The virtual clutch(for clutchless manuals)

[jakobnev]

I was thinking, many people who do clutchless manual ev-conversions complain about how hard it is to shift.

What i propose is to have rev-matching logic in the motor controller, that is operated with a clutch pedal. In the up position the motor is controlled with the throttle normally, in the down position the motor is automatically kept at the correct revs for the gear you are trying to get in or out of. In intermediate positions it's a compromise, allowing you to get off the clutch smoothly while finding the right throttle position.

Sensors for the motor and output shaft speeds and some switches for the gear selector will be needed.

Opinions?

[Frank Lee]

Will that be easier for you to build than putting a clutch in?

[jakobnev]

Originally Posted by Frank Lee

Will that be easier for you to build than putting a clutch in?

Well, whoever does it first is going to encounter some hurdles, but for those that follow, it will be far easier than adding a physical clutch to an electric motor.

[Frank Lee]

Or the pedal could be done away with in favor of a VW auto-stick style shift lever.

[dcb]

I've thought about rev-matching EV's before. If you have a gate switch for each gear, a throttle position sensor (duh), and have a vehicle speed signal, and you program in all the gear ratios, then the controller should have enough information.

i.e. you are going 20mph in 2nd, you lift the throttle to slip it into neutral and move the stick towards 3rd, the gate switch tells the controller to synch, the controller figures out what rpm is appropriate for 3rd at 20mph (because it knows all the ratios), and drops the rpm accordingly. Ditto for going from 3rd to 2nd except the controller will have to increase the rpm.

It should only do it for a brief pulse when the gate switch is first closed, the gate switches need to close before the gear engages (some fudge there), and only if the throttle is at zero.

If you want to be extra safe, have the controller do the actual gear changes, and install a little h-gate on a joystick or some switch box affair, or just up/down pushbuttons (or???). Not trivial, per-se, but doable, then the controller can synchronize the unloading of the drivetrain, the slip into neutral, the rpm match and the snick into the appropriate gear, all with the push of a button and very little chance of making a mistake in the process (once calibrated). You basically need two strong servos to take control of the gearbox.

[jakobnev]

dcb: KISS

[dcb]

It is simple, in terms of not having to install additional sensors. Most cars have(had) a speed sensor already, and a motor rpm signal is fairly common as well.

If you added reliable x-y pots to your stick shift, I bet a controller could sort it out and know which gear you are heading for.

[jakobnev]

dcb: those bits indeed, but then you went on to talk about mechanizing the shifting itself.

[dcb]

here is simple:

assuming you already have a speed and rpm signal on the vehicle,

program in the ratios, or "train" the cpu once at runtime (let it capture the rpm to speed ratio for the different gears).

have TWO easy access pushbuttons on the gearshifter.

When you press the left one it holds the rpm necessary to slip it into the next lower gear than you were just in.

When you press the right one it holds the rpm necessary to slip it into the next higher gear than you were just in.

If the controller doesn't see the expected rpm change immediately, it should cancel the button command and assume it is still in gear, or something, and do whatever the throttle says.

[Frank Lee]

or you could use a VW style autostick shift lever as I said...