SP6 Installation and Setup V0.91
Sportdevices © 2019
20/NOV/2019
4.2
Ratio Configuration
Ratio is a
key
parameter which is used on several processes of Sportdyno, and also on SP6 for speed
control:
It is used to convert Roller Torque to Engine Torque. Due to the gearbox torque
conversion, normally torque at roller will be higher than at engine.
It is used for drawing the Engine RPM axis, and as reference for the torque and power
peak values.
On SP4 and SP6, it is used to calculate an estimation of engine RPM (from roller RPM),
since only roller RPM is used for speed control, but all target values are referred to
engine speed.
There are three ways to provide ratio to Sportdyno:
Using capacitive or inductive clamp:
Although Engine RPM Channel is not directly used
for the three functions described below, Sportdyno will perform an histogram from
engine rpm and roller rpm channels to get the Ratio value before starting the test, and
(by default) after the test is finished
Fixed ratio
: in certain cases when Ratio value is known ratio can be setup directly (for
instance engine test bed when there is a fixed transmission from engine to flywheel /
brakes)
Test Ratio
:
this option will open the “Test Ratio” window. Based on the vehicle’s
Engine RPM gauge this tool will determine the ratio value from Roller channel and the
entered value for Engine RPM. The main disadvantage of this method is that normally
all vehicle’s Engine RPM gauges have an error between 10% and 20%, thus Ratio value
will have this error too.
NOTE: When using
OBDII
Interface Engine RPM can easily be acquired from the
vehicle’s ECU for the Ratio calculation.
