Dyno-ing an engine (Help)

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Dyno-ing an engine (Help)

Postby AE92-5ONIC » Thu Jun 20, 2013 8:33 pm

At uni I'm required to test the affects around the performance parameters of an engine (Yamaha 223cc 4-stroke). I had my first play around/familiarising myself around the engine-dyno rig today and was wondering how I actually manage to get the output I want from the engine.

I've got a water brake dynamometer with the engine output shaft connected to the dyno. What is the correct way to run the system if I'm trying to record the engine parameters (torque, power, fuel consumption, engine temperatures etc.) at different engine RPMs (say 1000 RPM increments) in terms of controlling the load on the engine and the engine speed?

I am a bit of a newbie, so help would be greatly appreciated,

Cheers

EDIT:
- Open the load valve on the control panel all the way up (counter clockwise) and
then turn it ½ a turn clockwise.
- Start the vehicle and warm the engine up.
- Using the throttle lever, increase the engine RPM and turn the load valve
clockwise until the engine RPM starts to decrease. You want the throttle at the
wide-open position and regulate the engine RPM with the load valve.
- When the desired RPM is achieved take readings.

Does that sound about right?
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Postby DLF » Fri Jun 21, 2013 2:15 pm

Sounds about right.

I did the same tests at uni on a SR20 using an eddy-current dyno, but the principle of operation is the same. Warm up the engine off-load, add load until the RPM decreases a little, then throttle all the way open and the change the RPM using the load control.

Couple of things to remember:

- When you change the load, do this slowly. The dynos are way stronger than the engine, so if the load is changed too quickly, things tend to start breaking.
- Watch your cooling. Most common way to destroy an engine on a bench dyno is to seize it, due to the cooling system being either undersized, or in the case of plate heat exchangers, setting the cooling water flow too low.


Cheers
Dean
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