|The MAHLE-EVO range extender. Click to enlarge.|
MAHLE has selected EVO Electric Ltd., a developer of electric drive solutions for the automotive sector (earlier post), as a partner for the development of its range extender engine for electric-drive vehicles.
The engine is a “clean sheet” design optimized for cost, weight, NVH, package size and installation flexibility. It is a 900cc, twin-cylinder, 4-stroke gasoline unit with an output of 30 kW at 4,000 rpm. An axial flux generator has been fully integrated within the crankcase to provide a compact modular solution. Fuel consumption of the engine is 240 g/kWh minimum, and it meets Euro 6 emission requirements.
Under the agreement, EVO Electric will be responsible for the design and manufacture of generators based on its advanced Axial Flux technology. MAHLE Powertrain will be responsible for engine design, development and manufacture plus the overall system integration and marketing of the concept to vehicle manufacturers and industry observers.
The engine is currently undergoing further development testing at the MAHLE Powertrain headquarters in Northampton, UK prior to being installed in a test vehicle in the coming months.
The MAHLE range extender was designed to optimize fuel efficiency across a range of driving conditions and to minimize cost, volume, weight, noise, vibration and harshness. The range extender engine has been sized to be suitable for a typical C-segment passenger car.
MAHLE analyzed fleet vehicle drive data, using a drive style analysis toolset it developed, to identify the typical daily usage pattern of such passenger cars. A detailed design study then led to the selection of the 900 cc twin cylinder 4-stroke gasoline engine layout and EVO Electric’s Axial Flux generator.
Unlike radial flux motors with a cylindrical rotor turning within a cylindrical stator, axial flux motors use a disc-like rotor sandwiched between two (or facing one) disc-like stator(s). Advantages to this type of motor design include higher torque density; better cooling due to higher contact area; high efficiency due to lower cooling losses; and better overload capacity.
A key feature of the engine is the oil system that enables the engine to be installed vertically or horizontally for increased package flexibility. The entire system (including generator) weighs 70 kg and has a power output of 30 kW, and is already being presented to the industry, including vehicle manufacturers. (Weight is 50 kg without the generator.)
EVO Electric is working with a number of automotive industry partners to bring its advanced Axial Flux motor/generator technology to market. In addition to the MAHLE collaboration, EVO now has confirmed orders and commitments with a number of customers including: Jaguar Land Rover, Lotus and Nissan Motor (as announced previously); two other global car manufacturers; two global bus and truck manufacturers; and three premium electric vehicle manufacturers.