ZF company presented eAMT (electrified Automated Manual Transmission) for hybrids. It is designed for budget front-wheel drive vehicles and consists of a conventional one-clutch robotic gearbox and an electric motor on the rear axle. The experimental transmission was installed on the Dacia (Renault) Duster SUV.
The one-clutch robotic gearbox in fact is manual, in which the shift forks and clutch are driven automatically. Automakers like these boxes for their simplicity and low cost. But the shortcomings are great: delays and jerk at switching, caused by a power flow break. Plus, low reliability of clutch.
According to ZF experts, their development has brought to naught the shortcomings of the robotic box. The work of the electric motor on the rear axle is coordinated with the clutch drive. The electric motor is activated every time the clutch is opened. Thus, it was possible to get rid of jerks at gear changes.
The electric drive of rear wheels also works in other situations: with a sharp acceleration, when an additional impulse is required, or when the front wheels slip on a slippery surface.
The demonstration vehicle is designed as a plug-in hybrid. It implements all the modes typical for hybrids: motion on electric traction with the motor off, coasting, automatic motor shutdown and energy recuperation during braking.
It’s still not known when eAMT will be mounted on the serial cars. This development is targeted at the cheapest vehicles.
Photo: 2018 Dacia Duster