Rolls-Royce partner Yuchai launches flywheel range extender, boasts 4.8 kWh/L efficiency
Yuchai Group, a Guangxi state-owned powertrain manufacturer with a joint venture with Rolls-Royce Power Systems and long-standing supply relationships with automakers including Dongfeng and BAIC, announced the launch of its Flywheel Range Extender System at its 2026 Global Partner Conference on January 24, as reported by IT-home.
The company described the system as the world’s first flywheel-based range-extender technology brand and stated that it achieves a peak power generation efficiency of more than 4.8 kWh per liter. The announcement represents a technology branding update in China’s commercial vehicle and non-road powertrain sector.
Formally known as Guangxi Yuchai Machinery Group, Yuchai is not a vehicle manufacturer and does not produce complete vehicles. The company operates as an independent engine and power system supplier under state ownership by the regional state assets authorities in Guangxi. Yuchai maintains a joint venture with Rolls-Royce Power Systems under the MTU Yuchai Power entity and supplies engines and power systems to multiple domestic vehicle manufacturers, including Dongfeng and BAIC, primarily in commercial vehicle applications.
According to Yuchai, the Flywheel Range Extender System departs from the industry-standard architecture that combines an internal combustion engine with a separate generator motor. The system integrates the flywheel rigidly and coaxially with the engine crankshaft, forming a single physical structure in which the power source and power generation components are structurally unified. Yuchai stated that the configuration is paired with intelligent coupling control algorithms and adaptive energy management strategies for different operating conditions.
Yuchai stated that the integrated structure reduces the number of connecting components and increases electromechanical integration. The company said the simplified layout improves system reliability and enables the core power unit to operate without scheduled maintenance throughout its service life, according to disclosures made at the conference.
In terms of efficiency, Yuchai stated that the engine’s high-efficiency operating range fully overlaps with the generator’s high-efficiency operating range. For diesel applications, the company claimed the system achieves a maximum power generation efficiency of 4.8 kWh per liter and a maximum comprehensive fuel savings rate of up to 50 percent compared with conventional range-extender solutions.
Yuchai stated that the Flywheel Range Extender System has been deployed across commercial vehicle and non-road equipment applications, with output coverage ranging from 15 kW to 600 kW. Applications cited by the company include long-haul logistics trucks, urban buses, mining transport vehicles, port machinery, and large agricultural equipment.
At the conference, Yuchai introduced a full product matrix based on the FRS platform, including models such as YCS04, YCK08N, and YCK16. The company stated that these systems have been adopted by manufacturers, including FAW Jiefang, Dongfeng, XCMG, Sany, and Caterpillar.
The Flywheel Range Extender System will continue deployment across commercial and industrial vehicle segments following its January 2026 unveiling.
