New 2 cylinder range extender engine from Lotus Engineering and Fagor Ederlan Group shows the latest development of the award winning Range Extender Engine and is perfect for small urban and city cars

In a small car where every bit of space and weight is vital, the new Lotus Fagor Ederlan Range Extender occupies substantially less packaging space (44% less) and 16% less weight in the vehicle than the larger three cylinder engine, used in the revolutionary Lotus Evora 414E and the Jaguar Limo Green development vehicles. Almost as importantly, the engine and generator can be laid in any orientation from vertically to horizontally, where it has a height of just 32.7 cm, so the whole package can be located almost anywhere in the vehicle.

But with a small size comes a big and efficient punch. Producing 20 kW of power and 66 Nm of torque, the 0.9 litre 2 cylinder four stroke Lotus Fagor Ederlan Range Extender Engine operates at its most efficient engine speed range of between 1500 and 3500 rpm. However, the engine does not power the wheels directly but generates electricity via a generator to charge batteries which then provides electricity to an electric motor connected to the wheels.

Dany Bahar, Chief Executive of Group Lotus, explains, “Almost without exception, the automotive industry agrees that the future of road transport will include the increased use of range extender hybrid engines. They are the perfect solution for city vehicles which do most of the driving under plug in pure electric mode, so having an occasional use range extender to literally extend the driving range of the vehicle beyond plug in mode is perfect so eliminating range anxiety.”

Demand from Lotus Engineering’s global client base has proven that there is a desire for a smaller and lighter range extender engine which would be more suitable for city and urban vehicles where weight and size are more important than top speed and acceleration.

Mark James, Director of Lotus Engineering, explains the thinking behind the new Range Extender “Ever since we first unveiled the range extender concept to the motor industry at the Frankfurt motorshow, just two years ago, we have been inundated with interest from vehicle manufacturers all over the world, all wanting a cost effective way of delivering a range extender solution. This has been achieved with the collaboration of Fagor Ederlan Group and now we have a production solution and are working closely with several global OEMs to deliver production applications.”

Miguel Mateo, Commercial Director – Range Extender Business Unit for Fagor Ederlan, said, “High technology is not just the concept or the end product, it is also the manufacturing process, which of course is related to how the product is designed in the first place and the Lotus Fagor Ederlan Range Extender is a perfect example of a high tech, elegantly simple design that is efficient and cost effective to manufacture. We have also included the Fagor Automation developed generator and inverter and integrated all of this technology into one whole package, so with Lotus we can deliver this solution to the global automotive industry.”


The Lotus Fagor Ederlan Range Extender in more detail - how it works

A range extender is used on Series Hybrid cars where the vehicle is powered by electric motors. How far the vehicle will travel on pure EV mode depends entirely on the size of the vehicle and the capacity of the batteries that the vehicle carries. However, in a city or urban environment, most vehicles will travel no more than 50 km (30 miles) so the batteries are typically specified to accommodate this distance. Should the driver wish to drive the vehicle further, the super efficient engine will start and power a generator which then supplies electricity to power the electric motor.

Light weight is critical for range extenders and even more so for small city and urban cars, where the engine is not being used all the time. Therefore the new 2-cylinder range extender engine weighs 16% less than the larger three cylinder engine at just 45 kg.

The engine is optimised to generate power at engine speeds between 1500 and 3500 rpm allowing a lightweight simple 2 valve per cylinder engine architecture and eliminating the need for a complex and expensive 4 valve per cylinder design. As well as an Integrated Exhaust Manifold, the Lotus Fagor Ederlan Range Extender engine has an innovative new Integrated Intake Manifold that gives a significant reduction in weight and package size. The generator supplied by Fagor Automation is driven directly off the crankshaft to reduce weight, package size and cost. The engine, generator and power electronics are controlled using a Lotus controller to improve communication and efficient running of the systems. The engine architecture and engine management system are designed to offer flex-fuel capability to allow the engine to run on renewable alcohol fuels.

Lotus Engineering and Fagor Ederlan Group also offer a larger and more powerful 1.3 litre, three cylinder range extender engine with the 50 kW supercharged variant used in the hybrid Evora 414Evolution.

A more powerful 30 kW two cylinder belt driven centrifugal supercharger range extender engine has also been developed by Lotus Engineering, for use where space and weight are more of a premium than unit cost.

The three cylinder supercharged engine uses a belt driven centrifugal supercharger to produce 50 kW peak electrical power at 3500 rpm and weighs just 58 kg. The naturally aspirated variant which produces 35 kW weighs 51 kg.

Lotus Range Extender engines have already been fitted to a number of concept and research vehicles including the Jaguar Limo Green research vehicle, the Proton Emas and Lotus’ own Evora 414E.