lotus engineering seating systems overview …insidepenton.com/waw/gregorypeterson-lotus.pdflotus...
TRANSCRIPT
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Presentation Topics
Ischial Tuberosities
(Sit Bones)
• Interior design philosophies
• Safety systems vs. weight
• Seat comfort vs. weight
• Current cars vs. Lotus projected 2020 interior system masses (some
surprises)
• Interior Mass Reduction Opportunities
• Summary Remarks
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Holistic Approach to Interior Mass Reduction
Ischial Tuberosities
(Sit Bones)
• Component integration/modularization
• Use interior components as stressed
members
• Use air to replace material
• Use electronics/electrical systems to
replace mechanical systems
7.6 kg
2012 C Class (passenger)
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Component Integration/Modularization
• Console show surface is air distribution duct for rear seat occupants
• Molded in seat support system replaces
traditional seat risers and contributes to body structure
• Steering column module integrates primary instruments and pedals
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Use Interior Components as Stressed Members
Ischial Tuberosities
(Sit Bones)
• Synergistic approach helps to reduce mass in other systems
• Potential to reduce or eliminate
structural reinforcements
• Typically requires a systems approach
to provide cost offsets for more expensive materials
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Integrated Seat Structure
Used on Audi 4000Q, VW Golf & Jetta and Ford Thunderbird (1980’s)
•Seat mounts to the strongest structures in the interior
•Reduces weight of traditional seat track mechanism
•Eliminates local floor reinforcements & mounting
fasteners
•Adds structure to body by “boxing” sill and tunnel
•Assists in transferring side impact loads
•Improves underbody aerodynamics
12.936 kg
(Adjuster & risers -
Power unit)
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Applying Light Sport Aircraft Design Principles to Automotive Interiors
• 1,000 lb. maximum dry weight
• Complete interior weight is less than the weight of one automotive front seat –
includes:
• Instrument panel
• Seats
• Trim panels – front and rear
• Console/Armrest
• Floors – front & rear
• Carbon fiber based construction
Styling and CAD by ICON Aircraft
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• IP Weight
• < 2.4 lbs.
• Weight normalized to mid-size car width: approximately 3 lbs.
• Material: Carbon Fiber w/Foam Core Sandwich
• 3 ply with 1c1 0.25 H60 reinforcement and 8 ply outer flanges
• Upper and lower core reinforcement H60
• Mounting bracket: 8 ply
Structural Instrument Panel & Air Ducts - LSA
• Opportunity for 3 lb. carbon fiber IP
• Integrates cross-car beam into “A”
surface
• Show surface is the support
structure
• Carbon fiber & CF foam core sandwich construction
• Potential for using air distribution
ducting as a structural component
Styling and CAD by ICON Aircraft
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Use Air to Replace Materials
Ischial Tuberosities
(Sit Bones)
• Air injected plastics offer potential for reduced
weight
• Potential for reduced cost
• May need covering to achieve Class A
surface
• Active Noise Cancellation Using Audio System
• Provides attenuation in sub-200Hz region
• Potential for 10 kg to 20 kg mass reduction
• Requires higher capacity system than base
units for most vehicles
• Lightweight Cupholder
http://www.automoblog.net/2011/11/15/2013-ford-escape-innovations-tease-ahead-of-debut/
2013 Ford Escape Instrument Panel
Lotus Elise Cupholder
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Use Electronics/Electrical Systems to Replace Mechanical Systems
Ischial Tuberosities
(Sit Bones)
• Utilize a central touch screen as an actuator for key controls
• Integrate haptic features into screen
• Solenoid actuated transmission selector can save > 2.5 kg
• Solenoid actuated parking brake system can save > 3.0 kg compared to a foot
operated parking brake
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Safety Systems and Mass Reduction
• Interior safety systems are key toproviding a safe environment for
vehicle occupants
• Safety systems are a mature
technology
• Safety system mass is not a large
contributor to vehicle weight
• Potential to reduce air bag mass is low
• Risk/benefit ratio for potential massreduction is relatively high
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Basic Seating Bio-Mechanics
• Increased torque creates stresses on thehuman body that can generate discomfort
and fatigue
• Creating a seated position that allows the
body to be in a balanced state helps to
reduce extraneous torques
• Minimizing extraneous torques is not
necessarily a mass intensive process
Correct Yoga postures utilize the principle of
minimizing external torques
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Pelvis and Ischial Tuberosities
Ischial Tuberosities
(Sit Bones)
• The body needs to be supported byits skeletal structure
• Minimal physiological differencesin the sit bones despite wide
variations in body size and weight
• Advantageous to use a seat insert that supports the ischial tuberosities to
rotate occupant pelvis forward
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Anatomy of the Spine
Lordotic Curvature Kyphotic Curvature
• The lordotic spine shape (“S” curve)places the head near the centroid of
the spine
• The kyphotic spine shape (“C” curve)
creates an increased torque acting on
the spine
• An increased torque acting on the
spine creates stress that can cause discomfort
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ProBax Technology – Improved Spatial Awareness
Typical Seat Lotus ProBax Seat
Moment Arm Acting on Spine Moment Arm Acting on Spine
Head CG Head CG
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ProBax – Results from Lotus Elise
• Average reduction in distance from skull to head restraint - 18.9 %
• Effect is greater for taller drivers (up to 70% improvement)
• Improvement from posture change – no user adjustments required
• Simple - light-weight - cost-effective
Pre-06 MY Elise Seat ProBax Elise Seat
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Media Seat Comfort Assessment
‘Forget your Maybachs and Rolls-Royce Phantoms.
The most comfortable car seat in the world could just be in
the little Lotus Elise’
Source: The Daily Telegraph
• Foam Thickness: < 1.5”
• Composite structure
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2020 Low Mass Driver Seat Summary BOM - Projection
•Mass reduction total: 6.33 kg (24%)
Driver's Seat Mass Reduction AnalysisVENZA BASELINE
(kg)
Ford Fiesta Seat Starting
Point (kg)
Starting Mass (kg) 26.92 18.47
Itemized Mass Deltas to baseline Low Development
Normalization to Venza
Best A2MAC1 Power Equipment (300C+Venza Lumbar) -- 0.00
Safety Equipment delta to From Fiesta - Venza -- -0.12
Azera Frame -- -3.64
Composite Seat Frame -- 0.00
Sizing Adjustment --
Back -- -1.52Cushion -- 0.66
Light weighting Content (Benchmark based)
300C Power equipment replacement (with Venza lumbar) -- 6.74
Remove springs (back and cushion) -- 0.00
Remove Foam volume (ergo foam replacement -- 0.00
-- 0.00
Remove Garnish and trim -- 0.00
--
Mass Results (kg) 26.92 20.59
Mass Reduction (kg) -6.33
Mass Reduction Percentage -24%
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
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2012 Car A Driver Seat (power)
22.839 kg vs. 2020 Projected 20.59 kg
Mass is within 11% of Lotus 2020 Projections
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2020 Low Mass Passenger Seat Summary BOM - Projection
•Mass reduction total: 12.20 kg (53%)
•Magnesium seat structure
•No springs, reduced foam mass and integrated trim & garnish
Passenger's Seat Mass Reduction AnalysisVENZA BASELINE
(kg)
Ford Fiesta Seat Starting
Point (kg)
Starting Mass (kg) 23.18 16.96
Itemized Mass Deltas to baseline High Development
Normalization to Venza
Safety Equipment delta to From Fiesta - Venza -- -0.12
Azera Frame replacement -- 0.00Composite Seat Frame -- -3.25
Longitudinal Rails from 300C (Fiesta is a hybrid rail/structure) -- 0.00
Sizing Adjustment --
Back -- -1.52Cushion -- 0.66
Light weighting Content (Benchmark based)
300C Power equipment replacement (with Venza lumbar) -- 0.00
Remove springs (back and cushion) -- -0.26
Remove Foam volume (ergo foam replacement -- -0.39Add Manual Seat Adjustment Bar --
Remove Garnish and trim -- -1.10
--
Mass Results (kg) 23.18 10.98
Mass Reduction (kg) -12.20
Mass Reduction Percentage -53%
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
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Light Weight Front Seat Overview
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
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2020 Rear Seat Projection vs 2012 C Class Sedan
•Mass reduction total: 22.38 kg (47%)
•Production seat is 13% lighter than Lotus 2020 Projection
Rear Seat Mass Reduction AnalysisVENZA BASELINE
(kg)
Nissan Qashqai starting
point (kg)
Starting Mass (kg) 47.808 26.478
Itemized Mass Deltas to baseline High Development
Normalized to Venza Volume 47.81 28.27
Normalization to Venza
Remote Rear Cargo unlocking system -- 0.33
Back Frame normalized for center seatbelt (2-3)section -- 0.00
Add Venza Seatbelt Anchor 1.75
Modular seatback Laser welded roll formed
Mold seat lower into composite floor proposal -1.22
Utilize blow molded reinforced seatback frame (30% reduction) -3.70 --
Mass Results (kg) 47.81 25.43
Mass Reduction (kg) 38.57 -22.38
Mass Reduction Percentage -0.47
2012 C Class Production Rear Seat20.1 kg
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
• Normalize to Venza size: 20.1 kg x 10% = 22.1 kg
• Projected 2020 mass optimized rear sear: 25.43 kg
• Normalized C class rear seat is over 3 kg lighter than Lotus 2020 projections
Note: CUV rear seat vs. sedan rear seat
2020 Lotus Low Mass Seat
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Light Sport Aircraft Seat Design
� ICON A5 LSA Seats
LSA maximum allowable dry weight: 1,000 lbs
Total interior weight: <One typical passenger car front seat
•Carbon fiber-foam core laminated shell
•<1.5” thick cushions
•<7 lbs. each
www.iconaircraft.com
Styling and CAD by ICON Aircraft
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2020 Total Interior System Projections - Low Mass Model
Interior
Seats 97.9 kg 39% 55.2 kg 94%
Instrument Panel|Console|Insulation 43.4 kg 17% 25.8 kg 105%
Hard Trim 41.4 kg 17% 24.3 kg 105%
Controls 22.9 kg 9% 16.0 kg 108%
Safety 17.9 kg 7% 17.9 kg 100%
HVA/C and Ducting 13.7 kg 5% 11.3 kg 81%
Closure Trim 13.3 kg 5% 2.4 kg 75%
Total 250.6 kg 152.8 kg 96%
System
High
Development
Mass
High
Development
CostSub-System
% of
Interior
Venza
Baseline
mass
•Mass reduction total: 97.8 kg (39%)
•Projected cost: 4% savings vs. baseline
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
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Summary Remarks
• An holistic, total vehicle approach is required to maximize mass reduction
• The cost and mass of all systems must be assessed in terms of their
contribution to reducing the vehicle cost and mass rather than in isolation
• The cost for discrete sub-systems and components may need to increase
relative to historical targets to provide the least cost, total vehicle mass
reduction solution
• An holistic approach to interior system mass reduction has the potential to
reduce cost
CHINA
7th Floor, New Jinqiao Tower
No. 28 New Jinqiao Road, Pudong
Shanghai. PR CHINA 201206
Phone +86 (21) 5030 9990
MALAYSIA
Malaysia Sdn. Bhd. Lot G-5, Enterprise 3 Technology Park Malaysia
Lebuhraya Puchong-Sungai Besi
Bukit Jalil. 57000 Kuala Lumpur
Phone +60 (3) 8996 7172
Please reply to:
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Telephone:
Email:
Website: lotuscars.com/engineering
UNITED KINGDOM
Potash Lane
Hethel, Norwich
NR14 8EZ
Phone +44 (0) 1953 608423
USA
1254 N. Main Street
Ann Arbor
MI 48104
Phone +1 734 995 2544
Gregory E. Peterson
Senior Technical Specialist
586-698-1933