PDA

View Full Version : Lotus Range Extender Engine Revealed



Wouter Melissen
09-07-2009, 08:50 AM
Lotus will introduce a very interesting new engine at Frankfurt:


Lotus Engineering, the world-renowned automotive consultancy division of Lotus, unveils its Range Extender engine at the 63rd Frankfurt International Motor Show. In a series hybrid vehicle, the Range Extender engine is attached to an electricity generator and provides a highly efficient source of energy to power the electric motor directly or charge the vehicles battery. The battery can also power the electric motor which enables the design of a drivetrain that has low emissions, optimised performance and acceptable range.

The Lotus Range Extender engine features an innovative architecture comprising an aluminium monoblock construction, integrating the cylinder block, cylinder head and exhaust manifold in one casting. This results in reduced engine mass, assembly costs, package size and improved emissions and engine durability.

The three-cylinder 1.2 litre Range Extender engine is optimised between two power generation points, giving 15 kW of electrical power at 1,500 rpm and 35 kW at 3,500 rpm via the integrated electrical generator. Its low mass of 56 kg makes it ideal for the series hybrid drivetrain configurations for which it is designed. The engine uses an optimised two-valve port-fuel injection combustion system to reduce cost and mass and, in line with Lotus Engineering’s extensive research into renewable fuels, can be operated on alcohol-based fuels or gasoline.

For successful market uptake of series hybrid vehicles with acceptable driving range, vehicle manufacturers must overcome the challenges of high vehicle cost. The Lotus Range Extender engine not only offers the advantage of a cost effective design, but also its high efficiency and low mass will enable the downsizing of expensive batteries whilst maintaining vehicle efficiency and range. The engine has been designed using production methodologies and the parts procured from low volume potential production suppliers, offering a fast route to market for original equipment manufacturers wanting to source a dedicated range extender for series hybrid vehicles.

Paul Newsome, Managing Director of Lotus Engineering said: “As the world changes, Lotus Engineering continues to change with it, continuously developing solutions for more sustainable transportation. The Lotus Range Extender engine is another example of Lotus Engineering developing new technologies for efficient performance, this time in the area of series hybrid vehicles. The engine concept we have created with its optimised combustion and compact, low mass, low cost construction is a clear demonstration of the expertise and progressive approach Lotus takes for its own research and for its clients.”

The Lotus Range Extender engine has been developed as part of the ‘Limo-Green’ project funded by the UK’s Technology Strategy Board, a collaboration between Lotus Engineering, Jaguar Cars Ltd, MIRA Ltd and Caparo Vehicle Technologies, demonstrating a large, lightweight, prestigious executive saloon with less than 120 g/km CO2 emissions.

Simon Wood, Technical Director of Lotus Engineering said: “Most series hybrid vehicles that are currently being developed will use adaptations of existing, conventional engines which are therefore compromised in the efficiency that they can achieve, designed as they are for a wide range of operating conditions. Designing the Lotus Range Extender purely for use in series hybrids has allowed us instead to develop an optimised engine that has high thermal efficiency, low fuel consumption, multi-fuel capability and a 35 kW peak output from a 1.2 litre, low cost architecture over the precise operating range required by a series hybrid drivetrain.”

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.

ruim20
09-07-2009, 09:00 AM
Hum, block and head in a single piece, a squematic is required! i'm very curious to see how the valves look like.

lightweight
09-07-2009, 09:03 AM
Good to see some innovative thinking once again from Lotus Engineering.

I assume that such an engine would not apply to the Prius, as its operating principle suggests that the electric motor helps the engine.

With this concept the engine helps the electric motor.

Such a principle is used by the Chevrolet Volt and all its future GM derivatives and the Fisker Karma (although it admittedly needs a bigger thermal engine).

One setback that needs to be checked is how they are going to service the engine, since it is of monoblock construction.

BTW I think that Bugatti used monoblock construction on its first Grand Prix engines, but later chose a more conventional setup for practical reasons.

EDIT: They didn't mention in the press release the fuel savings of such an engine.

Wouter Melissen
09-07-2009, 09:06 AM
Hum, block and head in a single piece, a squematic is required! i'm very curious to see how the valves look like.

As mentioned above, the monoblock was quite commonly used in the past.

Wouter Melissen
09-07-2009, 09:07 AM
EDIT: They didn't mention in the press release the fuel savings of such an engine.

I guess they would need to fit it into a car to get any figures like that.

jcp123
09-07-2009, 10:51 AM
Interesting.

As far as hybrids go, I always wondered why they didn't have a separate little generator driven by some 90 or 150cc engine used solely for charging batteries for while en route? This would eliminate the larger gas motor found on current hybrids, simplify the car by just having electric drive, and reduce fuel consumption by just running the generator with the little Briggs + Stratton motor or whatever. Somewhat akin to how the diesel-electric locomotives run. Seems to me that would be an instant 100mpg vehicle right there.

lightweight
09-07-2009, 10:52 AM
Jaguar said at the press release of the XJ that they plan to introduce a hybrid XJ.

Since Jaguar is quoted as co-developer of this technology, it seems that this system is going to be featured in the XJ.

This is backed also by this press kit mentioning the ‘Limo-Green’ project funded by the UK’s Technology Strategy Board and by the link below mentioning that "Jaguar told Autocar this technology could find its way into its road cars"

Autocar - Lotus reveals eco engine (http://www.autocar.co.uk/News/NewsArticle.ASpx?AR=242968)

culver
09-07-2009, 12:02 PM
I wounder how well that will package with other drive line components. One of the things to note about the Volt is that GM integrated the electric generator and the electric drive into one assembly. Part of that is likely the need to put all those parts under the hood of an existing car platform (The Volt uses a modified GM small car chassis). However, GM's integrated unit likely does package better than a setup where the gas generator and electric drive motor are packaged totally separately from each other. Of course I am just speculating based on a single CAD picture.

I do think an integrated head and block is an interesting idea. The last automotive like engine that I'm aware of to use that setup was the Offenhouser Indy car I4s. At the time the integrated head and block allowed those engines to handle VERY high boost pressures because there was no head gasket to fail. However, those Offy engines also trace back to the 1950s so some of that may be legacy and happenstance.

henk4
09-07-2009, 12:50 PM
I wounder how well that will package with other drive line components. One of the things to note about the Volt is that GM integrated the electric generator and the electric drive into one assembly. Part of that is likely the need to put all those parts under the hood of an existing car platform (The Volt uses a modified GM small car chassis). However, GM's integrated unit likely does package better than a setup where the gas generator and electric drive motor are packaged totally separately from each other. Of course I am just speculating based on a single CAD picture.

I do think an integrated head and block is an interesting idea. The last automotive like engine that I'm aware of to use that setup was the Offenhouser Indy car I4s. At the time the integrated head and block allowed those engines to handle VERY high boost pressures because there was no head gasket to fail. However, those Offy engines also trace back to the 1950s so some of that may be legacy and happenstance.

another example is the Crosley 750 cc, very often in specials for the SCCA racing in the fifties.

drakkie
09-07-2009, 01:48 PM
I guess they would need to fit it into a car to get any figures like that.

As everybody knows the mathematical models that can be made are as accurate as real measurements can be. I'm sure they made those.

culver
09-07-2009, 01:49 PM
I didn't know about the Crosleys. The Offys were used into the 1980s.

lightweight
09-07-2009, 03:20 PM
As everybody knows the mathematical models that can be made are as accurate as real measurements can be. I'm sure they made those.

Can Mathematical models on fuel consumption cannot take into account varying engine loads and different engine speeds etc?

They can always gen damn close, but an exact figure can be given only with testing.

Wouter Melissen
09-07-2009, 11:10 PM
As everybody knows the mathematical models that can be made are as accurate as real measurements can be. I'm sure they made those.

That was not my point. Every car is different so the fuel savings will also differ depending on the individual car this engine will be mounted in.

wstander
09-08-2009, 06:33 AM
That was not my point. Every car is different so the fuel savings will also differ depending on the individual car this engine will be mounted in.

Concur.

This appears to be a means to power electric storage, just like the Chevrolet Volt system. (One conjures up images of when GM owned Lotus, but never mind:-) conspiracy theories....)

I can see it placed in a number of light chassis, most of which are non-Western origin.....

Wouter Melissen
09-08-2009, 06:57 AM
Concur.

This appears to be a means to power electric storage, just like the Chevrolet Volt system. (One conjures up images of when GM owned Lotus, but never mind:-) conspiracy theories....)

I can see it placed in a number of light chassis, most of which are non-Western origin.....

The difference being that this engine was developed from scratch for this specific purpose. The engine(generator) in the Volt is a modified Ecotec engine that was developed for use in conventional cars. I would think there is a lot of efficiency to gain if you don't need the engine to be able to rev freely from say 1000 to 6000 rpm.

drakkie
09-08-2009, 11:36 AM
That was not my point. Every car is different so the fuel savings will also differ depending on the individual car this engine will be mounted in.

Exactly this can also be calculated. If the models of the engine are complete, then it is relatively easy to put it in any existing vehicle simulation. You'd be surprised at how exact the models can become.



The difference being that this engine was developed from scratch for this specific purpose. The engine(generator) in the Volt is a modified Ecotec engine that was developed for use in conventional cars. I would think there is a lot of efficiency to gain if you don't need the engine to be able to rev freely from say 1000 to 6000 rpm.

Exactly this will be the benefit over the Volt. However the ECU of the Volt limits the range this engine operates in anyway. The exact numbers I forgot, will try and find them in my notes again.

4wheelsonline
09-15-2009, 06:14 PM
Every car must have it's own engine that will suite to it's better performance. That's what the word efficiency comes in. Since we know many are car makers or designers are modifying this auto parts. For experimentation if it works or not.:D

G35COUPE
09-15-2009, 10:18 PM
So, how is designing these complex cars any different from or better than trying to make a regular NA car lighter, and more fuel efficient? Except for the BMW concept car, I am not convinced that these cars have made real progress in fuel efficiency.

pimento
09-15-2009, 10:29 PM
You think a Jag XJ that has comparable fuel efficiency and emmisions as a new Prius is not progress?

lightweight
10-23-2009, 07:48 AM
Some more info - See page 14 (http://viewer.zmags.com/publication/0651a0a9#/0651a0a9/1)

CapnBoost
10-26-2009, 06:59 AM
Other than the cast as one bit, this sounds a lot like the Chevy Volt.

RacingManiac
10-26-2009, 11:09 AM
Other than the cast as one bit, this sounds a lot like the Chevy Volt.

This is made for a Chevy Volt type of application....except other than using a normal car engine, this engine is made to be a generator...