MAHLE Modular Hybrid Powertrain for Large Passenger Cars and Light Commercial Vehicles

Vehicle manufacturers are experiencing a shift in legislation and customer attitudes towards powertrain technologies. To support the pathway towards net-zero emissions by 2050, technologies that significantly reduce CO₂ emissions will be needed. This will require increasing levels of electrification, and in the areas of compact cars and urban transportation, the adoption of pure battery electric powertrains is expected to become the dominant technology. For large passenger cars and light commercial vehicles (LCVs) meeting all customer requirements, including range, payload, towing capability, and purchase cost with a pure electric vehicle is challenging and requires the use of heavy and expensive battery packs, which have a high embedded CO₂ content.

The study builds on the work previously presented on the MAHLE modular hybrid powertrain (MMHP) concept and examines the suitability of this powertrain configuration to meet the future needs of large passenger cars and LCVs. In the MMHP concept, the full dynamic performance of the vehicle is provided by the electric traction motor, along with the ability to drive in pure-electric mode with a reduced battery capacity (and a reduced range) using the plug-in capability. On long journeys, or when charging is not available, drive can be supplemented, and battery state-of-charge maintained, through use of a compact, highly efficient dedicated hybrid engine.

The paper also presents the latest test results from our 3-cylinder dedicated hybrid engine, running on both conventional 95 RON gasoline and alternative sustainable low-carbon fuels. The engine concept features a combination of the pre-chamber-based combustion layout, high geometric compression ratio, cooled exhaust gas recirculation (EGR) and aggressive Miller-cycle operation, to enable high brake thermal efficiency levels to be achieved. Finally, drive-cycle analysis, based on engine test results, will also be used to show the efficiency of the entire powertrain system in these applications, based on the different fuels used.