Tuesday 8th September 2009

Lotus Unveils 'Range Extender'

New three-cylinder Lotus lump designed for hybrid car makers

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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
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

[stuart-b]

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]

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?

Edited by kambites on Tuesday 8th September 11:12

[bosscerbera]

Monoblocks are not a Lotus innovation.

Looks interesting though.

[Don]

It's probably intended as a "generator".

[theJT]

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.

[JoePublic]

Don said:

It's probably intended as a "generator".

I suspect so. Some indication of whether it's a 'parallel' or 'serial' hybrid would certainly be interesting.

[stifler]

kambites said:

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

That is not as daft as it sounds. Michelin have introduced a "wheel station" which has electric motors and suspension built into a unit that fits inside one of their wheels. This would be the ideal concept engine to power it.

The Michelin thingy is featured in the current Practical Performance Car magazine.

[Twincam16]

I know Lotus have said it won't go in a Lotus, but I wonder what kind of handling and P-T-W ratio you would get if you put that engine in a Caterham.

Surely Caterham and Lotus are on cordial enough terms to allow this? Would certainly make for a spectacular showcase for the new engine if the journalists were taken to a track and told to have a good thrash to test the engine's limits, rather than poddle around town in a wheeled wardrobe that reprimands you for going over 20 and has a 'dead polar bears per mile' counter on the dashboard in place of a trip meter.

[stifler]

bosscerbera said:

Monoblocks are not a Lotus innovation.

Looks interesting though.

Indeed. Hart 412T and probably many before that.

[sa_20v]

Don said:

It's probably intended as a "generator".

Ya, look at the image - that's no conventional gearbox!

[ctallchris]

The engine is designed to generate electricity rather than to power a car. As it will be completely detatched from the drivetrain the max rpm is unimportant. as for power output with electric drive 45HP should keep a car moving at 80 mph and leave additional energy to charge the batteries. they are obviously going for low cost / low maintenance (hence the SOHC) and the single block construction is probably only possible as the block will not be expanding and contracting as much as it would were the engine being ragged.

I am a bit surprised they went for something that powerful for a mobile generator although it does look highly sensible. may they sell a billion units and bring out the new elan!

[Twincam16]

bosscerbera said:

Monoblocks are not a Lotus innovation.

Weren't the '30s Grand Prix Bugatti sleeve-valve straight-eights monoblocks?

[ctallchris]

JoePublic said:

Don said:

It's probably intended as a "generator".

I suspect so. Some indication of whether it's a 'parallel' or 'serial' hybrid would certainly be interesting.

That would be serial component
engine > generator > battery > motor > wheels

If it was a parallel system it would need a gearbox

[Staffy1984]

Don said:

It's probably intended as a "generator".

+1 That was my first thought, this engine could never comfortably power a big Jag, it would sound awefully laboured and would take years to get anywhere, but this engine could comfortably provide power for the electric motors until they can be adequately charged.

[bosscerbera]

stifler said:

kambites said:

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

That is not as daft as it sounds. Michelin have introduced a "wheel station" which has electric motors and suspension built into a unit that fits inside one of their wheels. This would be the ideal concept engine to power it.

The Michelin thingy is featured in the current Practical Performance Car magazine.

Individually powered wheels has to be the way EVs will end up. The British supercar concept, the Lightning, uses this idea.

The Lotus motor's 35kW isn't much power whatever way it's used to 'extend-a-range' though. And if several were to be used, even two creates a 'weight budget' that would enable a much more powerful engine to be used. kW/BHP-per-kg (noted, motor/generator included) doesn't look very impressive - maybe it's exceptionally cheap?

[Insight]

is this not the same technology as my car, the Honda Insight (that is over 10 years old?)

"The gasoline engine is a 70 hp (52 kW; 71 PS), 1-liter, ECA series 3-cylinder unit providing lean burn operation with an air fuel ratio that can reach 25.8 to 1.[10] The electrical motor assist adds in another 10 kW (13 hp) when called on, and similarly provides significant deceleration when used in regenerative mode for braking. (This both improves fuel efficiency and also dramatically extends the lifetime of brakes). When the car is not moving, for example, at a stop light, the engine shuts off. The digital displays on the dashboard display fuel consumption instantaneously. On the manual transmission up and down arrows suggest when to shift gears."

http://en.wikipedia.org/wiki/Honda_Insight

[dublet]

Presumably that's 35kW of electricity in output, not in kinetic energy?

Should be plenty to drive 4 electric wheel motors. I wonder if they're going to make these available for conversion of ICE powered cars.

[RJDM3]

This tech has already been developed in germany over a year ago and is a much more powerful package than this one.

[bobbylondonuk]

So ..... a 45hp 3 cyl 1.2l engine powers an electric motor and battery storage.

Best fuel efficient idea for a hybrid given the current state of electricity charge points and other infrastructure deficiencies for alternate fuels world wide.

Probably a design that will be mass sold for the next decade till proper infrastructure and cheap technological advances are made for alternate power source.

[stifler]

bosscerbera said:

stifler said:

kambites said:

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

That is not as daft as it sounds. Michelin have introduced a "wheel station" which has electric motors and suspension built into a unit that fits inside one of their wheels. This would be the ideal concept engine to power it.

The Michelin thingy is featured in the current Practical Performance Car magazine.

Individually powered wheels has to be the way EVs will end up. The British supercar concept, the Lightning, uses this idea.

The Lotus motor's 35kW isn't much power whatever way it's used to 'extend-a-range' though. And if several were to be used, even two creates a 'weight budget' that would enable a much more powerful engine to be used. kW/BHP-per-kg (noted, motor/generator included) doesn't look very impressive - maybe it's exceptionally cheap?

Off Topic but back in the sixties there was a concept going around the car mags of a 6 wheeled car to be called the British Lion. It was to have an engine driving a hydraulic pump with a hydraulic motor in each upright driving all 6 wheels. It never got any budget iirc.