Dwain Swick wrote: > We have been building our version of an automatic transmission for a few > years now. Our EVGlide is a modified Powerglide. We are connecting the > motor directly to the transmission thru a coupler and adapter plates. We > eliminate the torque converter. We cut off the bell housing as it is no > longer needed. This makes a compact motor/transmission unit. We add an > auxiliary pump to maintain pressure when stopped. The valve body has been > modified to make it a manual shift. Most gear ratio's allow the vehicle to > run 40 to 45 mph in low gear so low gear is all that is needed on most > city streets. > I don't know much about controlling the four wheel drive, but it seems the > drive could be adapted to the EVGlide. I would think the weight of the > F150 and the extra drag of the four wheel drive, you would want an eleven > inch motor. > The normal automatic will tend to shift to a higher gear at a lower speed. > This will make an electric motor tend to pull more amps which will give > you poorer performance and shorter range. The manual shift puts the > driver in control. With the EVGlide, the gears are a planetary and always > engaged. The clutches are internal and controlled hydraulically. When you > move the shifter to a new position, you instantly get that gear. > Because the unit doesn't use the torque converter, there isn't any need > for an oil cooler. The slippage in the torque converter is where the oil > gets hot.
I'm not saying that the EVGlide would be a poor choice, however, there are a couple of points that bear clarification. Retaining the original Ford automatic is the easiest and least costly option. Going to some other automatic will require more fabrication and swapping the Ford automatic for a Ford manual will require additional work to retrofit the clutch and shifter linkages (for snowplowing with a manual you will probably want the clutch). Retaining the torque converter provides additional torque multiplication and may allow you to use the 9" motor while going without a torque converter may force you to a larger motor. The Ford automatics are fully manual shift for first and second gears. That is, if you select "1", the transmission will start in, and remain in, first gear; if you select "2", it will start in and remain in second gear. If you select "D", it will start in first and upshift through the gears according to its programming, which will not likely be the same shift points you would choose for a series DC motor. The factory transmission "cooler" is *inside* one of the end caps of the engine radiator. It serves two purposes: if the tranny fluid temperature exceeds that of the engine coolant, it cools the fluid; if the tranny fluid temperature is lower than that of the engine coolant, it *heats* the tranny fluid. This latter point is important since you plan to use the truck for snow plowing, which typically occurs in cold climates. The clutch packs in automatic transmissions rely on o-rings to hold the oil pressure behind the pistons that applies the clutches. With age, these seals tend to harden; they also tend to harden at low temperatures. If you put the vehicle in gear at low temperature, oil pressure can leak around the seal and prevent the clutches from engaging properly. The natural instinct when the vehicle doesn't begin moving is to apply more throttle, which raises the oil pressure. Eventually the oil pressure reaches the point where the piston suddenly (violently) applies, sometimes with the result that the o-ring is dislodged completely. If the o-ring becomes dislodged, that set of clutches becomes non-functional and you "lose" that gear (and possibly others, depending on the transmission design). For snow plowing, I would suggest plumbing in an electric heater into the tranny fluid loop. Indeed, I would consider circulating the heated tranny fluid through the stock heater core as a means of providing cabin heat (which you will certainly need anyway). If you keep the stock automatic, the easiest option is to use the stock tranny pump and simply idle the motor to maintain line pressure. This is likely to be less efficient than using a separate pump to maintain line pressure since once the motor RPM exceeds some level, the stock pump will build more pressure than necessary and you will be wasting energy circulating fluid through bypass circuits. What sort of DC/DC converter do you have in your present EV? I did a lot of snow plowing growing up, and we had to run pair of 12V batteries because the alternator could have difficulty keeping up due to the additional lights and the load of the pump to raise and/or angle the blade every few minutes. Depending on how much snow you have to plow, you may have to do something similar or look to a beefier DC/DC converter. Cheers, Roger. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
