dpansier
Well Known Member
I recently spent time going thru some patents regarding the control of alternators in fuel efficient vehicles.
I found the designers have come up with some very novel alternator control devices that save significant amounts of fuel. In addition to measuring battery voltage some of the alternator control devices have the ability to monitor the engine load, road speed, electrical load demand, engine and ambient temperature. By carefully monitoring these parameters, the alternator output is controlled to meet the electrical demands using the least amount of engine horsepower and improving the fuel consumption numbers of the vehicle.
For example, the battery was not charged when going up a hill and heavily charged on the way down.
Thinking through this exercise on how this information could be used to improve the efficiency of our sport planes I realized many of the gains would not apply to our aircraft needs as the engine loading parameters are quite different.
One thing apparent was the power requirements of the alternator, a fully loaded 60 amp alternator can demand 5 or more horsepower.
A simple method to recover this lost power on takeoff would be to install a switch in the alternator field control wire, the switch would open when the throttle was firewalled and closed when slightly pulled back allowing the alternator to provide normal output. The throttle method could be used with fixed pitch props and the high RPM prop control could be used with constant speed props.
Not sure if I can feel 2.5% improvement in the seat of the pants with 200HP total but with a fixed pitch installation the % would be greater.
These thoughts are worth what you paid for them.
I found the designers have come up with some very novel alternator control devices that save significant amounts of fuel. In addition to measuring battery voltage some of the alternator control devices have the ability to monitor the engine load, road speed, electrical load demand, engine and ambient temperature. By carefully monitoring these parameters, the alternator output is controlled to meet the electrical demands using the least amount of engine horsepower and improving the fuel consumption numbers of the vehicle.
For example, the battery was not charged when going up a hill and heavily charged on the way down.
Thinking through this exercise on how this information could be used to improve the efficiency of our sport planes I realized many of the gains would not apply to our aircraft needs as the engine loading parameters are quite different.
One thing apparent was the power requirements of the alternator, a fully loaded 60 amp alternator can demand 5 or more horsepower.
A simple method to recover this lost power on takeoff would be to install a switch in the alternator field control wire, the switch would open when the throttle was firewalled and closed when slightly pulled back allowing the alternator to provide normal output. The throttle method could be used with fixed pitch props and the high RPM prop control could be used with constant speed props.
Not sure if I can feel 2.5% improvement in the seat of the pants with 200HP total but with a fixed pitch installation the % would be greater.
These thoughts are worth what you paid for them.