Simulated gearboxes for EVs

The Lexus L110 has two gears within a planetary gearset, the Open Inverter forum has replacement boards so you can select 1st or 2nd gear. Very handy for use in a heavier vehicle, it will actually take off up a hill and a lot more regen holding power down hill. I'm looking at driving one into the front of the Super Duty Ford 3sp+over drive box in my motorhome.
No Jerking parts Coulomb, all rotating mass, just allows the torque increase at low speeds required to move a heavy vehicle, yet no overspeed the electric motor rotor/s that was the problem in the Gen 1 and Gen 2 Prius that limited electric only drive forcing the ICE to be spun to avoid MG1 over speed.
They added a second gearbox (planetary set) in the later version to help with the over speed problem, but a multi ratio selectable single planetary set would have solved the problem and made the option of declutching the ICE and using MG1 as a high torque assistance on launch shifting to direct drive at some stage is required. It would also save the ICE having to rev like there's no tomorrow on a long full load hill climb ......

T1 Terry
 
It's not that IC engines need gearboxes because they're (inherently) inefficient, it's because they are intrinsically constant-torque (with torque tailing off at very low speeds and very high speeds because of the practicalities of implementation). So a gearbox is needed in order that the engine can be kept at - or near - its power peak, and thereby maximise torque at the roadwheels.

Whereas, electric motors tend to be constant power through the speed range (though torque will of course have to be limited at the very lowest speeds). So no need for a gearbox, as full power is available at all speeds (the lowest excepted).
 
I don't really see the value of a gearbox. My car works fine with its single gear ratio. That's the beauty of an electric drive system.

I think we may see high/low range in the future, particularly with off road electric vehicles
 
And with the XPower you get the authentic vibrations as you pass through the Warp barrier
The MG4 did its best initially to trash its gearbox by leaving its oil all over the road and people's driveways thankfully they made a fix out of a meccano set to sort it, maybe that's where they are getting the bar to hold the under tray on.
 
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The MG4 did its best initially to trash its gearbox by leaving its oil all over the road and people's driveways thankfully they made a fix out of a meccano set to sort it, maybe that's where they are getting the bar to hold the under tray on.
That’s a blast from the past. I’ve still got my original case of the stuff in green and red from the 1950’s. I built many an ev from that - and a lot of cwv’s too they worked beautifully day and night without wires - clockwork vehicles 🤩
 
That’s a blast from the past. I’ve still got my original case of the stuff in green and red from the 1950’s. I built many an ev from that - and a lot of cwv’s too they worked beautifully day and night without wires - clockwork vehicles 🤩
Will be worth a fair bit of money now as a set!

Or alternatively you could offer to fix folks under tray characteristics for them as a wee sideline👍
 
It's not that IC engines need gearboxes because they're (inherently) inefficient, it's because they are intrinsically constant-torque (with torque tailing off at very low speeds and very high speeds because of the practicalities of implementation). So a gearbox is needed in order that the engine can be kept at - or near - its power peak, and thereby maximise torque at the roadwheels.

Whereas, electric motors tend to be constant power through the speed range (though torque will of course have to be limited at the very lowest speeds). So no need for a gearbox, as full power is available at all speeds (the lowest excepted).

I think Hyundai / kia are using a motor on one of their EV's that has both star and delta configuration in it's field windings with 2 sets of MOSFETS in the inverter so it can alter the 'power band' of the motor by switching between the two field windings at essentially the speed of light.

Not sure how good it is in practice but it sounds much simpler and reliable than a 2 speed gearbox, the drop in price of the semiconductor sets used in the inverters have seemingly made this viable for EV's now, the double motor windings are cheap to manufacture.
 
With the latest design in winding the com without requiring hundreds of solder joints, the ability to switch from star to delta on the fly and producing motors that can spin much faster and use planetary gear sets to reasonably efficiently use that high rpm low torque to produce low rpm high torque, the single speed drive works.
I can see this developing into smaller motors that require less battery power to spin, a range of ratios and switching the field windings to suit the power requirement at that moment, and that leading to a more efficient power train and leading to even longer range from smaller battery packs.

There will always be the market for dual motor massive torque vehicles, the V8 would have never made it into passenger cars without it, but there will also be the market for the economical 4 cyl equivalent ........ never going to win the drag off the lights, but while the dual motor monster battery is in the ultra fast charging bay emptying their wallet into the yet another battery full of go power, the little 4 cyl equivalent will continue of past to their over night accommodation and plug in to the cheap power a slow charger offers.

EV's are a new novel thing, no market for an ecobox yet, but the time will come. I very much doubt the gear changing will have much driver control, maybe via the right foot like an auto does today, the design mission will be smaller, cheaper motor and battery pack, in a family oriented vehicle.

At the moment it is all about the latest flashy gadgets and connect-ability to the other flashy things the driver might own or at one time want to connect to via the car .... the phone already does that but, hey, look at all the flashing lights .... pretty :rolleyes: :cool: until it doesn't work anymore

T1 Terry
 
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