Idea for recovering Energy from Idling engine

[eee]

Hi everybody, I am wondering if if would be possible to fool the computer so that it has a strong bias on kicking on the alternator while at idle.

If I know where the voltage reading that controls the alternator is, then I could add and subract a bias voltage depending on whether the engine is idling or not idling.

Suppose normally the voltage reading of V is taken

V= Vbatt

If this were to be changed to

V= Vbatt - Vbias where Vbias -0.5V for engine at idle and +0.5 V for engine not at idle .....

then there alternator should likelier kick on at idle.

Any idea how hard it would be to do this?? Not sure if it makes a difference, but my car is OBD1.

Combined with an HHO system, that can turn battery energy into mechanical energy, I think this might gain significant mpg's