Is it OK to use one vnp10n07 to drive four high-Z injectors?

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HotCat
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Is it OK to use one vnp10n07 to drive four high-Z injectors?

Post by HotCat »

The doc said vnp10n07 can sink at least 7A before internal current limit, I am still not sure if it is the right thing to do. The four high-Z injectors only draw 4A and I have a large aluminium frame to guarantee the effect heat sink
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by Fred »

HotCat, break it down in to two of them. You're too close to the limit and the instantaneous current can be higher than the steady state current. Thus if you do this, though it might work, and won't get very hot, the injectors will not open well and performance and predictability of tune will be poor.

You have a crank sensor setup, so you "need" two to get semi sequential fueling anyway.

I understand the cost of these parts in China, however you can also use other FETs with fet drivers if you prefer. Fancy fets like these are just "nicer" and "easier" they're not essential. At about 2usd each, the cost of two, even in China, would (probably) be worth it for me.

I hope that helps.

Fred.
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by HotCat »

Thanks Fred, I decide to use semi sequential fuel injection. But doing so, I was unable to share stock harness to connect injectors. Which type of connector to choose to connect my custom injectors wire to board or solder it directly to PCB? I should put PT2 PT3 on fuel injection and PT4 for vehicle speed input, is that OK?

I am continue revising my board according to Jaguar and Ravage project, Feb should be the harvest season for FreeEMS
1.PNG
Excellent heat sink to mount vnp10n07, I should go semi sequential fuel injection
2.JPG
A lot of effort was put on making the board geometry compatible with stock ECU
3.JPG
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by Fred »

There is no VSS, though if you want to run custom code to do that, choose the pin with the PA on it, which MIGHT be PT7. I don't know when/if there will be an official VSS input. It's generally not important, though, unless you have to drive your dash, too.

What are you doing for ignition, though? Currently it has to be on PT2 up and the fuel channels after that. It could change soonish, though.

Fred.
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by HotCat »

Fred wrote:There is no VSS, though if you want to run custom code to do that, choose the pin with the PA on it, which MIGHT be PT7. I don't know when/if there will be an official VSS input. It's generally not important, though, unless you have to drive your dash, too.
you mean VSS is not essential to EMS? I used to believe that EMS can calculate which gear the vehicle was on via VSS and tach and ajust fuel or ignition timing slightly according to that. or VSS was used to implement the fuel cut or cruise control
Fred wrote: What are you doing for ignition, though? Currently it has to be on PT2 up and the fuel channels after that. It could change soonish, though.
oh, my mistake, PT2, PT3 should be my ignition output for wasted spark and PT4, PT5 should be semi sequential fuel injection, and PT7 assign to VSS.
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by Fred »

Sure, you can get ratio from VSS + RPM, but use it for what? Sure you can implement a speed cut with it, but why, speed cuts get removed from most cars. You could do cruise control, yes, which would be useful. You can also do gear based boost control like that. It's not needed to run the engine and run it well, though. Adjusting fueling for gear makes little sense. Only heat affects tune, and you could calculate that in other more accurate ways. For example, what's the difference between 1st gear up a 45* grade with 2 tonnes of concrete in the back, and 5th gear on a slight grade? The answer is nothing. Well, except air flow, but your software based purely on gear would do the wrong thing in that case, where the higher gear has better cooling for the same heat output.

Those pinnings sound good if you checked the data sheet for Pulse Accumulator pin assignment and I was right.

Fred.
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by HotCat »

I think my FireCat schema work will be locked down, each sheet was heavily revised according to your discussion and claim. Yes, you are right, none of the subcircuit of Puma board is 100% right, they are either lack of capacitances or the marked value was incorrect.

I remove many unessential interfaces such as narrow band O2, VSS input, AC relay control. And make my injection circuit configurable either to be batch fired or semi sequential fired. I use screwed connector to connect wide band O2 input and custom injector wire
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by Fred »

You should keep the relay control and any general IO that you have pins for. Keep the VSS stuff on PT7 too, I'd love to see you hacking that to work. It just won't be official for a while/long time, that's all. This isn't necessarily about being official, though... :-)

Before you go printing boards, I'd like to have a look at your schems in a PDF and I'd also like Dan and Preston and Huff and others to take a look for you. Let's make it as good as it can be! :-)

Fred.

PS, check out engine number 10!! If you need me to download the video files for you and host them so that you can watch, let me know! I know youtube is/was blocked there.
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by HotCat »

Fred wrote: PS, check out engine number 10!! If you need me to download the video files for you and host them so that you can watch, let me know! I know youtube is/was blocked there.
youtube was banned permanently by Chinese government, none of those videos I can see :roll:, sendspace was banned also. Can you download the video and mail to me directly at 58846400@qq.com, this mail box accept ultra large file, I really want to see it.

BTW I think my engine should be number 15, my HW is plug & play, as soon as my board pass bench testing, it will make my engine idle in the same day

This is my HW specs that I've committed to readme.MD of my git repo

Core IO specs:

1 RPM/Position VR for 60-2 wheel pattern
6 Standard 'CORE' analog inputs(IAT,CHIT,TPS,EXO,BRV,MAP)
2 ignition drives for 4 cylinders wasted spark(PT2,PT3)
2 injector drives(HI-Z ONLY). Can setup to either do semi sequential fuel injection or do batch injection(PT4,PT5)
1 Fuel Pump relay drive.
1 dash board tacheometer drive.
1 pair of idle air valve drive.
1 gas tank ventilation valve drive.
1 switched +5V output for TPS.
5 Ground connections(CPU,Ignition,Analog Sensors, O2 Sensor and Lowside drives)
1 "12V" connections to power 2 voltage regulators

Special effort was put on making PCB geometry nearly identical as OEM ECU and reuse OEM metal case, connector and aluminium frame for heat sink. It is a mixture of SMD and through hole so that it can be assembled at home and it is almost plug and play for my Citroen ZX
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Re: Is it OK to use one vnp10n07 to drive four high-Z inject

Post by Fred »

LOL @ thinking you'll be exactly 15! (And not 11, 12, 13, 14, 16, 17 etc) :-)
HotCat wrote:1 RPM/Position VR for 60-2 wheel pattern
The code is currently too ineffecient to run past 3k RPM. When you get closer I'll put some time into optimising it or producing a simpler version for 60-2 users and high RPM users on lower counts. I know how, so don't worry.
1 Fuel Pump relay drive.
1 dash board tacheometer drive.
1 pair of idle air valve drive.
1 gas tank ventilation valve drive.
1 switched +5V output for TPS.
Which pins?
5 Ground connections(CPU,Ignition,Analog Sensors, O2 Sensor and Lowside drives)
CPU, analogue should be one ground, but it comes in from the head/block/battery for the CPU and then goes out to the sensors from the ECU. ignition drive should share CPU ground IF it's low current. If it's high current, it should be isolated. Injector and low side ground(s) should be isolated.

What do you need an O2 sensor ground for? That worries me. That should typically have its own controller which grounds independently and just shares a signal line. Heater grounds for built in O2 stuff should be isolated.

Fred.
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