[2024 Green Mobility] 'The Most Electric-Like Hybrid' Renault XM3 E-Tech

Renault Korea Awarded Smart Green Prize
Freely Switching Between Motor and Engine

Renault Korea has introduced a 'multi-mode gearbox' in the XM3 E-Tech Hybrid vehicle to maximize power efficiency.

On the 25th, Renault Korea received the Smart Green Award at the 2024 Korea Green Mobility Awards for this achievement. The XM3 E-Tech Hybrid vehicle, which claims to be the 'hybrid closest to an electric vehicle,' is equipped with a dual motor system consisting of a drive electric motor (36kW/205Nm) and an HSG auxiliary motor (15kW/50Nm) that also functions as a generator, combined with a 1.6 gasoline engine. It is explained that the clutchless multi-mode gearbox coordinates these two motors and the engine to deliver balanced high energy efficiency and driving performance.

The multi-mode gearbox, developed with technology from the Renault F1 team, is a transmission dedicated to E-Tech. It uses a combination of 4-speed engine transmission and 2-speed electric motor transmission, allowing for a much wider variety of gear combinations through the 2-speed electric motor. Since starting and launching are always done in electric vehicle mode, it offers the fast responsiveness and reaction characteristic of electric vehicle (EV) driving.

When the multi-mode gearbox shifts, the HSG auxiliary motor intervenes. The HSG auxiliary motor controls the engine's rpm to match the rotational speed difference before and after shifting. This enables smooth and quick gear changes while suppressing noise and shock. The multi-mode gearbox, which connects the engine, two electric motors, and the drive shaft according to each situation, weighs less than 50kg.

Through this, the XM3 E-Tech Hybrid always starts in EV mode using the high-voltage battery at initial launch. It starts with the 36kW drive electric motor, accelerating smoothly and comfortably. When low-speed EV driving continues, the engine does not participate in driving but only charges the battery, operating in a series hybrid mode that extends EV driving. When more power is needed, such as on uphill roads, the gasoline engine also delivers power in parallel hybrid mode. Conversely, on downhill slopes, active regenerative braking quickly charges the high-voltage battery. When battery charging is needed during driving, the engine can simultaneously deliver power and charge the battery while maintaining electric motor drive in a series-parallel hybrid driving mode.