Q&A Forum
My dyno uses a large hydraulic pump for the load/brake. I have an electro-proportional flow control for regulating the load. I would like to have a brake control mode that simply applies a specific amount of brake. Example: 25% brake force, which will set my control valve at a specific flow rate (say 15 gpm) Then as I increase the speed of the roller, it will build pressure up to my maximum allowed system pressure. I just want to be able to set a constant voltage signal to the brake control, without the PID control.
This mode would be used to warm up the motorcycle, or simulate road conditions during tuning, and check drive-ability. I just want a small amount of resistance on the drum. A Dynojet 250i has this feature, you can set the brake % just to give some additional loading.
Hi,
This is possible in the Sequencer Brake control plugin. Just set the brake % you want and for how long you want it.
Hi HansL, are you still using hydraulic dyno? Whic brake control mode are you using?
Thanks
Eric
Yes, I'm still using it. Here it is in action. https://www.youtube.com/watch?v=3YNmy1b6qtY
I use the BRAKE SWEEP and control the brake with the BRAKE SWEEP % mode.
I can't use the most current version of the software though. I am stuck in an older version. The reason is because in the newer control method, it will not allow you to put in a negative or (-) percent in the amount of brake pressure adjustment. The older software allowed you do do that. For my dyno, I need to start at a certain brake percentage, say 50%, and reduce the percent every second by roughly 2 percent, or it will stall/dog out the engines. The newer software only allows you to increase the brake percent, I need to reduce it.
The higher the drum speed, the more GPM I'm putting out, so the more horsepower it takes to accelerate the drum. It's exactly the opposite of an eddy current brake, I need to reduce my flow control/orifice size. The faster I'm turning the drum, the harder the brake works at the same brake percent, it's not a consistent force like an electric brake.
I have asked Jostein to allow a negative brake percent a couple times, but I must be the only one in the world that has this setup. I don't want to pull down from max RPM on these very expensive motorcycles, I have to limit the amount of time they spend at 5000+ RPM, so I need to pull up like a traditional dyno.
Does that make sense?
Hi HansL, are you still using hydraulic dyno? Whic brake control mode are you using?
Thanks
Eric
Here is an example of how I need to make a pull. You will notice that I start the brake at a higher percent, and have to reduce that percent over the course of the run as RPM/Drum speed increases. I am also somewhat trying to limit the pressure within my hydraulic system. I do not run it over 4000 PSI. My goal is to sweep, not stall out the engine and use the brake to be the only thing that allows acceleration. I use the drum inertia, plus the hydraulics.
Hi Hans, very nice setup, It works very well! I also have hydraulic dyno but without drum, I mount engine directly to dyno chassis. I think that the brake mode you are using Is the only one Who works good on hydraulic dyno, so start at 50% of brake (or similar) and then decrease brake % to allow rpm goes up. Hope next month Will start test with my dyno I Will let you know.
Which kind of brake valve are you using?
What sw release are you using?
Nice looking setup.
I must be on something around 3.2.153 based on the dates.
I am using a Sun Hydraulics proportional throttle valve. https://www.sunhydraulics.com/model/FPHK
I drive it with an XMD https://www.sunhydraulics.com/model/XMD-01
I'm assuming you could use a smaller valve, but I needed a lot of flow and pressure (hydraulic HP) to be able to hold back some of these 140 ftlbs of torque Harleys when tuning the maps. I can static hold something like 140 HP on my dyno.
I work in hydraulics for a living, so I have access to the best stuff that exists.
Dear Yourdyno, please give us hydraulic guys the ability to once again decrease brake control % even when increasing RPM!!! I want to use all the new features and gauges, but I can't.
Lots of people run from high to low RPM, all the tractor pulling people for example. You don't need a minus in front of the sweep rate. If the start RPM is higher than end RPM, then YourDyno understands that this is a sweep down. The sweep rate is just the rate in RPM/s, whether up or down.
@hansl, very nice valve setup. What is the price of the valve + driver?
@admin now that Im thinking about, im in agree with you, I remember from my last dyno test, (about 4 years ago) that was not necessary Minus sign "-".
What Is the difference in dyno purposes between proportional flow valve and flow regolulation valve like this in link?
@admin That is not how I do the runs. I start at LOW RPM, say 2000 RPM. The Brake needs start the run at 50% braking command. As the pull starts and RPM increases, the brake needs to decrease by 2% per second while the RPM is increasing until the run ends at 6000 RPM. At that point, the end of the run, the brake may be only at 35%.
If I can't put in a negative number, the brake will go 50% to 65% when doing a pull from 2000-6000 RPM, the way the new software is programed. This creates to much hydraulic resistance, (because the bike is also accelerating the drum and my hydraulic flow is going up at the same time) and will stall out the engine.
The valve/manifold/driver setup I use is around $700 US. This driver also has Canbus built in, and can use multiple inputs (Can, 0-10v, 4-20ma, etc) and all it's ramping is adjustable via a phone. It's pretty much the gold standard in industry currently.
@admin now that Im thinking about, im in agree with you, I remember from my last dyno test, (about 4 years ago) that was not necessary Minus sign "-".
What Is the difference in dyno purposes between proportional flow valve and flow regolulation valve like this in link?
The Walvoil flow control you are linking to is basically a manually adjusted version of proportional valve I am using. The flow rate of my valve is controlled electrically. The YourDyno software can control the flow rate of the my hydraulic system in the same way it can control an eddy current brake.
I need my hydraulic valve to be electronic so I can do static RPM tuning, controlled by the dyno controller.
Perhaps this printout will make it more clear. Results vs Time. Run starts at 2000 RPM, brake needs to start at 58%, then drop to 44% after about 7 seconds. All while the engine/drum RPM is rising. The hydraulics on this dyno is suplimenting the roller inertia, to allow for a longer pull.
How your setup works Is all clear and It Is the same way I want to use my dyno. I have a 1" flow valve controlled by stepper motor, I think It works similar your valve.
I saw that in your setup you have a big roller, I think It helps a lot the brake, It avoid RPM oscillations when engine enter in Powerband. In my previous dyno setup i have no inertia mass and It was very difficult test the engine from low RPM to higher RPM because RPM goes up and down. Now I add 2 car's flywheel, not tested yet, I hope It will works.