Servo driver?

[Tim_Duggan]

Awesome! Can't wait to hear how this pans out! Might be best to start on the rich side of a good needle for the first couple of runs - I'd dare say as the temp comes up quicker in a restricted cooling environment, the extra fuel safety margin will be a good idea. Plus if it burns more fuel and still cleans out - more power!

 

[dwilfong]

This is a new eng setup with the billet piston in it. I will have to break it in before I test the system. This will give me time to log some temps before I test the valve. Hoping that this will burn more fuel.

The custom billet pipe I have will give it plenty to burn. If it pans out this monster will make some killer power.

Now I just have to find a prop to tame it.

 

[dwilfong]

Well it all fit. Now one more test. start the eng on the stand and see what happens. If all goes well will try running the system on Sunday.

Here are a few pics.

 

[dwilfong]

Well I bench tested it today after I heat cyl the new P/L.

The system holds 90psi after a Little adjustment to the lines. also got a laser inferred heat gun.

The logger is on the money with recording the heat.

cold eng 91deg no flow thew the system. could only get the eng to 120 on the stand and there was just a little flow in the line.

The system is responding to the heat and stabilized at 120. now will it work under a load that is the question?

Will run it tomorrow and let every one know.

Here goes nothing.I got my fingers crossed.

 

[dwilfong]

well gave it a try but could not tell if it will control temp in could water. the water temp here in FL is 82 right now.

But it dose open up and the eng temps are good. No difference in my set up with the custom head and .080 hole in it to start with.

but the .060 hole in the valve is more than good to cool the eng.

Temps from 200 to 220 for the runs vale hooked up or not.

this was on my 1.01 at 80 to 86MPH in my SGX 90 boat pushing it right on the buoys hard.

still Little rich for the break in.

Will need to have some one test it in some colder water to see what it can do.

So who is game for some testing?

David

 

[Tim_Duggan]

It's winter here now so I can test in cold water. Just have to finish repairing the test mule.

Did you get any logger data with and without the valve?

 

[dwilfong]

Yes I will post some logs as soon as I Email them to my home computer.

 

[Tim_Duggan]

Got a new toy today. Arduino Pro Mini. No header pins which makes it very thin, and it's also a little smaller than the nano. Weighs in at only 2 grams. It's smaller in area than a receiver - even the small ones......

Nano on the left, Pro mini on the right.

 

[dwilfong]

Here are some logs from the test.

The sensor cam undone on the last one . I was testing the throttle response.

 

[Tim_Duggan]

That second graph is interesting! About 20 seconds from hitting the water to flattening out somewhat around the 220* F region.

Was the first log with water restriction operational or without?

 

[dwilfong]

the second one was with cooling valve running. you can see at the end when I leaned it out how the temp raised. .060 restriction dose put some heat in the eng. I think that this system will work the best in colder water. In 80+ water temp it is not needed.

Got my nano today. now comes the pain in the ars writing the script

 

[Tim_Duggan]

I also think the effect of controlling the temperature better will be more obvious on smaller engines with less HP than the big blocks.

Start off with the example servo script in the arduino software (known as the arduino IDE), called sweep. Power the servo from a battery pack, not from the nano, and hook up the negative to the arduino ground also - in other words the signal wire to the servo going from one of the outputs on the arduino. the pos and neg for the servo connecting directly to the pos and neg of the battery, and a wire going from the negative of the battery pack to the ground of the arduino. If it's all hooked up Ok and you can get the script into the nano OK, the servo should sweep one way then sweep back the other until you unplug it. (see youtube for example vids) If you need help, PM me. From there, go to the "knob" script in the servo examples.

The script called knob is very similar to what your 555 servo driver is doing.

When you open up the sample scripts, you can alter some of the values and get a feel for it. One thing that is not immediately obvious from the tutorials but is useful is that you can program in the minimum and maximum travel of the servo. In the script you'll see a line that says;

myservo.attach(9)

you can change it to something like this;

myservo.attach(9, 600, 2200)

What this means is you are telling the arduino you have a servo attached to Pin9, it's min pulsewidth is 600 milliseconds and it's max pulsewidth is 2200 milliseconds. If you don't asign the min,max, it defaults to 544 / 2400 which I find is a bit too much and the servo is trying to drive past it's end points. Play around with the values - I just used an approximate number in my example here.

 

[Charles Perdue]

David, you may want to drop your temps just a little. Water boils at about 212 and when it turns to steam, it is difficult to maintain consistent temps as the wet area is constantly changing. Steam does not conduct the heat away from the engine as effeciently as water.

I have had the best results at settings of about 180 to 190 degrees.

Charles

 

[dwilfong]

I was thinking about the water boiling and making steam pockets. but under pressure the boiling temp is higher.

Think about a car 15psi cap and it will run at 220 with out boil over.

with the restriction on the line after the head I bet the pressure gets pretty high. so what is the boiling point at higher pressure?

Then with out boil in the system what is the beast temp to burn high nitro?

these are the question I ask my self.

the temp where taken right at the top of the ex port on the case.

The next test will be with a K probe in the hole in head and one in the ex right at the ex port.

Will see what this shows.

David

 

[Tim_Duggan]

Charles raises a good point and adds some excellent feedback regarding his findings. Thanks Charles. B)

I can't help but wonder if the water temp coming out of the outlet is anywhere near the temp of the head material right at the sensor, given that the sensor is not directly exposed to the water. Is the water in the head long enough for the water temp to escalate to boiling point? To put a finer point on it, the sensor is not reading water temp, it's reading the head temp. Yes they are inter-related but it's not known exactly what the water temp is.

David,

If the system is doing it's job properly - the .060" restrictor should be removed to see if the valve is adequate to build the heat and adversly lower the temp if it gets hotter when you lean on it. After all, when the valve is at the cold position, it flows less than just a .060" restrictor, right? If the temp drops too much after the valve opens up after peak temp is hit because the valve isn't fast enough to react, then you could creep up on the restrictor size until it flattens out the temp to minimise flutter. Its all about making the temp stable.

How did you go with the Nano programming?

 

[dwilfong]

the valve is the .060 restrictor. with out the valve there is a .080 hole drilled in the head for restriction. I am going to check the head temp with the k probe put in the hole in the head that the resistor is in now to control the valve. this will tell me the temp of the button. will also keep the sensor on the case at the top of the ex to see what is what. I can also put a sensor on the water outlet to see the actual water temp. This will tell the whole story. Have my kid down for Fathers day this weekend so no time to mess with the nano, But I did down load the utility for windows. and it has all the libraries in it. Will get with you when I get down to it. I think between the two of us we can get it going for the needle control is short order.

Got a little side tracked with the NR.46 P/L for my CMB.45RS project the last few days.

 

[Charles Perdue]

I was thinking about the water boiling and making steam pockets. but under pressure the boiling temp is higher.

Think about a car 15psi cap and it will run at 220 with out boil over.

with the restriction on the line after the head I bet the pressure gets pretty high. so what is the boiling point at higher pressure?

Then with out boil in the system what is the beast temp to burn high nitro?

these are the question I ask my self.

the temp where taken right at the top of the ex port on the case.

The next test will be with a K probe in the hole in head and one in the ex right at the ex port.

Will see what this shows.

David

Yes you are right about the water pressure raising the boiling point.

However, there is not consistent pressure in the cooling system on these boat engines. Your water pickup hole is in the left side of the rudder blade (wrong in my opinion), when the rudder is moved to make the right turn, the water is taken away from the left side of the rudder blade when it needs it the most. The water pressure drops to zero. Also, when the boat is turning, it is putting the greastest load on the engine at the same time.

I am not trying to put you down in any way. I am just trying to help keep you thinking on the right track.

Charles

 

[dwilfong]

I was thinking about the water boiling and making steam pockets. but under pressure the boiling temp is higher.

Think about a car 15psi cap and it will run at 220 with out boil over.

with the restriction on the line after the head I bet the pressure gets pretty high. so what is the boiling point at higher pressure?

Then with out boil in the system what is the beast temp to burn high nitro?

these are the question I ask my self.

the temp where taken right at the top of the ex port on the case.

The next test will be with a K probe in the hole in head and one in the ex right at the ex port.

Will see what this shows.

David

Yes you are right about the water pressure raising the boiling point.

However, there is not consistent pressure in the cooling system on these boat engines. Your water pickup hole is in the left side of the rudder blade (wrong in my opinion), when the rudder is moved to make the right turn, the water is taken away from the left side of the rudder blade when it needs it the most. The water pressure drops to zero. Also, when the boat is turning, it is putting the greastest load on the engine at the same time.

I am not trying to put you down in any way. I am just trying to help keep you thinking on the right track.

Charles

My blade has it on the right . :huh:

 

[Charles Perdue]

Then I stand corrected, carry on, just don't turn left....

 

[dwilfong]

Then I stand corrected, carry on, just don't turn left....

I try not to but you know how that goses. :lol: