Help to Design EGR Valve Simulator- Cheater

[Resqueline]

1- Yes you can. Their voltage drop will be slightly less but it may not matter.

2- Ok, didn't notice at the time. I take it your post is what applies to your car then.

3- I still don't get the coil measurement thing. The coil is connected between pins 1 & 5. What test lead colors did you put where?

4- There are three possible ways to chip more Bhp out of a turbo-diesel. One is increasing the fuel amount only, the other is increasing the turbo pressure and the fuel amount, and the third is advancing the injection timing. Doing the third will increase your MpG as well.

5- Water injection seems to have almost the same effect as EGR but with none of the side effects. It'll even clean off exisitng carbon buildups. It seems to cool the incoming charge, increase the knock resistance (gas), and the resulting steam may even increase the cylinder pressure. Using it you can increase boost pressure and advance timing. It was used on some (radial engined) aircraft for extra boost at takeoff, adding some 20% more hp it seems.
It's a challenge to make it work in freezing conditions though, as you have to add sufficient amounts of antifreeze.

 

[joseico90]

1- What type capacitor will that have to be? electrolytic?

2- That's right, post 1, that's my valve.

3- If I remember well..

-I used a standard dig multimeter, selected 20v DC & tapped into cables to pins 1 & 5 to check coil voltage whit engine running, I
was puzzled to find pin 1 to be positive, the same happened measuring at pin 4 & 6.

Then I measured a 1.5v AA battery and polarity was indicated as normal on the meter dig display.. no minus (-) sign on the left side of the display. Hope makes sense...quite possibly I'm doing ( or missing) something wrong so I'll check again soon.

(BTW next time I'll check engine ground and Pin 6 as indicated)

4-Din't know that..thanks.

5-New to me that too..

6-Need to Get a 47k resistor and a 1µF as you said, just in case, I wish I had means of measuring the frequency.

(sidenote).. I've built and flown lots of RC modelplanes and in latter years went all electric, so I remember the first frame rate ESC's, nasty things they were, damaging the commutators etc

7- I meant to ask you..

a) Have you tested this circuit on a virtual simulation?
Is there any potential risk in damaging the ECU with this circuit?

(probably the risks factors are more likely to be..human related, meaning..me )

b) What happens with regards to coil (ohms) and pot (total) impedances/resistance and ECU seeing any different?
remember I don't know much about this.. plus English is not my first language, although I use it all the time where I live, England.

8-Will be interesting to see how the water injection system project goes..

BTW, I would like to make a donation to the forum, as a thank you, and to contribute here, how do I go about it?

Thanks

Tony.

 

[Resqueline]

1- Yes, that's what the symbol says, and even though 4.7µF plastic cap's do exist they're expensive - and not needed here.

3- Strange.. Let's contribute it to human error until proven otherwise..

6- Some DMM's have a frequency range. GM used 10Hz on the old OBD-1 systems. Didn't know the old 50Hz speed controllers were hard on commutators.

7-
a) No, it's only tested using my head & calculator.
No risk to the ECM whatsoever, regardless of any potentially incorrect pin connections.
b) The coil impedance is set to 1kΩ here. It may need to be changed if the ECU objects though.
The emulated pot resistance is quite close but the ECU doesn't check this - or even rely on it being close.

8- Don't wait up for it, it's been in my head only for a number of years now, but who knows - one day..
Donations, gee, never thought about that.. A thanks now & then seems to keep us going. You could shoot Ian a PM about it though if you like.

 

[joseico90]

Hi there,

Thank you,

Could you tell me what this means please?

"It may need to be changed if the ECU objects though"

Thanks,

 

[Resqueline]

Well, if the ECU sets an error code, and you rule out other causes, then it's just a matter of replacing the 1kΩ with a lower resistance - until the ECU is satisfied.
If the ECU should be so clever that it looks for an inductive kickback then the resistor will have to be replaced with an inductor. It's just trial & error, nothing more.

 

[joseico90]

I see,

Thanks, I hope I can come back for assistance if need be

I will report how all goes and post pictures etc

I'll be making a start maybe Tuesday if I can get the bits locally.

Got to walk the dog now..wife says

 

[joseico90]

Got all the bits today
Hoping I'll have time tomorrow to assemble it.

 

[joseico90]

Thank you!

-Circuit finished
-Now is protected in black heat shrink tubing and provisionally fitted in the car.
-Plugged it today and no dash warning, good I thought!
-Plugged my OBD gear and saw live data, looked ok as the ECU seem happy to see 1.3v at pin 6.
-Accelerating made voltage to drop by approx 0.2v instead of rising, but no errors appeared. ( I wonder why that is )

See graphs, with the real valve and with the simulator.

I've booked a ECU remap with EGR deletion included (Valve shut full time)

Look forward to it..

 

[Resqueline]

Huh, inverted function - and the ECU is still happy..
Ok, maybe the wiring is like markm suggested instead then, and that you could use the diode cheater circuit you found in the beginning..
I'll need you to measure the voltages (relative to engine ground, and connecting the real EGR valve) to verify this.

 

[joseico90]

Huh, inverted function - and the ECU is still happy..
Ok, maybe the wiring is like markm suggested instead then, and that you could use the diode cheater circuit you found in the beginning..
I'll need you to measure the voltages (relative to engine ground, and connecting the real EGR valve) to verify this.

ECU might interpret this low voltage and lack of increase as EGR rate too low, might not be a bad thing after all.

yep tomorrow I might do some measuring,

Got a remap coming soon! yeppee

 

[joseico90]

Huh, inverted function - and the ECU is still happy..
Ok, maybe the wiring is like markm suggested instead then, and that you could use the diode cheater circuit you found in the beginning..
I'll need you to measure the voltages (relative to engine ground, and connecting the real EGR valve) to verify this.

Tell me what you need and I can do here, let's see if we can get this perfected even if it means building another one..

Just for the sake of it, as with the ECU remap with EGR delete this one might suffice, but would be good to get the simulator spot on so others can use it too.

 

[Resqueline]

Just measure the voltages on all the pins (in particular 1, 5, & 6) in two conditions; with little or no EGR, and with more EGR.

 

[joseico90]

With the real valve connected, engine at idle unless otherwise stated and @ normal running temp.

Car Ground to:

1= 14.2v
2= 5v
4= 0.01v
5= 9.5v
6= 1.5v

Tapping At Valve Leads;

Pins 1+5= 4.4v (pin 1 shows as the possitive on my meter)
Pins 2+4= 5v (pin 2 shows as the possitive on my meter)
Pins 2+6= 3.38v
Pins 6+4= 1.58v

Pin 6 tipically returned 1.6v to 1.75v during this test (at engine ground & pin 6)
max V is while accelerating to open the valve.

While driving as per the graphs recorded on OBD pin 6 voltage with the real valve usually ranges from 1.13v to 1.88v.

 

[Resqueline]

Ok, there seems to be a discrepancy between the connector diagram and what you measure.
Pins 1 and 5 seems to have changed places (pin 1 being B+) and this may be the reason the circuit didn't work.
When you accelerate, does pin 5 drop in voltage while pin 6 increases? Measure relative to engine ground (= pin 4).
After you've tested this you can try to reinstall the cheater (swapping pins 1 & 5).
It seems to me that the transistor you used has a little lower gain than I expected.
You can compensate for this by replacing the 33k resistor with a 27k or 22k resistor.

 

[joseico90]

Ok, there seems to be a discrepancy between the connector diagram and what you measure.
Pins 1 and 5 seems to have changed places (pin 1 being B+) and this may be the reason the circuit didn't work.
When you accelerate, does pin 5 drop in voltage while pin 6 increases? Measure relative to engine ground (= pin 4).
After you've tested this you can try to reinstall the cheater (swapping pins 1 & 5).
It seems to me that the transistor you used has a little lower gain than I expected.
You can compensate for this by replacing the 33k resistor with a 27k or 22k resistor.

Hi,

Just measured.

REAL VALVE;
.
-Ground to pin 5 @ idle=9.6v average accelerating (very..very short peaks of 13v flashed on the meter's LCD), then 9.5v average

-Pin 4 to pin6 same results.

Pin 6 @ ilde 1.48v, accelerating peaks at 1.6v

(While driving pin 6 returns up to 1.88v approx)

-The transistor is a 2N3904

SIMULATOR;

Inverting pins 1-5 now gives me 2.2v and up to 2.4v accelerating (car stationary).

According to the document, if the doc is correct.... the "correct V range at pin 6 should be less than 1.1v to approx 3v or more".
Thing is..that info is mainly to check the valves.

It seems the ECU it's not that bothered, as the car has been running with the valve with pin 6 returning min 1.5v to 1.9v max, and with the cheater giving 1.2-1/3v...(yesterday) and so far with no issues even at OBD level in either case. Maybe petrol engines management are more fussy, while diesels aren't?

Hey, thanks for your time and patience.

 

[twister]

Hi,

Just measured.

REAL VALVE;
.
-Ground to pin 5 @ idle=9.6v average accelerating (very..very short peaks of 13v flashed on the meter's LCD), then 9.5v average

-Pin 4 to pin6 same results.

Pin 6 @ ilde 1.48v, accelerating peaks at 1.6v

(While driving pin 6 returns up to 1.88v approx)

-The transistor is a 2N3904

SIMULATOR;

Inverting pins 1-5 now gives me 2.2v and up to 2.4v accelerating (car stationary).

According to the document, if the doc is correct.... the "correct V range at pin 6 should be less than 1.1v to approx 3v or more".
Thing is..that info is mainly to check the valves.

It seems the ECU it's not that bothered, as the car has been running with the valve with pin 6 returning min 1.5v to 1.9v max, and with the cheater giving 1.2-1/3v...(yesterday) and so far with no issues even at OBD level in either case. Maybe petrol engines management are more fussy, while diesels aren't?

Hey, thanks for your time and patience.

This has been a very interesting thread! I think if the frequency of the computer output was known and the pinout was known, it could have been designed to mimic the actual egr valve exactly. I wonder if the frequency changes or the pulse width changes? It would be interesting to see the signal on an oscilliscope. I wonder if you had just blocked off the valve and then left the valve hooked up, would work?
Is the nitrous oxide really such a bad pollutant? There is one farmer in Canada that has made a exhaust cooler for his tractor and then he injects it into the ground as he cultivates.I am curious to see how this works out. So if nitrous oxide is good for plants, why are we ruining the efficiency of our motors?
Also, isn't nitrous oxide the same as what the hotrodders use to greatly increase the power of their motors?

 

[joseico90]

Hi,

yep the valve was left after the mods, the idea is to get rid of it as it's a bit heavy and I'd rather have a solid state circuit instead.

See my mods thread here http://www.renaultforums.co.uk/showthread.php?t=125843

IMO EGR on diesels is a messy business, these valves are a pain and expensive too. I'm not having my engine sucking all that rubbish.
My car exhaust gases are less smokey and smelly now after the mods.

I've ordered a digital multi tester that can measure Hz, I'm interested to find exactly what the erg actuator freq is.

 

[twister]

I am very interested too, to know the frequency of the egr actuator is. You said that the only difference between your 80hp motor and the 100hp motor, was in the ECU program. I wonder if a cheater box could be created to increase the hp. to 100? Can you show any maps of the injector solenoids? Or for that matter show everything that your computer program shows? Thanks.

 

[joseico90]

I am very interested too, to know the frequency of the egr actuator is. You said that the only difference between your 80hp motor and the 100hp motor, was in the ECU program. I wonder if a cheater box could be created to increase the hp. to 100? Can you show any maps of the injector solenoids? Or for that matter show everything that your computer program shows? Thanks.

Hi there,

I'm waiting to receive this.. apparently it's able to measure Hz
http://www.ebay.co.uk/itm/230746727...X:IT&_trksid=p3984.m1439.l2649#ht_2848wt_1270

-Yes there are tuning boxes to increase BHP available, but I've opted for a professional ECU remap, it's better to remap, when possible.

-I'm no expert on ECU software, I do have diagnostics tools but I don't do any reprogramming.

Thanks.

 

[joseico90]

remap

ECU remap booked for next Thursday,
(with EGR valve operation delete included)