Peugeot has revealed that its Le Mans hypercar, due to enter competition in 2022, will be powered by a 2.6-liter, twin-turbo, 90° V6, producing 500kW (680bhp) and weighing in at 165kg. This will be coupled to a 200kW (268bhp) MGU.
“The architecture of the Peugeot HYBRID4 500kW powertrain is the result of a highly detailed brief shaped by the new FIA WEC regulations,” explained François Coudrain, Peugeot Sport’s WEC program powertrain director. “We initially considered a single turbo, but that would have prevented us from achieving our engine’s center of gravity target. A twin-turbo V6 block offers the best trade-off between technology, weight, packaging of the engine’s ancillaries, reliability and performance.”
The engine will be coupled to a sequential seven-speed transmission, and the driver will be able to adjust the level of engine braking generated by the electric motor under deceleration and the force applied by the brakes to achieve the optimum blend between electric/hydraulic braking. Optimal energy management, both under acceleration and during energy recovery (capped by the regulations at 200kW), will consequently be key to the car’s performance and efficiency.
The 200kW motor generator unit will drive the front wheels. “It will be equipped with a lightweight, high-efficiency, single-speed transmission and a latest-generation inverter to transfer battery power to the motor,” said Coudrain. “It will have the capacity to instantly use all the energy available in the battery thanks to the powertrain’s energy management system strategies. PSA Motorsport’s experience of the WRC and Formula E will contribute to the development of the software employed to manage the computer and energy systems [braking energy recovery, power under acceleration, anti-lag system, reduced fuel consumption].”
The high-density, high-power, high-voltage battery (900V) is to be developed jointly by Peugeot and Saft, a Total subsidiary. Saft notes that its cell chemistry favors power density over energy, consistent with the needs of endurance racing.
“The main parameter will be to optimize how the energy stored in the battery is used,” explained Kamen Nechev, Saft’s CTO. “To achieve this, you need an extremely short charge time combined with high-capacity storage cells to form a package that enables maximum power to be delivered as rapidly as possible. The most competitive solution resides in the management of charge optimization and the amount of power available in real time.” The batteries will be assembled at Peugeot Sport’s new facility in Versailles-Satory, near Paris.
According to Peugeot, although the internal combustion engine delivers 500kW (680bhp) and the motor generator unit has a capacity of 200kW (268bhp), the regulations set a maximum total power output of just 500kW during races. To adapt to the different situations in competition, the company says the LMH powertrain will function as follows:
• The regulations forbid the use of electrical energy below 120km/h, so the motor generator unit will only engage once this speed has been reached. The car must pull away from standstill under the power of its internal combustion engine alone
• At full power, the power output of the bi-turbo V6 will be capped at 300kW (408bhp) and adjusted as a function of the power delivered by the motor generator unit at 200kW (268bhp), which is directly dependent on the battery level
• When the motor generator unit comes into use, the car will automatically switch to four-wheel drive, thereby modifying its driveability – through high-speed corners, for example
• When the high-density battery is empty, the internal combustion engine reverts to 500kW (680hp) power output and the car returns to rear-wheel drive. During races, the battery will be fully charged prior to the start by means of a mains-connected plug-in hybrid charger. Once out on the track, the battery will function completely independently and be charged only by the kinetic braking energy recovery system
Peugeot notes that the following exceptions are covered by the regulations:
• The power output of the internal combustion engine may be increased by 3% to 515kW (700bhp) at the end of straights when the battery is empty, so the electric motor is working as a 15kW alternator. This configuration is applied automatically by the car’s electronics
• The vehicle may run with either the internal combustion engine or the electric motor, or both concurrently, in the pitlane or when speed is restricted to 60km/h.
Peugeot said it is expecting to bench test early iterations of the powertrain in the first half of 2021.
