Lotus Engineering is unveiling the ‘EVE Hybrid’ (Efficient, Viable, Environmental) technology demonstrator at the 77th Geneva International Motor Show. Developed for, and in close R & D engineering cooperation with its shareholder Malaysian automaker Proton Holdings Bhd, it showcases how OEMs can introduce lower-emissions variants to existing model ranges that currently only offer conventional gasoline and diesel powertrains.
Lotus Engineering believes the application of hybrid technology is a key route for CO2 emissions reduction and that for the next five years it may remain more viable to integrate hybrid technologies into existing model ranges than to develop expensive new dedicated hybrid platforms.
The EVE Hybrid program is focused on establishing the processes for integrating hybrid technology with minimal development time and cost, overcoming many of the challenges associated with integrating hybrid technology into existing platforms through intelligent, compact and discreet packaging of additional systems.
The research and development program was undertaken by a cross-functional team of Lotus and Proton engineers working together at Lotus Engineering’s Hethel headquarters and Shah Alam, Kuala Lumpur. The resulting EVE Hybrid demonstrator, based on a Proton Gen.2 compact midsize car with a 1.6-liter gasoline engine, showcases a trio of production-representative technologies:
Micro-hybrid start-stop system. A starter-alternator system was integrated that switches the engine off when the vehicle stops. The engine restarts automatically when the brake pedal is released. As a result, noise, emissions and fuel consumption are reduced. The unit runs on the standard vehicle 12 volt electrical system and combines both starter motor and alternator functionality. The start-stop system delivers fuel savings of 5% with a 5% reduction in CO2 emissions.
Full parallel hybrid drive. A bespoke 30 kW, 144V motor is packaged between the engine and transmission. It delivers electric drive or regenerative braking via an additional clutch linking the motor to the drivetrain. The motor provides the same start-stop functionality as the micro-hybrid with the additional benefit of electrical drive or drive assist, either boosting the drivetrain performance or providing economy and emissions benefits by operating as an electric vehicle. The motor is powered by a 144 volt battery located in the trunk.
Lotus worked with specialist suppliers ElektroMagnetix and Turbopower Systems on the motor/generator and power electronics. Both are water-cooled and include an auxiliary power unit to support the vehicle’s 12 volt systems.
An additional clutch supplied by AP Racing is packaged inside the motor and connects the IC engine to the traction motor. This enables the engine to be switched off for electric drive only use.
Testing has confirmed simulation predictions of 28% fuel efficiency improvement and 22% CO2 emissions reduction.
Continuously Variable Transmission. The integration of a Punch CVT gives benefits in fuel consumption and emissions control. In addition, its compact package assisted in the application of a hybrid electric drive and it provides smooth acceleration and low transmission noise.
Lotus made various changes to the baseline Proton gasoline 1,597cc CamPro engine. The main modification is the redesign of the front end accessory drive (FEAD) to accommodate a Valeo ‘StARS’ starter/alternator, which drives the micro hybrid start-stop system.
The redesigned FEAD also accommodates a Sanden hybrid Heating Ventilation and Air Conditioning (HVAC) compressor that operates by conventional belt drive and has an additional electrically driven capability which enables continued air conditioning operation when the engine is stopped.
The engineers replaced the belt-driven Power Assisted Steering (PAS) and water pumps with electric units to enable the investigation into the economy benefits of such units. To accommodate the additional hybrid functionalities , Lotus Engineering upgraded the Engine Management System (EMS) to a Siemens VDO torque-based unit and re-calibrated it.
The EVE Hybrid uses a Cobasys Series 1000, NiMH, 30kW 144V module that incorporates an integrated cooling system. This traction battery pack is securely mounted on the trunk floor, displacing approximately 47 liters of luggage space.
|Performance of Different EVE Configurations|
|Micro hybrid||Full hybrid||CVT|
|MPG (NEDC)||39.2||41 (+5%)||50.2 (+26%)||41 (+5%)|
|Max. torque (Nm)||148 @4,000rpm||148 @4,000rpm||233 (180 continuous)
|Power||82 kW (110 hp)||82 kW (110 hp)||105 kW (141 hp)||82 kW (110 hp)|
|0-62 mph (seconds)||12.6||12.6||9||12.6|
|Top speed (mph)||118||118||118||118|
|CO2 (g/km)||172||164 (-5%)||134 (-22%)||164 (-5%)|