
To achieve level 2 and inject onto the back of the intake valve you would need prior knowledge of what the direct injection is going to be on that cylinder and a guarantee the direct pulse would not be aborted or shortened, and you would need to X-Tau or similar accel/decel model the puddle behind the intake valve to achieve parity with direct injection.
Larger injectors running at up to 33% duty cycle during IVO solves and simplifies it I think at least theoretically. Since only two injectors would be running at a time, the low pressure fuel system would not need an accumulator (or very strong pump) to handle the huge demand of say 12000cc of injector being open at once like you might expect from 6 x 2000cc injectors. The only overkill is in the injector sizing, but it appears to solve so many of the issues I think it merits investigation.
There would appear to be two theoretical causes of (minor) lambda glitches in 12 injector systems on GT-Rs. One could be puddling behind the closed intake valves (which should be solved if we inject only through IVO) and the other could be when the secondaries are enabled or disabled part way through an existing injection event. Apparently the glitches can be improved with a ramp in/out, but I don't know if this means that it is due to puddling or mid event secondary enable/disable.
To achieve level 2 and inject onto the back of the intake valve you would need prior knowledge of what the direct injection is going to be on that cylinder and a guarantee the direct pulse would not be aborted or shortened, and you would need to X-Tau or similar accel/decel model the puddle behind the intake valve to achieve parity with direct injection.
Larger injectors running at up to 33% duty cycle during IVO solves and simplifies it I think at least theoretically. Since only two injectors would be running at a time, the low pressure fuel system would not need an accumulator (or very strong pump) to handle the huge demand of say 12000cc of injector being open at once like you might expect from 6 x 2000cc injectors. The only overkill is in the injector sizing, but it appears to solve so many of the issues I think it merits investigation.
There would appear to be two theoretical causes of (minor) lambda glitches in 12 injector systems on GT-Rs. One could be puddling behind the closed intake valves (which should be solved if we inject only through IVO) and the other could be when the secondaries are enabled or disabled part way through an existing injection event. Apparently the glitches can be improved with a ramp in/out, but I don't know if this means that it is due to puddling or mid event secondary enable/disable.
Let's do it! Next project? I already enabled one unused output
And those features are clammed up like a virgin on prom night, lets get at it!
6 injectors slaved to their respective DI counterparts would be awesome. Eliminates a lot of the hassle of running an additional controller, increases efficiency by using SFI, safer etc. Getting spark to cut when DI does would also be a great fix. Some NLS pops are better than testing the strength of the pistons IMO.
I've evaluated it before. The fundamental problem is that the factory injectors are in the combustion chamber directly and the DME plays with the injector timing with multiple bursts, spraying late in to compression, etc. While the factory injector IPW is indexed off high pressure there is no mechanism to index low pressure injections to low fuel pressure in a 1:1 or similar mapping with high pressure, which is part of the initial reason we abandoned the AIC6 in favor of a smarter solution for PI control to start with.
Maybe the largest issue is that the port injection is not meant to supplement the factory fuel injectors, but to take volume off the factory fuel pump, which has a non-linear deficiency. So this also points away from a 1:1 mapping.
What I have considered is adding a digital input in to our PI controller to cut injection when DI cuts injection, on the order of 1000hz, compared to say the 10hz we get via CANbus, but no one has yet convinced me its worth the effort.
The multiple bursts can be turned off. I am assuming they are N54 only, not N55 given its solenoid injectors. The injection windows can be altered, or we could consider whether to tolerate part of the injection after IVC, but that would degrade to level 1 improvement.
Interesting point about the high pressure compensation of DI pulse widths. How about when mirroring occurs the compensation can be flattened to only compensate for the DI contribution?
The "injector sizing" table is referenced by load and RPM if I recall, so a second version of that for when PI is active should fix non linearities?
Interesting point about the high pressure compensation of DI pulse widths. How about when mirroring occurs the compensation can be flattened to only compensate for the DI contribution?
The "injector sizing" table is referenced by load and RPM if I recall, so a second version of that for when PI is active should fix non linearities?
Look at it another way... You can put a lot of effort in to designing theoretically and practically performing port injection control schemes. I know we've put a lot of effort in to our implementation. But at the end of the day, the port injection itself only exists to mask a fundamental issue with our high pressure system. Specifically the fuel pump unable to keep pressure up with high volume. We don't need a better port injection control scheme (IMHO) what we need is a better high pressure fuel pump.
That's kinda what I said as a patch. Cut spark as well so you don't have a super lean mix getting popped with fuel cut to that cylinder in the event of a misfire.
Kinda a bandaid for a bandaid bit safer till we have PTcan integration
