The British Touring Car Championship welcomed a newcomer to the Silverstone round of the 2021 BTCC championship with the race weekend debut of the new 2022 Cosworth BTCC Hybrid.
Cosworth Electronics Head of Support, Neal Bateman, says, ‘We have been working tirelessly to prepare the all-new BTCC Hybrid car ahead of its competitive debut in 2022, and the Silverstone weekend was an important milestone in its development.’ Cosworth’s hybrid package has completed multiple private test days onboard the Toyota Corolla test car, accumulating the equivalent of more than an entire season’s worth of mileage. However, it still needed to collect essential data from an actual race weekend, hence the hybrid car taking part at Silverstone.
The entire hybrid system is in one unit. The battery management, motor control strategies, cooling, and control surrounding the internal combustion engine are managed by Cosworth’s Antares 8 ECU. This arrangement allowed Cosworth to cut crucial weight and free up additional space for the packaging of other components.
The battery pack sits in a unique safety cell located where the existing success ballast box sits, enabling easy accessibility and keeping the weight within an already defined area. Another apt solution was incorporating the electric motor into the gearbox. Considering that the gearboxes are a spec part across the grid, it made sense to integrate the motor in this way. Cosworth went down this route to satisfy the requirement of the cars needing to run on electric power only while in the pits.
The hybrid drive unit is a very susceptible component that delivers high loads and suffers from gearbox heat-soak. Cosworth overcame some of the packaging challenges by utilising a remote cooling system, separating the cooling into two small radiators, one for the battery whilst the other supports the motor and its control unit. Thus, Cosworth mounted the coolers below the headlights and behind the front bumper. This move provided the scope to maximise the limited space left in areas of freestream airflow, a priority when it comes to efficient cooling of any component. The combination of the cooling package and control capabilities allow precise and accurate management of the motor’s temperature.
Cosworth’s hybrid element performed encouragingly during the shakedown, two practice sessions, qualifying and the three races over the weekend. Working in combination with the M-Sport engine through a spec Xtrac gearbox, the hybrid system gives the drivers up to 15 seconds of additional electric energy per lap in a push-to-attack-or-defend configuration. The system also solely powers the car in the pitlane for the start of each session and regenerates electrical energy during braking.
Cosworth managed to run through all the programmes that typically occur during a race event during the weekend. It also got the chance to run the car in traffic, following other vehicles close, providing an understanding of the temperatures on hybrid components, including the motor and battery in traffic. It was also essential to get a sense of how the coolers of these components coped in hot turbulent air.
‘We are very pleased to have been able to run the Hybrid car in proper race conditions,’ says Bateman. We’ve been able to manage the battery and systems in between sessions too. It was great to have the car running in traffic during race two, to get proper temperature into the hybrid element in the draft of other cars. Despite the focus not being on performance, we built up some speed throughout the weekend and showed some real pace. It’s been a positive step for us; we’ve learnt a lot from this race weekend, and we are looking forward to the remainder of our testing programme.’
TOCA Hybrid Test Driver, Andrew Jordan, added ‘We found pace throughout the weekend getting up to the top two or three in terms of lap time. We got some good fast laps in during race one and the fastest lap during race two. We’re very close to the front now regarding pace, so it’s been a good test. Everything has run smoothly this weekend, which is good. It’s a big change for the teams next year, so to be able to show strong reliability stands the system in good stead for next year.’