[Diy_efi] DIY WB as daily driver

[Brian Dessent]

bcroe at juno.com wrote:
> 
> The heater tends to draw less current as it gets hotter,
> partially compensating.  However this effect is not 100%,
> since the heater actually needs to BE hotter to decrease
> current.  A fancy system might actually measure resistance
> (applied voltage divided by current flowing) and continuously
> adjust power for the resistance representing the correct
> temperature.  Part of the problem is that not every sensor
> has the same resistance.

Well the idea is to maintain a given set temperature, no?  What if the
wb controller measured the cold resistance and the hot resistance of
the  heating element, and do regulation based on this (the
differential)?  Is the heater a wound nichrome wire or a ceramic block
(or something else)?  Its resistance should have a pretty linear
tempco.  This would probably require a microprocessor, but it might have
the benefit of having a crude EGT estimate output.

Brian

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