Electric motor/thermal engine drive for a vehicle in which the electric motor functions as a flywheel, starter motor, and generator

DETAILED DESCRIPTION According to the present invention, the engine unit for a vehicle is an engine unit of the above-mentioned type wherein: a) said electric motor is constructed and arranged to provide at rest and at low rotational speeds a maximum torque greater than the resisting torque of the thermal engine at rest, and greater than about one third of the maximum torque of the thermal engine, in order to perform safely the starter function down to the lowest forecast temperature; b) said electric motor is constructed and arranged to provide a maximum volumic torque of active parts of at least about 10 Nm/dm.
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3 ; c) the controls associated with said electric motor are capable of providing the power corresponding to the maximum torque.
According to an interesting embodiment, the maximum torque of the electric motor is higher than about two thirds of the maximum torque of the thermal engine, and the maximum volumic torque of active parts is at least about 20 Nm/dm.
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According to another embodiment, the electric motor maximum torque is substantially equal to the maximum torque of the thermal engine, and the maximum volumic torque of active parts is of about 30 Nm/dm.
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The rotor of the electric motor is dimensioned in such a way that it has an inertia sufficient to allow a steady operation of the thermal engine, so that it can replace the inertia flywheel of the thermal engine.
By the resisting torque of the engine is meant the torque necessary for overcoming the friction of the engine and the compression generated in the cylinders.
Such an electric motor can thus serve as a starter for starting the thermal engine.
However, contrary to conventional starters, this electric motor can be coupled permanently to the thermal engine and rotate at the same time as the latter.
Since the electric motor has a torque higher than the resisting torque of the thermal engine, it can be capable of driving both a broken-down thermal engine and the vehicle itself over reduced distances.
However, if an uncoupling device (clutch or simple "claw coupling") has been provided between the motor and the engine, the electric motor, since it is no longer braked by the thermal engine not being fed, can drive the vehicle under good conditions, being capable of performing the same service as a purely electric vehicle if the electric motor, the controls thereof and the batteries are of sufficient size and power