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DIY hybrid?
I have an idea for a DIY hybrid conversion:
* Start with a car with a small engine and a manual transmission, maybe a small pickup truck.
* Add a motor (a small forklift motor, perhaps?) and attach it to the crankshaft with a motorcycle-type chain or a strong belt.
* Since brushed DC motors don't work very well for regen, regen will be implemented with a heavy duty alternator modified to operate at the hybrid system voltage and with a control signal from the control electronics.
* The original alternator will be replaced with the modified one and a DC/DC converter used to keep the 12v system working.
* The electrical drive system will be under independent control (Insight manual-style) to allow the driver to choose gas or electric power.
* A relay will be used to turn off the engine for EOC and EV mode.
* A panel with switches and indicators will be added to allow the driver to manually manipulate the operation of the hybrid system.
* Since it's a hybrid, the electrical system does not have to be very powerful. 96v or even 48v should be enough.
* An additional spring will be added to the accelerator to provide a clear indication of the most efficient engine operating point, above which power should be obtained from the electrical system.
* Since the crankshaft speed will vary greatly, run the power steering from a motor (maybe a vacuum cleaner motor?) under electronic control. The power assist will be greatest when stopped (maybe indirectly sense load using current to save energy?) and ramped down as speed increases. (For what it's worth, a 120v vacuum cleaner motor will start to rotate with just 12v, so it might perform well enough at 48 or 96v for our application.)
The most complex part will likely be the control electronics. It will, for instance:
* Be based mostly around hardware for easy development and reliability.
* Coordinate the transition between gas and electric power. The car could start on electric power alone, and if the driver chooses, the engine powers up once it reaches a minimum operating RPM.
* Manage the main battery pack. In normal mode, it will restrict the amount of power, but in EV mode, it will allow as much as the hardware is capable of. That is done to reduce resistance losses in the batteries.
* If the brake pedal is depressed, disable electric assist and maybe automatically regen at the optimum rate, while allowing the driver to fine tune the amount with the control lever.
* In EV mode, maybe tap into the TPS to allow the accelerator pedal to work.
Some issues are:
* Would turning the engine at low speeds be a problem? Maybe an auxiliary oil pump should be used to ensure lubrication at all speeds? (How does the new Insight solve that problem?)
* Would the engine have enough friction to greatly affect EV mode performance?
* Would the motor have enough friction to greatly affect normal (hybrid) mode efficiency? Maybe a one way clutch can solve this?
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If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year.
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