Lotus Unveils 'Range Extender'

It's rare that a three-cylnder 1.2-litre motor gets our juices flowing here at PH Towers, but Lotus Engineering's new 'Range Extender' engine is more interesting than most.

Have no fear, sports fans, as the Range Extender is unlikely to find its way into a Lotus-badged product any time soon - Lotus Engineering's primary focus is to develop technology for other manufacturers to use.

It's been designed as an off-the-shelf engine for any production series hybrid, and could be sold to any number of car companies. Okay, so that's not particularly exciting in itself, but it's surely a rather nice potential money spinner for Lotus - and that means more development cash for proper sports cars.

The Lotus Range Extender could even find its way into a Jaguar, as it's been developed with Jaguar as part of the UK Technology Strategy Board's 'Limo-Green' scheme, a project funded by Lotus Engineering, MIRA, Caparo and Jaguar. If the new engine does end up in a series production Jag, it could be part of the company's project to make an executive saloon with a CO2 output of less than 120g/km.

What's really clever about the new engine, says Lotus, is its design: the cylinder head, block and exhaust manifold are all integrated into one casting, creating what the boffins at Hethel call a 'monoblock'. This eliminates the need for a cylinder head gasket and around 17 other separate parts. The weight of the unit is also reduced, while durability and fuel consumption are both improved.

Technical specification

1.2 litre 3-cylinder with 2 valves per cylinder, SOHC
Belt driven
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

Comments (138) Join the discussion on the forum

  • stuart-b 08 Sep 2009

    The idea seems good, but power and RPM seem rather limited? How come it only revs to 3,500 rpm?? Surely this will make it pretty tiring to drive? As max power is max RPM.

    Not sure what car over 500kg, could make use of this?

  • kambites 08 Sep 2009

    I assume that "max rpm" is the motor RPM not the engine. Electric motors (1) are so quiet that you wont be able to hear it anyway and (2) always generate peak power at maximum speed because they have constant torque.

    It does seem to be rather a low power figure though. Maybe the idea is that they can have one on each wheel? hehe

    Edited by kambites on Tuesday 8th September 11:12

  • bosscerbera 08 Sep 2009

    Monoblocks are not a Lotus innovation.

    Looks interesting though. smile

  • Don 08 Sep 2009

    It's probably intended as a "generator".

  • theJT 08 Sep 2009

    It does sound a little weak. Especially when compared to the 160ish bhp that BMW are quoting for their 1.5 litre 3 cylinder job in that 'efficient dynamics' thing that was on here last week. I know this is probably tuned far more for economy than power, but 47 bhp just doesn't sound like a useful ammount when you think of all the heavy safty kit we have to haul around on cars these days.

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