In the recent years powertrain electrification has earned special focus in the race for reducing fuel consumption and CO_2 emission. Future targets for CO_2 emissions are difficult to achieve with conventional powertrains with internal combustion engines only. Powertrains with an engine disconnect device are entering the market in different ranges of electric power, from mild hybrid up to plug-in hybrids. In this paper, we would like to present a mild hybrid drivetrain concept, which enables engine disconnect without the need of an additional disconnect clutch. This relatively simple concept uses a one-way clutch (OWC) in combination with a dual clutch transmission and a small electric motor, thus making it interesting for mild hybrid and 48V systems. This systems needs no conventional disconnect clutch, thus offering the following key features: 1. no additional actuation for disconnect clutch; 2. reduced complexity as no additional clutch control is needed; 3. one-way clutch has nearly zero drag torque in disconnected state; 4. package space benefits; 5. driving features such as electric driving, boosting, load point shift, coasting, engine braking and recuperation; 6. enabler for a simple mild hybrid layout. The paper also shows the fuel consumption advantages realized with this mild hybrid concept.
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