The inaugural season for the brand new hybrid technology of the British Traveling Automotive Championship (BTCC) got here to an finish on October ninth, 2022, marking the first-ever hybrid traveling automotive championship international to finish a season. BTCC’s hybrid machine is spec one advanced via Cambridge, UK, primarily based Cosworth.
The principle goal for the hybrid pressure was once 15 seconds of deployment according to lap when the machine was once to be had to a given motive force. This translated to that automotive gaining 15m inside the ones 15 seconds, assuming a nook go out pace of 100km/h. The setting up frame, TOCA, didn’t need it to behave like a DRS, simplest being deployed in some areas of the circuit and simplest rewarding chasing drivers, because it believes this overtaking is just too fabricated. As an alternative, it sought after a push-to-pass machine that drivers may just use on the go out of a nook to check out and produce them along fighters within the subsequent nook. Then again, the driving force in entrance would additionally be capable to push to shield that place, preserving racing shut.
The motor, the inverter and the ancillaries had to be basically off-the-shelf parts for price causes. The one section that sits out of doors of that’s the battery, which has been designed uniquely for BTCC via Delta-Cosworth. As a result of this can be a hybrid machine, and it isn’t the main motive force for the automobile, top potency isn’t the primary motive force. For the specification, BTCC wanted a machine that might ship the obligation at the lap the driving force calls for and push power again to the battery to recuperate a portion of that.
The Cosworth hybrid package deal is in response to TOCA’s requirement for low voltage (sub 60V) and is designed to interchange the BTCC’s luck ballast idea, permitting it to be a racing instrument slightly than only a advertising gimmick. Anything else under 60V is classified as low voltage, and the hybrid machine’s top voltage is round 56.5-57V from the battery. The operating vary is between 43 and 57V, with a nominal reasonable of about 51V.
The motor is an Emrax 188 – an axial flux, exterior everlasting magnet rotor unit. When it comes to keep an eye on, 3 stages have been deemed enough for the BTCC software on price grounds. The motor weighs simply 7.3kg and produces 30kW of constant energy and 50Nm of constant torque with a top of 90Nm. It’s slightly small, too, being 188mm in diameter and 77mm deep. The axial flux structure was once selected for pace matching along the interior combustion engine because the motor is fastened parallel to the gearbox and pushed off its enter shaft. As such, it needed to be rpm matched to the engine and makes use of what’s referred to as P2 hybrid structure, a extremely versatile approach of facilitating parallel hybridisation.
Cosworth made up our minds to construct the BTCC hybrid unit in a P2 off-axis pressure module configuration at a 1:1 ratio, which sees the electrical motor parallel to the crankshaft axis for a extra compact axial package deal. This minimises the adjustments vital to put in force it with the prevailing ICE and transmission. The design provides compatibility with the collection’ racing transmission and addresses the tight packaging necessities of the BTCC drivetrain.
The continual energy determine of 30kW is accomplished maximum successfully at 6500rpm, however it might run as much as 8000rpm for a couple of seconds, although some magnetic box weakening. Being direct pressure with the ICE, the electrical pressure will spin at engine rpm, which, for 95 according to cent of a BTCC automotive’s on-track existence, is between 4000 and 7000rpm. Below deployment, the machine adheres to a present prohibit of 650 amps. It most often runs round 25kW output, which equates to about 35Nm of torque thru that pace vary. The motor controller is a Sevcon unit provided via Voltsport, which does the calibration. It achieves 96 according to cent potency.
The Sevcon unit controls the motor without delay and is, in flip, managed via the Cosworth Antares 8 automobile keep an eye on unit [VCU], which runs all programs onboard the automobile. The Antares 8 VCU controls the entire torque call for to and from the hybrid machine and manages the switching accordingly. The switchgear throughout the Sevcon unit is understated however efficient MOSFET era, with a switching frequency of 12kHz, specified in response to the BTCC accountability cycle.