I would venture to say that an electric car shouldn't need a clutch. You are talking about a friction clutch activated by magnets correct? or an actually magnetic coupling. My shoot from the hip guess to get the kind of holding power you would need for anything over an AC pump the size gets large and heavy. As does the power usage.
The clutch in the system was replaced by a powder ferromagnetic coupler, while the transmission itself was a three-speed mechanical unit similar to that of the Dauphine—but with synchromesh on all gears.
The system used a dash-mounted push button control panel where the driver could select forward or reverse and a governor that sensed vehicle speed and throttle position.
A "relay case" containing electromagnetic switches received signals from the governor and push bottons and then controlled a coupler, a decelerator to close the throttle during gear changes, and a solenoid to select operation of the reverse-first or second-third shift rail—and a reversible electric motor to engage the gears. The system was thus entirely electromechanical, without hydraulics, pneumatics or electronics.
Ciro,this is interesting; a Jaguar patent for an electromagnetic clutch transmission - but it must be quite recent as it was filed from Southfield Michigan and that implies a more recent origin.
Please note section 0043:
"In normal operation of the selector mechanism (FIG. 4), the selector knob 15 and the detent plate 24 are connected to one another by means of a first clutch device. The first clutch device comprises an electromagnet clamp 34 vertically fixed on the detent plate 24 in front of a first steel ring 35 fixed to the selector knob 15. The electro-magnet clamp is controlled by the transmission control unit 26 in order to engage or disengage the detent plate 24 with the selector knob 15 as it will be described further."
There are lots of clutch types that could possibly be used in F1. But once you consider how the clutch is used in an F1 drivetrain you'll appreciate why the carbon multi-disc friction clutch is the best choice, for weight, inertia, simplicity, reliability and size. You could use electromagnetics, hydrodynamics, hydrostatics, friction, fluid traction, etc., if weight were not an issue.
The clutch is only needed to compensate for the speed difference between the rear wheels and the crankshaft, typically when accelerating from a stop. Once the crank and rear wheel (or more specifically the crank and transmission input shaft) speeds are synchronized in low gear, the clutch is kept locked.
Carbon friction materials have unusual friction properties that make carbon clutches somewhat difficult to modulate. An electromagnetic clutch would definitely give much better control.
riff_raff
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