Lamborghini's New Transverse Dual-Clutch Transmission Is an Engineering Marvel
Lamborghini revealed drivetrain details for its upcoming plug-in hybrid V-12 flagship on Tuesday, giving us an idea of what to expect under the skin of the Aventador's 1001-hp successor, codenamed LB744.
The biggest news is the addition of an all-new transverse eight-speed dual-clutch transmission mounted behind the engine, a first for a V-12-powered Lamborghini. The gearbox's design is more groundbreaking than you might think, as we found-out first hand talking to its engineers.
The Italian supercar maker went transverse with the LB744's transmission for two reasons, the first being weight.
"We decided to do a transverse because we can push the center of gravity really [to] the front," Davide Bizzarri, head of motion at Lamborghini, told Road & Track at a preview event in Italy.
The second reason is packaging. If Lamborghini had gone with a more traditional, longitudinally mounted transmission out back, the length of the LB744 would have been extended. With the compact transverse casing, engineers could also fit a working diffuser without having to ruin the car's proportions.
Where the DCT really gets interesting is how it incorporates the electric motor.
"In the usual case, you would put the e-motor between the engine output and the input of the gearbox," Lamborghini CTO Roven Mohr told Road & Track. "We decided not to go in this direction. We have it in a different position in a kind of side shaft, and this position allows us in a very compact format to, on one hand, decouple the e-motor from the wheels, or from the engine."
In other words, the Sant'Agata carmaker placed the electric motor on top of the gearbox, independent of the driveline. It has its own shaft within the transmission, with its own fork and synchronizers. Depending on the drive mode or driving conditions it can connect with the wheels or the V-12 independently.
Allowing the e-motor to connect directly to the wheels, independently of the engine, means the LB744 can maintain its all-wheel-drive even in pure electric mode. Conversely, the e-motor can connect to the V-12 without having to also connect itself to the wheels. That means it can charge the battery using the combustion engine without the car in motion. Then there's the traction control aspect of it all. Here's what Mohr told us:
If for instance the driver pushes the throttle and the engine produces more power than is really possible to transfer to the wheels because it's slippery, because you're already at the traction limit, then you can use the e-motor to recuperate this additional power that the combustion engine provides. In a standard car, you would simply cut [the engine] off. You use this to transfer the energy from the motor [to] the battery. It's a kind of intermediate energy storage.
So instead of cutting spark or using the brakes to apply traction control, Lamborghini has discovered a way to use the electric motor's regenerative capabilities to not only keep the car from ending up in a ditch, but using the extra energy from the V-12 that would otherwise be wasted and put it back into the battery. Genius.
There's a more practical side of allowing the e-motor to spin the transmission independent of the V-12, too. While most manufacturers are putting all their faith in the front wheels when it comes to full-electric mode and reverse, Lamborghini has a different approach.
"We put the capacity to do reverse to the front axle but we were really scared, especially when [the car is] parked downhill," Bizzarri told Road & Track. "It's really not good because the front tires are smaller. So [with this setup] you have the full capability of four-wheel-drive. Also when you reverse, we have this [e-motor] running in reverse."
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