More Lotus hybrid details revealed

Lotus used the recent Goodwood Festival of Speed to showcase its sophisticated take on plug-in hybrid (PHEV) technologies in a range-extended electric Evora.

The Evora 414E is one of three Brit-made PHEVs to find partial funding from the UK government’s Technology Strategy Board through the REEVolution (Range Extended Electric Vehicles) project, alongside Jaguar’s XJ_e and Infiniti’s UK-designed EMERG-E. All three put in appearances at Goodwood.

The 414E embodies a fair collection of pointers to the ways in which high-end car-makers might differentiate their electric product both within their own line-ups and from competitors.

The all-British powertrain uses two EVO Electric-sourced motors driving the rear wheels through an Xtrac transmission. They draw power from a 17kWh battery pack that can be charged from a power outlet and/or from Lotus’s purpose-built range extender engine.

Lotus claims the battery pack will give the 414E up to 48km of pure-electric drive. Extended range figures haven’t been released.

The car will be available with several variants of Lotus’s range extender engine. It will come in three- or two-cylinder versions, supercharged or naturally aspirated, with outputs of 50kW, 35kW and 20kW.

It’s part of an unusually diverse configuration, driving an EVO-made electric generator capable of sending energy to either the battery pack or direct to the EVO traction motors. In kickdown, it sends all the spark it can muster, from both battery pack and range extender engine, direct to the motors. To help keep it light and compact and reduce production costs, the generator runs direct off the crankshaft.

The top-spec supercharged 1.3-litre triple is optimised to run between 1500 and 3500rpm, generating up to 50kW. The atmo version produces up to 35kW. Optimising the engine to run between 1500 and 3500rpm has allowed Lotus to keep it light and simple, using two instead of four valves per cylinder. It’s been designed from scratch to run on both petrol and alcohol fuels (methanol and ethanol).

The engine, generator and power electronics are controlled using a Lotus controller to improve communication and efficient running of the systems.

Depending on spec, the system is good for up to 304kW and 1000Nm of torque - enough to shove the 414E to 100km/h in a little over four seconds, then on a top speed of 209km/h. This compares to about 400Nm for the Tesla Roadster Sport and an estimated 880Nm for the Mercedes-Benz SLS AMG E-Cell.

The company has expressed a CO2 emissions target of just 55g/km combined (NEDC) for the top-spec 414E.

Lotus has fitted the car with a paddle-switched seven-speed virtual gearing system designed to emulate the feel of a good dual-clutch auto hitched up to a high-performance petrol engine. It even modulates drive torque to emulate the physical sensations of up- and downshift, with synthesised engine sounds to match.

The company says there’s more to this than playing games. It gives drivers better control over deceleration by simulating engine braking. And, of course, uses the now familiar regenerative technologies to turn excess momentum during deceleration into energy to feed back to the battery pack. But, unlike most such systems, it’s not restricted to a preset, static kinetic energy absorption rate.

More like Audi’s paddle-operated multi-level system, the 414E gives the driver control over regeneration and unbraked deceleration levels by paddling down by one, two or three virtual gears.

And, thanks to the aural simulation systems, it’s all served up with the tactile and visceral sensation of a normal Lotus. It can also be switched off to allow the driver to run the thing in a simple auto mode.

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