Lotus Evora development project sees a 1.2-litre engine twinned with two electric motors creating impressive, silent performance

What is it?

This is Lotus’s experimental 414E, an Evora-based serial hybrid which was also the basis for the recent Infiniti Emerg-E concept car. The 414E project has been funded by the UK taxpayer, via a share of the government’s Technology Strategy Board REEV project, which totalled £19m between all the parties involved.

The TSB supplies funding for projects that will help build the UK’s automotive supply base through the development of vital new technologies. With the full and partial electrification of the car very much part of the future, the TSB is particularly interested in building the UK’s expertise in electric vehicles.

Lotus had a number of partners for the development of the technology that makes up the 414E including Nissan (Infiniti’s parent company) Xtrac, Evo Electric and Jaguar Land Rover. JLR, however, shifted direction during the project and decided to abandon the range-extending ‘Limo Green’ project and build a conventional parallel hybrid - the recently shown XJ-e concept - instead. 

Lotus says that the project also helped it bring small component manufacturers - such as those involved with battery manufacturing - up to speed on what is required to become a ‘Tier 1’ supplier, the type of company that supplies global car manufacturers directly. 

Fitting a ‘range-extender’ electric drivetrain into the Evora was the project that was used as the basis for building this knowledge base. Lotus says the 414E spurred it on to help develop sophisticated Synchronous Axial flux Drive Motors with integral inverters, massively improved accuracy of the motor’s torque output (from errors of 25 per cent to just 2 per cent) and new cut-off safety systems for use in an accident. 

Lotus has also used the project to develop sophisticated software control systems for hybrid drivetrains and even a virtual development programme that allows it to drive virtual test cars around a virtual Hethel test track.

There are two sources of power in the 414E. A new 15kWh battery pack which weighs 250kg and is fitted into the space normally occupied by the Evora’s rear seats. Lotus is claiming a range of 30 miles on a full charge and the ability for the battery to deliver a serious slug of power when the driver demands it.

The engine/generator is the latest version of Lotus’s bespoke 1.2-litre, three-cylinder, petrol unit. It is built around a single aluminium block, with the cylinder head, exhaust manifold integrated into one unit.

Good for 47bhp, when in charging mode it runs between 1500 and 3500rpm and can consume methanol, ethanol or petrol. The generator is mounted directly on the crankshaft. This engine is used to supply charge directly to the wheel motors either when the battery has dropped to a 30 per cent charge (at which point it stops driving the wheels) or when the driver is demanding full-bore acceleration. The motors drive the wheels through a single speed transmission.

Despite the 414E gaining 377kg over the 1382kg showroom Evora, the 4.4 second 0-62mph sprint and impressive (especially for a car driven by electric motors) top speed of 133mph is a function, say Lotus, of the new battery and motor design.

What's it like?

From the outside, the 414E is hardly different from the petrol-driven original. The interior has also hardly changed, with the push-button autobox interface on the centre console used to control the drivetrain. Lotus has also engineered a useful locking ‘Park’ mode for the single-speed transmission.

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The 414E pulls away very strongly in EV mode, the twin motors delivering a sense of deep-down muscle as well as being impressively linear in their delivery of forward motion. And with the heavy battery placed right in the centre of the car, the Evora’s trademark poise, delicacy and balance is hardly troubled. Press on and the range-extender kicks in to feed extra juice to the motors.

Lotus admits it has done virtually no work on silencing the engine, though it is well insulated from the car’s structure. Even at this early stage of development, the engine/generator is capable of kicking in for as little as a couple of seconds as well as more extended interventions.

While the sense of effortless electric thrust on the sodden Hethel track was quite addictive, I can quite see why this drivetrain might be seen as unsuitable for a Lotus. With no gear changing, a seamless stream of torque and, often, no engine noise this can hardly be called a engaging enthusiast’s car. But as far as pure serial hybrid drivetrains go, however, once the range-extender is silenced it could well be the best.

Should I buy one?

You can’t and you’re highly unlikely to be able to buy one in the future. Even if the 414E’s Infiniti sister car was commissioned, for example, the Lotus range-extender motor is not due to enter series production for another two years.

However, the 414E’s task as a research and development special will continue for at least another 12 months. Lotus engineers say that they are working on fitting it with the Halo Sonic system which generates exterior noise to alert pedestrians and interior noise - possibly even synthesised petrol engine sounds - for the interior.

The company is also working on building an artificial gearshift system for the electric drivetrain, which uses paddle shifters to allow the driver to experience ‘gear shifts’ and the sensation of the hitting the torque limits of a conventional internal combustion engine.

Operating the paddles will introduce small torque interruptions to the delivery of the electric motor and even imitate the way torque delivery drops on most combustion engines as the redline is approached.

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Lotus Evora 414E Hybrid

Price n/a; 0-62mph 4.4sec; Top speed 133mph; Economy 30 miles battery, 270 miles generator; CO2 55g/km; Kerbweight 1759kg; Engine type three-cylinder, 1198cc petrol/generator. Installation rear mid, transverse; Electric motors driving each rear wheel. Power Range Extender 47bhp @ 1500-3500rpm; Electric motors, 201bhp and 367lb ft each. Gearbox single speed


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IAD 2 October 2012

'sophisticated Synchronous

'sophisticated Synchronous Axial flux Drive Motors with integral inverters'  I'm wondering if you hit 88mph would it send you back to the future?

Harry P 2 October 2012

Step in the right direction

Surely this is an important development vehicle for the British car industry. No car with batteries is going to be light, even if it is a Lotus?  I agree with TegTypeR’s comments about artificial internal noises etc.   Range extenders are the only really viable solution for battery powered cars outside of city only use.  But is this car not just an attempt to catch up with GM with their Ampera/ Volt  which is already available?  


Broughster 2 October 2012

Agree with Teg

I so agree with Teg's post. You are going to get all the advantages of extremely refined speed and so then you start trying to engineer those advantages out? What a nonsense...

EV's and hybrids are best when they play by their own rules rather than being forced to follow outdated convention.