Mercedes-Benz details new engine developed with Geely

29 May 2025

At the 2025 Vienna Motor Symposium, Mercedes-Benz detailed their new MGE engine, the latest member of the Mercedes-Benz FAME (Family of Modular Engines), developed in collaboration with Geely Holding [6445]. During development, Geely founded Aurobay (a division of Horse Powertrain), which then became the engineering partner for the cooperation. Mercedes-Benz is responsible for design and development while Aurobay oversees the supplier network and the manufacturing of the engine. Mercedes-Benz refers to the engine as M 252.

The 1.5 L four-cylinder gasoline engine, designed for transverse applications, has a peak power output of 140 kW, a maximum torque of 300 Nm and a peak BTE of 39.4%. The engine is equipped with a highly efficient combustion system with 12:1 compression ratio, Miller intake valve timing and λ=1 operation over the operating range. It also features NANOSLIDE® technology, a fully variable oil pump, six-jet multi-hole injectors and a split lubrication circuit.

In split lubrication, the oil circuit is divided into two permanently applied pressure levels using a hydraulic valve with low or high oil pressure supplied to components as needed. For example, the camshaft adjusters are supplied with high oil pressure to ensure high adjustment speeds under all operating conditions.

The exhaust gas turbocharger of the M 252 features a double scroll turbine (DST) with a scroll connection valve (SCV) driven by an electrical actuator. Pulse turbocharging is present with a closed SCV while backpressure is minimized when the SCV is open and enables an engine efficiency at peak power of around 35%. To reduce boost-air temperature and increase charge-air cooling efficiency, the compressor housing features high-temperature water cooling.

Manufacturing will take place at Aurobay’s Yiwu plant and at the Mercedes-Benz joint venture partner Beijing Benz Automotive in Beijing. The engine is designed for global applications. Mercedes-Benz will launch the M 252 engine in a 48 V powertrain application in the new CLA, as the HEV variant of the new MMA (Mercedes Modular Architecture) platform and will be capable of electric drive. Aurobay will utilize the engine in a high-voltage PHEV concept in its new Lynk & Co 900 model of the newly upgraded SPA EVO architecture.

As much as 85% of the parts are shared by both companies, with only 15% adapted to vehicle-specific requirements. For their individual vehicle applications, each partner will use its own control strategy, emissions aftertreatment system and air intake components. Due to differences in vehicle architecture, the engine mounting angle is company-specific: Mercedes-Benz will mount the engine at 0˚, while Aurobay will mount it at up to 16˚ requiring oil pans tailored for the different applications. The engine will be started by the electric motors integrated into the transmissions, allowing the omission of a 12 V starter and improving engine start characteristics.

Source: Mercedes-Benz