EVO Electric and MAHLE partnering on 2-cylinder range extender engine for EVs

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.

Source: Green Car Congress

EVO Electric Ltd. Launches New Generation of High Power Density Axial Flux Motor and Generators

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)., Source: Dr. M. Lampérth. Click to enlarge.

EVO Electric, LTD., a 2007 spin out from Imperial College London, has launched its new generation of Axial Flux motor and generator technology. The new technology offers improved cost, performance and efficiency of hybrid and electric vehicle powertrains; applications include hybrid, plug-in hybrid and all-electric vehicles, range extenders, auxiliary power units (APU) and integrated starter-generator (ISG) systems.

EVO’s latest design has a demonstrated peak power density of 5 kW/kg (2.5 kg/kW nominal). (Weight measurements included all motor/generator components including housing, shaft and resolver.) Representing a 33% increase over the previous generation of EVO motors, the new generation of Axial Flux products offers the highest power density among electric motors currently available for automotive applications, according to the company.

The reported power density puts EVO’s electric machines well above the US Department of Energy’s targets for 2015 and 2020 (1.3 and 1.6 kW/kg, respectively).

EVO has performed extensive reliability, endurance, shock and vibration testing along with road tests to confirm the potential of the new motors. The machines also cost less to manufacture than other permanent-magnet motor/generators, due to their higher power and torque densities (and hence lower material costs) and a simple yet robust machine design optimized for low-cost, high-volume manufacturing.

EVO is now collaborating with automotive industry partners to develop drive systems and other products for a range of vehicle platforms. For example, EVO says it has supplied high-torque machines with peak outputs of 200 kW/660 N·m (100 kW/240 N·m nominal) and weighing only 40kg to a number of hybrid and electric vehicle developers. EVO is also developing larger models for commercial vehicle applications and an ultra-compact motor suitable for light-duty electric vehicle applications.

In 2009, EVO Electric was selected as one of the winners of the UK’s LowCVP Technology Challenge.

EVO Axial Flux motors were also featured in the Lotus Evora 414E Hybrid, a concept vehicle unveiled by Lotus Engineering at the 80^th Geneva International Motor Show. The Lotus vehicle features two EVO drive motors, each providing 152 kW (207 PS, 204 hp) of power and 400 N·m (295 lb-ft) of torque, and a unique 35 kW range extender system featuring EVO’s electric generator technology.

Axial flux motors. 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.

Although the axial flux concept is not new, commercialization has been hampered by materials limitations and design tradeoffs. A number of companies and research organizations are working with axial flux technology currently.

EVO is backed by Imperial Innovations plc, which supports scientist-entrepreneurs in the commercialization of their ideas and has exclusive access to scientific and technological developments coming out of Imperial College London.

Source: Green Car Congress