Toyota-BMW Engine Collaboration Spins Off Sports Cars

TURIN – Confirmation that Toyota is progressing with a sports car being developed in association with BMW is coming these days from both Japan and Germany.

In the past three years, the automakers have made repeated public announcements about their joint technology-development programs for hybrid and fuel-cell propulsion systems. Last year they agreed to look into collaborating on a sports car platform, as well.

The project reportedly has been deemed feasible and two different sports cars are in the pipeline, although both still are far from official unveiling.

BMW first may use the shared platform for the next-generation Z4 roadster, whereas Toyota sources say the shared body-composite structure and production platform will give life to the next-generation Supra coupe developed from the FT-1 (Future Toyota One) at Toyota's Calty design studio in California and first unveiled in January at the North American International Auto Show in Detroit.

Despite rumors in Italy that Pininfarina will produce one of the two sports cars, economy of scale and technology transfer suggest the body structure will be manufactured by BMW in Germany and it would make sense to have the car completed by the Italian coachbuilder dedicated to small production volume.

However, each automaker will make its own decision.

Actual production is expected to launch in early 2017, with pre-launch introduction late in 2016.

BMW reportedly is leading the development of the cars’ chassis, banking on its experience with aluminum, carbon fiber and high-strength steel to create a lighter and stiffer composite body structure, while Toyota is focusing on high-performance hybrid technology and energy storage and recuperation.

BMW is expected to produce the direct-injection, turbocharged 4-cyl. engine in 1.6L or 2.0L versions for both sports cars. They are not intended to compete head-on, as BMW will offer a lighter roadster with pure front-engine and rear-wheel-drive layout and Toyota rolls out an all-wheel-drive, high-performance hybrid employing the superconductor hybrid technology recently showcased in the Yaris Hybrid R hatchback.

The difference is that the new-generation Supra will feature rear-wheel drive from the 4-cyl. internal-combustion engine via a transaxle, plus front-wheel drive from two separate electric motors developed and built in-house by Toyota.

Toyota also would provide its electric motors and hybrid technology for applications in other BMW Group production models. Toyota's electric motors do more than power the wheels; the two motors on the front axle work as electric generators during braking, and supplement the gasoline engine during acceleration.

A third motor, located between the engine and the 6-gear sequential transmission, operates as a generator in two different modes: during deceleration to feed the supercapacitor, and during acceleration to directly power the rear wheels. In doing so the generator works similarly to a traction-control system, redirecting torque as electric energy to the rear wheels, to boost acceleration and improve handling.

Depending on the radius of the curve, the system can send more torque to the outside rear wheel allowing for higher cornering speeds into middle-speed curves; apply more braking force to the inside wheel on fast curves, or even brake and accelerate each wheel independently on slow curves to adjust the yaw effect for a better line, to limit steering angle and understeer.