Comments to the JASO Pulse verification
1. JASO does not only specify the discharge
R
value of 2.5s but also the related RC components,
- for D2 2.2F & 1.2
- for A2 4.7F & 0.6
➔ Therefore the UCS 200N include the required components.
2. JASO also specifies a very short pulse duration of 2.5s for A2 and D2 which is the result of the above mentioned RC
networks. Because the rise time constant (1s) is in the same range as the discharge time constant
R
both parameters
are influenced by each other. That means the discharge time constant is already influenced by the rise time constant.
➔ Therefore it is no more possible to make a pure graphical evaluation of the
R
parameter as usually made by the
100% to 36.7% wave shape level. The graphical evaluated
R
value seems much longer due to the influence of the
rise time constant
3. The real
R
can be easily calculated by the following method:
- Measure the time at which the decay has reached 70% of the peak voltage
- Measure the time at which the decay has reached 30% of the peak voltage
These 2 points are far enough away from the 100% point of the wave and therefore far enough away from
the influence of the risetime constant).
➔ Calculate the real
R by
using the following formula:
Note: JASO requires both, to match the
R
requirement and to use the related RC components. Therefore it is not
possible simply to match the waveform so that the user can detect 2.5s as time constant between 100%
and 36.7% manually out of the measured waveform. This would need to change the internal RC
components accordingly so that these values would no more be in the JASO spec (e. g. 2.2F & 1.2)
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