Lotus Engineering Seating Systems Overview
Ward’s Interior Conference
May 22, 2013
5/21/2013
Presentation Topics
•
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
Ischial
Tuberosities
(Sit Bones)
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Interior Design Philosophies
© Lotus Cars Limited
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Holistic Approach to Interior Mass Reduction
•
Component integration/modularization
•
Use interior components as stressed
members
•
Use air to replace material
•
Use electronics/electrical systems to
replace mechanical systems
Ischial
Tuberosities
(Sit Bones)
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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
7.6 kg
2012 C Class (passenger)
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Use Interior Components as Stressed Members
•
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
Ischial
Tuberosities
(Sit Bones)
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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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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
•
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
Styling and CAD by ICON Aircraft
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Use Air to Replace Materials
•
Air injected plastics offer potential for reduced
weight
•
Potential for reduced cost
•
May need covering to achieve Class A
surface
2013 Ford Escape Instrument Panel
•
•
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
Ischial
Tuberosities
(Sit Bones)
Lightweight Cupholder
Lotus Elise Cupholder
http://www.automoblog.net/2011/11/15/2013-ford-escape-innovations-tease-ahead-of-debut/
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Use Electronics/Electrical Systems to Replace Mechanical Systems
•
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
Ischial
Tuberosities
(Sit Bones)
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Safety Systems vs. Weight
© Lotus Cars Limited
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Safety Systems and Mass Reduction
•
Interior safety systems are key to
providing 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 mass
reduction is relatively high
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Seat Comfort vs. Weight
© Lotus Cars Limited
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Basic Seating Bio-Mechanics
• Increased torque creates stresses on the
human 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
• The body needs to be supported by
its skeletal structure
• Minimal physiological differences
in 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
Ischial
Tuberosities
(Sit Bones)
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Anatomy of the Spine
•
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
Lordotic Curvature
Kyphotic Curvature
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Lotus ProBax Technology - Implementation
ProBax
Insert
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ProBax Technology – Seat Integration
ProBax
Insert
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ProBax Technology – Improved Spatial Awareness
Moment Arm Acting on Spine
Head CG
Typical Seat
Moment Arm Acting on Spine
Head CG
Lotus ProBax Seat
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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
•
•
Foam Thickness: < 1.5”
Composite structure
‘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
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Competitive Review of Production Seats
© Lotus Cars Limited
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2020 Low Mass Driver Seat Summary BOM - Projection
•Mass reduction total: 6.33 kg (24%)
Driver's Seat Mass Reduction Analysis
Starting Mass (kg)
Itemized Mass Deltas to baseline
Normalization to Venza
Best A2MAC1 Power Equipment (300C+Venza Lumbar)
Safety Equipment delta to From Fiesta - Venza
Azera Frame
Composite Seat Frame
Sizing Adjustment
Back
Cushion
Light weighting Content (Benchmark based)
300C Power equipment replacement (with Venza lumbar)
Remove springs (back and cushion)
Remove Foam volume (ergo foam replacement
Remove Garnish and trim
Mass Results (kg)
VENZA BASELINE
(kg)
Ford Fiesta Seat Starting
Point (kg)
26.92
18.47
Low Development
--------
0.00
-0.12
-3.64
0.00
-------
6.74
0.00
0.00
0.00
0.00
-1.52
0.66
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)
Mass is within 11% of Lotus 2020 Projections
22.839 kg vs. 2020 Projected 20.59 kg
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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 Analysis
Starting Mass (kg)
VENZA BASELINE
(kg)
Ford Fiesta Seat Starting
Point (kg)
23.18
16.96
Itemized Mass Deltas to baseline
Normalization to Venza
Safety Equipment delta to From Fiesta - Venza
Azera Frame replacement
Composite Seat Frame
Longitudinal Rails from 300C (Fiesta is a hybrid rail/structure)
Sizing Adjustment
Back
Cushion
Light weighting Content (Benchmark based)
300C Power equipment replacement (with Venza lumbar)
Remove springs (back and cushion)
Remove Foam volume (ergo foam replacement
Add Manual Seat Adjustment Bar
Remove Garnish and trim
Mass Results (kg)
Mass Reduction (kg)
Mass Reduction Percentage
High Development
--------
-0.12
0.00
-3.25
0.00
-1.52
0.66
-------
0.00
-0.26
-0.39
-1.10
23.18
10.98
-12.20
-53%
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 (Class C) Driver Seat (manual)
21.684 kg
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2011 Car B (Class C) Driver Seat (manual)
22.563 kg
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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 Analysis
Starting Mass (kg)
VENZA BASELINE
(kg)
Nissan Qashqai starting
point (kg)
47.808
26.478
Itemized Mass Deltas to baseline
Normalized to Venza Volume
Normalization to Venza
Remote Rear Cargo unlocking system
Back Frame normalized for center seatbelt (2-3)section
Add Venza Seatbelt Anchor
Modular seatback Laser welded roll formed
Mold seat lower into composite floor proposal
Utilize blow molded reinforced seatback frame (30% reduction)
High Development
28.27
47.81
---
0.33
0.00
1.75
2020 Lotus Low Mass Seat
-1.22
-3.70
--
Mass Results (kg)
47.81
25.43
Mass Reduction (kg)
38.57
-22.38
Mass Reduction Percentage
-0.47
•
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
2012 C Class Production Rear Seat
20.1 kg
Please note that Toyota engineers were required to use legacy
geometry/hardware that limited their ability to reduce mass
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Lightweight Non-Automotive Seats
© Lotus Cars Limited
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Light Sport Aircraft Seat Design
ICON A5 LSA Seats
LSA maximum allowable dry weight: 1,000 lbs
•Carbon fiber-foam core laminated shell
•<1.5” thick cushions
•<7 lbs. each
www.iconaircraft.com
Total interior weight: <One typical passenger car front seat
Styling and CAD by ICON Aircraft
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Interior Mass Reduction Opportunities Summary
© Lotus Cars Limited
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2020 Total Interior System Projections - Low Mass Model
•Mass reduction total: 97.8 kg (39%)
•Projected cost: 4% savings vs. baseline
System
Sub-System
Venza
Baseline
mass
% of
Interior
High
Development
Mass
High
Development
Cost
Interior
Seats
Instrument Panel|Console|Insulation
Hard Trim
Controls
Safety
HVA/C and Ducting
Closure Trim
Total
97.9
43.4
41.4
22.9
17.9
13.7
13.3
kg
kg
kg
kg
kg
kg
kg
39%
17%
17%
9%
7%
5%
5%
250.6 kg
55.2
25.8
24.3
16.0
17.9
11.3
2.4
kg
kg
kg
kg
kg
kg
kg
152.8 kg
94%
105%
105%
108%
100%
81%
75%
96%
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
© Lotus Cars Limited
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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
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Please reply to:
Job title:
Telephone:
Email:
Website:
Gregory E. Peterson
Senior Technical Specialist
586-698-1933
gregg.peterson@lotus-usa.com
lotuscars.com/engineering
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