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Lotus Engineering Study Concludes Vehicle Mass Improvement of 38% by 2020 vs a Conventional Current Vehicle Can Be Achieved at Only 3% Cost

27 April 2010

2020 Toyota Venza
The Lotus Engineering 2020 lightweight Toyota Venza. Click to enlarge.

Lotus Engineering has conducted a detailed study to develop a commercially viable mass reduction strategy for mainstream passenger vehicles. This study, released by the International Council on Clean Transportation (ICCT), focused on the use of lightweight materials and efficient design and demonstrated substantial mass savings.

When compared with a benchmark Toyota Venza crossover utility vehicle, a 38% reduction in vehicle mass, excluding powertrain, can be achieved for only a 3% increase in component costs using engineering techniques and technologies viable for mainstream production programs by 2020. The 2020 vehicle architecture utilizes a mix of stronger and lighter weight materials, a high degree of component integration and advanced joining and assembly methodologies.

Based on US Department of Energy estimates, a total vehicle mass reduction of 33% including powertrain, as demonstrated on the 2020 passenger car model, results in a 23% reduction in fuel consumption.

Lighter vehicles are cleaner and more efficient. That philosophy has always been core to Lotus’ approach to vehicle engineering and is now more relevant than ever. Lightweight Architectures and Efficient Performance are just two of our core competencies and we are delighted to have completed this study with input from the National Highway Traffic Safety Administration and the US Environmental Protection Agency to provide direction for future CO2 reductions. We believe that this approach will be commonplace in the industry for the future design of vehicles.

—Dr. Robert Hentschel, Director of Lotus Engineering

The study investigated scenarios for two distinct vehicle architectures appropriate for production in 2017 and 2020. The near-term scenario is based on applying industry leading mass-reducing technologies, improved materials and component integration and would be assembled using existing facilities. The mass reduction for this nearer term vehicle, excluding powertrain, is 21% with an estimated cost saving of 2%.

A benchmark Toyota Venza was disassembled, analyzed and weighed to develop a bill of materials and understand component masses. In developing the two low-mass concepts, Lotus Engineering employed a total vehicle mass-reduction strategy utilizing efficient design, component integration, materials selection, manufacturing and assembly. All key interior and exterior dimensions and volumes were retained for both models and the vehicles were packaged to accommodate key safety and structural dimensional and quality targets. The new vehicles retain the vision, sight line, comfort and occupant package of the benchmarked Toyota Venza.

A highly efficient total vehicle system level architecture was achieved by developing well integrated sub-systems and components, innovative use of materials and process and the application of advanced analytical techniques.

—Darren Somerset, CEO of Lotus Engineering Incorporated, Lotus’ North American engineering division which led the study

Mass and Cost Summary
Base Toyota VenzaLotus Engineering Design
SystemWeight (kg)2020 Venza2017 Venza
% Mass reduction% Cost factor% Mass reduction% Cost factor
Body 383 42% 135% 15% 98%
Closures/Fenders 143 41% 76% 25% 102%
Bumpers 18.0 11% 103% 11% 103%
Thermal 9.25 0% 100% 0% 100%
Electrical 23.6 36% 96% 29% 95%
Interior 252 39% 96% 27% 97%
Lighting 9.90 0% 100% 0% 100%
Chassis/Suspension 379 43% 95% 26% 100%
Glazing 43.7 0% 100% 0% 100%
Misc. 30.1 24% 99% 24% 99%
Totals 1290 38% 103% 21% 98%

Body. The body includes the floor and underbody, dash panel assembly, front structure, body sides and roof assembly. The baseline Toyota Venza body-in-white contained more than 400 parts and the revised 2020 model reduced that part count to 211. The body-in-white materials used in the baseline Venza were 100% steel, while the 2020 model used 37% aluminium, 30% magnesium, 21% composites and 7% high strength steel. This reduces the structure mass by 42% from 382 kg to 221 kg.

The low mass 2020 body-in-white would be constructed using a low energy joining process proven on high speed trains; this process is already used on some low volume automotive applications. This low energy, low heat friction stir welding process would be used in combination with adhesive bonding, a technique already proven on Lotus production sports cars. In this instance, the robotically controlled welding and adhesive bonding process would be combined with programmable robotic fixturing, a versatile process which can be used to construct small and large vehicles using the same equipment.

Closures/Fenders. The closures include all hinged exterior elements, for example, the front and rear doors and the rear liftgate. One alternative approach included fixing the primary trunk section to improve the structure, reduce masses and limit exposure to high voltage systems. A lightweight access door was provided for checking and replacing fluids.

The closures on the baseline Toyota Venza were made up of 100% steel. The low mass Venza closures/fenders would be made up of 33% magnesium, 21% plastic, 18% steel, 6% aluminium with the other 22% consisting of multiple materials. The mass savings are 41%, a reduction from 143 kg to 84 kg.

Interior. The interior systems consist of the instrument panel, seats, soft and hard trim, carpeting, climate control hardware, audio, navigation and communication electronics, vehicle control elements and restraint systems. There is a high level of component integration and electronic interfaces replace mechanical controls on the low mass model.

For the 2020 model the instrument panel is eliminated replaced by driver and passenger side modules containing all key functional and safety hardware. A low mass trim panel made from a high quality aerated plastic closes out the two modules. The air conditioning module is incorporated into the console eliminating the need for close out trim panels; heated and cooled cupholders are integrated into the HVA/C module.

The audio/HVA/C/Navigation touch screen contains the shifter and parking brake functions and interfaces with small electric solenoids. This eliminates conventional steel parking brake and shifter controls and cables as well as freeing up interior space.

The front seats mount to the structural sill and tunnel structure eliminating conventional seat mounting brackets (10 kg) and the need to locally reinforce the floorpan. The composite front seat structure utilizes proven foam technology; the seat mass is reduced by up to 50%. The rear seat support structure is moulded into the composite floorpan eliminating the need for a separate steel support structure. The front and rear seats use a knit to shape fabric that eliminates material scrap and offers customers the opportunity to order their favorite patterns for their new vehicle.

Four removable carpet modules replace the traditional full floor carpeting; this reduces mass and allows cost effective upgrading of the carpet quality. The floorpan is grained in all visible areas. The 2017 production interior mass was reduced from 250 kg to 182 kg with projected cost savings of 3%. The 2020 production interior mass was 153 kg with projected cost savings of 4%.

Chassis/Suspension. The chassis and suspension system was composed of suspension support cradles, control links, springs, shock absorbers, bushings, stabilizer bars and links, steering knuckles, brakes, steering gearbox, bearings, hydraulic systems, wheels, tires, jack and steering column.

The chassis and suspension components were downsized based on the revised vehicle curb weight, maintaining the baseline carrying capacity and incorporating the mass of the hybrid drive system.

The total vehicle curb weight reduction for the 2020 vehicle was 38%, excluding the powertrain. Based on the gross vehicle weight, which includes retaining the baseline cargo capacity of 549 kg and utilizing a hybrid powertrain, the chassis and the suspension components were reduced in mass by 43%, with projected cost savings of 5%.

Front and Rear Bumpers. The materials used on the front and rear bumpers were very similar to the existing model to maintain the current level of performance. One change was to replace the front steel beam with an aluminium beam which reduced mass by 11%. The use of a magnesium beam was analysed but at the current time exceeded the allowable price factor.

Heating, Ventilation and Air Conditioning. The air conditioning system was integrated into a passenger compartment system and an engine compartment system. This section addressed the under hood components which included the compressor, condenser and related plumbing. The under hood components were investigated for technologies and mass.

The study showed a relatively small mass difference for the underhood air conditioning components based on both vehicle mass and interior volume. Because of the highly evolved nature of these components, the requirements for equivalent air conditioning performance and the lack of a clear consensus for a future automotive refrigerant, the mass and cost of the Toyota Venza compressor, condenser and associated plumbing were left unchanged for both the 2017 and 2020 models.

Glazing. The glazing of the baseline vehicle was classified into two groups: fixed and moving. The fixed glass is bonded into position using industry standard adhesives and was classified into two sub groups: wiped and non-wiped.

Factors involved in making decisions about glazing materials include the level of abrasion it is likely to see during the vehicle life, the legislative requirements for light transmissibility, the legislative requirements for passenger retention and the contribution it will make to interior noise abatement.

The specific gravity of glass is 2.6 and the thickness of a windshield is usually between 4.5 mm and 5 mm, therefore the mass per square meter of 5 mm glass is approximately 13 kg. The high mass of glass provides a strong incentive to reduce the glazed area of the body, reduce the thickness of the glass and find a suitable substitute that is lighter. Fixed glass on the side of the vehicle offers the best opportunity for mass reduction.

The mass of the baseline glazing was retained for both the 2017 and 2020 models; this was a conservative approach. It is possible that coated polycarbonate materials may become mainstream in the 2017 - 2020 timeframe for fixed applications.

Electrical/Lighting. The estimated mass savings for using thinwall cladding and copper clad aluminium wiring, as used on the 2017 model was 36% versus the baseline model. The lighting technologies section reviewed included diodes, xenon and halogen. The study also reviewed a variety of wireless technologies under development for non-transportation applications that could be used in this time period pending successful development for mobile applications.

Powertrain study. The study also included a powertrain component, the goal of which was to calculate the powertrain mass, accounting for the mass reduction of the major vehicle systems, by allowing a reduction of the powertrain system horsepower and torque but maintaining similar vehicle performance. Lotus Engineering selected a charge sustaining hybrid for the powertrain system to match vehicle performance in terms of range and as the most likely to be adopted by industry and the public.

Overall powertrain system mass was reduced 13.2% from 410.4 kg to 356.2 kg including fuel mass reduction to maintain equivalent driving range.

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April 27, 2010 in Fuel Efficiency, Materials, Vehicle Systems | Permalink | Comments (16) | TrackBack (0)

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Comments

Greetings,

I've been working on a list of things that all car makers could be doing to improve efficiency:

http://neilblanchard.vox.com/library/post/more-ways-for-auto-makers-to-build-more-efficient-vehicles.html

One of the things to add to what Lotus has done, is to add multiple latches to the doors -- this would improve the the strength of the overall structure, allowing the weight to be reduced because the door opening frames do not need to be reinforced as much. And the overall shell is complete, which increases the strength.

Another thing that adds efficiency in several ways, would be to redesign the wheels and the suspension, so that the wheels are rigid and non-inflating, and the suspension does all the dampening -- and the shock absorbers could then generate more electricity than they otherwise would. This would eliminate the need for an alternator; especially if, you had a plug in charger.

So, greatly improved rolling resistance and reduced unsprung weight, which leads to reduced energy to keep the car moving, combined with regenerative shock absorbers (which can be tunable for ride and handling), which eliminates the need for an alternator.

I hope you can read the rest of my list!

Sincerely, Neil

So when the Big 3 said redesigning for composites would raise the price of vehicles prohibitively, they didn't really take a hard look at it.

This demonstrates that the Big-3 have not been saying the truth for decades about cost of lighter vehicles. The Big-3 look more and more like the tobacco industries of the last century. Why governments have not taken them to court yet? Misleading the public and forcing the country to import 13+ millions barrels of oil a day and waging expensive oil wars with many casualties is a very serious offense good for 1000+ years in jail.

By the way, a very recent (April 2010) Canada wide survey found that Toyota produces the best and the most trusted vehicles by a very wide margin. The recent attacks by USA's organisations seem to have positive effects. The publicity that Toyota is getting is worth $$$ millions. The numerous attacks back fired and convinced us to keep on buying Toyotas.

Four removable carpet modules replace the traditional full floor carpeting; this reduces mass and allows cost effective upgrading of the carpet quality. The floorpan is grained in all visible areas.

My dad's old 1957 Dodge truck implemented this idea. Eventually, the previous owner 'upgraded' to lurid yellow-green deep pile shag carpeting.

Some ideas are better left for dead.

The OEM's are driven by marketing, ie giving people a reason to spend on a new vehicle. Lightening the vehicle involves a serious re-engineering of production. If they don't perceive a marketing benefit, it won't happen.
The Lotus study begs a question; can their methods give the designer greater structural freedom? To this untrained eye, it looks like it does!

nordic:

This may be just the beginning of a multi-year vehicle weight reduction process. A Japan University has very recently produced a new ultra strong, light weight, resilient, transparent, poly-plastic, 2 to 5 times stronger than steel and 7 times as much as aluminium. This new ultra strong poly-plastic has extensive future potential for car windows, body parts etc. Interesting prospect for future ultra light weight e-vehicles requiring much less energy to move around.

No what the big three said was if you try and do THIS THIS is what it will cost us to do it at that timeline as far as we can figure out right now. Now that was a fair number of years ago.

Also remember because of labor contracts some things the big three would have LOVED

Grr stupid thing posted halfway through post...

As I was saying because of labor contracts some things the big three would have loved to do that would have made for lighter cars they couldnt do at all.

Wintermane:

How did the Big-3 managed to make their vehicles grow so much (in size and fuel consumption) if labor contracts were such a problem?

Didn't they rather take advantage of our 'My car is Bigger and Longer than yours' and 'My car is heavier than Yours' acquired or induced attitude to progressively build bigger and bigger gas guzzlers?

They must have had an agenda like 2 tonnes are more profitable than one tonne and then 4 tonnes are more profitable than two tonnes. Of course, the oil industries were rejoicing and certainly encouraging the Big-3 to produce bigger and bigger monsters.

Another well known reason is that the Big-3 always had problems making a GOOD smaller engine and smaller car like the Japaneses, Koreans and Europeans do. Will that also be an ongoing problem with Big-3 electrified vehicles. Time will tell.

If local labor force is an unmanageable road block, well... there are other good workers around. New GM and Ford are well aware of where they are.

In simple trueth they didnt. They had already made full sized vans and such for decades so making suvs wasnt an issue.
Also remember there realy are only 2 long haul family cars .. mini vans and suvs. And alot of americans go on VERY long road trips several times a year.

Now min vans kinda sorta suck monkey puke so.......

It would make alot of sense to make yearly licencing fee dependent on vehicle weight. Perhaps more than on CO2 or engine size, because CO2 and engine size can indirectly be charged for thru the fuel tax.
That would motivate car makers to keep reducing weight and consumers to go for lighter vehicles, and would discourage people from buying SUVs and other heavy vehicle they don't really need.

I'm wondering why heavy vehicles are not charged much higher for third party insurance, because in accidents they cause, they do much more damage to others than lighter vehicles.
Frequently we can read about traffic accidents where an SUV and a passenger car collided, driver of the small car was killed or left in serious condition, and the driver of SUV was unharmed, or just slightly injured. GM did some testing 10+ yrs ago and found that when two vehicles collide head-on, one vehicle twice as heavy as the other, the driver of lighter vehicle has 10 times more chances to get killed.
Heavy cars (say over 2 tons, or over 1.8 ton) are menace on the road, and would be reasonable to ban them access to fast lane on 3+ lanes highways, like for heavy trucks.

Well said MG.

Many seem to think that large vehicles, i.e with large interior for up to 6 people, need to weight 4 tonnes and must be built like a brick. That will be proven false within 5 to 10 years when 5 to 6 passenger e-vehicles weight will be reduced from 4000+ lbs to around 2000 lbs. with lighter materials. New ultra strong poly-plastics, 2 to 5 times stronger than steel and 7 times stronger than aluminium may be one of the many new new materials used.

Registration fees based on weight make sense because vehicle weight is what damages roads and pollutes most.

Not realy the only things that realy damage roads these days are 18 wheelers and the like just plain weather does all the rest. It used to be true that a 4-5 ton truck would damage roads but that was back when roads were much thinner and poorly made with poor substrates.

Also remember not all suvs are all that heavy we have small and mid sized suvs.

As for why they dont hammer on bigger car drivers.. because THEY ARE DRIVING THEM. They also avoid it because if even 10 such families move out that could cost them basly tax wise... happens to be one of the BAD as all hell side effects of our tax system that those that earn alot are vital to the government far more so then poor or middle income people.

"Powertrain mass was 410 kg"

Wow, and they say batteries are heavy!

wintermane:

Moving/driving heavy over sized vehicles require more energy (i.e. imported oil) with current gas guzzlers. Moving the same heavy weights around with electricity will also require more energy (i.e. electrical energy from polluting coal power plants in many areas). When a 115 lbs lady goes shopping in a 3+ ton VUS or Mr. goes to work in a similar VUS or (4x4) Pick-up they are not helping the country to manage the current growing energy crisis. This lack of common sense is driving the USA economy in deeper trade deficits and adversely affecting the value of the US $. You cant compensate by asking China to over value its currency because China is also making the same mistake with more and more gas guzzlers and running its first trade deficit in decades.

Accelerated transition to electrified vehicles could help both countries with their growing oil import cost. Aggressive Government interventions may be required to do it by 2030 or before. Higher performance,lower cost batteries and much lighter vehicles are required before e-cars become affordable. For now, e-vehicles are more readily accepted in China than in USA. This will affect their respective future trade deficits and general economy.

Canada, with its huge oil and NG reserves, surplus and export, does not have exactly the same problem. It could afford to use gas guzzlers and NG power plants much longer without affecting its economy.

With regards to taxes, government revenues can be maintained or increased different ways. A very small financial transaction fee could be used while reducing speculation. A Federal general sales tax on goods and services could also help to replace gas taxes. A special 10% to 20% tax on all junk food would be a win-win etc etc.

What a load of BS.
What the Big 3 said about the cost of redesigning for composites is just words.
What Lotus said about the cost of redesigning for 38% weight savings is just words.
Year to date (April 1st) auto sales, per the Wall Street Journal:
http://online.wsj.com/mdc/public/page/2_3022-autosales.htmlFprd
Vehicle . . . . . . . % of US Mkt
Cars . . . . . . . . . . . .52%
Light Trucks/SUVs . .48%
Mid Sized cars . . . . .25%
Small Cars . . . . . . .18%
Ford F Series . . . . 4%
Silverado . . . . . . . . 2.8%
Civic . . . . . . . . . . . .2.1%
Large SUVs . . . . . . . 2%
Ford Escape . . . . . .1.8%
Chevy Impala . . . . 1.5%
Hyundai Sonata . . . 1.2%
Nissan Versa . . . . . 1.2%
Chevy Equinox . . . . 1.2%
Prius . . . . . . . . . .. . .1.1%

Lotus essentially sells no cars.

If they are right – it is only in their own minds.

These numbers are TODAY – Not back in those evil days when we were all slaves to GM
Face reality

This demonstrates that the Big-3 have been saying the truth for decades about cost (or at least the marketability) of lighter vehicles.

The rest is fantasy.

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