Mahle GmbH, Stuttgart, Germany, has developed a new, fully integrated and modular plug-in hybrid drive that can reportedly be tailored to suit a wide range of vehicle applications. The Mahle Modular Hybrid Powertrain (MMHP) is said to incorporate a highly efficient two- or three-cylinder, turbocharged gasoline engine featuring the company’s latest technologies.
In comparison with established hybrid technologies, it is said to be more cost-efficient, more compact and lighter. The performance of the electric powertrain used in MMHP reportedly reduces the requirements for the combustion engine, enabling the development of a cost-optimised ‘Dedicated Hybrid Engine (DHE).’
This engine concept was designed exclusively for hybrid applications and is said to benefit from the use of the passive Mahle Jet Ignition (MJI®) system, consisting of a small prechamber housing a conventional spark plug fitted within the engine’s combustion chamber.
The ignition system generates hot radical jets, which create a very short combustion event within the engine’s cylinder, thus enabling a high compression ratio and a high exhaust gas recirculation rate, leading to reduced fuel consumption. The use of port fuel injection (PFI), a single overhead camshaft (SOHC) without variable valve timing control, and simple two-valve per cylinder technology are said to minimise costs.
Dr Martin Berger, Director at Mahle Powertrain, Mahle’s Engineering Services business area, stated, “In order to avoid penalties, vehicle manufacturers must comply with the EU’s legislative target of fleet average CO2 emissions of 59.4 g/km by 2030. Electrification is leading the way as the industry’s chosen technology to achieve this.”
“The advancement of hybrid technology is crucial for the industry as a whole to achieve future emissions targets,” he continued. “As a result of the focus on reduced emissions and strict schedules, new vehicle and technology development must occur within a much tighter timeframe. The Mahle Modular Hybrid Powertrain (MMHP) offers vehicle manufacturers a low-cost and quick, off-the-shelf solution, easing the process.’’
The dual-mode hybrid arrangement was selected for the MMHP as it is said to combine the best features of both series and parallel hybrid architectures, allowing flexible vehicle operation while providing optimal NVH behavior. When battery SOC is high, the vehicle can operate as a pure EV, whereas when SOC is low and at slow driving speeds it can switch to series hybrid mode. At higher vehicle speeds, however, the combustion engine can be connected directly to the wheels in a parallel hybrid arrangement.
Due to the incorporation of a gearbox with customisable transmission ratios, the engine can run flexibly at any given vehicle speed. Options for one-, two-, and four-speed transmissions are available, depending on application requirements. The motor can also be designed with different power/torque outputs. When combined with optimised battery sizing, this is expected to allow full scalability of the hybrid powertrain for the majority of applications.
“The modular hybrid powertrain from Mahle features the perfect combination of efficiency, performance, and range without jeopardising driving pleasure,” added Berger. “The powertrain’s compact size can also help comply with design-related packaging constraints, while the relatively low weight enhances efficiency and performance.”