Lotus Range Extender Becoming More Real

The Lotus Range Extender Engine is moving from concept to production. If it sells, it will provide manufacturers a much faster method of moving into the Extended-Range Electric Vehicle (E-REV) market. That means they can move to lower emissions and higher fuel efficiency for less money than developing their own system (like GM and the Chevy Volt).

Lotus Engineering and Fagor Ederlan completed a joint technical and market study analysing the best route to production. The study ended with an agreement to develop the engine for series production for sale by Fagor Ederlan.

The 3-cylinder range extender was debuted in the 414E Hybrid and PROTON Emas concept vehicles at the Geneva Motor Show.

Lotus Range Extender Engine

Lotus Engineering is bringing an all new engine to the Frankfurt Auto Show. The new engine was specifically designed to be used in an extended range electric vehicle (E-REV).

You can think of E-REV as a plug-in electric vehicle with a built in gas motor used not to move the car, but to recharge the battery when it gets low. This extends the range the electric vehicle can go on one charge.

The Chevy Volt, for instance, will be able to travel 40 miles on all electric power after being plugged in (overnight). Once the battery gets low, the gas engine will kick in to keep the battery charged until you can plug the vehicle in once again.

The Lotus Range Extender engine is a three cylinder 1.2 litre capable of producing 15 kW of electrical power at 1,500 rpm and 35 kW at 3,500 rpm via the integrated electrical generator. The aluminium monoblock construction, integrates the cylinder block, cylinder head and exhaust manifold in one casting. This results in reduced engine mass (56 kg), assembly costs, package size and improved emissions and engine durability.

The engine uses a two-valve port-fuel injection combustion system which reduces cost and mass. It can also be used with alcohol based fuels.

The Lotus Range Extender engine reduces cost in design and mass, allowing for the inclusion of the large (and heavy!) battery packs necessary in an E-REV. Lotus expects the engine offers a fast route to market for original equipment manufacturers wanting to source a dedicated range extender for series hybrid vehicles.


Technical details:
Technical specification of the Lotus Range Extender engine

General - 1.2 litre 3-cylinder with 2 valves per cylinder, SOHC
Belt driven
Construction - Monoblock with Integrated Exhaust Manifold
All aluminium
Balance shaft (optional)
Direct-coupled generator
Bore and Stroke - 75.0 mm x 90.0 mm
Compression ratio - 10:1
Maximum power - 35 kW (47 bhp) at 3500 rpm via integrated electrical generator
Peak torque - 107 Nm at 2500 rpm
Maximum BMEP - 11.2 bar
Maximum Engine Speed - 3500 rpm
Fuel System - Port fuel injection, Lotus EMS
Fuel - 95 RON ULG / ethanol / methanol
Dry weight - 56 kg

Key features of the Range Extender engine in detail:
Monoblock
The Range Extender features a novel engine architecture incorporating a monoblock construction that blends the cylinder head and block together eliminating the need for a cylinder head gasket, improving durability and reducing weight. Approximately 17 parts are eliminated using this approach and the water jacket is better optimised.

Integrated Exhaust Manifold
Lotus Engineering designed and developed a new advanced cylinder head design featuring an integrated exhaust manifold. The production-ready technology can significantly reduce manufacturing costs, emissions and weight. An integrated exhaust manifold has potential to:
o Reduce parts count: 18 fewer components resulting in lower inventory, production, logistics and aftermarket costs
o Weight reduction: total system mass reduction resulting from elimination of separate exhaust manifold
Improved engine durability


Generator
Attached to the engine via the crankshaft, the generator sustains vehicle operation beyond the range provided by the batteries.

Additional Benefits
The Lotus Range Extender engine generates a reduction in emissions through faster light-off of the close-coupled catalytic converter with a reduction in heat loss between the exhaust port and catalyst inlet. Engine operating range is optimised to deliver more efficient running, which also aids underhood thermal management.

Utilisation of the monoblock construction results in an assembly cost reduction, while there is also a reduced catalyst loading requirement because less heat is lost on engine start-up between the exhaust port and catalyst inlet.

Increased vehicle integration flexibility is achieved because of the reduction in mass and the reduced package size leads to reduced space requirements. Particular emphasis has also been placed on the coupling of the generator and NVH signature.

Lotus Safe and Sound Hybrid Technology

The blind have a serious problem when it comes to hybrid cars. Since the gas engine shuts off when the hybrid car slows down or is stopped, there is no sound to warn them a hybrid car is there or is moving towards them. This has them so worried, they have petitioned the federal government and the individual state governments to pass an ordinance requiring vehicles to make a minimum amount of sound.



Lotus has introduced a new system to do just that. The nice part of the system is, while the gas engine is off, the sound system replicates the sound. But, if the gas engine kicks in, the sound system shuts itself off.



Lotus has a demonstration video.





Press Release Follows:



Lotus introduces 'Safe & Sound' Hybrid



Lotus Engineering, the world renowned automotive consultancy division of Lotus, has developed technologies to synthesise external sound on electric and hybrid vehicles to counteract the growing concern these 'quiet' vehicles pose to pedestrians and cyclists. A simulation of a real engine sound is used on the 'Safe & Sound' Hybrid technology demonstrator vehicle, making it instantly recognisable that the vehicle is in motion.



Electric and hybrid vehicles, a favourite choice of the environmentally conscientious have recently come in for criticism from blind and partially sighted people. Due to the almost silent operation of hybrid vehicles at slower speed when running on electric power, the independent travel of the blind and partially sighted may be put at risk as they cannot hear these quiet vehicles as they approach, making crossing a road or walking through a car park hazardous.



The Lotus 'Safe & Sound' Hybrid technology demonstrator uses a standard Toyota Prius, one of the highest volume and most advanced hybrid vehicles to demonstrate the sound synthesis application and compensate for the lack of engine noise emitted by the vehicle when running on an electric motor. What has resulted is the same environmentally conscious hybrid vehicle, without the potential risk to pedestrians and cyclists.



The solution that Lotus has devised is a novel reapplication and development of its Sound Synthesis technology. This is a part of the Lotus suite of patented active noise technologies which comprise three main systems, Active Road Noise Cancellation, Engine Order Cancellation and Sound Synthesis.



To synthesise the engine sound, a road speed signal is taken from the vehicle and a waterproof loudspeaker system is positioned adjacent to the radiator allowing the sound to emanate from the front of the vehicle. Once the vehicle has passed, the sound is not heard. When the car is operating on the electric motor only, throttle and speed dependent synthesised sound projects a realistic engine sound in front of the vehicle. The technology was designed around the behaviour of a conventional engine, using an existing engine sound which makes it instantly recognisable with the pitch and frequency helping to identify vehicle distance and speed. If the hybrid's engine starts operating, at higher speeds or throttle demands or lower battery levels, the control system automatically stops the external synthesis. When the powertrain control system switches the car back to running on the electric motor only, the synthesis controller instantaneously sets the system running again. It is all completely automatic and the driver hears almost none of the additional sound.



In order to generate the engine sound, recordings of a suitable donor engine were made and analysed to establish the characteristic frequencies at different engine speeds. These frequencies are then entered into the synthesis controller in the form of a 'voice' which outputs the sound through an amplifier and out through the loudspeakers.