Building an engine dyno.

[Dessertrunner]

We have a running engine, you won't beleive what the problem was. Forgot that the engine needed to be earthed. Once I did that up it went doesn't have exhaust so it loud. The drive shaft seems to run real smoth. I need to mount load cell then hook up the variac to control the retarder.

For today thats a enough, everyone have a great day and a great week.
Tony

[SilverSpear]

Glad to know you got it working Tony! A+++ to what you are doing.

Looking forward to see some figures next week or so

[Dessertrunner]

Strain guage installed, its all down the PLC now and retarder control. I need to set up the engine controls so during the test I can get away from the unit. Don't want a rod through my head.

At this point I should need to come clean and say that pretty early in the development the Subaru ECU will have to go. The reason is that the unit is to difficult to make changes on the fly. There is no after market way to simply change the fuel & timing maps.

After I get base data from the existing ECU I am changing to a Wolf ECU. My reason for that is Robbie at Wolf has been great and will help me through any issues I may come up against. In addiation its the only way I can have the ECU grow with the engine development as it happens. Any injector changes will take a matter of minutes to adjust for.

That all for now will keep you posted.
Tony

[Dessertrunner]

Hit a snag, I need to redo the drive shaft from the engine to the belt drive. I am not happy with the current one so I will start that part again.
It will be a while as I am going on holiday for a couple of weeks so it will have to wait till I return.
Tony

[dynomatt]

Bummer about the snag Tony,

Why have you decided it's not good? Did it fail?

[Dessertrunner]

It didn't fail but I felt that it could put to much end & side load on the crank. Also direct coupled pto shafts are not kind to crankshaft type bearing, for example if there is the slighest out of balance on the shaft they will load up the engine bearing.
Given you experiance I am trying to make sure that there is no way it could cause the bearing to fail.

Any ideas were I can get a dead gearbox to mate up? Still had no luck with fly wheel tried MRT and they never call back.
Tony

[lazer]

This is a realy cool project you have here. I've always wanted to do this.

About controlling the retarder:

Have you considered using PWM (Pulse with modulation) Basically if you use this technique you can vary the current to the retarder seamlessly from you computer or via a potentiometer.
I have a bachelor in electronics and use this method to control all power demanding devices.


Lars

[Dessertrunner]

Hi Lars,
Okay what I am doing what using a variac to control the voltage from 0 to 24. I had planned to us a stepper motor to drive the dial on the variac. All this would be driven from the PLC or computer.

I would love for you to jump in and help with advise as I need all the help I can get.
Tony

[oab_au]

Originally Posted by lazer

This is a realy cool project you have here. I've always wanted to do this.

About controlling the retarder:

Have you considered using PWM (Pulse with modulation) Basically if you use this technique you can vary the current to the retarder seamlessly from you computer or via a potentiometer.
I have a bachelor in electronics and use this method to control all power demanding devices.


Lars

Yes I agree this system would make it much easier to control all the coils in the retarder, in one easy knob.
I think I said this before.

Harvey.

[Dessertrunner]

Not sure how we do the mudulation, you can't do it with relays as it to slow or are we talking about different things. Turning the coils on and off will be pretty hard on the engine.
It was my understanding that the normal system reduces the load by dropping the voltage feed to the coils. Would like to know if that not correct.
Tony

[oab_au]

Originally Posted by Dessertrunner

Not sure how we do the mudulation, you can't do it with relays as it to slow or are we talking about different things. Turning the coils on and off will be pretty hard on the engine.
It was my understanding that the normal system reduces the load by dropping the voltage feed to the coils. Would like to know if that not correct.
Tony

Setting up the PWM is no problem, you can set the frequency to be fast enough not to be felt by the engine. You can do a kit like the one you used for the 6 speed center, or buy a commercial one. It just depends on the current that has to flow to the coils. The switching FET need to be large enough to carry the current.

Harvey.

[lazer]

If you want I can design the driver circuit for you??
The original retarder control system is only 4 stages (they don't have any linear control of the retarder) that is switched with relays. I would connect it in stage 4 config (all coils connected) and then just hook up a (rather big) transistor array to control it. The transistor array has to be controlled by a dedicated pwm circuit (like a 555 circuit) or by your computer via the parallel/serial port (someone have to write a program to control it).
We can also do both so that you can choose if you want to control it via a knob or the computer.

PWM is the method which professional dynoes control the load

[Dessertrunner]

That would be good if you can do a circut. I am using a PLC then most likely Mod bus it to the PC. My guess is the plc can provide the pulse as it can provide the pulse for a stepper driver. You know I used 555's nearly 30 years ago, pretty amazing they are still being used.
Tony

[lazer]

Yes PLC's can be used. What kind are you using?
And yes for simple things I love using 555's
Didn't realize that it was that old but Wiki claims that it is indeed 30 years old

[Dessertrunner]

Not to get off topic but when the 555's came out they blue everyone away because they made complex circuts simple.
I use Automation Direct 06's through out my factory and farms.
http://www.automationdirect.com.au/